[Federal Register Volume 87, Number 77 (Thursday, April 21, 2022)]
[Proposed Rules]
[Pages 23920-24023]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-06423]



[[Page 23919]]

Vol. 87

Thursday,

No. 77

April 21, 2022

Part II





 Department of Energy





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10 CFR Parts 429 and 431





Energy Conservation Program: Test Procedures for Walk-In Coolers and 
Walk-In Freezers; Proposed Rule

Federal Register / Vol. 87 , No. 77 / Thursday, April 21, 2022 / 
Proposed Rules

[[Page 23920]]


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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2017-BT-TP-0010]
RIN 1904-AD78


Energy Conservation Program: Test Procedures for Walk-In Coolers 
and Walk-In Freezers

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of 
Energy.

ACTION: Notice of proposed rulemaking and announcement of public 
webinar.

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SUMMARY: The U.S. Department of Energy (``DOE'') proposes to amend the 
test procedures for walk-in coolers and walk-in freezers to harmonize 
with updated industry standards, revise the test methods to more fully 
represent field energy use, and better account for the range of walk-in 
cooler and walk-in freezer component equipment designs. DOE also 
proposes to revise certain definitions applicable to walk-ins. DOE is 
seeking comment from interested parties on the proposal and announcing 
a public meeting to collect comments and data on its proposal.

DATES: DOE will accept comments, data, and information regarding this 
proposal no later than June 21, 2022. See section V, ``Public 
Participation,'' for details. DOE will hold a webinar on Monday, May 9, 
from 1:00 p.m. to 5:00 p.m. See section V, ``Public Participation,'' 
for webinar registration information, participant instructions, and 
information about the capabilities available to webinar participants.

ADDRESSES: Interested persons are encouraged to submit comments using 
the Federal eRulemaking Portal at www.regulations.gov, under docket 
number EERE-2017-BT-TP-0010. Follow the instructions for submitting 
comments. Alternatively, interested persons may submit comments by 
email to <a href="/cdn-cgi/l/email-protection#a7f0eee4e195979690f3f797979697e7c2c289c3c8c289c0c8d1"><span class="__cf_email__" data-cfemail="7126383237434140462521414140413114145f151e145f161e07">[email protected]</span></a>. Include docket number EERE-2017-BT-
TP-0010 in the subject line of the message.
    No telefacsimiles (``faxes'') will be accepted. For detailed 
instructions on submitting comments and additional information on this 
process, See section V of this document.
    Although DOE has routinely accepted public comment submissions 
through a variety of mechanisms, including postal mail and hand 
delivery/courier, the Department has found it necessary to make 
temporary modifications to the comment submission process in light of 
the ongoing coronavirus 2019 (``COVID-19 pandemic''). DOE is currently 
suspending receipt of public comments via postal mail and hand 
delivery/courier. If a commenter finds that this change poses an undue 
hardship, please contact Appliance Standards Program staff at (202) 
586-1445 to discuss the need for alternative arrangements. Once the 
COVID-19 pandemic health emergency is resolved, DOE anticipates 
resuming all of its regular options for public comment submission, 
including postal mail and hand delivery/courier.
    Docket: The docket, which includes Federal Register notices, public 
meeting attendee lists and transcripts (if a public meeting is held), 
comments, and other supporting documents/materials, is available for 
review at www.regulations.gov. All documents in the docket are listed 
in the www.regulations.gov index. However, some documents listed in the 
index, such as those containing information that is exempt from public 
disclosure, may not be publicly available.
    The docket web page can be found at www.regulations.gov/docket/EERE-2017-BT-TP-0010. The docket web page contains instructions on how 
to access all documents, including public comments, in the docket. See 
section V for information on how to submit comments through 
www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: 
    Dr. Stephanie Johnson, U.S. Department of Energy, Office of Energy 
Efficiency and Renewable Energy, Building Technologies Office, EE-2J, 
1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: 
(202) 287-1943. Email <a href="/cdn-cgi/l/email-protection#4a0b3a3a26232b24292f193e2b242e2b382e391b3f2f393e232524390a2f2f642e252f642d253c"><span class="__cf_email__" data-cfemail="87c6f7f7ebeee6e9e4e2d4f3e6e9e3e6f5e3f4d6f2e2f4f3eee8e9f4c7e2e2a9e3e8e2a9e0e8f1">[email protected]</span></a>.
    Mr. Michael Kido, U.S. Department of Energy, Office of the General 
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121. 
Telephone: (202) 586-8145. Email: <a href="/cdn-cgi/l/email-protection#eba68288838a8e87c5a0828f84ab839ac58f848ec58c849d"><span class="__cf_email__" data-cfemail="4d00242e252c282163062429220d253c63292228632a223b">[email protected]</span></a>.
    For further information on how to submit a comment, review other 
public comments and the docket, or participate in a public meeting (if 
one is held), contact the Appliance and Equipment Standards Program 
staff at (202) 287-1445 or by email: 
<a href="/cdn-cgi/l/email-protection#95d4e5e5f9fcf4fbf6f0c6e1f4fbf1f4e7f1e6c4e0f0e6e1fcfafbe6d5f0f0bbf1faf0bbf2fae3"><span class="__cf_email__" data-cfemail="c382b3b3afaaa2ada0a690b7a2ada7a2b1a7b092b6a6b0b7aaacadb083a6a6eda7aca6eda4acb5">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: DOE proposes to maintain previously approved 
incorporations by reference and to incorporate by reference the 
following industry standards into part 431:
    ANSI/AHRI Standard 420-2008, ``Performance Rating of Forced-
Circulation Free-Delivery Unit Coolers for Refrigeration,'' copyright 
2008.
    AHRI Standard 1250 (I-P)-2009, ``Standard for Performance Rating of 
Walk-in Coolers and Freezers,'' (including Errata sheet dated December 
2015), copyright 2009, except Table 15 and Table 16.
    AHRI Standard 1250-2020, ``Standard for Performane Rating of Walk-
in Coolers and Freezers,'' copyright 2020.
    Copies of AHRI 420-2008, AHRI 1250-2009, and AHRI 1250-2020 can be 
obtained from the Air-Conditioning, Heating, and Refrigeration 
Institute, 2111 Wilson Boulevard, Suite 500, Arlington, VA 22201, or by 
going to www.ahrinet.org.
    ANSI/ASHRAE Standard 16-2016, ``Method of Testing for Rating Room 
Air Conditioners, Packaged Terminal Air Conditioners, and Packaged 
Terminal Heat Pumps for Cooling and Heating Capacity,'' approved 
October 31, 2016.
    ANSI/ASHRAE Standard 23.1-2010, ``Methods of Testing for Rating the 
Performance of Positive Displacement Refrigerant Compressors and 
Condensing Units that Operate at Subcritical Temperatures of the 
Refrigerant,'' ANSI approved January 28, 2010.
    ANSI/ASHRAE Standard 37-2009, ``Methods of Testing for Rating 
Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment,'' 
approved June 24, 2009.
    Copies of ANSI/ASHRAE 16, ASHRAE 23.1-2010, and ANSI/ASHRAE 37 can 
be obtained from the American Society of Heating, Refrigerating and 
Air-Conditioning Engineers, 180 Technology Parkway, Peachtree Corners, 
GA 30092, or by going to: www.ashrae.org.
    ASTM C518-17, ``Standard Test Method for Steady state Thermal 
Transmission Properties by Means of the Heat Flow Meter Apparatus,'' 
ASTM approved May 1, 2017.
    ASTM C1199-14, ``Standard Test Method for Measuring the Steady 
state Thermal Transmittance of Fenestration Systems Using Hot Box 
Methods,'' ASTM approved February 1, 2014.
    Copies of ASTM C518-17 and ASTM C1199-14 can be obtained from the 
American Society for Testing and Materials, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959, or by going to www.astm.org.
    NFRC 102-2020 [E0A0], ``Procedure for Measuring the Stready-State 
Thermal Transmittance of Fenestration Systems.''
    Copies of NFRC 102-2020 can be obtained from the National 
Fenestration Rating Council, 6305 Ivy Lane, Ste. 140, Greenbelt, MD 
20770, or by going to www.nfrc.org/.

[[Page 23921]]

    See section IV.M of this document for a further discussion of these 
standards.

Table of Contents

    I. Authority and Background
    A. Authority
    B. Background
II. Synopsis of the Notice of Proposed Rulemaking
III. Discussion
    A. Scope and Definitions
    1. Scope
    a. Liquid-Cooled Refrigeration Systems
    b. Carbon Dioxide Systems
    c. Multi-Circuit Single-Packaged Refrigeration Systems
    d. Ducted Units
    2. Definitions
    a. Walk-In Cooler and Walk-in Freezer
    b. Doors
    c. High-Temperature Refrigeration Systems
    d. Ducted Fan Coil Units
    e. Multi-Circuit Single-Packaged Refrigeration Systems
    f. Attached Split Systems
    g. Detachable Single-Packaged System
    h. CO<INF>2</INF> Unit Coolers
    i. Hot Gas Defrost
    B. Industry Standards
    1. Standards for Determining Thermal Transmittance (U-factor)
    2. Standard for Determining R-Value
    3. Standards for Determining AWEF
    a. Changes Consistent With Subpart R, Appendix C
    b. CFR Language Not Adopted in AHRI 1250-2020
    c. Changes That May Impact the Determination of AWEF
    d. Additional Amendments
    C. Proposed Amendments to the Test Procedure in Appendix A for 
Measuring the Energy Consumption of Walk-In Doors
    1. Procedure for Determining Thermal Transmittance (U-Factor)
    a. Reference to NFRC 102 in Place of NFRC 100
    b. Exceptions to Industry Test Method for Determining U-Factor
    c. Calibration of Hot Box for Measuring U-Factor
    2. Additional Definitions
    a. Surface Area for Determining Compliance With Standards
    b. Surface Area for Determining U-Factor
    3. Electrical Door Components
    4. Percent Time Off Values
    5. EER Values
    6. Air Infiltration Reduction
    D. Proposed Amendments to the Test Procedure in Appendix A for 
Display Panels
    E. Proposed Amendments to the Test Procedure in Appendix B for 
Panels and Non-Display Doors
    1. Specimen Conditioning
    2. Total Insulation and Test Specimen Thickness
    3. Parallelism and Flatness
    4. Insulation Aging
    5. Determining Energy Consumption of Panels That Are Not Display 
Panels
    F. Proposed Amendments to Subpart R, Appendix C, To Determine 
Compliance With the Current Energy Conservation Standards
    1. Refrigeration Test Room Conditioning
    2. Temperature Measurement Requirements
    3. Hierarchy of Installation Instructions and Specified 
Refrigerant Conditions for Refrigerant Charging and Setting 
Refrigerant Conditions
    a. Dedicated Condensing Unit Charging Instructions
    b. Unit Cooler Charging Instructions
    c. Single-Packaged Dedicated System Setup and Charging 
Instructions
    d. Hierarchy of Setup Conditions if Manufacturer-Specified Setup 
Conditions Cannot Be Met
    4. Subcooling Requirement for Mass Flow Meters
    5. Instrument Accuracy and Test Tolerances
    6. CO<INF>2</INF> Unit Coolers
    7. High-Temperature Unit Coolers
    G. Proposal To Establish Appendix C1
    1. Off-Cycle Power Consumption
    a. Off-Cycle Test Duration and Repetition
    b. Off-Cycle Operating Tolerances and Data Collection Rates
    c. Off-Cycle Load Points
    d. Modification to AWEF Calculations
    2. Single-Packaged Dedicated Systems
    a. AHRI 1250-2020 Methods for Testing
    b. Waivers
    c. Suitability of the Single-Packaged Test Methods in AHRI 1250-
2020
    d. Single-Packaged Refrigerant Enthalpy Method
    e. Multi-Circuit Single-Packaged Dedicated Systems
    f. CO<INF>2</INF> Single-Packaged Dedicated Systems
    3. Detachable Single-Packaged Dedicated Systems
    4. Attached Split Systems
    5. Systems for High-Temperature Freezer Applications
    6. Systems for High-Temperature Applications
    7. Variable-, Two-, and Multiple-Capacity Systems
    a. Dedicated Condensing Units
    b. Indoor Matched Pair and Single-Packaged Units
    c. Revision to EER Calculation for Outdoor Variable-Capacity and 
Multiple-Capacity Refrigeration Systems
    d. Digital Compressors
    8. Defrost
    a. Adaptive Defrost
    b. Hot Gas Defrost
    9. Refrigerant Glide
    10. Refrigerant Temperature and Pressure Instrumentation 
Locations
    11. Updates to Default Values for Unit Cooler Parameters
    12. Calculations and Rounding
    H. Alternative Efficiency Determination Methods
    1. Doors
    2. Refrigeration Systems
    I. Sampling Plan for Enforcement Testing
    J. Test Procedure Costs and Impact
    1. Doors
    2. Panels
    3. Refrigeration Systems
    K. Compliance Date and Waivers
    L. Organizational Changes
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Order 12866 and 13563
    B. Review Under the Regulatory Flexibility Act
    1. Description of Why Action Is Being Considered
    2. Objective of, and Legal Basis for, Rule
    3. Description and Estimate of Small Entities Regulated
    4. Description and Estimate of Compliance Requirements
    a. Doors
    b. Panels
    c. Refrigeration Systems
    5. Duplication, Overlap, and Conflict With Other Rules and 
Regulations
    6. Significant Alternatives to the Rule
    C. Review Under the Paperwork Reduction Act of 1995
    D. Review Under the National Environmental Policy Act of 1969
    E. Review Under Executive Order 13132
    F. Review Under Executive Order 12988
    G. Review Under the Unfunded Mandates Reform Act of 1995
    H. Review Under the Treasury and General Government 
Appropriations Act, 1999
    I. Review Under Executive Order 12630
    J. Review Under Treasury and General Government Appropriations 
Act, 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
    M. Description of Materials Incorporated by Reference
V. Public Participation
    A. Participation in the Webinar
    B. Procedure for Submitting Prepared General Statements for 
Distribution
    C. Conduct of the Webinar
    D. Submission of Comments
    E. Issues on Which DOE Seeks Comment
VI. Approval of the Office of the Secretary

I. Authority and Background

    Walk-in coolers and freezers (collectively, ``WICFs'' or ``walk-
ins'') are included in the list of ``covered equipment'' for which DOE 
is authorized to establish and amend energy conservation standards and 
test procedures. (42 U.S.C. 6311(1)(G)) DOE's energy conservation 
standards and test procedures for WICFs are currently prescribed at 
subpart R of part 431 of title 10 of the Code of Federal Regulations 
(``CFR''). The following sections discuss DOE's authority to establish 
test procedures for WICFs and relevant background information regarding 
DOE's consideration of test procedures for this equipment.

A. Authority

    The Energy Policy and Conservation Act, as amended (``EPCA''),\1\ 
authorizes DOE to regulate the energy efficiency of a number of 
consumer products and certain industrial equipment. (42 U.S.C.

[[Page 23922]]

6291-6317) Title III, Part C \2\ of EPCA, added by Public Law 95-619, 
Title IV, section 441(a), established the Energy Conservation Program 
for Certain Industrial Equipment, which sets forth a variety of 
provisions designed to improve energy efficiency. This covered 
equipment includes walk-in coolers and walk-in freezers, the subject of 
this document. (42 U.S.C. 6311(1)(G))
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    \1\ All references to EPCA in this document refer to the statute 
as amended through the Energy Act of 2020, Public Law 116-260 (Dec. 
27, 2020).
    \2\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
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    Under EPCA, the energy conservation program consists essentially of 
four parts: (1) Testing, (2) labeling, (3) Federal energy conservation 
standards (``ECS''), and (4) certification and enforcement procedures. 
Relevant provisions of EPCA include definitions (42 U.S.C. 6311), test 
procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315), 
energy conservation standards (42 U.S.C. 6313), and the authority to 
require information and reports from manufacturers (42 U.S.C. 6316).
    The Federal testing requirements consist of test procedures that 
manufacturers of covered equipment must use as the basis for: (1) 
Certifying to DOE that their equipment complies with the applicable 
energy conservation standards adopted pursuant to EPCA (42 U.S.C. 
6316(a); 42 U.S.C. 6295(s)), and (2) making representations about the 
efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE must 
use these test procedures to determine whether the equipment complies 
with relevant standards promulgated under EPCA. (42 U.S.C. 6316(a); 42 
U.S.C. 6295(s))
    Federal energy efficiency requirements for covered equipment 
established under EPCA generally supersede State laws and regulations 
concerning energy conservation testing, labeling, and standards. (42 
U.S.C. 6316(a) and 42 U.S.C. 6316(b); 42 U.S.C. 6297) DOE may, however, 
grant waivers of Federal pre-emption for particular State laws or 
regulations, in accordance with the procedures and other provisions of 
EPCA. (42 U.S.C. 6316(a))
    Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures 
DOE must follow when prescribing or amending test procedures for 
covered equipment. EPCA requires that any test procedures prescribed or 
amended under this section must be reasonably designed to produce test 
results that reflect the energy efficiency, energy use or estimated 
annual operating cost of a given type of covered equipment during a 
representative average use cycle and requires that test procedures not 
be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))
    EPCA also requires that, at least once every 7 years, DOE evaluate 
test procedures for each type of covered equipment, including walk-ins, 
to determine whether amended test procedures would more accurately or 
fully comply with the requirements for the test procedures to not be 
unduly burdensome to conduct and be reasonably designed to produce test 
results that reflect the energy efficiency, energy use, and estimated 
operating costs during a representative average use cycle. (42 U.S.C. 
6314(a)(1))
    In addition, if the Secretary determines that a test procedure 
amendment is warranted, the Secretary must publish proposed test 
procedures in the Federal Register and afford interested persons an 
opportunity (of not less than 45 days' duration) to present oral and 
written data, views, and arguments on the proposed test procedures. (42 
U.S.C. 6314(b)) If DOE determines that test procedure revisions are not 
appropriate, DOE must publish its determination not to amend the test 
procedures. (42 U.S.C. 6314(a)(1)(A)(ii)) DOE is publishing this notice 
of proposed rulemaking (``NOPR'') in satisfaction of the 7-year review 
requirement specified in EPCA.

B. Background

    For measuring walk-in energy use, DOE has established separate test 
procedures for the principal components that make up a walk-in (i.e., 
doors, panels, and refrigeration systems), with separate test metrics 
for each component. 10 CFR 431.304(b). For walk-in doors and display 
panels, the efficiency metric is daily energy consumption, measured in 
kilowatt-hours per day (``kWh/day''), which accounts for the thermal 
conduction through the door or display panel and the direct and 
indirect electricity use of any electrical components associated with 
the door. 10 CFR 431.304(b)(1)-(2) and 10 CFR part 431, subpart R, 
appendix A, ``Uniform Test Method for the Measurement of Energy 
Consumption of the Components of Envelopes of Walk-In Coolers and Walk-
In Freezers'' (``appendix A''). The thermal transmittance through the 
door, which inputs into the calculation of thermal conduction, is 
determined using National Fenestration Rating Council (``NFRC'') 100-
2010, ``Procedure for Determining Fenestration U-factors'' (``NFRC 
100'').
    For walk-in non-display panels and non-display doors, DOE codified 
in the CFR standards established in EPCA based on the R-value 
metric,\3\ expressed in units of (h-ft\2\-[deg]F/Btu),\4\ which is 
calculated as the thickness of the panel in inches (``in.'') divided by 
the K-factor.\5\ See 10 CFR 431.304(b)(3) and 10 CFR part 431, subpart 
R, appendix B, titled ``Uniform Test Method for the Measurement of R-
Value for Envelope Components of Walk-In Coolers and Walk-In Freezers'' 
(``appendix B''). (See also, 42 U.S.C. 6314(a)(9)(A)) The K-factor is 
calculated based on American Society for Testing and Materials 
(``ASTM'') C518, ``Standard Test Method for Steady-State Thermal 
Transmission Properties by Means of the Heat Flow Meter Apparatus'' 
(``ASTM C518''), which is incorporated by reference at 10 CFR 431.303. 
Id.
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    \3\ The R-value is the thermal resistance, or the capacity of an 
insulated material to resist heat-flow. See Section 3.3.3 of ASTM 
C518. See 42 U.S.C. 6313(f)(1)(C) for the EPCA R-value requirements 
for non-display panels and doors.
    \4\ These symbols represent the following units of measurement--
h: hour; ft\2\: square foot; [deg]F: degrees Fahrenheit; Btu: 
British thermal unit.
    \5\ The K-factor represents the thermal conductivity of a 
material, or its ability to conduct heat, in units of Btu-in/(h-
ft\2\-[deg]F). See Section 3.3.1 of ASTM C518.
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    For walk-in refrigeration systems, the efficiency metric is Annual 
Walk-in Energy Factor (``AWEF''), which is the ratio of the total heat, 
not including the heat generated by the operation of refrigeration 
systems, removed, in Btu, from a walk-in box during one-year period of 
usage for refrigeration to the total energy input of refrigeration 
systems, in watt-hours, during the same period. AWEF is determined by 
conducting the test procedure set forth in American National Standards 
Institute (``ANSI'')/Air-Conditioning, Heating, and Refrigeration 
Institute (``AHRI'') Standard 1250P (I-P), ``2009 Standard for 
Performance Rating of Walk-In Coolers and Freezers,'' (``AHRI 1250-
2009''), with certain adjustments specified in the CFR. See 10 CFR 
431.304(b)(4) and 10 CFR part 431 subpart R, appendix C, ``Uniform Test 
Method for the Measurement of Net Capacity and AWEF of Walk-In Cooler 
and Walk-In Freezer Refrigeration Systems'' (``subpart R, appendix 
C''). A manufacturer may also determine AWEF using an alternative 
efficiency determination method (``AEDM''). 10 CFR 429.53(a)(2)(iii). 
An AEDM enables a manufacturer to utilize computer-based or 
mathematical models for purposes of determining an equipment's energy 
use or energy efficiency performance in lieu of testing, provided 
certain prerequisites have been met. 10 CFR 429.70(f).
    On August 5, 2015, DOE published its intention to establish a 
working group

[[Page 23923]]

under the Appliance Standards and Rulemaking Federal Advisory Committee 
(``ASRAC'') to negotiate energy conservation standards to replace the 
standards established in the final rule published on June 3, 2014 (79 
FR 32050; ``June 2014 ECS final rule''). 80 FR 46521. The established 
working group (``ASRAC Working Group'') assembled its recommendations 
into a Term Sheet \6\ (Docket EERE-2015-BT-STD-0016, No. 56) that was 
presented to, and approved by, ASRAC on December 18, 2015 (``ASRAC Term 
Sheet'').
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    \6\ Appliance Standards and Rulemaking Federal Advisory 
Committee Refrigeration Systems Walk-in Coolers and Freezers Term 
Sheet, available at https://www.regulations.gov/document/EERE-2015-BT-STD-0016-0056.
---------------------------------------------------------------------------

    The ASRAC Term Sheet provided recommendations for energy 
conservation standards to replace standards that had been vacated by 
the United States Court of Appeals for the Fifth Circuit in a 
controlling order issued August 10, 2015. It also included 
recommendations regarding definitions for a number of terms related to 
the WICF regulations, as well as recommendations to amend the test 
procedure that the ASRAC Working Group viewed as necessary to properly 
implement the energy conservation standards recommendations. 
Consequently, DOE initiated both an energy conservation standards 
rulemaking and a test procedure rulemaking in 2016 to implement these 
recommendations. The ASRAC Term Sheet also included recommendations for 
future amendments to the test procedures intended to make DOE's test 
procedure more fully representative of walk-in energy use.
    On December 28, 2016, DOE published a final rule amending the WICF 
test procedures (``December 2016 final rule''), consistent with the 
ASRAC Term Sheet recommendations and including provisions to facilitate 
implementation of energy conservation standards for walk-in components. 
81 FR 95758. Subsequently, on July 10, 2017, DOE published a final rule 
amending the energy conservation standards for WICF refrigeration 
systems (``July 2017 ECS final rule''). 82 FR 31808.
    AHRI published an updated industry test standard for walk-in 
refrigeration systems in 2020, ``2020 Standard for Performance Rating 
of Walk-in Coolers and Freezers,'' (``AHRI 1250-2020''). This test 
procedure included updated calculations for the determination of 
default values for equipment with electric defrost and hot gas defrost. 
DOE published a final rule for hot gas defrost unit coolers on March 
26, 2021 (``March 2021 final rule'') that amended the test procedure to 
rate hot gas defrost unit coolers using the modified default values for 
energy use and heat load contributions in AHRI 1250-2020. These 
amendments ensure that ratings for hot gas defrost unit coolers are 
consistent with those of electric defrost unit coolers. 86 FR 16027.
    Under 10 CFR 431.401, any interested person may submit a petition 
for waiver from DOE's test procedure requirements. DOE will grant a 
waiver from the test procedure requirements if DOE determines either 
that the basic model for which the waiver was requested contains a 
design characteristic that prevents testing of the basic model 
according to the prescribed test procedures, or that the prescribed 
test procedures evaluate the basic model in a manner so 
unrepresentative of its true energy consumption characteristics as to 
provide materially inaccurate comparative data. 10 CFR 431.401(f)(2). 
DOE may grant the waiver subject to conditions, including adherence to 
alternate test procedures specified by DOE. Id. DOE has granted interim 
waivers and/or waivers to the manufacturers listed in Table I.1 from 
either appendix A or subpart R, appendix C.

              Table I.1: Manufacturers Who Received a Test Procedure Waiver/Interim Waiver From DOE
----------------------------------------------------------------------------------------------------------------
                                                                                                   Waiver from
                 Manufacturer                               Subject                 Case No.         appendix
----------------------------------------------------------------------------------------------------------------
Jamison Door Company.........................  PTO for Door Motors.............        2017-009               A
HH Technologies..............................  PTO for Door Motors.............        2018-001               A
Senneca Holdings.............................  PTO for Door Motors.............        2020-002               A
Hercules.....................................  PTO for Door Motors.............        2020-013               A
HTPG.........................................  CO2 Unit Coolers................        2020-009                C
Hussmann.....................................  CO2 Unit Coolers................        2020-010                C
Keeprite.....................................  CO2 Unit Coolers................        2020-014                C
RefPlus, Inc.................................  CO2 Unit Coolers................        2021-006                C
RSG..........................................  Multi-Circuit Single-Package            2022-004                C
                                                Dedicated Systems.
Store It Cold................................  Single-Package Dedicated Systems        2018-002                C
CellarPro....................................  Wine Cellar Refrigeration               2019-009                C
                                                Systems.
Air Innovations..............................  Wine Cellar Refrigeration               2019-010                C
                                                Systems.
Vinotheque...................................  Wine Cellar Refrigeration               2019-011                C
                                                Systems.
Vinotemp.....................................  Wine Cellar Refrigeration               2020-005                C
                                                Systems.
LRC Coil.....................................  Wine Cellar Refrigeration               2020-024                C
                                                Systems.
----------------------------------------------------------------------------------------------------------------

    On June 17, 2021, DOE published a request for information (``RFI'') 
to collect information and data to consider amendments to DOE's test 
procedures for walk-ins (``June 2021 RFI''). 86 FR 32332. DOE received 
comments in response to the June 2021 RFI from the interested parties 
listed in Table I.2.

Table I.2 List of Commenters With Written Submissions in Response to the
                              June 2021 RFI
------------------------------------------------------------------------
                                   Reference in this
          Commenter(s)                   NOPR           Commenter type
------------------------------------------------------------------------
Air-Conditioning, Heating, &      AHRI..............  Industry
 Refrigeration Institute.                              Association
Anthony International...........  Anthony...........  Manufacturer
Appliance Standards Awareness     ASAP..............  Efficiency
 Project.                                              Organization

[[Page 23924]]

 
Pacific Gas and Electric          CA IOUs...........  Utility
 Company, San Diego Gas and                            Association
 Electric, and Southern
 California Edison;
 collectively, the California
 Investor-Owned Utilities.
Daikin US Corporation...........  Daikin............  Manufacturer
Hussmann Corporation............  Hussmann..........  Manufacturer
Imperial Brown, Inc.............  Imperial Brown....  Manufacturer
Keeprite Refrigeration, Inc.....  Keeprite..........  Manufacturer
Lennox International............  Lennox............  Manufacturer
National Refrigeration & Air      National            Manufacturer
 Conditioning Canada Corp..        Refrigeration.
Northwest Energy Efficiency       NEEA..............  Efficiency
 Alliance.                                             Organization
National Fenestration Rating      NFRC..............  Industry
 Council.                                              Association
------------------------------------------------------------------------

    In response to the June 2021 RFI, DOE also received comments 
specific to energy conservation standards (``ECS''), which it will 
address in a future walk-in ECS rulemaking notice.
    A parenthetical reference at the end of a comment quotation or 
paraphrase provides the location of the item in the public record.\7\
---------------------------------------------------------------------------

    \7\ The parenthetical reference provides a reference for 
information located in the docket of DOE's rulemaking to develop 
test procedures for walk-ins. (Docket No. EERE-2017-BT-TP-0010, 
which is maintained at www.regulations.gov). The references are 
arranged as follows: Commenter name, comment docket ID number, page 
of that document.
---------------------------------------------------------------------------

II. Synopsis of the Notice of Proposed Rulemaking

    In this NOPR, DOE is proposing to expand the scope of its walk-in 
coolers and freezers test procedure to include carbon dioxide 
(``CO<INF>2</INF>'') unit coolers, multi-circuit single-packaged 
dedicated systems, and ducted fan coil units. DOE has also tentatively 
determined that liquid-cooled refrigeration systems are within the 
scope of DOE coverage authority for walk-ins but is not proposing to 
add an applicable test procedure at this time.
    In this NOPR, DOE is proposing to alter the definitions of walk-in 
cooler and walk-in freezer, door, door surface area, and single-
packaged dedicated systems. DOE is also proposing new definitions for 
door leaf, hinged vertical door, non-display door, roll-up door, 
sliding door, high-temperature refrigeration systems, ducted fan coil 
units, multi-circuit single-packaged dedicated systems, attached split 
systems, detachable single-packaged dedicated systems, CO<INF>2</INF> 
unit coolers, and hot gas defrost.
    In this NOPR, DOE is proposing to make the following revisions to 
appendix A: (1) Reference NFRC 102-2020 as the applicable test 
procedure to determine door ``U-factor'' in place of NFRC 100 (DOE 
proposes to adopt AEDM provisions for doors in 10 CFR 429.53 to allow 
calculation of door energy use representations); (2) provide further 
detail on and distinguish the area to be used for determining 
compliance with standards and the area used to calculate a thermal load 
from U-factor; (3) establish a percent time off (``PTO'') specific to 
door motors; and (4) reorganize appendix A so that it is easier to 
follow.
    Additionally, DOE is proposing to modify appendix B to improve test 
representativeness and repeatability. Specifically, DOE is proposing to 
make the following revisions to appendix B: (1) Reference the updated 
industry standard ASTM C518-17; (2) include more detailed provisions 
for determining measuring insulation thickness and test specimen 
thickness; (3) provide additional guidance on determining parallelism 
and flatness of a test specimen; and (4) reorganize appendix B as a 
step-by-step procedure so it is easier to follow.
    DOE is also proposing to include walk-in doors and walk-in panels 
in the list of covered equipment in the same sampling plan for 
enforcement testing that is used for walk-in refrigeration systems. See 
10 CFR 429.110(e)(2).
    DOE is proposing two sets of changes for the refrigeration system 
test procedure. One set of changes would be grouped into proposed 
revisions to subpart R, appendix C, and the other set of changes is 
being proposed through the establishment of a new appendix C1 to 
subpart R of part 431 (``appendix C1''). DOE has tentatively determined 
that the changes to subpart R, appendix C, would not affect AWEF 
ratings and therefore would not require any retesting or 
recertification. These proposed changes, if adopted, would be required 
starting 180 days after the test procedure final rule is published. DOE 
has tentatively determined, however, that the proposed appendix C1 
would affect the measurement of energy use; therefore, DOE is proposing 
to establish a new metric, AWEF2, in appendix C1 which would require 
retesting and recertification. The requirements proposed in appendix 
C1, if adopted, would take place on the compliance date of amended 
energy conservation standards that DOE may ultimately decide to adopt 
as part of a separate rulemaking assessing the technological 
feasibility and economic justification for such standards.
    DOE is proposing to make the following revisions to subpart R, 
appendix C:
    (1) Specify refrigeration test room conditions;
    (2) provide for a temperature probe exception for small diameter 
refrigerant lines;
    (3) incorporate a test setup hierarchy for installation 
instructions for laboratories to follow when setting up a unit for 
test;
    (4) allow active cooling of the liquid line in order to achieve the 
required 3 [ordm]F subcooling at a refrigerant mass flow meter;
    (5) modify instrument accuracy and test tolerances; and
    (6) address current test procedure waivers for CO<INF>2</INF> unit 
coolers tested alone and high-temperature unit coolers tested alone by 
incorporating amendments appropriate for this equipment.
    Additionally, DOE is proposing a new metric, AWEF2, associated with 
a new appendix C1, which would include the proposed changes to subpart 
R, appendix C. DOE is proposing the following provisions be included in 
appendix C1, which would be required to demonstrate compliance 
coincident with the compliance date of any amended energy conservation 
standards, should such standards be established:
    (1) Adoption of AHRI 1250-2020;
    (2) provide for testing single-packaged dedicated systems, 
detachable single-packaged dedicated systems, attached split systems, 
CO<INF>2</INF>, variable-, two-, and multiple-capacity dedicated 
condensing units, indoor variable-, two- and multiple-capacity matched 
pairs,

[[Page 23925]]

matched refrigeration systems for high-temperature applications, and 
multi-circuit single-packaged dedicated systems;
    (3) add a single-packaged dedicated system refrigerant enthalpy 
test procedure; and
    (4) add a new energy metric, AWEF2, to reflect the proposed changes 
in the test procedure that would result in a significant change to 
energy use values.
    Table II.1 summarizes the current DOE test procedure, DOE's 
proposed changes to the test procedure, the attribution for each 
proposed change, and the location of the proposed test procedure.

          Table II.1--Summary of Changes in Proposed Test Procedure Relative to Current Test Procedure
----------------------------------------------------------------------------------------------------------------
                                    Current DOE test      Proposed test                            Proposed in
        WICF component(s)              procedure           procedure(s)         Attribution          appendix
----------------------------------------------------------------------------------------------------------------
Doors and Display Panels........  Incorporates by      Incorporates by      Reduce test burden.               A
                                   reference NFRC 100-  reference NFRC 102-
                                   2010 for             2020 for
                                   determining U-       determining U-
                                   factor as part of    factor and allows
                                   determining energy   for AEDMs to be
                                   consumption.         used for
                                                        determining energy
                                                        consumption.
Doors and Display Panels........  Uses surface area    Requires that area   Improve                           A
                                   of the door or       of the aperture or   representative
                                   display panel        surface area used    values.
                                   external to the      to determine the U-
                                   walk-in to convert   factor be used to
                                   U-factor into a      convert U-factor
                                   conduction load.     into a conduction
                                                        load.
Doors...........................  Uses a percent time  Establishes a        Improve                           A
                                   off value of 25      percent time off     representative
                                   percent for door     value of 97          values and
                                   motors (as they      percent specific     addresses
                                   are considered       to door motors.      inconsistent
                                   ``other                                   values across
                                   electricity-                              waivers granted.
                                   consuming
                                   devices'').
Non-display Doors and Panels....  Incorporates by      Incorporates by      Updates to the                    B
                                   reference ASTM       reference ASTM       applicable
                                   C518-04.             C518-17.             industry test
                                                                             procedures.
Non-display Doors and Panels....  Does not include     Includes detailed    Ensure test                       B
                                   detailed             provisions for       repeatability.
                                   provisions for       determining and
                                   determining and      measuring total
                                   measuring total      insulation
                                   insulation           thickness and test
                                   thickness and test   specimen thickness.
                                   specimen thickness.
Non-display Doors and Panels....  Requires that the    Provides guidance    Ensure test                       B
                                   test specimen meet   on determining       repeatability.
                                   a parallelism and    parallelism and
                                   flatness tolerance   flatness of the
                                   of <plus-            test specimen.
                                   minus>0.03 inches
                                   but provides no
                                   guidance on
                                   measurement.
Refrigeration Systems...........  Does not include     Includes guidance    Ensure test                        C
                                   guidance on test     on test room         repeatability.
                                   room conditioning.   conditioning.
Refrigeration Systems...........  Does not include an  Includes an          Reduce test burden.                C
                                   allowance for        allowance for
                                   measuring            measuring
                                   refrigerant          refrigerant
                                   temperatures with    temperatures with
                                   surface-mounted      surface-mounted
                                   measuring            measuring
                                   instruments.         instruments for
                                                        small diameter
                                                        tubes.
Refrigeration Systems...........  Does not include     Includes guidance    Ensure test                        C
                                   guidance for unit    for unit charging    repeatability.
                                   charging or a        and a setup
                                   setup condition      condition
                                   hierarchy.           hierarchy.
Refrigeration Systems...........  Does not include     Includes provisions  Improve                            C
                                   provisions for       for testing CO2      representative
                                   testing CO2 unit     unit coolers.        values.
                                   coolers.
Refrigeration Systems...........  Does not include     Includes provisions  Improve                            C
                                   provisions for       for testing high-    representative
                                   testing high-        temperature unit     values.
                                   temperature unit     coolers alone.
                                   coolers alone.
Refrigeration Systems...........  Incorporates by      Incorporates by      Updates to the                     C1
                                   reference AHRI       reference AHRI       applicable
                                   1250-2009, ASHRAE    1250-2020, ASHRAE    industry test
                                   23.1-2010, and       37, and ASHRAE 16.   procedures.
                                   AHRI 420-2008.
Refrigeration Systems...........  Single-packaged      Includes multiple    Improve                            C1
                                   dedicated systems    methods for          representative
                                   are tested using     testing single-      values.
                                   the refrigerant      packaged dedicated
                                   enthalpy method      systems.
                                   for matched pairs.
Refrigeration Systems...........  Does not include     Includes provisions  Improve                            C1
                                   provisions for       for testing          representative
                                   testing attached     attached split       values.
                                   split systems or     systems or
                                   detachable single-   detachable single-
                                   packaged dedicated   packaged dedicated
                                   systems.             systems.
Refrigeration Systems...........  Does not include     Includes provisions  Improve                            C1
                                   provisions for       for testing multi-   representative
                                   testing multi-       circuit single-      values.
                                   circuit single-      packaged dedicated
                                   packaged dedicated   systems.
                                   systems.
Refrigeration Systems...........  Does not include     Includes provisions  Improve                            C1
                                   provisions for       for testing ducted   representative
                                   testing ducted fan   fan coil units.      values.
                                   coil units.
Refrigeration Systems...........  Does not include     Includes provisions  Improve                            C1
                                   provisions for       for testing high-    representative
                                   testing high-        temperature          values.
                                   temperature          matched-pair and
                                   matched-pair and     single-packaged
                                   single-packaged      dedicated systems.
                                   dedicated systems.

[[Page 23926]]

 
Refrigeration Systems...........  Does not include     Includes provisions  Improve                            C1
                                   provisions for       for testing of       representative
                                   testing of           variable, two-,      values.
                                   variable- and        and multiple-
                                   multiple-capacity    capacity dedicated
                                   dedicated            condensing units
                                   condensing units     and variable, two-
                                   nor variable- and    , and multiple-
                                   multiple-capacity    capacity outdoor
                                   outdoor matched      matched pairs.
                                   pairs.
----------------------------------------------------------------------------------------------------------------

    DOE has tentatively determined that the proposed amendments 
described in section III of this NOPR would not alter the measured 
energy consumption of walk-in doors without motors or the R-value of 
walk-in non-display doors and non-display panels or require retesting 
or recertification solely as a result of DOE's adoption of the proposed 
amendments to the test procedures, if made final. Additionally, DOE has 
tentatively determined that the proposed amendments, if made final, 
would not increase the cost of testing.
    Further, DOE has tentatively determined that the proposed 
amendments described in section III of this NOPR would alter the 
measured energy consumption or efficiency of walk-in doors with motors 
and would only require retesting or recertification because of DOE's 
adoption of the proposed amendments to the test procedures, if made 
final. Additionally, DOE has tentatively determined that the proposed 
amendments, if made final, would not increase the cost of testing for 
doors with motors.
    DOE has also tentatively determined that the proposed amendments to 
subpart R, appendix C, described in section III.F of this NOPR would 
not alter the measured efficiency of walk-in refrigeration systems and 
would not require retesting or recertification as a result of DOE's 
adoption of the proposed amendments to the test procedures, if made 
final. Additionally, DOE has tentatively determined that the proposed 
amendments, if made final, would not increase the cost of testing.
    Finally, DOE has tentatively determined that the proposed 
provisions of appendix C1 described in section III.G of this NOPR would 
alter the measured efficiency of walk-in refrigeration systems. 
However, the proposed procedure in appendix C1 would only require 
retesting or recertification when a future energy conservation standard 
would take effect. Additionally, DOE has tentatively determined that 
the proposed provisions in appendix C1, if made final, would increase 
the cost of testing. Tentative cost estimates are discussed in section 
III.J of this document.
    Discussion of DOE's proposed actions are addressed in detail in 
section III of this NOPR.

III. Discussion

    In the following sections, DOE proposes certain amendments to its 
test procedures for walk-in doors, panels, and refrigeration systems. 
For each proposed amendment, DOE provides relevant background 
information, explains why the amendment merits consideration, discusses 
relevant public comments, and proposes a potential approach.
    Many of the refrigeration system test procedure proposals under 
consideration in this NOPR stem from recommendations made by the ASRAC 
Working Group (see ASRAC Term Sheet Recommendation #6, EERE-2015-BT-
STD-0016, No. 56). The remainder of the refrigeration system, door, and 
panel test procedure amendments proposed in this NOPR are in response 
to issues identified by DOE and stakeholders in the time since the 
publication of the December 2016 final rule, including through 
petitions for test procedure waivers.

A. Scope and Definitions

    This NOPR applies to the test procedures for ``walk-in coolers and 
walk-in freezers.'' DOE defines ``walk-in cooler and walk-in freezer'' 
as: An enclosed storage space refrigerated to temperatures (1) above 32 
[deg]F for walk-in coolers and (2) at or below 32 [deg]F for walk-in 
freezers, that can be walked into, and has a total chilled storage area 
of less than 3,000 square feet, but excluding equipment designed and 
marketed exclusively for medical, scientific, or research purposes. 10 
CFR 431.302. (See also 42 U.S.C. 6311(20))
1. Scope
    The following sections discuss considerations and proposals 
regarding the scope of equipment covered by DOE's test procedures for 
walk-ins. As discussed, the DOE test procedures and standards apply to 
walk-in refrigeration systems, doors, and panels.
a. Liquid-Cooled Refrigeration Systems
    A -liquid-cooled refrigeration system rejects heat during the 
condensing process to a liquid that transports the heat to a remote 
location. This is in contrast to an air-cooled system, which rejects 
heat to ambient air during the condensing process. DOE understands that 
liquid-cooled refrigeration systems are typically used in facilities 
where either cooling water or glycol is plumbed throughout the building 
prior to installation of the refrigeration unit, although it is 
possible that some such systems use potable water for condenser cooling 
and dispose the water in a drain after it passes through the condenser. 
As discussed in the June 2021 RFI, liquid-cooled dedicated condensing 
units for walk-ins are readily available for a wide range of capacities 
and refrigerants from major walk-in refrigeration system manufacturers 
(see for example, Airdyne W-series indoor units (water-cooled), and 
Russell (water-cooled, glycol-cooled) \8\ 86 FR 32332, 32334.
---------------------------------------------------------------------------

    \8\ See Docket No. EERE-2017-BT-TP-0010-0001, Docket No. EERE-
2017-BT-TP-0010-0002, and Docket No. EERE-2017-BT-TP-0010-0003.
---------------------------------------------------------------------------

    DOE notes that the EPCA definition for walk-ins makes no 
distinction on how the condenser is cooled. (42 U.S.C. 6311(20)(A)) 
However, the current DOE test procedure for walk-in refrigeration 
systems, which incorporates by reference AHRI 1250-2009, does not 
address how to test liquid-cooled systems. Additionally, liquid-cooled 
dedicated condensing units are outside the scope of AHRI 1250-2020, 
being specifically excluded in section 2.2.4.
    In the June 2021 RFI, DOE requested comment on whether it should 
consider establishing a test procedure for liquid-cooled walk-in 
equipment. 86 FR 32332, 32334. Lennox, AHRI, Keeprite, National 
Refrigeration, and Hussmann recommended against establishing a separate 
test procedure for liquid-cooled refrigeration systems due to the small 
market size for such systems. (Lennox, No. 9 at p. 2; AHRI, No. 11 at 
p. 2; Keeprite, No. 12 at p. 1; National

[[Page 23927]]

Refrigeration, No 17 at p. 1; Hussmann, No. 18 at p. 2) Lennox, AHRI, 
Keeprite, and Hussmann also explained that the type of coolant used has 
the most impact on efficiency for liquid-cooled systems; however, 
coolants are not specified by the WICF system manufacturer. These 
stakeholders asserted that liquid-cooled systems do not have a large 
potential for energy savings since purchasers, rather than WICF 
manufacturers, specify the coolant system. (Lennox, No. 9 at p. 2; 
AHRI, No. 11 at p. 2; Keeprite, No. 12 at p. 1; Hussmann, No. 18 at p. 
2) Keeprite also stated that liquid-cooled systems are generally more 
efficient than air cooled models. (Keeprite, No. 12 at p. 1)
    ASAP recommended developing a test procedure for liquid-cooled 
systems since the systems are currently available in the market and 
there are no applicable test procedures. (ASAP, No. 13 at p. 1) ASAP 
stated that adopting test methods for liquid-cooled systems would 
provide purchasers with comparable ratings regardless of cooling type. 
Id. Daikin recommended considering EN 17432, ``Packaged refrigerating 
units for walk-in cold rooms--Classification, performance and energy 
consumption testing'' (``EN 17432''), which addresses water-cooled and 
liquid-cooled refrigeration systems. (Daikin, No. 17 at p. 1)
    DOE reiterates that the scope of the walk-in definition includes 
liquid-cooled equipment. DOE recognizes the potential benefit of a test 
procedure for liquid-cooled walk-ins and the value that a reliable test 
procedure can provide to facilitate comparable representations of 
energy use for consumers. DOE has tentatively determined that liquid-
cooled refrigeration systems may represent a small portion of the walk-
in market and the potential for energy savings is likely limited. 
Therefore, although liquid-cooled refrigeration systems are considered 
to be covered equipment, DOE is not proposing to amend its procedures 
to include liquid-cooled refrigeration systems at this time.
b. Carbon Dioxide Systems
    Currently, the DOE test procedure for walk-in refrigeration systems 
does not explicitly define scope based on refrigerant. See 10 CFR 
431.301, 10 CFR 431.304, and appendix A. DOE understands that the 
current test procedure, which is based on AHRI 1250-2009 (incorporated 
by reference, 10 CFR 431.303(b)), specifies test conditions that may 
not be consistent with the design and operation of carbon dioxide 
(``CO<INF>2</INF>'') refrigeration systems; i.e., although AHRI 1250-
2009 does not specifically exclude CO<INF>2</INF> systems, the test 
method is not designed to accommodate such systems.
    The DOE test procedure for unit coolers requires testing with a 
liquid inlet saturation temperature of 105 [deg]F and a liquid inlet 
subcooling temperature of 9 [deg]F, as specified by Tables 15 and 16 of 
AHRI 1250-2009. However, CO<INF>2</INF> has a critical temperature of 
87.8 [deg]F; therefore, it does not coexist as saturated liquid and gas 
above this temperature. The liquid inlet saturation temperature of 105 
[deg]F and the liquid inlet subcooling temperature of 9 [deg]F 
specified in subpart R, appendix C, are not achievable by 
CO<INF>2</INF> unit coolers. DOE has granted waivers or interim waivers 
from subpart R, appendix C, for specific basic models of CO<INF>2</INF> 
unit coolers to the manufacturers listed in Table III.1 of this 
document. The alternate test procedure specified in these waivers 
modified the liquid inlet saturation temperature to 38 [deg]F and the 
liquid inlet subcooling temperature to 5 [deg]F. Pursuant to its waiver 
regulations, as soon as practicable after the granting of any waiver, 
DOE will publish in the Federal Register a notice of proposed 
rulemaking to amend its regulations so as to eliminate any need for the 
continuation of such waiver. 10 CFR 431.401(l). As soon thereafter as 
practicable, DOE will publish in the Federal Register a final rule to 
that effect. Id.

      Table III.1--Waivers Granted to Manufacturers of CO2 Walk-In
                          Refrigeration Systems
------------------------------------------------------------------------
                                    Interim waiver      Waiver decision
          Manufacturer             Federal Register    and order Federal
                                       citation        Register citation
------------------------------------------------------------------------
Heat Transfer Products Group      85 FR 83927 (Dec.   86 FR 14887 (Mar.
 (``HTPG'').                       23, 2020).          19, 2021).
Hussmann Corporation              86 FR 10046 (Feb.   86 FR 24606 (May
 (``Hussmann'').                   18, 2021).          7, 2021).
Keeprite Refrigeration            86 FR 12433 (Mar.   86 FR 24603 (May
 (``Keeprite'').                   3, 2021).           7, 2021).
RefPlus Inc. (``RefPlus'')......  86 FR 43633 (Aug.
                                   10, 2021).
------------------------------------------------------------------------

    The alternate test procedure granted in the CO<INF>2</INF> waivers 
and DOE's proposal with respect to refrigeration systems utilizing 
CO<INF>2</INF> as a refrigerant are further discussed in section 
III.F.6 of this document.
    As discussed in the June 2021 RFI, all CO<INF>2</INF> refrigerant 
waiver petitions DOE has thus far received address unit coolers. 86 FR 
32332, 32346. However, it is possible that other CO<INF>2</INF> 
refrigeration system configurations may be relevant in the future, e.g. 
dedicated condensing units, matched pairs, or single-packaged dedicated 
systems. DOE reviewed product literature and other information for 
CO<INF>2</INF> systems having some of these alternative configurations. 
Most of the information identified by DOE pertains to manufacturers 
operating in Europe.
    In the June 2021 RFI, DOE requested comment on the future expected 
use of walk-in refrigeration systems using CO<INF>2</INF>. 86 FR 32332, 
32346. Lennox, AHRI, National Refrigeration, and Hussmann stated that 
they are not aware of any transcritical \9\ CO<INF>2</INF> dedicated 
condensing units available in North America. (Lennox, No. 9 at p. 7; 
AHRI, No. 11 at p. 12; National Refrigeration, No 17 at p. 1; Hussmann, 
No. 18 at p. 14) National Refrigeration asserted that CO<INF>2</INF> 
tends to be used in large, complex multi-compressor systems and 
therefore, would not be used in smaller systems with just one dedicated 
condensing unit (National Refrigeration, No. 17 at p. 1) The CA IOUs 
stated that CO<INF>2</INF> unit coolers cannot be tested and rated at 
the temperatures and pressures used in the current test procedure for 
more traditional hydrofluorocarbon (``HFC'') refrigerants; however, 
single-packaged dedicated CO<INF>2</INF> refrigeration systems should 
be able to use the test methods established in AHRI 1250-2020 for 
single-packaged dedicated systems, because these test methods do not 
use refrigerant flow or refrigerant conditions for energy calculations. 
(CA IOUs, No. 14 at p. 4) Additionally, the CA IOUs urged DOE to ensure 
that the WICF test procedures and metrics continue to provide consumers 
with the information necessary to easily compare the

[[Page 23928]]

performance of products with the same utility. Id.
---------------------------------------------------------------------------

    \9\ CO<INF>2</INF> refrigeration systems are transcritical 
because the high-temperature refrigerant that is cooled by ambient 
air is in a supercritical state, above the 87.8 [deg]F critical 
point temperature, above which the refrigerant cannot exist as 
separate vapor and liquid phases.
---------------------------------------------------------------------------

    DOE preliminarily finds that, in the North American market, 
CO<INF>2</INF> is primarily used in large rack systems, and that there 
do not appear to be any CO<INF>2</INF> dedicated condensing units 
available. Hence, DOE tentatively finds that adopting a test procedure 
for CO<INF>2</INF> dedicated condensing units is currently not 
warranted. However, DOE has also tentatively determined that the test 
methods in AHRI 1250-2020 for single-packaged dedicated systems do not 
need to be modified for CO<INF>2</INF> refrigerant as long as these 
units are tested using air enthalpy or calorimeter test methods, rather 
than a refrigerant enthalpy method. DOE further discusses its proposals 
for testing single-packaged dedicated systems in section III.G.2 of 
this document.
    In this NOPR, DOE is proposing that walk-in refrigeration equipment 
utilizing CO<INF>2</INF> as a refrigerant meet the definition of a 
walk-in refrigeration system, but that the DOE test procedure, as 
proposed in this document, would apply only to (1) single-packaged 
dedicated systems and (2) unit cooler variants of CO<INF>2</INF> 
refrigeration systems. This proposal would exclude CO<INF>2</INF> 
dedicated condensing units from the proposed test procedure. The test 
procedures for CO<INF>2</INF> unit coolers and single-packaged 
refrigeration systems which use CO<INF>2</INF> as a refrigerant are 
outlined in more detail in sections III.F.6 and III.G.2.f of this 
document, respectively.
c. Multi-Circuit Single-Packaged Refrigeration Systems
    DOE has received a request for waiver and interim waiver from 
Refrigerated Solutions Group (``RSG'') from the test procedure in 
subpart R, appendix C, for basic models of single-packaged dedicated 
systems having multiple refrigerant circuits within a single unit that 
share a single evaporator and a single condenser. (Docket EERE-2022-BT-
WAV-0010, No. 1) In its petition, RSG stated that the current walk-in 
test procedure does not address multiple refrigeration circuits that 
are enclosed in a single unit. Id. Therefore, in this test procedure 
NOPR, DOE has initially determined that refrigeration systems with 
multiple refrigeration circuits that share a single evaporator and a 
single condenser and are used in walk-in applications meet the 
definition of ``walk-in cooler and walk-in freezer.'' Thus, DOE 
proposes to define ``multi-circuit single-packaged dedicated system'' 
in section III.A.2.e of this document. Additionally, DOE is proposing a 
test procedure for such systems.
d. Ducted Units
    DOE is aware that some walk-in evaporators and/or dedicated 
condensing units are sold with provisions to be installed with duct(s) 
to circulate air between the walk-in and the refrigeration system. The 
current definition of ``single-packaged dedicated system'' specifies 
that such systems do not have ``any element external to the system 
imposing resistance to flow of the refrigerated air;'' and the 
definition of ``unit cooler'' specifies that such equipment does not 
have ``any element external to the cooler imposing air resistance.'' 
(10 CFR 431.302) As such, unit coolers and single-packaged dedicated 
systems sold for ducted installation are not addressed by either 
definition--also, the current test procedure does not include 
provisions for setup of ductwork. While the definition for condensing 
unit does not exclude systems intended for ducted installation, the 
current test procedure does not include provisions for setup of 
ductwork for these components either.
    DOE has granted waivers from the test procedure in subpart R, 
appendix C, to Air Innovations, Vinotheque, Cellar Pro, and Vinotemp, 
and an interim waiver to LRC Coil, for walk-ins marketed for use as 
wine cellar refrigeration systems (see Table III.2). The waivers are 
discussed in more detail in sections III.A.2.c and III.G.6 of this 
document. Relevant to the present discussion of scope, the specific 
basic models for which waivers have been granted include equipment sold 
as ducted units. As a result of the test procedure waivers granted by 
DOE, DOE proposes to revise the single-packaged dedicated system 
definition to clarify that such systems may have provisions for ducted 
installation. DOE proposes to add a definition for ``ducted fan coil 
unit,'' the ducted equivalent of a unit cooler. In doing so, DOE 
preserves the standard industry definition of a unit cooler while 
expanding the scope of the test procedure to ducted units. DOE also 
proposes to add provisions in the test procedures to address setup of 
ductwork and the external static pressure that it imposes on 
refrigeration system fans--all in order to improve representativeness 
of the test procedure. These test procedure revisions are addressed in 
section III.G.6 of this document.

  Table III.2--Interim Waivers and Waivers Granted to Manufacturers of
         Walk-ins Marketed as Wine Cellar Refrigeration Systems
------------------------------------------------------------------------
                                                        Waiver decision
                                    Interim waiver    and order  Federal
          Manufacturer             Federal  Register        Register
                                       citation            citation
------------------------------------------------------------------------
Air Innovations.................  86 FR 2403 (Jan.    86 FR 23702 (May
                                   12, 2021).          4, 2021).
Vinotheque......................  86 FR 11961 (Mar.   86 FR 26504 (May
                                   1, 2021).           14, 2021).
CellarPro.......................  86 FR 11972 (Mar.   86 FR 26496 (May
                                   1, 2021).           14, 2021).
Vinotemp........................  86 FR 23692 (May    86 FR 36732 (July
                                   4, 2021).           13,2021).
LRC Coil........................  86 FR 47631 (Aug.
                                   26, 2021).
------------------------------------------------------------------------

2. Definitions
a. Walk-in Cooler and Walk-in Freezer
    The term ``walk-in cooler and walk-in freezer'' means an enclosed 
storage space refrigerated to temperatures, respectively, above, and at 
or below 32 [deg]F, that can be walked into, and has a total chilled 
storage area of less than 3,000 square feet; however, the term does not 
include products designed and marketed exclusively for medical, 
scientific, or research purposes. 10 CFR 431.302. (See also 42 U.S.C. 
6311(20))
    In this notice, DOE proposes to amend the definition of walk-in 
cooler and freezer to specify that a walk-in may be comprised of doors, 
panels, and refrigeration systems. As explained in section I.B of this 
document, DOE established separate test procedures and energy 
conservation standards for the principal components that make up a 
walk-in: panels, doors, and refrigeration systems. 76 FR 21580, 21582 
and 79 FR 32050, 32051-32052. DOE noted in a final rule published March 
7, 2011 (``March 2011 Compliance, Certification, and Enforcement 
(``CCE'') final rule'') that the legislative design standards set forth 
in EPCA provide the framework for a component-based approach since each 
design standard is based on the performance of a given component of the 
walk-in. 76 FR 12422, 12444. In order to align the definition with the 
regulatory scheme adopted by DOE, DOE proposes to revise the definition 
to mean an enclosed storage space, including but not limited to panels, 
doors, and refrigeration systems, refrigerated to temperatures, 
respectively, above, and at or below 32

[[Page 23929]]

degrees Fahrenheit that can be walked into, and has a total chilled 
storage area of less than 3,000 square feet; however, the terms do not 
include products designed and marketed exclusively for medical, 
scientific, or research purposes. DOE does not intend for this amended 
definition to expand the scope of the definition for walk-in coolers 
and freezers nor does it intend for this amended definition to expand 
the certification and compliance responsibilities of entities involved 
in manufacturing or assembling walk-ins or walk-in components. Instead, 
DOE's proposed revision to the definition of walk-in cooler and walk-in 
freezer clarifies that DOE has the authority to separately regulate 
walk-in components as well as a full walk-in system (including but not 
limited to panels, doors, and refrigeration systems). The March 2011 
CCE final rule adopted a definition for a walk-in manufacturer to 
specify the entities responsible for certification and/or compliance of 
walk-ins or walk-in components. 76 FR 12422, 12442-12444. DOE 
emphasizes that both the component manufacturer and the assembler bear 
the responsibility of standards compliance, even though the component 
manufacturer is the entity responsible for certification. An assembler 
may rely on the certification from the component manufacturer regarding 
whether the component being used is certified as compliant with DOE 
standards.
    Issue 1: DOE requests comment on its proposed changes to the 
definition for walk-in cooler and walk-in freezer.
b. Doors
    With respect to walk-ins, DOE defines a ``door'' as an assembly 
installed in an opening on an interior or exterior wall that is used to 
allow access or close off the opening and that is movable in a sliding, 
pivoting, hinged, or revolving manner of movement. For walk-in coolers 
and walk-in freezers, a door includes the door panel, glass, framing 
materials, door plug, mullion, and any other elements that form the 
door or part of its connection to the wall. 10 CFR 431.302. In the June 
2021 RFI, DOE requested feedback on the current definition of ``door.'' 
86 FR 32332, 32335.
    Hussmann stated that the current definition of door is sufficient. 
(Hussmann, No. 18 at p. 3) Anthony and AHRI stated that ``door'' is 
unclear and inadequately defined. (Anthony, No. 8 at p. 1; AHRI, No. 11 
at p. 2) AHRI commented that the current definition seems to describe 
an individual ``door'' opening, but that the requirement for testing 
uses the opening space in the walk-in regardless of whether it contains 
more than one ``door'' opening. AHRI suggested that the definition of 
``door'' should contain the door frame and all door components, and 
that DOE should differentiate between the number of openings for a 
specific door assembly inserted into the opening space, especially for 
display doors. (AHRI, No. 11 at pp. 2-3) Anthony asserted that any 
component that is part of the door assembly (e.g., door, frame, wiring) 
is within the definition of a WICF door. (Anthony, No. 8 at pp. 1-2)
    In the June 2021 RFI, DOE also requested comment specifically on 
the use of the term ``door plug'' within the definition of ``door.'' 86 
FR 32332, 32335. Anthony and AHRI stated that they were unfamiliar with 
the term ``door plug.'' (Anthony, No. 8 at pp. 1-2; AHRI, No. 11 at pp. 
2-3) Imperial Brown stated that the door plug is the moving part of the 
door that can swing or slide and comes attached to the frame. (Imperial 
Brown, No. 15 at p. 1) Hussmann stated that the term ``door plug'' is 
in reference to a regular door plug (i.e., plugging heaters from a door 
to a frame system), and that Hussmann does not use the term ``door 
plug'' interchangeably with a ``door.'' (Hussmann, No. 18 at p. 3)
    DOE recognizes that the current definition of ``door'' does not 
explicitly address that walk-in door assemblies may contain multiple 
door openings within one frame. DOE also notes that NFRC 100 includes 
several defined terms relating to door components (e.g., door leaf), 
which differ from the terms used in DOE's definition of ``door.'' 
Additionally, certain stakeholders commented that they are unfamiliar 
with the term ``door plug,'' whereas others use it to describe 
different components of the door assembly.
    DOE proposes to amend the definition of ``door'' to address doors 
with multiple openings within one frame; to include terminology that 
generally aligns with terminology used by the industry; and to remove 
use of the term ``door plug,'' which is being interpreted 
inconsistently by stakeholders. Specifically, DOE proposes to amend the 
definition of ``door'' to mean an assembly installed in an opening of 
an interior or exterior wall that is used to allow access or close off 
the opening and that is movable in a sliding, pivoting, hinged or 
revolving manner of movement. For walk-in coolers and walk-in freezers, 
a door includes the frame (including mullions), the door leaf or 
multiple door leaves (including glass) within the frame, and any other 
elements that form the assembly or part of its connection to the wall. 
DOE also proposes to define the term ``door leaf'' to mean the 
pivoting, rolling, sliding, or swinging portion of a door. DOE 
tentatively concludes that the proposed revision of ``door'' and 
proposed definition of ``door leaf'' better align with industry 
terminology and address doors with multiple openings within one frame. 
DOE does not intend for the proposed changes to the definition of 
``door'' and the newly defined term for ``door leaf'' to change the 
scope of applicability of the DOE test procedures or the applicability 
of standards for walk-in doors.
    As discussed in the June 2021 RFI, DOE differentiates WICF doors by 
whether such doors are ``display doors'' or not display doors (i.e., 
``passage doors'' or ``freight doors''). 86 FR 32332, 32335. A 
``freight door'' is a door that is not a display door and is equal to 
or larger than 4 feet wide and 8 feet tall. 10 CFR 431.302. A ``passage 
door'' is a door that is not a freight or display door. Id. The use of 
dimensions in the definition of freight door conveys that these doors 
typically allow large machines (e.g., forklifts) to pass through 
carrying freight. However, the definition does not address instances 
where one dimension exceeds the height or width requirement per the 
definition, but the other dimension is smaller than the other dimension 
requirement per the definition. In some cases, the surface area for 
such doors could be larger than 32 square feet, the area of a 4-foot by 
8-foot door provided in the definition (e.g., a door 5 feet wide and 7 
feet tall, with a surface area of 35 square feet); in other cases, the 
surface area could be smaller than 32 square feet (e.g., a door 5 feet 
wide and 6 feet tall, with a surface area of 30 square feet). As part 
of the June 2021 RFI, DOE reviewed the certified surface areas of 
freight and passage doors in DOE's Compliance Certification Management 
System (``CCMS'') Database. DOE found that many models certified as 
passage doors had rated surface areas greater than or equal to 32 
square feet while some models certified as freight doors had rated 
surface areas less than 32 square feet. 86 FR 32332, 32335.
    In the June 2021 RFI, DOE requested comment on whether height and 
width or surface area effectively distinguish between passage and 
freight doors and whether there are any building codes, standards, or 
industry practices to support or refute maintaining dimensions of a 
door as the defining characteristics separating freight and passage 
doors. Additionally, DOE sought comment on any other attributes other 
than size which would

[[Page 23930]]

appropriately distinguish passage and freight doors. Lastly, DOE sought 
comment on how to classify non-display doors with multiple openings 
where the individual door openings do not meet the definition of 
freight door, but the overall door assembly would meet the definition 
of a freight door per the dimension requirements in the freight door 
definition. Id.
    The CA IOUs generally supported DOE updating its definitions 
related to walk-in doors to prevent mis-categorization. Specifically, 
the CA IOUs suggested that DOE align with industry definitions for 
freight doors, such as vertical or sectional overhead doors, and 
consider differentiating doors based on opening characteristics (e.g., 
swing, horizontal slide, vertical slide, rollup) rather than size. (CA 
IOUs, No. 14 at p. 5)
    Imperial Brown stated that the door width-in-clear \10\ (or 
``WIC'') should be the determining factor for distinguishing passage 
and freight doors. Imperial Brown recommended that a freight door be 
identified as a door with a WIC of 48 inches or more and a height-in-
clear \11\ (``HIC'') of 78 inches or more, allowing for pallet and 
forklift traffic. (Imperial Brown, No. 15 at p. 1)
---------------------------------------------------------------------------

    \10\ Imperial Brown defined WIC as the clear opening width, 
typically from left frame jamb to right frame jamb. (Imperial Brown, 
No. 15 at p. 1)
    \11\ Imperial Brown defined HIC as the clear opening height, 
typically from door sill to frame header. (Imperial Brown, No. 15 at 
p. 1)
---------------------------------------------------------------------------

    AHRI stated that the current area cut-off of 4 feet by 8 feet is 
sufficient for distinguishing between passage and freight doors. AHRI 
stated that there are no specific dimensions that distinguish freight 
from passage doors and that the dimensions tend to be application 
specific. AHRI also commented that generally the height of passage and 
freight doors are similar, but that the width varies. (AHRI, No. 11 at 
p. 3)
    Regarding other characteristics that may distinguish passage and 
freight doors, both Anthony and Hussmann stated that they define 
passage doors and freight doors by whether the door is provided for 
personnel access to the WICF (i.e., passage doors) or provided for 
stocking of product with the use of equipment (i.e., freight doors). 
(Anthony, No. 8 at p. 2; Hussmann, No. 18 at pp. 3-4) Hussmann stated 
that passage doors must be large enough for individuals to pass through 
and meet requirements established by the Americans with Disabilities 
Act (``ADA''). (Hussmann, No. 18 at pp. 3-4)
    Regarding non-display doors that contain multiple openings, AHRI 
and Hussmann commented that it is not necessary to change how non-
display doors with multiple openings are classified. (AHRI, No. 11 at 
p. 3; Hussmann, No. 10 at p. 4) Imperial Brown stated that non-display 
doors with multiple openings should be considered freight doors only if 
they have an unobstructed WIC by HIC (i.e., there are no mullions in 
the opening) that meets the freight door dimensional requirements. 
(Imperial Brown, No. 15 at p. 1)
    Considering the comments received, DOE is not proposing to revise 
the definition of ``freight door'' at this time.
    DOE is proposing to define the term ``non-display door.'' Although 
the test procedures outlined in 10 CFR 431.304 and appendices A and B 
use the term ``non-display door,'' it is not currently defined. The 
proposed definition would provide that a ``non-display door'' would 
mean a door that is not a display door.
    Based on the input it has received, DOE has tentatively determined 
that differentiating walk-in doors based on opening characteristics 
would better align with industry terminology. Therefore, DOE is 
proposing to define three terms, which include some industry 
terminology identified in NFRC 100, to further differentiate among both 
display and non-display doors: ``Hinged vertical door,'' ``roll-up 
door,'' and ``sliding door'' (see proposed definitions set out in the 
regulatory text at the end of the document, proposed Sec.  431.302).
    Issue 2: DOE requests feedback on the proposed changes to the 
definition of ``door'' and the newly proposed definition for ``door 
leaf.'' DOE also seeks comment on the newly proposed definitions for 
certain door opening characteristics: ``Hinged vertical door,'' ``roll-
up door,'' and ``sliding door.''
c. High-Temperature Refrigeration Systems
    As discussed previously, DOE has granted several manufacturers 
waivers and interim waivers from the test procedure in subpart R, 
appendix C, for basic models of refrigeration systems marketed as wine 
cellar refrigeration systems (see section III.A.1.d). These 
manufacturers stated that walk-ins used for wine storage are intended 
to operate at a temperature range of 45 to 65 [deg]F and 50-70 percent 
relative humidity, rather than the 35 [deg]F and less than 50 percent 
relative humidity test condition prescribed in subpart R, appendix C.
    In the June 2021 RFI, DOE requested comment on how refrigeration 
systems marketed as wine cellar refrigeration systems should be defined 
to best represent the conditions under which these systems are designed 
to operate. 86 FR 32332, 32334-32335. AHRI, Lennox, and the CA IOUs 
recommended that DOE adequately define refrigeration systems marketed 
as wine cellar refrigeration systems and evaluate them as a separate 
efficiency class. (Lennox, No. 9 at p. 6; AHRI, No. 11 at p. 11; CA 
IOUs, No. 14 at pp. 3-4) AHRI and Hussmann suggested that refrigeration 
systems marketed as wine cellar refrigeration systems be defined as an 
enclosed storage space designed to be cooled to between 45 [deg]F and 
65 [deg]F with a relative humidity range of 50 percent to 70 percent, 
and typically kept at 55 [deg]F and 55% RH. (AHRI, No. 11 at p. 2; 
Hussmann, No. 18 at p. 3) Daikin stated that refrigeration systems 
marketed as wine cellar refrigeration systems operate between 37.4 
[deg]F and 68 [deg]F, and between 70% and 85% relative humidity. 
(Daikin, No. 17 at p. 2)
    In the June 2021 RFI, DOE also requested feedback on walk-in 
applications other than wine cellar cooling that may have a target room 
temperature of 35 [deg]F and higher. 86 FR 32332, 32334-32335. Lennox, 
AHRI and Hussmann each stated that wine cellars are the only walk-in 
applications with a temperature range between 45 [deg]F and 65 [deg]F 
and with a relative humidity between 50 percent and 70 percent. 
(Lennox, No. 9 at p. 2; AHRI, No. 11 at p. 2; Hussmann, No. 18 at pp. 
2-3) Daikin stated by way of example that florist coolers operate at 68 
[deg]F and between 90% to 95% humidity. (Daikin, No. 17 at p. 2)
    DOE understands from these comments that there are walk-in 
applications other than wine cellars that require cooling to 
temperatures higher than 35 [deg]F. To provide for testing of such 
walk-ins using test conditions that result in measurements of energy 
use in a representative average-use cycle DOE proposes to define walk-
ins designed to operate at cooling temperatures above 45 [deg]F as 
employing a ``high-temperature refrigeration system''--which would mean 
a walk-in refrigeration system which is not designed to operate below 
45 [deg]F.'' The proposed definition would provide for the testing of 
such units using specified conditions representative of their average 
use, i.e., cooling the refrigerated space to a temperature above 45 
[deg]F. See the corresponding test procedure provisions proposed in 
section III.G.6 for further details.
d. Ducted Fan Coil Units
    DOE has granted waivers to Air Innovations, Vinotheque, Cellar Pro, 
and Vinotemp, and an interim waiver to LRC Coil for walk-ins that are 
marketed

[[Page 23931]]

as wine cellar refrigeration systems that are designed and marketed as 
ducted units. (See Table III.2) The definitions for single-packaged 
units and unit coolers currently exclude ducted units, resulting in the 
lack of a test procedure for such units. 10 CFR 431.302. Specifically, 
the current single-packaged unit definition excludes units with ``any 
element external to the system imposing resistance to flow of the 
refrigerated air.'' Similarly, the current unit cooler definition 
specifically excludes units with ``element[s] external to the cooler 
imposing air resistance.'' Id.
    In the June 2021 RFI, DOE requested comment on changing the 
``single-packaged dedicated system'' and ``unit cooler'' definitions to 
address units that are designed to be installed with ducts. 86 FR 
32332, 32346. Lennox and AHRI both stated that the ASHRAE 210P 
committee \12\ is working to define a ``ducted unit cooler'' and is 
currently considering defining it as ``an assembly, including means for 
forced air circulation, capable of moving air against both internal and 
non-zero external flow resistance, and elements by which heat is 
transferred from air to refrigerant to cool the air, with provision for 
ducted installation.'' (Lennox, No. 9 at p. 6; AHRI, No. 11 at p. 11) 
Lennox and AHRI both urged DOE to work with the ASHRAE 210P committee 
to find an appropriate solution. (Lennox, No. 9 at p. 7; AHRI, No. 11 
at p. 12)
---------------------------------------------------------------------------

    \12\ The American Society of Heating, Refrigerating and Air-
Conditioning Engineers (``ASHRAE'') has formed the ASHRAE Standard 
Project Committee 210 (``ASHRAE 210P'') to evaluate and revise its 
``Method of Testing and Rating Commercial Walk-in Refrigerators and 
Freezers.'' See spc210.ashraepcs.org/.
---------------------------------------------------------------------------

    To clarify that refrigeration systems that have provision for 
ducted installation are indeed included in the DOE test procedure, DOE 
is proposing an appropriate term and a definition for the term ``ducted 
unit cooler'' mentioned by commenters and is also proposing to revise 
the definition for single-packaged dedicated system to clarify that 
such a system can have provision for ducted installation. DOE proposes 
to adopt the new term, ``ducted fan-coil unit,'' which would be defined 
as an assembly including means for forced air circulation capable of 
moving air against both internal and non-zero external flow resistance, 
and elements by which heat is transferred from air to refrigerant to 
cool the air, with provision for ducted installation. DOE is also 
proposing to revise the current single-packaged dedicated system 
definition to mean a refrigeration system (as defined in 10 CFR 
431.302) that is a single-packaged assembly that includes one or more 
compressors, a condenser, a means for forced circulation of 
refrigerated air, and elements by which heat is transferred from air to 
refrigerant.
    Issue 3: DOE requests comment on the proposed definition of 
``ducted fan coil unit'' and on the proposed modification to the 
``single-packaged dedicated system'' definition.
e. Multi-Circuit Single-Packaged Refrigeration Systems
    As discussed in section III.A.1.c, DOE is proposing to include a 
test procedure for evaluating the energy consumption of single-packaged 
units that contain multiple refrigeration circuits. As discussed, these 
units differ from larger multi-circuit refrigeration systems in that 
the refrigeration circuits are housed within an assembly and share a 
single condenser and a single evaporator. DOE proposes to define a 
``multi-circuit single-packaged refrigeration system'' as a single-
packaged dedicated system (as defined in 10 CFR 431.302) that contains 
two or more refrigeration circuits that refrigerate a single stream of 
circulated air.
    Issue 4: DOE requests comment on the proposed definition for multi-
circuit single-packaged dedicated refrigeration systems.
f. Attached Split Systems
    DOE is aware of some refrigeration systems that are sold as matched 
pairs in which the dedicated condensing unit and unit cooler are 
permanently attached to each other with structural beams. When these 
units are mounted to the refrigerated box, these beams extend through 
the wall of the walk-in, connecting the unit cooler inside the 
refrigerated box with the dedicated condensing unit outside the 
refrigerated box. The functionality of an attached split system may be 
similar to that of a matched pair system but may also have similarities 
to a single-packaged dedicated system, since they are single 
assemblies. The DOE test procedure does not currently define such 
systems, nor does it provide any unique test provisions for them--
thereby affecting the ability of manufacturers to provide test results 
reflecting the energy efficiency of this equipment during a 
representative average use cycle. DOE discusses its proposal for 
testing such units in section III.G.4 of this document. DOE has 
initially determined that attached split systems are a type of matched 
pair system and proposes to define these systems as matched pair 
refrigeration systems designed to be installed with the evaporator 
entirely inside the walk-in enclosure and the condenser entirely 
outside the walk-in enclosure, and the evaporator and condenser are 
permanently connected with structural members extending through the 
walk-in wall.
    Issue 5: DOE requests comment on the proposed definition for 
attached split system.
g. Detachable Single-Packaged System
    DOE is aware of some refrigeration systems that are designed to be 
installed with the evaporator unit exchanging air through the wall or 
ceiling of the walk-in as would be the case in a single-packaged 
system, but with the condensing unit installed either next to the 
evaporator unit or installed remotely and connected to the evaporator 
with refrigerant lines as is done in split systems. The current DOE 
test procedure does not define such systems or provide testing 
provisions specific to this configuration. DOE discusses its proposal 
for testing such units in section III.G.3 of this document. DOE has 
initially determined that these units are a type of single-packaged 
dedicated system, and proposes to define a detachable single-packaged 
system as a system consisting of a dedicated condensing unit and an 
insulated evaporator section in which the evaporator section is 
designed to be installed external to the walk-in enclosure and 
circulating air through the enclosure wall, and the condensing unit is 
designed to be installed either attached to the evaporator section or 
mounted remotely with a set of refrigerant lines connecting the two 
components.
    Issue 6: DOE requests comment on the proposed definition for 
detachable single-packaged dedicated system.
h. CO<INF>2</INF> Unit Coolers
    As discussed in section III.A.1.b, DOE is proposing to adopt test 
procedures for unit coolers designed for use in CO<INF>2</INF> 
refrigeration systems, these proposals are discussed in detail in 
section III.F.6 of this document. CO<INF>2</INF> systems are designed 
and built to operate using CO<INF>2</INF> as a refrigerant, which has 
the potential to reach pressures much higher than conventional 
refrigerants. With the air enthalpy test method, CO<INF>2</INF> single-
packaged refrigeration systems would use the same test methods as 
conventional-refrigerant single-packaged dedicated systems (see DOE's 
proposal discussed in section III.G.2.f). However, the proposed test 
procedure for CO<INF>2</INF> unit coolers would alter the inlet 
refrigerant test conditions as compared to conventional refrigerants 
(see section III.F.6). To clarify the scope

[[Page 23932]]

of the proposed unit cooler test procedure, DOE is proposing to define 
a CO<INF>2</INF> unit cooler as one that includes a nameplate listing 
only CO<INF>2</INF> as an approved refrigerant.
    Issue 7: DOE requests comment on the proposed definition of 
CO<INF>2</INF> unit coolers. DOE also requests comment on whether any 
distinguishing features of CO<INF>2</INF> unit coolers exist that could 
reliably be used as an alternative approach that can differentiate them 
from those unit coolers intended for use with conventional 
refrigerants.
i. Hot Gas Defrost
    As discussed previously, DOE published a final rule that amended 
the test procedure to rate hot gas defrost unit coolers using the 
modified default values for energy use and heat load contributions in 
AHRI 1250-2020. 86 FR 16027. At that time, DOE did not adopt a 
definition for ``hot gas defrost.'' However, as discussed in more 
detail in section III.G.8.b, DOE is proposing that equipment with hot 
gas defrost installed at the factory may be marketed using 
representations of performance with hot gas defrost activated. This 
would be a voluntary representation by the manufacturer. To ensure that 
the scope of this voluntary representation is clear, DOE is proposing 
to define ``hot gas defrost'' as a factory-installed system where 
refrigerant is used to transfer heat from ambient outside air, the 
compressor, and/or a thermal storage component that stores heat when 
the compressor is running and uses this stored heat to defrost the 
evaporator coils.
    Issue 8: DOE requests comment on the proposed definition for hot 
gas defrost. Specifically, DOE requests comment on if this proposed 
definition is sufficient to identify which equipment is sold with hot 
gas defrost capability installed and which is not.

B. Industry Standards

    The current DOE test procedure for walk-in coolers and freezers 
incorporates the following industry test standards: NFRC 100-2010 into 
appendix A; ASTM C518 into appendix B; and AHRI 1250-2009, AHRI 420-
2008,\13\ and ASHRAE 23.1-2010 \14\ into subpart R, appendix C. The 
following sections detail the industry standards DOE is proposing to 
incorporate by reference in the NOPR and the relevant provisions of 
those industry standards that DOE is proposing to adopt.
---------------------------------------------------------------------------

    \13\ AHRI 420-2008, ``Performance Rating of Forced-Circulation 
Free-Delivery Unit Coolers for Refrigeration'' (``AHRI 420-2008'').
    \14\ ANSI/ASHRAE 23.1-2010, ``Methods of Testing for Rating the 
Performance of Positive Displacement Refrigerant Compressors and 
Condensing Units that Operate at Subcritical Temperatures of the 
Refrigerant'' (``ASHRAE 23.1-2010'').
---------------------------------------------------------------------------

1. Standards for Determining Thermal Transmittance (U-Factor)
    Appendix A references NFRC 100 as the method for determining the U-
factor of doors and display panels. NFRC 100 allows for computational 
determination of U-factor by simulating U-factor using Lawrence 
Berkeley National Lab's (``LBNL'') WINDOW and THERM software, provided 
that the simulated value for the baseline product in a product line is 
validated with a physical test of that baseline product and the 
simulated value is within the accepted agreement with the physical test 
value as specified in section 4.7.1 of NFRC 100.\15\ Section 4.3.2.1 of 
NFRC 100 references NFRC 102-2010, ``Procedure for Measuring the Steady 
state Thermal Transmittance of Fenestration Systems'' (``NFRC 102-
2010''), as the physical test procedure for determining U-factor. NFRC 
102-2010 is based on ASTM C1199-09, ``Standard Test Method for 
Measuring the Steady state Thermal Transmittance of Fenestration 
Systems Using Hot Box Methods'' (``ASTM C1199-09'') with some 
modifications.
---------------------------------------------------------------------------

    \15\ Section 4.7.1 of NFRC 100 requires that the accepted 
difference between the tested U-factor and the simulated U-factor be 
(a) 0.03 Btu/(h-ft\2\-[deg]F) for simulated U-factors that are 0.3 
Btu/(h-ft\2\-[deg]F) or less, or (b) 10 percent of the simulated U-
factor for simulated U-factors greater than 0.3 Btu/(h-ft\2\-
[deg]F). This agreement must match for the baseline product in a 
product line. Per NFRC 100, the baseline product is the individual 
product selected for validation; it is not synonymous with ``basic 
model'' as defined in 10 CFR 431.302.
---------------------------------------------------------------------------

    Since DOE adopted this test procedure for determining U-factor of 
doors and display panels in 2011, NFRC has published updates to NFRC 
102, the most recent being NFRC 102-2020, which supersedes all previous 
versions of NFRC 102. The following are the identified substantive 
changes and additions in NFRC 102-2020 as compared to NFRC 102-2010, 
which is referenced in the current Federal test procedure via NFRC 100-
2010:
    1. Added a list of required calibrations for primary measurement 
equipment, including metering box wall transducer and surround panel 
flanking loss characterization and annual verification procedure, and 
incorporated a calibration transfer standard (``CTS'') calibration 
continuous characterization procedure; and
    2. The provisions regarding air velocity distribution were revised 
to be more specific to the type of fans used.
    Additionally, NFRC 102-2020 references the updated version of ASTM 
C1199 (ASTM C1199-14) instead of ASTM C1199-09. Based on a review of 
ASTM C1199-14, DOE has tentatively determined that the differences 
between editions are editorial.
    DOE is proposing to adopt by reference in appendix A, the following 
sections of NFRC 102-2020 for determining U-factor:
    <bullet> 2. Referenced Documents,
    <bullet> 3. Terminology,
    <bullet> 5. Apparatus,
    <bullet> 6. Calibration,
    <bullet> 7. Experimental Procedure (excluding 7.3. Test 
Conditions),
    <bullet> 8. Calculation of Thermal Transmittance,
    <bullet> 9. Calculation of Standardized Thermal Transmittance,
    <bullet> Annex A1. Calibration Transfer Standard Design,
    <bullet> Annex A2. Radiation Heat Transfer Calculation Procedure, 
and
    <bullet> Annex A4. Garage Panel and Rolling Door Installation.
    DOE is also proposing to incorporate by reference ASTM C1199-14, as 
it is referenced in NFRC 102-2020. Specifically, in the proposed test 
procedure in appendix A, DOE is proposing to reference the following 
sections of ASTM C1199-14 as referenced through NFRC 102-2020: Sections 
2, 3, 5, 6, 7 (excluding 7.3), 8, 9, and Annexes A1 and A2. DOE is not 
proposing to reference any other sections of NFRC 102-2020 or ASTM 
C1199-14 as they either do not apply or they are in direct conflict 
with other test procedure provisions included in the subpart R.
2. Standard for Determining R-Value
    As mentioned previously, section 4.2 of appendix B references ASTM 
C518 to determine the thermal conductivity, or K-factor, of panel 
insulation. EPCA requires that the measurement of the K-factor used to 
calculate the R-value be based on ASTM C518-2004 (``ASTM C518-04''). 
(42 U.S.C. 6314(a)(9)(A)(ii)) In December 2015, ASTM published a 
revision of this standard (``ASTM C518-15''). ASTM C518-15 removed 
references to ASTM Standard C1363, ``Test Method for Thermal 
Performance of Building Materials and Envelope Assemblies by Means of a 
Hot Box Apparatus'' (``ASTM C1363''), and added references to ASTM 
Standard E456, ``Terminology Relating to Quality and Statistics.'' 
Additionally, ASTM C518-15 relies solely on the International System of 
Units (``SI units''), with paragraph 1.13 clarifying that these SI unit 
values are to be regarded as standard. In July 2017, ASTM published 
another revision of ASTM C518 (``ASTM C518-17''). ASTM

[[Page 23933]]

C518-17 added a summary of precision statistics from an interlaboratory 
study from 2002-2004 in section 10 ``Precision and Bias.''
    As part of the June 2021 RFI, DOE requested comment on what issues, 
if any, would be present if DOE were to adopt the most current version 
of the standard, ASTM C518-17, for measuring panel K-factor. 86 FR 
32332, 32336. NFRC stated that the updates to ASTM C518-17 as compared 
to what is in ASTM C518-04 would have no substantial impact on the 
results of testing and no impact on test burden. NFRC also stated that 
adopting ASTM C518-17 would bring DOE test procedures in line with 
current industry methods and practice. (NFRC, No. 10 at p. 2) DOE did 
not receive any additional comments on potentially adopting ASTM C518-
17 for measuring panel K-factor.
    DOE has tentatively determined that the updates to ASTM C518-2004 
(the version of the industry test procedure specified by EPCA as the 
basis for calculating the K-factor) made in 2015 and 2017 do not 
substantively change the test method nor would adoption of the latest 
version in the DOE test procedure increase test burden. Therefore, DOE 
is proposing to amend its test procedure for determining R-value of 
insulation for non-display doors and panels by incorporating by 
reference ASTM C518-17. Specifically, in the proposed test procedure in 
appendix B, DOE is proposing to reference the following sections of 
ASTM C518-17:
    <bullet> 2. Referenced Documents,
    <bullet> 3. Terminology,
    <bullet> 5. Apparatus,
    <bullet> 6. Calibration,
    <bullet> 7. Test Procedures (excluding 7.3. Specimen Conditioning),
    <bullet> 8. Calculation, and
    <bullet> Annex A1. Equipment Design.
    DOE is not proposing to reference any other sections of ASTM C518-
17 as they either do not apply or they are in direct conflict with 
other test procedure provisions included in subpart R. As ASTM C518-17 
is an updated version of ASTM C518-2004, the DOE test procedure for 
determining the K-value remains based on ASTM C518-2004.
3. Standards for Determining AWEF
    DOE's current test procedure for WICF refrigeration systems is 
codified in appendix C to subpart R of part 431 and incorporates by 
reference AHRI 1250-2009, AHRI 420-2008, and ASHRAE 23.1-2010. AHRI 
1250-2009 is the industry test standard for refrigeration systems for 
walk-in coolers and freezers, including unit coolers and dedicated 
condensing units sold separately, as well as matched pairs. 81 FR 
95758, 95798.\16\ The procedure describes the method for measuring the 
refrigeration capacity and the electrical energy consumption for a 
condensing unit and a unit cooler, including off-cycle fan and defrost 
subsystem contributions. Using the refrigeration capacity and 
electrical energy consumption, AHRI 1250-2009 provides a calculation 
methodology to compute AWEF, the applicable energy-performance metric 
for refrigeration systems.
---------------------------------------------------------------------------

    \16\ Available at www.ahrinet.org. AHRI 1250-2009 incorporates 
by reference AHRI 420-2008 for testing of unit coolers and ASHRAE 
23-2005 for testing of dedicated condensing units. DOE has updated 
the reference for the latter test standard to ASHRAE 23.1-2010.
---------------------------------------------------------------------------

    The DOE test procedure for walk-in refrigeration systems adopts by 
reference the test procedure in AHRI 1250-2009 (excluding Tables 15 and 
16), with certain enumerated modifications. Generally, DOE's 
modifications to AHRI 1250-2009 address specific test conditions, 
tolerances, and instrumentation requirements, as well as specific 
instructions for how to address defrost energy use, unit coolers tested 
alone, and dedicated condensing units tested alone. See appendix C to 
subpart R of part 431.
    In 2014, AHRI published an update to AHRI Standard 1250 (``AHRI 
1250-2014'') which supersedes AHRI 1250-2009. After publication of AHRI 
1250-2014, DOE and other stakeholders supported the AHRI 1250 committee 
in its update of AHRI Standard 1250. Subsequently, in April 2020, AHRI 
published AHRI 1250-2020, which supersedes AHRI 1250-2014. AHRI 1250-
2020 incorporates many of the modifications and additions to AHRI 1250-
2009 that DOE currently prescribes in its test procedure. It also 
includes test methods for unit coolers and dedicated condensing units 
tested alone, rather than incorporating by reference updated versions 
of AHRI 420-2008 and/or ASHRAE 23.1-2010, and also includes test 
methods for single-packaged dedicated systems. Sections III.B.3.a to 
III.B.3.d detail the changes made to AHRI 1250-2020 as compared to AHRI 
1250-2009.
    In the June 2021 RFI, DOE requested comment on what issues, if any, 
would be present if DOE were to adopt AHRI 1250-2020 into the DOE test 
procedure. 86 FR 32332, 32336. The CA IOUs and NEEA stated their 
general support for the adoption of AHRI 1250-2020. (CA IOUs, No. 14 at 
p. 1; NEEA, No. 16 at pp. 1-2) Lennox, AHRI, and Hussmann supported the 
adoption of AHRI 1250-2020 with some reservations associated with the 
retest burden it may create. (Lennox, No. 9 at p. 2; AHRI, No. 11 at p. 
4; Hussmann, No. 18 at p. 6) Lennox, AHRI, and Hussmann asked DOE to 
evaluate if a full revision of the test standards was appropriate at 
this time. (Lennox, No. 9 at p. 2; AHRI, No. 11 at p. 4; Hussmann, No. 
18 at p. 6) DOE acknowledges the potential burden of a new test 
procedure and notes that a full cost evaluation of the proposed test 
procedure changes has been conducted and is discussed in section III.J. 
Therefore, DOE is proposing two sets of changes for the refrigeration 
system test procedure. One set of changes would be included as proposed 
revisions to subpart R, appendix C, and the other group would be 
proposed through the establishment of an appendix C1. DOE has 
tentatively determined that the changes to subpart R, appendix C, would 
not affect AWEF ratings and therefore not require retesting or 
recertification. These proposed changes, if adopted, would be required 
180 days after the test procedure final rule is published. DOE has also 
tentatively determined that the proposed provisions included in 
appendix C1 would affect the determination of energy use and would 
therefore require retesting and recertification of the proposed AWEF2. 
The provisions proposed in appendix C1, if adopted, would be required 
to be followed in conjunction with the compliance date of any amended 
energy conservation standards that DOE may end up adopting as part of a 
separate standards rulemaking.
    In this test procedure NOPR DOE is proposing to reference AHRI 
1250-2020 for use in appendix C1, but excluding:
    <bullet> Section 1 Purpose,
    <bullet> Section 2 Scope,
    <bullet> Section 9 Minimum Data Requirements for Published Ratings,
    <bullet> Section 10 Marking and Nameplate Data,
    <bullet> Section 11 Conformance Conditions, and
    <bullet> Section C10.2.1.1 Test Room Conditioning Equipment under 
section C10--Defrost Calculation and Test Methods.
    DOE is not proposing to reference these sections of AHRI 1250-2020 
since they either do not apply or conflict with other test procedure 
provisions included in the proposed appendix C1. Additionally, DOE is 
not proposing to reference ASHRAE 23.1-2010 or AHRI 420-2008 in the 
proposed appendix C1, as the materials referenced in these standards by 
AHRI 1250-2009 are now included within AHRI 1250-2020.

[[Page 23934]]

    Further, DOE is proposing to reference ASHRAE 16-2016 in the 
proposed appendix C1, as it is referenced in AHRI 1250-2020, but 
excluding:
    <bullet> Section 1 Purpose
    <bullet> Section 2 Scope
    <bullet> Section 4 Classifications
    <bullet> Normative Appendices E-M
    <bullet> Informative Appendices N-R
    DOE is not proposing to reference these sections of ASHRAE 16-2016 
as they either do not apply or conflict with other test procedure 
provisions that would be included as part of the newly proposed 
appendix C1.
    Similarly, DOE is proposing to reference ASHRAE 37-2009 in the 
proposed appendix C1, as it is referenced in AHRI 1250-2020, but 
excluding:
    <bullet> Section 1 Purpose,
    <bullet> Section 2 Scope,
    <bullet> Section 4 Classifications,
    <bullet> Informative appendix A Classifications of Unitary Air-
conditioners and Heat Pumps.
    DOE is not proposing to reference these sections of ASHRAE 37-2009 
as they either do not apply or conflict with other test procedure 
provisions that would be included as part of the newly proposed 
appendix C1.
a. Changes Consistent With Subpart R, Appendix C
    As mentioned previously, AHRI 1250-2020 incorporates many of the 
modifications and additions to AHRI 1250-2009 that DOE currently 
prescribes in its test procedure. The modifications in the following 
sections of subpart R, appendix C, were incorporated into AHRI 1250-
2020. Thus, if DOE were to adopt AHRI 1250-2020, DOE would remove the 
following sections from subpart R, appendix C:
    <bullet> Section 3.1.1, which modifies Table 1 (Instrumentation 
Accuracy) in AHRI 1250-2009;
    <bullet> Section 3.1.2, which provides guidance on electrical power 
frequency tolerances;
    <bullet> Section 3.1.3, which states that in Table 2 of AHRI 1250-
2009, the test operating tolerances and test condition tolerances for 
air leaving temperatures shall be deleted;
    <bullet> Section 3.1.4, which states that in Tables 2 through 14 in 
AHRI-1250-2009, the test condition outdoor wet bulb temperature 
requirement and its associated tolerance apply only to units with 
evaporative cooling;
    <bullet> Section 3.1.5, which provides tables to use in place of 
AHRI 1250-2009 Tables 15 and 16, which are excluded from the IBR in 10 
CFR 431.303. The update in AHRI 1250-2020 to Tables 15 and 16 would 
allow DOE to incorporate the AHRI 1250-2020 tables by reference if DOE 
were to adopt AHRI 1250-2020;
    <bullet> Section 3.2.1, which provides specific guidance on how to 
measure refrigerant temperature;
    <bullet> Section 3.2.2, which removes the requirement to perform a 
refrigerant composition and oil concentration analysis;
    <bullet> Section 3.2.4, which provides voltage requirements for 
unit cooler fan power measurements;
    <bullet> Section 3.2.5, which provides insulation and configuration 
requirements for liquid and suction lines used for testing;
    <bullet> Section 3.3.1, which gives direction for how to test and 
rate unit coolers tested alone;
    <bullet> Section 3.3.2, which clarifies that the 2008 version of 
AHRI Standard 420 should be used for unit coolers tested alone;
    <bullet> Section 3.3.3, which modifies the allowable reduction in 
fan speed for off-cycle evaporator testing;
    <bullet> Section 3.4.1, which specifies that the 2010 version of 
ASHRAE 23.1 should be used and that ``suction A'' condition test points 
should be used when testing dedicated condensing units and,
    <bullet> Section 3.5, which provides guidance on how to rate 
refrigeration systems with hot gas defrost.
    The entirety of section 3.4.2 of subpart R, appendix C, which 
provides instruction on how to calculate AWEF and net capacity for 
dedicated condensing units, would also be removed if AHRI 1250-2020 
were to be adopted, but the text in AHRI 1250-2020 that would replace 
it alters the text currently in section 3.4.2, which would result in a 
change to the current test procedure.
b. CFR Language Not Adopted in AHRI 1250-2020
    As mentioned previously, AHRI 1250-2020 incorporates many, but not 
all, of the modifications and additions to AHRI 1250-2009 that DOE 
currently prescribes in its test procedure. For example, section 3.2.3, 
which modifies the requirements in Section C3.4.5 of AHRI 1250-2009 to 
require only a sight glass and a temperature sensor located on the tube 
surface under the insulation to verify sub-cooling downstream of mass 
flow meters, was not incorporated into AHRI 1250-2020. DOE is 
proposing, however, to carry over this section into the newly proposed 
appendix C1.
    With respect to other current sections in subpart R, appendix C, 
sections that were not adopted by AHRI 1250-2020, DOE is proposing to 
revise those sections as part of this NOPR in the following manner:
    <bullet> Sections 3.3.4 and 3.3.5, which modify the defrost test 
procedure in AHRI 1250-2009, would not be carried over into the newly 
proposed appendix C1. This NOPR proposes a revised approach to account 
for defrost heat load and energy use. This topic and DOE's proposals 
are discussed in sections III.G.8.a and III.G.8.b; and
    <bullet> Section 3.3.7, which provides guidance on how to rate 
refrigeration systems with variable-speed evaporator fans would also 
not be carried over into the newly proposed appendix C1.
c. Changes That May Impact the Determination of AWEF
    Several changes in AHRI 1250-2020 may impact the AWEF calculation. 
These changes can be grouped into five categories, discussed in the 
following paragraphs: Off-cycle tests, single-packaged dedicated 
systems, defrost calculations, variable capacity, and unit coolers.
Off-Cycle Tests
    AHRI 1250-2020 updated the off-cycle tests in Sections C3.5 and 
C4.2 such that the total input wattage of the test unit is measured 
during the off cycle, rather than just the unit cooler fan input 
wattage. This change accounts for ancillary power from components such 
as crank case heaters and would deliver more representative off-cycle 
power results. As a result, if DOE were to incorporate this provision 
into its test procedure, it would affect the AWEF measurement for 
dedicated condensing units, matched pairs, and single-packaged 
dedicated systems by accounting for additional energy usage in the 
measured off-cycle power consumption value. In addition, updates made 
in AHRI 1250-2020 require that the measurement of unit cooler off-cycle 
power include the total electric power input to pan heaters and 
controls as well as the fan motors. AHRI 1250-2020 requires that off-
cycle fan speed be at least 50% of full speed or that duty cycle for 
cycling fans be at least 50%, consistent with the current requirements 
of section 3.3.3 of subpart appendix C.
Single-Packaged Units
    AHRI 1250-2020 added Section C9.1, which includes test methods for 
single-packaged refrigeration units. These methods allow for testing of 
single-packaged units with indoor and outdoor air enthalpy methods as 
specified in ASHRAE 37 and ASHRAE 16. These methods account for the 
heat leakage

[[Page 23935]]

that single-packaged dedicated systems are prone to experience by 
design. The inclusion of this heat leakage would lower single-packaged 
dedicated systems' net capacities and therefore lower their AWEFs. It 
would also make their net capacities more representative of field 
performance.
Defrost Calculations
    AHRI 1250-2020 combined the defrost calculations and test methods 
into Section C10 to AHRI 1250-2020. For systems using electric defrost, 
the defrost calculations for defrost heat contributed to the box load 
(Q<INF>DF</INF>) have been changed to three different equations 
depending on the system's gross capacity. In addition, new calculation 
methods for estimating the defrost energy of units with hot gas defrost 
have been added. The new default equations for electric and hot gas 
defrost heat and energy contributions are based on testing and analysis 
work conducted by AHRI and DOE, and therefore these values are expected 
to be more representative than previous equations for the default 
values.
    AHRI 1250-2020 also added two optional challenge \17\ tests for 
adaptive and hot gas defrost in appendices E and F, respectively. Both 
tests evaluate whether a unit has a system that functions as either an 
adaptive or hot gas defrost system. For compliance purposes, DOE 
requires that units are tested without activating adaptive defrost or 
hot gas defrost; therefore, neither challenge test included in AHRI 
1250-2020 would affect the calculation of AWEF. The defrost challenge 
tests and calculations are discussed in detail in sections III.G.8.a, 
and III.G.8.b of this document.
---------------------------------------------------------------------------

    \17\ The defrost challenge tests included in AHRI 1250-2020 are 
informative test methods that provide validation that defrost is 
occurring as would be expected in Appendix E for adaptive defrost 
control systems and in Appendix F for hot gas defrost systems. 
Neither challenge test is designed to quantify the energy use of the 
defrost system, but are intended to validate defrost system 
functionality.
---------------------------------------------------------------------------

d. Additional Amendments
    In addition to those changes enumerated in sections III.B.3.a 
through III.B.3.c of this document, AHRI 1250-2020 includes additional 
amendments that are inconsistent with the current DOE test procedure 
and would not be expected to impact calculated AWEF. This section 
discusses those changes.
    AHRI 1250-2020 added exclusions for liquid-cooled condensing 
systems in section 2.2.4. and excludes systems that use carbon dioxide, 
glycol, or ammonia as refrigerants in section 2.2.5. The current DOE 
test procedure is neutral with respect to refrigerant, and DOE 
considers all walk-in refrigeration systems to be covered equipment 
regardless of the refrigerant used. However, DOE recognizes that 
modifications may be necessary to the test method for different 
refrigerants (for example, see discussion in section III.F.6 for 
CO<INF>2</INF>).
    As discussed in section III.B.3.a, AHRI 1250-2020 updated many of 
the tolerances in Table 2 of section 4. Some of these updates are not 
included in the current CFR language. DOE proposes to adopt the 
tolerances in AHRI 1250-2020, Table 2 of section 4 in subpart R, 
appendix C. As discussed later, DOE expects that the updated tolerance 
values would improve the repeatability of the test procedure with no 
impact on test cost.
    AHRI 1250-2020 includes an updated list of references and the 
applicable versions of certain test standards in appendix A, 
``References--Normative.'' DOE proposes to reference AHRI 1250-2020 
appendix A in subpart R, appendix C. DOE expects that this modification 
would have no impact on test cost, while ensuring that more recent test 
standards are referenced.
    Both AHRI 1250-2009 appendix C and AHRI 1250-2020 appendix C 
provide specific test methods for testing walk-in cooler and freezer 
systems, whereas the body of the standard specifies test requirements 
and calculations for walk-in box load and for determining AWEF. 
Additionally, AHRI 1250-2020 includes the following updated provisions: 
Section C3 of AHRI 1250-2009 lists requirements for measuring 
temperature (Section C3.1), measuring pressure (Section C3.2), 
measuring refrigerant properties (Section C3.3), determining 
refrigerant flow (Section C3.4), determining unit cooler fan power 
(Section C3.5), and specifies measurement and recording intervals 
(Section C3.6). In AHRI 1250-2020, Section C3 has been expanded to 
include requirements for measuring off-cycle power (Section C3.5) and 
determining steady state refrigeration capacity and energy consumption 
(Section C3.6), which are applicable to all tests unless otherwise 
specified. Aside from single-packaged dedicated system tests and the 
off-cycle power tests discussed in the previous section and in Sections 
III.G.2 and III.G.1, respectively, of this document, DOE does not 
expect that the revisions made to Section C3 in AHRI 1250-2020 would 
impact test duration and is therefore proposing to incorporate these 
sections (except for Section C3.5) \18\ into subpart R, appendix C.
---------------------------------------------------------------------------

    \18\ DOE is proposing to incorporate Section C3.5 of AHRI 1250-
2020 appendix C as a part of the new appendix C1.
---------------------------------------------------------------------------

    Sections C3.1.3.1, C3.1.3.2, and C3.1.3.3 of AHRI 1250-2020 
specified refrigerant temperature measurement locations for unit 
coolers tested alone, matched pairs, and dedicated condensing systems 
tested alone. Specific changes include:
    <bullet> For unit coolers tested alone: Refrigerant entering 
temperature is measured within six pipe diameters upstream of the 
control device (Section C3.1.3.1).
    <bullet> For matched pairs, but not single-packaged dedicated 
systems: Refrigerant entering temperature is measured within the first 
six inches of the refrigerant pipe entering the unit cooler conditioned 
space, and the leaving temperature is measured within the last six 
inches of the refrigerant pipe leaving the unit cooler conditioned 
space (Section C3.1.3.2); and
    <bullet> For dedicated condensing units tested alone: Entering and 
leaving refrigerant temperatures are measured at the inlet and outlet 
of the unit using two independent measuring systems (Section C3.1.3.3).
    The modifications for measuring refrigerant temperature in AHRI 
1250-2020 are expected to improve the repeatability and reproducibility 
of the test procedure, but do not impact test setup or test duration; 
therefore, DOE is proposing to reference these sections in subpart R, 
appendix C.
    AHRI 1250-2020 added Section C7.5.1.1 to provide more detailed 
instructions for calculating system capacity beginning with measured 
temperatures instead of calculated enthalpies, which is what was done 
in AHRI 1250-2009. Section C7.5.1 also includes the determination of 
enthalpy from capacity test results.
    AHRI 1250-2020 added Section C9.2, which specifies an allowable 
heat balance of <plus-minus> 6 percent for single-packaged 
refrigeration capacity testing. AHRI 1250-2009 required a heat balance 
of <plus-minus> 5 percent for all systems. This change was made to 
align with ASHRAE 37, which AHRI 1250-2020 incorporates by reference 
for single-packaged testing.
    AHRI 1250-2009 included Section C12 ``Method of Testing Condensing 
Units for Walk-In Cooler and Freezer Systems for Use in Mix-Match 
System Ratings,'' which referenced AHRAE 23.1-2010. AHRI 1250-2020 now 
provides specific test methods for testing dedicated condensing units

[[Page 23936]]

tested alone. DOE has tentatively determined that the test procedure 
incorporated into AHRI 1250-2020 is the same as that in ASHRAE 23.1-
2010 and therefore does not impact test setup or burden. As a result, 
DOE proposes to no longer incorporate ASHRAE 23.1-2010 by reference.
    Section C13 of AHRI 1250-2009, ``Method of Testing Unit Coolers for 
Walk-In Cooler and Freezer Systems for Use in Mix-Match System 
Ratings,'' referenced AHRI 420-2008. AHRI 1250-2020 no longer 
references AHRI 420-2008 and instead outlines a method for unit coolers 
tested alone. As a result, DOE proposes to no longer incorporate AHRI 
420-2008 by reference. DOE has tentatively determined that the test 
procedure incorporated into AHRI 1250-2020 is the same as that in 
ASHRAE AHRI 420-2008 and therefore does not impact test setup or 
burden. As a result, DOE proposes to no longer incorporate AHRI 420-
2008 by reference.

C. Proposed Amendments to the Test Procedure in Appendix A for 
Measuring the Energy Consumption of Walk-in Doors

    Appendix A provides the test procedures to measure the energy 
consumption of the components of envelopes of walk-ins. Specifically, 
appendix A provides the test procedures to determine the U-factor, 
conduction load, and energy use of walk-in display panels and to 
determine the energy use of walk-in display doors and non-display 
doors. DOE notes that display panels are also subject to the energy 
consumption test procedure in appendix A. Display panels are discussed 
in section III.D of this document.
    In this NOPR, DOE is proposing to make the following revisions to 
appendix A, specific to display doors and non-display doors: (1) 
Reference NFRC 102-2020 in place of NFRC 100 and adopt AEDM provisions; 
(2) provide further detail on and distinguish the area to be used for 
determining compliance with standards and the area used to calculate a 
thermal load from U-factor; (3) establish a percent time off value 
specific to door motors; and (4) reorganize the test method so that it 
is easier to follow. The organizational changes include moving the test 
methods and measurement provisions for determining U-factor up before 
the provisions for calculating energy consumption and moving the 
percent time off values for all electrical components into a table. DOE 
has preliminarily determined that these changes would improve test 
representativeness and repeatability.
    DOE does not expect that the changes it is proposing in this 
section would have a substantive impact on energy consumption 
calculations for display doors or non-display doors, except in the case 
of testing doors with motors as described in the following paragraphs.
    The following sections describe the modifications that DOE is 
proposing to appendix A with respect to walk-in display doors and walk-
in non-display doors.
1. Procedure for Determining Thermal Transmittance (U-Factor)
a. Reference to NFRC 102 in Place of NFRC 100
    As discussed in section III.B.1 of this document, section 5.3 of 
appendix A requires manufacturers to determine thermal transmittance, 
or ``U-factor,'' according to NFRC 100. As also mentioned previously, 
NFRC 100 includes a computational method for determining U-factor, 
which involves simulating the U-factor using LBNL's WINDOW and THERM 
software. Section 4.1.1 of NFRC 100 provides validation requirements so 
that simulation, rather than a physical test, can be used for rating U-
factor for a product line. This approach may be less costly but can 
result in a different, and potentially less accurate, thermal 
transmittance value than the thermal transmittance value determined by 
physical test using NFRC 102. NFRC 100 defines a ``product line'' as a 
series of individual products of the same product type, and a ``product 
type'' as a designation used to differentiate between fenestration 
products based on fixed and operable sash and frame members. Section 
4.2.1 of NFRC 100 lists the allowable changes from product to product 
within a product line. DOE notes that ``product line'' is not 
synonymous with ``basic model'' as defined in 10 CFR 431.302. DOE 
understands that simulated U-factors of non-display doors using NFRC 
100 have generally not been accurately determined when compared to a 
physical test.
    In the June 2021 RFI, DOE noted it was considering incorporating by 
reference NFRC 102 as the test method for determining U-factor of walk-
in doors in place of NFRC 100 and adopting AEDM provisions for walk-in 
doors to replace the computational methodology in NFRC 100. 86 FR 
32332, 32336. As part of the June 2021 RFI, DOE requested comment on 
the accuracy of the computational method in NFRC 100 to predict U-
factor for display and non-display doors, the magnitude of the 
difference in U-factor determined using the computational method and 
using the physical test method, and whether the computational method 
could be modified to more closely match the results obtained from 
physical testing. DOE also sought comment on whether manufacturers are 
using the computational method in NFRC 100 to rate U-factors, whether 
there are other alternative methods for computationally determining U-
factor, and the costs associated with NFRC 100 or other computational 
methods compared to physical testing. 86 FR 32332, 32336.
    NFRC stated that the NFRC 100 computational method has been used to 
accurately simulate U-factors for display doors because the physical 
characteristics of a display door are similar to the windows and glass 
doors for which the NFRC 100 computational method was developed. NFRC 
also stated, however, that there has been limited success validating 
NFRC 100 simulations with physical tests for non-display doors because 
non-display doors, unlike windows and glass doors, have high amounts of 
insulation and significant thermal bypasses along the door perimeter. 
(NFRC, No. 10 at p. 1) Similarly, AHRI commented that while NFRC 100 is 
appropriate and accurate for display doors, it was not designed for 
non-display doors, but it is not aware of an industry test method 
better suited for non-display doors. (AHRI, No. 11 at p. 4) NFRC stated 
that while refinements to the computational method in NFRC 100 may be 
possible for more accurately determining U-factor of non-display doors, 
they have not yet been addressed due to limited usage of this method 
for specimens like non-display doors. NFRC also stated that the 
computational method does not always result in higher or more 
conservative U-factors than the U-factors determined through physical 
test, and that the test and simulation agreement vary in either 
direction. (NFRC, No. 10 at p. 1)
    Anthony and Hussmann stated that in their experience, the U-factors 
generated using the computational method in NFRC 100 generally align 
with the U-factors obtained from the physical test method, NFRC 102. 
(Anthony, No. 8 at p. 2; Hussmann, No. 18 at p. 5) Imperial Brown 
stated that it is possible to simulate U-factor of non-display doors if 
the door frame is included in the simulation and provided example 
simulation cross-sections. (Imperial Brown, No. 15 at p. 2)
    The CA IOUs recommended that the physical test method ASTM C1199 be

[[Page 23937]]

used for doors and window assemblies to provide a measured approach 
that can be compared to the current calculated method. (CA IOUs, No. 14 
at p. 5) Hussmann recommended using the computational method 
exclusively, except for the physical testing of one model per product 
line required for validation, stating that physical testing imposes an 
unnecessary burden on a manufacturer. (Hussmann, No. 18 at p. 5) 
Imperial Brown asserted that NFRC 102 is costly and time consuming to 
conduct, and that it is unrealistic to test all of the models they 
offer since the walk-in door market is highly customizable. Imperial 
Brown supported continuing to use NFRC 100 and recommended a ``safety 
factor'' be included to make up for potential inaccuracies of the 
computational method. (Imperial Brown, No. 15 at pp. 1-2)
    Anthony urged DOE to eliminate the requirement for a physical test, 
stating that there is no added value for it and that physical testing 
is more than two times the cost of the computational method. Anthony 
also stated, however, that if NFRC 100 remains the referenced industry 
test method, the test procedure should specify a course of action if 
the computational method results fall outside the 10 percent acceptance 
criteria. (Anthony, No. 8 at p. 2)
    NFRC stated that developing an AEDM would be inefficient as the 
computational method described in NFRC 100 has been shown to be 
accurate. (NFRC, No. 10 at p. 1) Additionally, NFRC estimated a cost of 
$2,000 for simulating U-factors for a typical product line of display 
doors (about 35-50 U-factor values). NFRC emphasized that there is no 
economy of scale in performing more physical tests because each sample 
must be tested on its own and requires its own specific setup and time 
to run. NFRC suggested that given the U-factors of non-display doors 
cannot typically be simulated within the agreement specified by NFRC 
100, the most economical way to determine U-factor for a product line 
would be to pick a few sizes within the range of offerings and use the 
worst-case U-factors to represent a range of sizes. (Id. At p. 2)
    In response to comments received on the accuracy of the 
computational method, DOE understands that there has been limited 
success in accurately simulating the U-factor of non-display doors 
using NFRC 100. Although stakeholders asserted that NFRC 100 can 
accurately simulate display door U-factors, the recommendation by one 
stakeholder that instruction be provided when the simulated value and 
tested value do not agree within the limits specified by NFRC 100 
suggests there may be instances when the computational method does not 
provide sufficiently accurate results. DOE recognizes that if display 
or non-display door manufacturers are unable to simulate U-factor using 
NFRC 100, they are currently required to physically test every door 
basic model, which may be unduly burdensome given the highly 
customizable nature of the market and thus high number of basic models 
to test.
    In this NOPR, DOE is proposing to remove reference to NFRC 100 from 
its test procedure and instead reference NFRC 102 and adopt provisions 
allowing manufacturers to use an AEDM. DOE emphasizes that allowing use 
of an AEDM would provide manufacturers with the flexibility to use an 
alternative method that yields the best agreement with a physical test 
for their doors. If manufacturers have had success using the 
computational method in NFRC 100, inclusion of AEDM provisions would 
enable manufacturers to continue using NFRC 100, provided that 
manufacturers meet the proposed AEDM requirements in 10 CFR 429.53 and 
10 CFR 429.70(f). Particularly, under the proposals, manufacturers 
would need to ensure that the output result of energy consumption from 
the AEDM is within the proposed 5 percent tolerance of an energy 
consumption result that includes a physical U-factor test. The proposed 
adoption of an AEDM is discussed in more detail in section III.H.1.
b. Exceptions to Industry Test Method for Determining U-Factor
    Section 5.3 of appendix A references NFRC 100 for determining U-
factor with the specific modifications to the industry standard listed 
in section 5.3(a). The first modification specifies that the average 
surface heat transfer coefficients during a test must be within <plus-
minus> 5 percent of the values specified through NFRC 100 in ASTM 
C1199. The second and third items modify the cold and warm side 
conditions from the standard conditions prescribed in NFRC 100. The 
final provision listed specifies the direct solar irradiance \19\ be 0 
Btu/(h-ft\2\).
---------------------------------------------------------------------------

    \19\ Solar irradiance is the power per unit area received from 
the sun in the form of electromagnetic radiation.
---------------------------------------------------------------------------

    As discussed in the June 2021 RFI, DOE has found that obtaining the 
standardized heat transfer values within the tolerances specified in 
section 5.3(a)(1) of appendix A on the warm-side and cold-side may not 
be achievable depending on the thermal transmittance through the door. 
86 FR 32332, 32340. Specifically, the warm-side heat transfer is 
dominated by natural convection and radiation and the heat transfer 
coefficient varies as a function of surface temperature. When testing 
doors with higher thermal resistance, less heat is transferred across 
the door from the warm-side to the cold-side, so the warm-side surface 
temperature is closer to the warm-side air temperature.
    Sections 6.2.3 and 6.2.4 of ASTM C1199 specify the standardized 
heat transfer coefficients and their tolerances as part of the 
procedure to set the surface heat transfer conditions of the test 
facility using the Calibration Transfer Standard (``CTS'') test. The 
warm-side surface heat transfer coefficient must be within <plus-minus> 
5 percent of the standardized warm-side value of 1.36 Btu/(h-ft\2\-
[deg]F), and the cold-side surface heat transfer coefficient must be 
within <plus-minus> 10 percent of the standardized cold-side value of 
5.3 Btu/(h-ft\2\-[deg]F) during the CTS test (ASTM C1199, Sections 
6.2.3 and 6.2.4). ASTM C1199 does not require that the measured surface 
heat transfer coefficients match or be within a certain tolerance of 
standardized values during the official sample test--although test 
facility operational (e.g., cold side fan settings) conditions would 
remain identical to those set during the CTS test. ASTM C1199 also does 
not require measurement of the warm-side surface temperature of the 
door. Rather, this value is calculated based on the radiative and 
convective heat flows from the test specimen's surface to the 
surroundings, which are driven by values determined from the 
calibration of the hot box using the CTS test (e.g., the convection 
coefficient). See ASTM C1199, Section 9.2.1. When testing doors with 
extremely high- or low-thermal resistance, the resulting change in 
warm-side surface temperature can shift the warm-side heat transfer 
coefficient out of the tolerance specified in the DOE test procedure. 
To ensure that these coefficients are within tolerance during the test 
would require recalibration of the hot box for each specific door.
    As part of the June 2021 RFI, DOE requested feedback on the 
tolerances currently specified in section 5.3(a)(1) of appendix A 
applied to the surface heat transfer coefficients used to measure 
thermal transmittance and whether they should be increased or omitted. 
86 FR 32332, 32340.
    In response, NFRC asserted that applying the surface heat transfer 
coefficient tolerances to the surface heat

[[Page 23938]]

transfer coefficients determined in the actual U-factor test is not a 
correct application of the NFRC 102 test method and recommended that 
the tolerances be removed from section 5.3(a)(1) of appendix A. NFRC 
additionally stated that the idea behind the CTS calibration tests is 
to set up a consistent set of fan speeds on both sides of the chamber 
or to create consistent cold and warm side environments for testing of 
all products. NFRC further stated that the convection currents will be 
influenced during sample testing by the surface temperatures of the 
test sample and that this is an expected and natural occurrence. (NFRC, 
No. 10 at pp. 3-4)
    Given DOE's experience with testing walk-in doors and the comments 
provided by NFRC, DOE is proposing to remove the requirement listed in 
section 5.3(a)(1) regarding the surface heat transfer coefficients and 
the tolerances on them during testing.
    Additionally, while DOE did not request specific comment on the 
surface heat transfer coefficients themselves (i.e., the warm side 
value of 1.36 Btu/(h-ft\2\-[deg]F) and cold side value of 5.3 Btu/(h-
ft\2\-[deg]F)), Anthony commented that the heat transfer coefficient 
applied to the cold side of the test specimen correlates to a wind 
speed roughly equivalent to 12.3 miles per hour (``mph''). Anthony 
stated that their field testing has demonstrated that the wind speed 
interior to the walk-in is below 5 mph. (Anthony, No. 8 at pp. 3-4)
    DOE is not proposing to deviate from the surface heat transfer 
coefficients specified in NFRC 102-2020 for calibration because 
additional investigation is needed. Deviating from these surface heat 
transfer coefficients would require test labs to change their test 
chamber calibration procedures and would require manufacturers to 
retest and re-rate all envelope components subject to the energy 
consumption test procedure in appendix A. DOE may consider changes to 
the surface heat transfer coefficients specified in NFRC 102-2020 for 
calibration in the future if more data became available regarding the 
internal and external conditions of walk-ins in various installations. 
At this time however, more data and Departmental analysis would need to 
be conducted to support any changes to the surface heat transfer 
coefficients specified in NFRC 102-2020.
    DOE also received comment on the direct solar irradiance 
requirement. NFRC stated that direct solar irradiance of 0 Btu/(h-
ft\2\) listed in section 5.3(a)(4) of appendix A is not an exception to 
NFRC 100 and should be removed from appendix A. (NFRC, No. 10 at p. 4) 
Consistent with DOE's proposal to remove reference to NFRC 100, DOE 
proposes to remove this requirement in section 5.3(a)(4) of appendix A.
c. Calibration of Hot Box for Measuring U-Factor
    As stated previously, NFRC 100 references NFRC 102 as the physical 
test method for measuring U-factor, which in turn incorporates by 
reference ASTM C1199. ASTM C1199 references ASTM C1363-05, ``Standard 
Test Method for Thermal Performance of Building Materials and Envelope 
Assemblies by Means of a Hot Box Apparatus'' (``ASTM C1363''). Section 
6.1 of ASTM C1199 and Annexes 5 and 6 of ASTM C1363 include calibration 
requirements to characterize metering box wall loss and surround panel 
flanking loss, but the frequency at which these calibrations should 
occur is not specified in these test standards. As part of the June 
2021 RFI, DOE sought comment on the frequency at which test 
laboratories perform each of the calibration procedures referenced in 
ASTM C1199 and ASTM C1363, e.g., those used to determine the 
calibration coefficients for calculating metering box wall loss and 
surround panel flanking loss. 86 FR 32332, 32340. DOE also requested 
comment on the magnitude of variation in the calibration coefficients 
measured during successive calibrations. Id.
    NFRC stated that because the referenced ASTM standards (i.e., ASTM 
C1199 and ASTM C1363) do not specify frequency of calibration, NFRC 102 
includes calibration frequency requirements in section 6.1. NFRC stated 
that section 6.1 requires that metering box wall loss and surround 
panel flanking loss be determined once and verified annually as these 
values would not inherently change over time. It noted that the 
verification of the metering box wall loss and surround panel flanking 
loss requires results to be within 2 Watts of previous characterization 
results. NFRC added that their experience shows that these results 
repeat well over time and that an increase in calibration frequency is 
unnecessary. (NFRC, No. 10 at p. 3)
    As NFRC stated, the most recent version of NFRC 102, NFRC 102-2020, 
includes calibration frequencies and requirements in section 6.1(A). 
The currently referenced version of NFRC 102, NFRC 102-2010, does not 
include these calibration requirements. For this reason and because of 
the comments provided by NFRC, DOE is proposing to adopt the 
calibration requirements in Section 6.1(A) of NFRC 102-2020.
2. Additional Definitions
a. Surface Area for Determining Compliance With Standards
    The surface area of display doors and non-display doors (designated 
as Add and And, respectively) are used to determine maximum energy 
consumption (``MEC'') in kWh/day of a walk-in door. 10 CFR 431.306(c)-
(d). Surface area is currently defined in section 3.4 of appendix A as 
``the area of the surface of the walk-in component that would be 
external to the walk-in cooler or walk-in freezer as appropriate.'' As 
currently written, the definition does not provide further detail on 
how to determine the boundaries of the walk-in door from which height 
and width are determined to calculate surface area. Additionally, the 
definition does not specify if these measurements are to be strictly 
in-plane with the surface of the wall or panel that the walk-in door 
would be affixed to, or if troughs and other design features on the 
exterior surface of the walk-in door should be included in the measured 
surface area. Inconsistent determination of surface area, specifically 
with respect to the measurement boundaries, may result in 
unrepresentative and inconsistent MEC values. Additionally, walk-in 
doors with antisweat heaters are subject to prescriptive standards for 
power use of antisweat heaters per square foot of door opening. 10 CFR 
431.306(b)(3)-(4). DOE considers the area of the ``door opening'' to be 
consistent with the surface area used to determine MEC.
    Display doors are fundamentally different from non-display doors in 
terms of their overall construction. For example, display door 
assemblies contain a larger frame that can encompass multiple door 
openings or leaves, and the entire assembly fits into an opening within 
a walk-in wall. Non-display doors differ in that they often are affixed 
to a panel-like structure that more closely resembles a walk-in wall 
rather than a traditional door frame.
    In the June 2021 RFI, DOE described how it applies the current test 
procedure definition for surface area when determining compliance with 
standards. 86 FR 32332, 32337. As part of the June 2021 RFI, DOE 
requested comment on how manufacturers determine surface area for the 
purpose of evaluating compliance with the MEC performance standards and 
with the prescriptive standards pertaining to antisweat heaters for 
both display and non-display doors. Id.
    AHRI and Hussmann stated that they determine surface area 
consistent with DOE, and that they do not see any

[[Page 23939]]

distinctions between display doors and non-display doors that warrant 
determining surface area differently. (AHRI, No. 11 at p. 7; Hussmann, 
No. 18 at p. 9) Anthony stated that they include the frame and frame 
flange as part of the door assembly when determining door surface area. 
Anthony also stated that, contrary to how they determine surface area, 
Figure 4-2 of NFRC 100-2017 excludes frame flanges. (Anthony, No. 8 at 
pp. 2-3) Imperial Brown stated that the area for non-display doors, 
And, should be the clear opening area, or WIC by HIC, which excludes 
the door frame portion of the door assembly. They also stated that the 
clear opening area may be smaller than the swinging or sliding portion 
of the door, which typically overlaps a portion of the door frame. 
(Imperial Brown, No. 15 at p. 2)
    With regard to the prescriptive anti-sweat heater standards, 
Anthony agreed that the power use of anti-sweat heat per square foot is 
consistent with the surface area used to determine MEC. (Anthony, No. 8 
at pp. 2-3) AHRI and Hussmann stated that they do not see a need to 
change requirements for the prescriptive standards pertaining to anti-
sweat heaters. (AHRI, No. 11 at p. 7; Hussmann, No. 18 at p. 9)
    In response to comments received, DOE notes that the description of 
surface area for determining MEC in the June 2021 RFI considers the 
structural differences between display and non-display doors and 
assumes different bounds for determining the surface area of display 
doors and non-display doors. As described previously, DOE includes the 
frame in the surface area calculation for display doors, whereas the 
panel-like frame of non-display doors has not been included in the 
surface area calculation. However, DOE has observed that many 
electrical components of non-display doors are sited on or within the 
frame to which the door is attached. If the non-display door frame is 
not considered as part of the non-display door, the frame would fall 
under the category of a walk-in panel. However, the current test 
procedure for panels does not account for electrical energy 
consumption. Many of the electrical components sited on the non-display 
door frame serve a function for operation of the door itself. For 
example, to keep non-display doors from freezing shut, anti-sweat 
heaters are used to prevent condensation from accumulating around the 
edge of the door.
    Comments received regarding surface area determination suggest that 
the approach provided in appendix A may result in inconsistent 
interpretations as to how to determine this measurement. To clarify 
this issue, DOE is proposing additional specification on how the 
surface area is measured. DOE is proposing that the surface area bounds 
of both display doors and non-display doors be the outer edge of the 
frame. Specifically, DOE proposes to revise the term ``surface area'' 
to ``door surface area,'' and to define the new term as meaning the 
product of the height and width of a walk-in door measured external to 
the walk-in. Under this definition, the height and width dimensions 
would be perpendicular to each other and parallel to the wall or panel 
of the walk-in to which the door is affixed, the height and width 
measurements would extend to the edge of the frame and frame flange (as 
applicable) to which the door is affixed, and the surface area of a 
display door and non-display door would be represented as Add and And, 
respectively. In addition, DOE proposes to move the defined term from 
the test procedure in appendix A because, as revised and in light of 
the following proposal in section III.C.2.b, this term does not apply 
to the proposed test procedure and is only relevant for determining 
compliance with the standards. Instead, DOE proposes to include the 
amended term and revised definition with the other definitions that are 
broadly applicable to subpart R in 10 CFR 431.302.
b. Surface Area for Determining U-Factor
    As stated previously, appendix A currently references NFRC 100, 
which in turn references NFRC 102 for the determination of U-factor 
through a physical test. When conducting a simulation, the U-factor is 
calculated using the projected fenestration product area (Apt), or the 
area of the rough opening in the wall or roof, for the fenestration 
product, less installation clearances. See NFRC 100, section 3. When 
conducting physical testing, the U-factor (Us) is calculated using 
projected surface area (As) and is then converted to the final 
standardized U-factor (UST). See ASTM C1199, sections 8.1.3 and 9.2.7 
as referenced through NFRC 102. Projected surface area (As) is defined 
as ``the projected area of test specimen (same as test specimen 
aperture in surround panel).'' See ASTM C1199, section 3.3 as 
referenced through NFRC 102.
    Currently, equations 4-19 and 4-28 of appendix A specify that 
surface area of display doors (Add) and non-display doors (And), 
respectively, are used to convert a door's U-factor into a conduction 
load. This conduction load represents the amount of heat that is 
transferred from the exterior to the interior of the walk-in.
    As discussed in section III.C.2.a, DOE is proposing to amend the 
definitions of And and Add to be specific to the exterior plane of the 
door, including the frame and frame flange as appropriate. Defining the 
area in this manner is inconsistent with the area (As) used to 
calculate U-factor in NFRC 102-2020.
    As part of the June 2021 RFI, DOE sought comment on this 
inconsistency and feedback on specifying additional detail for the 
surface area used to determine thermal conduction through a walk-in 
door to differentiate it from the surface area used to determine the 
maximum energy consumption of a walk-in door. 86 FR 32332, 32337.
    NFRC stated that the area used to convert U-factor into energy use 
and the area used to determine U-factor must be consistent when 
calculating conduction load from thermal transmittance. (NFRC, No. 10 
at pp. 2-3) NFRC also observed that NFRC 100, NFRC 102, ASTM C1199 and 
ASTM C1363 all define the area for U-factor based ``n ``projec''ed'' 
specimen ``r ``open''ng'' area in the wall through which the door is 
installed. Id. NFRC further asserted that since the surface area as 
defined by Add and And are different from the projected area, heat flow 
is miscalculated when the tested U-factor is inserted into equations 4-
19 and 4-28. Id. AHRI and Hussmann declared that they determine surface 
area in a manner consistent with the DOE regulations in 10 CFR parts 
429 and 431 and that they do not see a distinction that warrants 
determining surface area differently in these instances. (AHRI, No. 11 
at p. 7; Hussmann, No. 18 at p. 9)
    Imperial Brown stated that for a non-display door, the outer frame 
is equivalent to a walk-in panel and therefore the frame would have a 
limited impact on the U-factor calculation of the swinging or sliding 
portion of the door. (Imperial Brown, No. 15 at p. 2) Imperial Brown 
separately defined the two types of non-display doors they manufacture, 
defining a ``panel frame'' as a frame that is connected in-line with 
other walk-in panels and a ``flat frame'' as a frame that is typically 
used in retrofit applications or by door-only manufacturers which are 
non-insulating and mount over and are fastened to walk-in panels. (Id. 
at p. 1) Imperial Brown suggested that manufacturers not be required to 
separately test basic models for U-factor which differ in their frame 
type because they believe ``panel'' frames and ``flat'' frames to be 
equivalent in performance

[[Page 23940]]

once mounted. Imperial Brown recommended that the same U-factor 
determined for a door with a ``panel frame'' be used for an otherwise 
the same door with a ``flat frame.'' (Id. at p. 2)
    Based on this feedback, DOE has preliminarily determined that using 
the same area that is used to determine U-factor (As in NFRC 102 and 
ASTM C1199 as referenced) to convert U-factor into a conduction load, 
rather than the proposed revised term for door surface area in section 
III.C.2.a (Add or And) results in a more representative conduction load 
and provides for improved consistency in application of the test 
procedure across all walk-in doors. As such, DOE proposes to specify 
that the projected area of the test specimen, As, as defined in ASTM 
C1199, or the area used to determine U-factor is the area used for 
converting the tested U-factor, UST, into a conduction load in appendix 
A. DOE recognizes that this may not change ratings for some doors, 
where As is equivalent to And or Add, but it may result in slightly 
lower ratings of energy consumption for other doors, where As is less 
than And or Add. DOE expects that since this proposed detail would 
either result in a reduced energy consumption or have no impact, there 
would be no need for manufacturers to retest or re-rate. Additional 
details on how this proposed detail impacts retesting and re-rating are 
further discussed in section III.J.1.
    In response to Imperial Brown's assertion that the frame has a 
limited impact on the thermal performance of the door, DOE testing of 
non-display doors found that inclusion of the frame in the U-factor 
test (which resulted in a 34 to 52 percent increase in total door area) 
increased the heat transferred through the door assembly by 23 to 139 
percent compared to heat transfer through the door leaf alone. This 
implies that including the frame in the U-factor test does have a 
measurable impact on the thermal performance of the door assembly. 
Therefore, DOE also proposes to specify in appendix A that the U-factor 
test includes the frame of the door to improve consistency in 
application of the test procedure across all walk-in doors.
3. Electrical Door Components
    Sections 4.4.2 and 4.5.2 of appendix A include provisions for 
calculating the direct energy consumption of electrical components of 
display doors and non-display doors, respectively. For example, 
electrical components associated with doors could include, but are not 
limited to: Heater wire (for anti-sweat or anti-freeze application); 
lights (including display door lighting systems); control system units; 
and sensors. See appendix A, sections 4.4.2 and 4.5.2. For each 
electricity-consuming component, the calculation of energy consumption 
is based on the component's ``rated power'' rather than a measurement 
of its power draw. Section 3.5 of appendix A defines ``rated power'' as 
the electricity consuming device's power as specified (1) on the 
device's nameplate or (2) from the device's product data sheet if the 
device does not have a nameplate or such nameplate does not list the 
device's power.
    DOE has observed that walk-in doors often provide a single 
nameplate for the door, rather than providing individual nameplates for 
each electricity-consuming device. In many cases, the nameplate does 
not provide separate power information for the different electrical 
components. Also, the nameplate often specifies voltage and amperage (a 
measure of current) ratings without providing wattage (a measure of 
power) ratings, as is referenced by the definition of ``rated power.'' 
While the wattage is equal to voltage multiplied by the current for 
many components, this may not be true for all components that may be 
part of a walk-in door assembly. Furthermore, nameplate labels 
typically do not specify whether any listed values of rated power or 
amperage represent the maximum operation conditions or continuous 
steady state operating conditions, which could differ for components 
such as motors that experience an initial surge in power before power 
use levels off. These issues make calculating a door's total energy 
consumption a challenge for a test facility that does not have in-depth 
knowledge of the electrical characteristics of the door components.
    As part of the June 2021 RFI, DOE requested comment on whether, and 
if so how, an option for direct component power measurement could be 
included in the test procedure or DOE's CCE provisions to allow for a 
more accurate accounting of the direct electrical energy consumption of 
WICF doors. 86 FR 32332, 32338.
    ASAP supported adding an option for direct measurement of power 
consumed by door electrical components. (ASAP, No. 13 at p. 1) The CA 
IOUs also supported direct measurement of power used by door 
components, but more specifically for components designed to operate at 
partial nameplate power such as door motors or powered door closers. 
The CA IOUs stated that, in their experience, power measurement for 
resistance components like lighting and door heaters are not necessary 
if these components are designed to operate at full nameplate power. 
They recommended that the electrical energy consumption of door motors 
be reported per door opening and that the electrical energy consumption 
be calculated as the actual power consumption of the motor multiplied 
by the duration of the door opening and closing. (CA IOUs, No. 14 at p. 
4) Hussmann and Imperial Brown supported maintaining the current 
approach of using rated power for calculating direct electrical energy 
consumption and did not see a need for the measurement option. 
(Hussmann, No. 18 at p. 10; Imperial Brown, No. 15 at pp. 2-3) Imperial 
Brown also stated that control components are typically rated at 5 
Watts or less and that they should be excluded from the calculation of 
direct electrical energy consumption. (Imperial Brown, No. 15 at pp. 2-
3)
    DOE is not proposing to include provisions requiring measurement of 
power consumption of electrical door components in the test procedure 
in appendix A because additional investigation is needed. However, DOE 
has observed that some manufacturers may be certifying door motor power 
as the output power rating of the motor, rather than the input power of 
the motor. Thus, DOE is proposing to specify in appendix A that the 
rated power of each electrical component, P<INF>rated,u,t</INF>, would 
be the rated input power of each component because the input power 
represents power consumption.
    Additionally, DOE has observed through testing that the measured 
power of some walk-in door electrical components exceeds either the 
certified or nameplate power values of these electrical components. For 
the purposes of enforcement testing, DOE is proposing in 10 CFR 
429.134(q) that DOE may validate the certified or nameplate power 
values of an electrical component by measuring the power when the 
device is energized using a power supply that provides power within the 
allowable voltage range listed on the nameplate. If the measured input 
power is more than 10 percent higher than the power listed on the 
nameplate or the rated input power in a manufacturer's certification, 
then the measured input power would be used in the energy consumption 
calculation. For electrical components with controls, the maximum input 
wattage observed while energizing the device and activating the control 
would be considered the measured input power.
4. Percent Time Off Values
    The test procedure also assigns percent time off (``PTO'') values 
to various walk-in door components. PTO

[[Page 23941]]

values are applied to reflect the hours in a day that an electricity-
consuming device operates at its full-rated or certified power (i.e., 
daily component energy use is calculated assuming that the component 
operates at its rated power for a number of hours equal to 24 
multiplied by -1 - PTO)). PTO values are not incorporated in the rated 
or certified power of an electricity-consuming device. Table III.3 
lists the PTO values in the current DOE test procedure for walk-in 
doors.

      Table III.3--Assigned PTO Values for Walk-in Door Components
------------------------------------------------------------------------
                                                           Percent time
                     Component type                        off (PTO) (%)
------------------------------------------------------------------------
Lights without timers, control system or other demand-                25
 based control..........................................
Lights with timers, control system or other demand-based              50
 control................................................
Anti-sweat heaters without timers, control system or                   0
 other demand-based control.............................
Anti-sweat heaters on walk-in cooler doors with timers,               75
 control system or other demand-based control...........
Anti-sweat heaters on walk-in freezer doors with timers,              50
 control system or other demand-based control...........
All other electricity consuming devices without timers,                0
 control systems, or other auto-shut-off systems........
All other electricity consuming devices for which it can              25
 be demonstrated that the device is controlled by a
 preinstalled timer, control system or other auto- shut-
 off system.............................................
------------------------------------------------------------------------

    As discussed in the June 2021 RFI, DOE has granted waivers to 
several manufacturers of doors with motorized door openers, allowing 
for the use of a different PTO for motors. 86 FR 32332, 32338-32339. 
The manufacturers who requested and were granted waivers and the PTO 
defined in their alternate test procedure are shown in Table III.4.

Table III.4--PTO Values Granted in Decision and Orders for Manufacturers
                  of Doors With Motorized Door Openers
------------------------------------------------------------------------
                                                     Decision and order
           Manufacturer              Percent time     Federal Register
                                     off (PTO) (%)        citation
------------------------------------------------------------------------
HH Technologies...................              96  83 FR 53457. (Oct.
                                                     23, 2018).
Jamison Door Company..............            93.5  83 FR 53460. (Oct.
                                                     23, 2018).
Senneca Holdings..................              97  86 FR 75. (Jan. 4,
                                                     2021).
Hercules..........................              92  86 FR 17801. (Apr.
                                                     6, 2021).
------------------------------------------------------------------------

    In the June 2021 RFI, DOE requested comment on the current PTO 
values for all electricity-consuming devices, whether these values 
should be amended, and whether specific values should be added for 
certain electrical components, such as motors. 86 FR 32332, 32339.
    In response, Hussmann stated that they determine energy consumption 
consistent with DOE's regulations in parts 429 and 431 and do not see a 
need to change the current PTO values. (Hussmann, No. 18 at p. 10) ASAP 
supported adding specific PTO values for motorized door openers because 
they believe it will provide similar treatment for these components as 
for other electrical components and eliminate the need for ongoing test 
procedure waivers. (ASAP, No. at p. 1) The CA IOUs recommended that DOE 
reduce the usage factor of door opening motors from 75 percent to 5 
percent or less (i.e., implement a PTO of 95 percent or greater). In 
their comments, the CA IOUs provided anecdotal data for two food 
service sites where doors were open an average of 20 and 40 minutes per 
day. The CA IOUs observed that if these doors had motors, the motor on 
time would be even less than the time recorded in the open position. 
Additionally, the CA IOUs recommended that DOE explore the differences 
in opening patterns among passage, freight, and display doors and 
potentially adjust the door motor PTO based on door opening pattern for 
each corresponding class. (CA IOUs, No. 14 at pp. 5-6)
    As shown in Table III.4, each manufacturer requested a PTO value 
specific to their door and motor characteristics, resulting in four 
different PTO values. For this proposal, DOE evaluated a PTO that could 
be used to consistently evaluate energy consumption of doors with 
motors and would be sufficiently representative. Recognizing that the 
PTO values requested in the waivers are relatively close to one 
another, DOE calculated an average PTO value based on the information 
received in the waivers and is proposing to specify one PTO value for 
all basic models of doors with motors to use. This approach results in 
a more representative test procedure for doors with motors as compared 
to the current value specified for other electricity-consuming devices 
in appendix A. The intent of the PTO value is not to reflect 
behaviorally-related energy consumption of each individual installation 
of a door with a motor, but to provide a more representative means for 
comparison of walk-in door performance.
    DOE calculated an average PTO value, as follows. For each motorized 
door offering from manufacturers that were granted waivers, DOE used 
the cycle rating as specified in the product literature. When a cycle 
rating was not provided in the product literature, DOE used its 
previously estimated number of door openings per day of 60 for passage 
doors and 120 for freight doors, respectively.\20\ 75 FR 55068, 55085.

[[Page 23942]]

DOE then calculated the PTO range for each motor offering using the 
cycle rating or DOE's cycle assumption, the maximum opening size 
offered by the manufacturer, and the minimum and maximum operating 
speeds of the motor. DOE averaged these PTO ranges across each motor 
offering and then averaged them across all manufacturers. This yielded 
an average PTO of 97 percent.
---------------------------------------------------------------------------

    \20\ DOE's previously estimated door openings per day were 
relevant for a proposal to address door opening infiltration in the 
test procedure introduced in a supplemental notice of proposed 
rulemaking from September 9, 2010. Ultimately, DOE did not adopt 
test procedure provisions addressing door opening infiltration, 
having determined that a typical door manufacturer has very few 
direct means for reducing the door infiltration on its own. 76 FR 
21580, 21595 (Apr. 15, 2011).
---------------------------------------------------------------------------

    Considering the waivers granted, DOE's own calculations, and 
comments received, DOE is proposing to adopt a door motor PTO value of 
97 percent for display doors with motors and non-display doors with 
motors.
    As discussed in the June 2021 RFI, DOE is aware that some 
manufacturers design and market walk-in cooler display doors for high 
humidity applications. Ratings from the CCMS database show these doors 
have more anti-sweat heater power per door opening area than standard 
cooler display doors. 86 FR 32332, 32339. Section 4.4.2(a)(2) of 
appendix A requires a PTO value of 50 percent be used when determining 
the direct energy consumption for anti-sweat heaters with timers, 
control systems, or other demand-based controls situated within a walk-
in cooler door (which would include walk-in cooler doors marketed for 
high humidity applications). This approach assumes that the anti-sweat 
heaters are not operating for 50 percent of the time. DOE recognizes 
that anti-sweat heaters may be in operation for a different amount of 
time in high humidity installations than in standard installations. In 
the June 2021 RFI, DOE requested comment on whether the current PTO of 
50 percent is appropriate for evaluating direct energy consumption of 
anti-sweat heaters with controls for walk-in cooler doors marketed for 
high humidity applications and the amount of time per day or per year 
that anti-sweat heaters with controls are off for high humidity doors. 
Id.
    In response, DOE received comments from Anthony, AHRI, and Hussmann 
regarding the maximum energy consumption of high humidity doors. 
(Anthony, No. 8 at p. 3; AHRI, No. 11 at pp. 7-8; Hussmann, No. 18 at 
p. 10) However, as the responses of these comments were more focused on 
the standards, DOE plans to address these comments as part of a 
separate standards rulemaking for this equipment. DOE did not receive 
any comments regarding whether the PTO in the test procedure for anti-
sweat heaters with controls sited on high humidity doors should be 
modified nor any data on the amount of time the anti-sweat heaters 
operate on high-humidity doors as compared to standard doors (i.e., 
cooler display doors). DOE is not proposing any changes to the PTO 
values for anti-sweat heaters sited on high humidity doors at this 
time.
5. EER Values
    To calculate the daily energy consumption associated with heat loss 
through a walk-in door, appendix A requires dividing the calculated 
heat loss rate by specified energy efficiency ratio (``EER'') values of 
12.4 Btu per Watt-hour (``Btu/W-h'') for coolers and 6.3 Btu/(W-h) for 
freezers. Appendix A, sections 4.4.4(a) and 4.5.4(a). DOE selected EER 
values of 12.4 Btu/(W-h) for coolers and 6.3 Btu/(W-h) for freezers 
because these are typical EER values of walk-in cooler and walk-in 
freezer refrigeration systems, respectively.\21\ 75 FR 186, 209 (Jan. 
4, 2010); 76 FR 21580, 21593-21594 (Apr. 15, 2011). The DOE test 
procedure in subpart R, appendix C, also assigns nominal EER values, 
which correspond to the appropriate adjusted dew point temperature in 
Table 17 of AHRI 1250-2009,\22\ when testing the refrigeration systems 
of walk-in unit coolers alone. The resulting EER values for unit 
coolers tested alone are 13.3 Btu/(W-h) for coolers and 6.6 Btu/(W-h) 
for freezers, which are different than the EER values of 12.4 Btu/(W-h) 
and 6.3 Btu/(W-h), respectively, applied to walk-in doors, as described 
previously. In the June 2021 RFI, DOE sought feedback on the EER values 
specified in appendix A used to calculate daily energy consumption for 
walk-in doors and the values used to test unit coolers as specified in 
subpart R, appendix C. Specifically, DOE requested comment on whether 
the EER values used for door testing and unit cooler testing consistent 
with each other, and if so, which values are more representative. 86 FR 
32332, 32339.
---------------------------------------------------------------------------

    \21\ The difference in EER values between coolers and freezers 
reflects the relative efficiency of the refrigeration equipment for 
the associated application. 75 FR 186, 197. As the temperature of 
the air surrounding the evaporator coil drops (that is, when 
considering a freezer relative to a cooler), thermodynamics dictates 
that the system effectiveness at removing heat per unit of 
electrical input energy decreases. Id.
    \22\ The dewpoint temperature to be used for testing unit 
coolers alone is defined in section 3.3.1 of appendix C to be the 
Suction A saturation condition provided in Tables 15 or 16 of 
appendix C (for refrigerator unit coolers and freezer unit coolers, 
respectively). Table 15 for refrigerator unit coolers defines the 
Suction A saturation condition (i.e., dewpoint temperature) as 25 
[deg]F. Table 16 for freezer unit coolers defines the Suction A 
dewpoint temperature as -20 [deg]F. Furthermore, section 7.9.1 of 
AHRI 1250-2009 specifies that for unit coolers rated at a suction 
dewpoint other than 19 [deg]F for a coolers and -26 [deg]F for a 
freezer, the Adjusted Dewpoint Value shall be 2 [deg]F less than the 
unit cooler rating suction dewpoint--resulting in adjusted dewpoint 
values of 23 [deg]F and -22 [deg]F for refrigerator unit coolers and 
freezer unit coolers, respectively.
---------------------------------------------------------------------------

    Anthony responded that the EER values referenced in subpart R, 
appendix C (i.e., 13.3 Btu/(W-h) for coolers and 6.6 Btu/(W-h) for 
freezers), better reflect current compressor efficiency for walk-in 
refrigeration systems. (Anthony, No. 8 at p. 3) National Refrigeration 
encouraged DOE to keep the current EER values, stating that they 
believe the values are accurate, but did not specify if they were 
referring to walk-in door or refrigeration system EER values. (National 
Refrigeration, No. 17 at p. 1) Keeprite, Lennox, and AHRI all supported 
maintaining the EER values applicable to unit coolers in subpart R, 
appendix C. (Keeprite, No. 12 at p. 2; Lennox, No. 9 at p. 4; AHRI, No. 
11 at p. 8)
    Based on the comments received, it is not clear that there is an 
advantage to harmonizing the EER values between appendix A and subpart 
R, appendix C. Therefore, DOE is not proposing to change the subpart R, 
appendix C, EER values pertaining to walk-in refrigeration systems.
    Additionally, with respect to envelope components, DOE is not 
proposing to align the EER values in appendix A for calculating the 
energy consumption of envelope components with the EER values used for 
testing unit coolers alone in subpart R, appendix C, at this time. DOE 
originally defined nominal EER values in appendix A because an envelope 
component manufacturer generally cannot control what refrigeration 
equipment is installed, and the defined EER value is intended to 
provide a nominal means of comparison rather than reflecting an actual 
walk-in installation. 76 FR 21580, 21593 (Apr. 15, 2011). In other 
words, the EER values used to estimate energy consumption of the 
envelope components is a constant. DOE notes that the difference 
between the EER values used in appendix A for doors and those used in 
subpart R, appendix C, for unit coolers is seven percent for coolers 
and five percent for freezers, which would have minimal impact on rated 
values but would require manufacturers to retest and re-rate energy 
consumption without necessarily providing a more representative test 
procedure.

[[Page 23943]]

6. Air Infiltration Reduction
    EPCA includes prescriptive requirements for doors used in walk-in 
applications which are intended to reduce air infiltration. 
Specifically, walk-ins must have (A) automatic door closers that firmly 
close all walk-in doors that have been closed to within 1 inch of full 
closure (excluding doors wider than 3 feet 9 inches or taller than 7 
feet), and (B) strip doors, spring-hinged doors, or other method of 
minimizing infiltration when doors are open. (42 U.S.C. 6313(f)(1)(A)-
(B)) DOE previously proposed methods for determining the thermal energy 
leakage due to steady state infiltration through the seals of a closed 
door and door opening infiltration. DOE did not ultimately adopt these 
methods as part of the test procedure because DOE concluded that steady 
state infiltration was primarily influenced by on-site assembly 
practices rather than the performance of individual components. 76 FR 
21580, 21594-21595 (April 15, 2011) (``April 2011 final rule''). 
Similarly, DOE stated that, based on its experience with the door 
manufacturing industry, door opening infiltration is primarily reduced 
by incorporating a separate infiltration reduction device at the 
assembly stage of the complete walk-in. Id. In the June 2021 RFI, DOE 
invited comment on whether it should account for steady state and/or 
door opening infiltration in its test procedure. 86 FR 32332, 32340-
32341. DOE also requested test methods and calculations to quantify 
heat load, the associated costs of any suggested methods, and 
supporting data on door usage patterns. Id.
    ASAP encouraged DOE to incorporate a measurement of air 
infiltration into the test procedure for walk-in doors because it would 
improve representativeness and encourage the development and deployment 
of technologies that could reduce infiltration and save energy. (ASAP, 
No. 13 at p. 2) The CA IOUs recommended that DOE consider specifically 
incorporating door opening infiltration energy into the test procedure. 
They also suggested that DOE validate the actual savings of devices 
such as air curtains to determine if the test method should be refined 
to more accurately represent these features in the determination of 
walk-in performance. (CA IOUs, No. 14 at p. 6) In contrast, Imperial 
Brown stated that including air infiltration in the test procedure 
would be burdensome and cost prohibitive because most WICF doors are 
custom-made. (Imperial Brown, No. 15 at p. 3)
    DOE is not proposing to include air infiltration in the test 
procedure for determining energy consumption of walk-in envelope 
components at this time because additional investigation is needed. DOE 
intends to consider data on the magnitude of air infiltration for walk-
ins as it becomes available for appropriate evaluation of the 
representativeness of including it in the test procedure for walk-in 
doors. However, as previously mentioned, EPCA requires air infiltration 
limiting devices on all doors. (42 U.S.C. 6313(f)(1)(A)-(B)) Even 
though air infiltration is not currently evaluated as part of the 
current test procedure and is thus not part of the performance 
standard, all walk-in doors are subject to the prescriptive 
requirements pertaining to air infiltration limiting devices.

D. Proposed Amendments to the Test Procedure in Appendix A for Display 
Panels

    Appendix A specifies the test procedure to determine energy 
consumption of walk-in display panels, which are not currently subject 
to any performance standards in terms of daily energy consumption, but 
are subject to the prescriptive requirements at 10 CFR 431.306.
    In the June 2021 RFI, DOE requested specific comment on the current 
test procedure for determining energy consumption for display panels 
and whether any amendments to this procedure were warranted. 86 FR 
32332, 32342. In response, Anthony and NFRC commented that the test 
procedure for display panels should be identical to the test procedure 
for display doors. (Anthony, No. 8 at p. 4; NFRC, No. 10 at p. 4)
    DOE is proposing that the changes proposed throughout section III.C 
for determining conduction load and energy consumption of display doors 
would also be applicable to determining display panel conduction load 
and energy consumption, except for the provisions applicable to 
electrical components and percent time off values.

E. Proposed Amendments to the Test Procedure in Appendix B for Panels 
and Non-Display Doors

    The insulation R-value of walk-in non-display panels and non-
display doors is determined using appendix B. In this NOPR, DOE is 
proposing to modify appendix B to improve test representativeness and 
repeatability. Specifically, DOE is proposing to make the following 
revisions to appendix B: (1) Reference the updated industry standard 
ASTM C518-17; (2) include more detailed provisions on measuring 
insulation thickness and test sample thickness; (3) provide additional 
guidance on determining parallelism and flatness of test specimen; and 
(4) reorganize appendix B so it is easier for stakeholders to follow as 
a step-by-step test procedure.
    DOE does not expect that the changes it is proposing in this 
section would have a significant impact on measured R-value of 
insulation. Rather, the revisions proposed for appendix B address 
repeatability issues that DOE has observed through its testing of the 
insulation of walk-in panels.
    The following sections describe the modifications that DOE is 
proposing to appendix B, the test procedure for determining the R-value 
of walk-in envelope component insulation. DOE discusses the proposed 
changes specifically in the context of walk-in panels; however, DOE 
notes that non-display doors are also subject to the prescriptive R-
value requirement at 10 CFR 431.306(a)(3) and that the R-value for 
walk-in door insulation is determined using appendix B.
1. Specimen Conditioning
    In the June 2021 RFI, DOE noted that the test specimen conditioning 
instruction and example given in section 7.3 of ASTM C518 conflict with 
the provision in section 4.5 of the DOE test procedure at appendix B 
that requires testing per ASTM C518 be completed within 24 hours of 
specimens being cut for the purpose of testing. 86 FR 32332, 32341-
32342. Section 7.3 of ASTM C518 directs that a test specimen be 
conditioned prior to testing and states that this be done per material 
specifications. If material specifications for conditioning are not 
provided, the specimen preparation shall be conducted so as not to 
expose the specimen to conditions which would change the specimen in an 
irreversible manner. Section 7.3 of ASTM C518 provides an example of a 
material specification that requires test specimen conditioning at 72 
[deg]F and 50 percent relative humidity until less than a one percent 
change in mass is observed over a 24-hour period. As part of the June 
2021 RFI, DOE sought comment on whether manufacturers of insulation 
specify conditioning for insulation materials that differ from the 
typical approach described in ASTM C518. DOE also requested feedback on 
whether more than one 24-hour conditioning period is ever needed to 
complete specimen conditioning given ASTM's requirement regarding 
change in mass. Lastly, DOE requested data on panel performance for 
conditioning times less than 24 hours, specifically,

[[Page 23944]]

how conditioning time impacts the accuracy, repeatability, and 
representativeness of the test. 86 FR 32332, 32342.
    Imperial Brown stated that the panel should cure for 30 days before 
a test specimen is cut and that the test specimen should be tested 
within 24 hours of being cut. Imperial Brown asserted that conditioning 
for longer than 24 hours would create an issue with outgassing, 
particularly on a small test specimen. Additionally, Imperial Brown 
observed that the 180-day conditioning period specified in ASTM C1029-
2015, ``Standard Specification for Spray-Applied Rigid Cellular 
Polyurethane Thermal Insulation'' would be unrealistic and a 
significant test burden. (Imperial Brown, No. 15 at p. 3)
    In response to the suggestion by Imperial Brown that a panel should 
cure for 30 days before a test, DOE notes that section 4.5 of the 
current test procedure in appendix B already specifies that foam 
insulation be tested after it is produced in its final chemical form. 
For foam-in-place insulation, this means the foam has cured as intended 
and is ready for use in a finished panel. In response to the comments 
received regarding outgassing of the test specimen for conditioning 
times beyond 24 hours, preliminary tests conducted by DOE demonstrate 
negligible change in mass of the test specimen within 24 to 48 hours 
and negligible difference in R-value when compared to a test specimen 
from the same foam that was tested within 24 hours. Regarding the 180-
day conditioning period specified in ASTM C1029-2015, DOE has 
tentatively concluded that this timeframe for testing is unrealistic 
and burdensome. Considering all the information at hand, DOE is not 
proposing any changes to the current requirement that testing be 
completed with 24 hours of the test specimen being cut from the 
envelope component. Correspondingly, DOE is not proposing to reference 
Section 7.3 of ASTM C518-17 regarding specimen conditioning.
2. Total Insulation and Test Specimen Thickness
    Section 4.5 of appendix B currently requires that K-factor of a 1 
<plus-minus> 0.1-inch sample of insulation be determined according to 
ASTM C518-04. The walk-in envelope component insulation R-value is 
determined by dividing the envelope component insulation thickness by 
the K-factor. As mentioned in the June 2021 RFI, the measurement of 
total insulation thickness is important in determining the envelope 
component's insulation R-value. 86 FR 32332, 32341. As part of the June 
2021 RFI, DOE requested comment on how panel thickness is typically 
measured. Id. DOE did not receive any comments in response to this 
request.
    In order to make the test procedure in appendix B more repeatable, 
DOE is proposing to include instructions for determining both the total 
insulation thickness as well as the test specimen insulation thickness 
prior to conducting the test to determine K-factor using ASTM C518-17. 
DOE is also proposing step-by-step instructions for specimen 
preparation, including detailed instructions of the number and 
locations of thickness and area measurements and from where the test 
specimen should be removed from the overall envelope component. DOE 
proposes to require the following steps for determining the total 
thickness of the foam, t<INF>foam</INF>, from which the final R-value 
would be calculated:
    <bullet> The thickness around the perimeter of the envelope 
component is determined as the average of at least 8 measurements taken 
around the perimeter, but avoiding the edge region; \23\
---------------------------------------------------------------------------

    \23\ Edge region means a region of the panel that is wide enough 
to encompass any framing members. If the panel contains framing 
members (e.g., a wood frame) then the width of the edge region must 
be as wide as any framing member plus an additional 2 in. <plus-
minus> 0.25 in. See section 3.1 of appendix B.
---------------------------------------------------------------------------

    <bullet> The area of the entire envelope component is calculated as 
the width by the height of the envelope component;
    <bullet> A sample is cut from the center of the envelope component 
relative to the envelope component's width and height. The specimen to 
be tested using ASTM C518-17 would be cut from the center sample;
    <bullet> The thickness of the sample cut and removed from the 
center of the envelope component is determined as the average of at 
least 8 measurements, with 2 measurements taken in each quadrant;
    <bullet> The area of the sample cut and removed from the center of 
the envelope component is determined as the width by the height of the 
cut sample;
    <bullet> Any facers on the sample cut from the envelope component 
shall be removed while minimally disturbing the foam and the thickness 
of each facer shall be the average of at least 4 measurements;
    <bullet> The average total thickness of the foam shall then be 
determined by calculating an area-weighted average thickness of the 
complete envelope component less the thickness of the facers.
    For preparing and determining the thickness of the 1-inch test 
specimen, DOE proposes to include the following steps:
    <bullet> A 1 <plus-minus> 0.1-inch-thick specimen shall be cut from 
the center of the cut envelope sample removed from the center of the 
envelope component;
    <bullet> Prior to testing, the average of at least nine thickness 
measurements at evenly-spaced intervals around the test specimen shall 
be the thickness of the test specimen, L.
    Issue 9: DOE requests feedback on the proposed provisions relating 
to test specimen and total insulation thickness and test specimen 
preparation prior to conducting the ASTM C518-17 test.
3. Parallelism and Flatness
    The test procedure for determining R-value also requires that the 
two surfaces of the tested sample that contact the hot plate assemblies 
(as defined in ASTM C518) maintain <plus-minus> 0.03 inches flatness 
tolerance and maintain parallelism with respect to one another within a 
tolerance of <plus-minus> 0.03 inches.\24\ See appendix B, section 4.5. 
As mentioned in the June 2021 RFI, the current test procedure does not 
provide direction on how flatness and parallelism should be measured or 
calculated. 86 FR 32332, 32341. As part of the June 2021 RFI, DOE 
sought comment on how flatness and parallelism are determined by test 
laboratories and whether the DOE test procedure should include 
instruction on how to determine these parameters. Id. While DOE 
received no comments in response to this request for comment, DOE 
believes that accurate and repeatable determination of a specimen's R-
value requires the specimen under test to be both flat and parallel. 
Therefore, DOE proposes to include the following steps for determining 
the parallelism and flatness of the tested specimen in appendix B:
---------------------------------------------------------------------------

    \24\ Maintaining a flatness tolerance means that no part of a 
given surface is more distant than the tolerance from the ``best-fit 
perfectly flat plane'' representing the surface. Maintaining 
parallelism tolerance means that the range of distances between the 
best-fit perfectly flat planes representing the two surfaces is no 
more than twice the tolerance (e.g., for square surfaces, the 
distance between the most distant corners of the perfectly flat 
planes minus the distance between the closest corners is no more 
than twice the tolerance).
---------------------------------------------------------------------------

    <bullet> Prior to determining the specimen thickness, the specimen 
would be placed on a flat surface and gravity will determine the 
specimen's position on the surface. As specified previously, a minimum 
of nine thickness measurements would be taken at equidistant positions 
on the specimen. These measurements would be associated with side 1 of 
the specimen.
    <bullet> The least squares plane of side 1 is determined based on 
the height measurements taken. The theoretical height of the least 
squares plane is

[[Page 23945]]

determined at each measurement location in the x and y (length and 
width) direction of the specimen.
    <bullet> The difference at each measurement location between actual 
height measurement and theoretical height measurement based on the 
least squares plane is calculated. The maximum value minus the minimum 
value is the flatness associated with this side (side 1). In order for 
each side of the specimen to be considered flat, this value would need 
to be less than or equal to 0.03 inches.
    <bullet> Flip the specimen so that side 1 is now on the flat 
surface and let gravity determine the specimen position on the surface. 
Repeat the above steps for side 2 of the specimen.
    <bullet> To determine if each side of the specimen is parallel, the 
theoretical height at the four corners (i.e., at points (0,0), (0,12), 
(12,0), and (12,12)) of the specimen must be calculated using the least 
squares plane. The difference in the maximum and minimum heights would 
represent the parallelism of one side and would need to be less than or 
equal to 0.03 inches for the specimen to be considered parallel.
    Issue 10: DOE requests feedback on the proposed provisions relating 
to determining parallelism and flatness of the test specimen.
4. Insulation Aging
    In the April 2011 final rule, DOE adopted a test procedure that 
referenced two industry test standards \25\ that considered aging of 
insulation for foams that experience aging. 76 FR 21580, 21588-21592. 
However, after receiving comments concerning test burden and the 
availability of labs to conduct the test procedure, DOE re-evaluated 
its earlier decision and removed this portion of the walk-in panel test 
procedure in the final rule published May 13, 2014 (``May 2014 final 
rule''). 79 FR 27388, 27405-27406. Although the current test procedure 
for determining panel R-value does not account for aging, manufacturers 
have raised concern regarding insulation aging and its potential effect 
on testing results.
---------------------------------------------------------------------------

    \25\ DOE referenced DIN EN 13164:2009-02, ``Thermal insulation 
products for buildings--Factory made products of extruded 
polystyrene foam (XPS)--Specification'' and DIN EN 13165:2009-02, 
``Thermal insulation products for buildings--Factory made rigid 
polyurethane foam (PUR) products--Specification.''
---------------------------------------------------------------------------

    ``Aging'' of foam insulation refers to how diffusion of blowing 
agents out of the foam and diffusion of air into the foam impacts 
thermal resistance of insulation materials. The gaseous blowing agents 
contained in the foam provide the foam with much of its insulating 
performance, represented by the R-value of the foam material. Because 
air has a lower insulating value than the blowing agents used in foam 
insulation, the increased ratio of air to blowing agent reduces the 
foam insulation performance, which reduces the R-value of the foam 
material. The building industry uses long-term thermal resistance 
(``LTTR'') to represent the R-value of foam material over its lifetime 
by describing the insulating performance changes due to diffusion over 
time. The presence of impermeable facers on a foam structure may delay 
the rate of aging or reduce the decrease in R-value when compared to a 
foam structure that is unfaced or has permeable facers. Blowing agents 
and temperature and humidity conditions may also affect the amount or 
rate of aging that occurs in a foam structure.
    Since the May 2014 final rule, DOE worked with the Oak Ridge 
National Laboratory (``ORNL'') to conduct a study on performance aging 
and thermal bridging of walk-in cooler and freezer panels.\26\ In this 
study, multiple panels from five manufacturers were allowed to age 
intact (i.e., with facers attached) at room temperature, with 1-inch 
samples taken from the middle of a given panel for testing according to 
the test procedure in appendix B. These samples were tested upon 
receipt of the panels and extracted at various times throughout 5 years 
from intact panels (i.e., with facers attached). Aging panels with 
their facers attached is representative of how panels are stored and, 
ultimately, installed for use in a walk-in box. Appendix B does not 
test with facers because, as previously stated, the DOE test procedure 
evaluates only the R-value of the foam insulation--not the R-value of 
the entire panel.
---------------------------------------------------------------------------

    \26\ A presentation on ORNL's study can be found online at 
https://www.osti.gov/biblio/1844325-impact-thermal-bridging-imperfections-aging-effective-value-walk-cooler-freezer-panels. DOE 
acknowledges that panels are shipped for assembly in walk-ins with 
the foam already in final chemical form between facers. Thus, the 
most applicable evaluation of change in insulation R-value over time 
is demonstrated by the red data points (labeled ``2'') for the foam 
that remained intact with the facers on slides 26 through 30 of 
ORNL's presentation.
---------------------------------------------------------------------------

    Based on DOE evaluation of product literature, there are two common 
ways to manufacture walk-in panels: (1) Foaming metal skins in place 
using closed cell polyurethane foam (``PUF'') or (2) gluing layers of 
previously-hardened foam to metal skins. DOE research suggests that PUF 
is the most common insulation used in walk-ins. To manufacture PUF 
panels, the PUF is injected and hardened using jigs that firmly 
maintain exterior panel dimensions until the foam has cooled and 
hardened. This process encourages standardization of panel dimensions 
as jigs are expensive and typically have limited adjustability. 
Extruded polystyrene (``XPS'') is used by some manufacturers to 
construct walk-in panels. XPS-based walk-ins are built in layers of 
XPS, a previously-hardened foam material that is shipped in sheets to 
the original equipment manufacturer (``OEM''), where it is cut to the 
desired shape and assembled. Customization is more common with XPS 
panels. XPS strongly resists water absorption, preventing panels from 
losing their insulative properties should water or condensation leaks 
develop. Other layered panel assembly materials include 
polyisocyanurate and expanded polystyrene (``EPS'') which are used less 
but are still offered by some manufacturers. Polyisocyanurate has 
similar advantages to XPS, but generally has lower thermal resistivity 
at lower temperature conditions. EPS also has similar advantages to XPS 
in terms of moisture absorption, but generally has a lower R-value. The 
study conducted at ORNL evaluated four panel brands manufactured with 
PUF and one panel brand manufactured using XPS. The R-value of 
insulation measured by ORNL at the initial test date and most recent 
test date are summarized in Table III.5.

   Table III.5--Summary of R-value Test Results at Initial Test Date and Most Recent Test Date From ORNL Study
----------------------------------------------------------------------------------------------------------------
                                                                           Number of years after
         Label                  Foam type          Temperature condition       initial test           R-value
----------------------------------------------------------------------------------------------------------------
F1.....................  PUF....................  Freezer...............  0 (initial test)......            31.2
                                                                          2.3...................            30.9
F2.....................  PUF....................  Freezer...............  0 (initial test)......            31.8
                                                                          4.2...................            30.3

[[Page 23946]]

 
C1.....................  PUF....................  Cooler................  0 (initial test)......            28.2
                                                                          4.8...................            26.8
C2.....................  XPS....................  Cooler................  0 (initial test)......            25.0
                                                                          4.7...................            23.1
C3.....................  PUF....................  Cooler................  0 (initial test)......            28.0
                                                                          0.5...................            27.8
----------------------------------------------------------------------------------------------------------------

    Based on ORNL's study, DOE considers the effects of foam insulation 
aging for walk-in refrigeration panels sold with facers to be minimal 
when panel facers remain attached to the foam (i.e., when the panel 
remains intact.). DOE understands that for the purposes of 
certification and represented R-values, manufacturers are determining 
their represented R-value by testing specimens from panels at the point 
of manufacture (i.e., R-value without aging). For assessment and 
enforcement testing conducted to support the enforcement of DOE's 
energy conservation standards, DOE is generally able to test samples 
within one to three months after receipt. The time lag from when the 
panel is manufactured and when testing is conducted at a lab is 
typically significantly shorter than that evaluated in the ORNL study; 
therefore, DOE expects any reduction in R-value to be even less during 
the period from date of manufacture to assessment or enforcement test 
date. Additionally, walk-in panels received by DOE for assessment and 
enforcement testing are evaluated upon arrival to ensure that they are 
received intact (i.e., with facers) and undamaged and testing of the 
specimen is completed within 24 hours of sample removal from the panel, 
as specified in section 4.5 of the DOE test procedure in appendix B. 
DOE does not expect any reduction in R-value within 24 hours of the 
sample being cut from the panel.
    Issue 11: DOE seeks comment on other comparable data or studies of 
aging of foam panels that are representative of the foam insulation, 
blowing agents, and panel construction currently used in the 
manufacture of walk-in panels. DOE also requests comment on whether 
manufacturers have been certifying R-value at time of manufacture or 
after a period of aging.
5. Determining Energy Consumption of Panels That Are Not Display Panels
    When DOE initially established the test procedures for components 
of a WICF in its April 2011 final rule, DOE adopted a test method for 
measuring the overall thermal transmittance of a walk-in panel, 
including the impacts of thermal bridges \27\ and edge effects (e.g., 
due to framing materials and fixtures used to mount cam locks). 76 FR 
21580, 21605-21612. This method was based on an existing industry test 
method, incorporating by reference ASTM C1363. Id. However, after 
receiving comments concerning test and cost burden and the lack of 
availability of labs to conduct the test procedure, DOE re-evaluated 
its earlier decision and removed this portion of the walk-in panel test 
procedure in the May 2014 final rule. 79 FR 27388, 27405-27406. As 
previously stated, the current test procedure in appendix B for non-
display panels evaluates insulation R-value according to ASTM C518-04. 
In the June 2021 RFI, DOE requested information regarding panel 
construction factors that would affect overall thermal transmission and 
the magnitude of these effects. 86 FR 32332, 32342. DOE also requested 
comment on alternative test methods to measure overall thermal 
transmittance of a panel assembly along with the number of labs that 
are qualified to run ASTM C1363. Id.
---------------------------------------------------------------------------

    \27\ Thermal bridging occurs when a more conductive material 
allows an easy pathway for heat flow across a thermal barrier.
---------------------------------------------------------------------------

    ASAP and the CA IOUs encouraged DOE to consider a test method that 
captures overall thermal transmittance of walk-in panels. (ASAP, No. 13 
at p. 2; CA IOUs, No. 14 at p. 5) The CA IOUs specifically recommended 
that the ASTM C1363 test be conducted on a wall panel assembly that 
includes the panel joint to ensure the joint locking mechanism does not 
significantly affect the thermal conductance of the assembly. The CA 
IOUs also suggested that the tested joint assembly use a manufacturer-
recommended sealant representative of field installation. (CA IOUs, No. 
14 at p. 5)
    Imperial Brown urged DOE to maintain the current test procedure for 
non-display panels based on insulation R-values determined using ASTM 
C518. Imperial Brown stated that ASTM C1363 is unduly burdensome given 
the custom nature of the walk-ins they manufacture and that this would 
substantially increase their testing requirements. Imperial Brown also 
remarked that the effect of panel edges or accessories is of little 
value to the overall energy consumption of a walk-in and that 
considering these effects would be equivalent to considering one 
opening of the walk-in door per day. Specifically, Imperial Brown 
stated that the panel edges and accessories are not considered when 
calculating box loads and sizing refrigeration equipment because they 
do not consider them to be an important factor in heat loss. Imperial 
Brown also stressed that retesting will be required every few years as 
they switch to different insulation chemicals to comply with other 
regulations coming into effect (e.g., the Environmental Protection 
Agency (``EPA'') phasedown of HFCs. (Imperial Brown, No. 15 at p. 3)
    NFRC stated that all labs qualified to run NFRC 102 are qualified 
to run ASTM C1363 and that there are currently ten labs accredited by 
NFRC to run NFRC 102, and thus ASTM C1363. (NFRC, No. 10 at p. 4)
    While commenters indicated that there are more laboratory 
facilities now able to conduct an overall U-factor test procedure, the 
concerns previously expressed regarding cost and test burden, which led 
to the removal of this test procedure in the May 2014 AEDM final rule 
(79 FR 27388, 27405-27406), remain. At this time, DOE is not proposing 
to include a test procedure for determining energy consumption of non-
display panels and is proposing to maintain the R-value of insulation 
test procedure in appendix B with the proposed amendments as described 
previously in sections III.E.1 through III.E.4.

F. Proposed Amendments to Subpart R, Appendix C, to Determine 
Compliance With the Current Energy Conservation Standards

    Subpart R, appendix C, provides the test procedures to determine 
the AWEF and net capacity of walk-in refrigeration

[[Page 23947]]

systems. DOE is proposing to modify subpart R, appendix C, to improve 
test representativeness and repeatability. Specifically, DOE is 
proposing to make the following revisions to subpart R, appendix C: (1) 
Specify refrigeration test room conditions; (2) provide for a 
temperature probe exception for small diameter refrigerant lines; (3) 
incorporate a test setup hierarchy for laboratories to follow when 
setting up a unit for test; (4) allow active cooling of the liquid line 
in order to achieve the required 3 [deg]F subcooling at a refrigerant 
mass flow meter; and (5) modify instrument accuracy and test 
tolerances.
    DOE does not expect that the changes it is proposing in this 
section would alter measured capacity values or AWEF--which means that 
no retesting or recertification would be required. Rather, the 
revisions proposed for subpart R, appendix C, address repeatability 
issues that DOE has observed through its testing of walk-in 
refrigeration systems.
    The following sections describe the modifications that DOE is 
proposing to subpart R, appendix C.
1. Refrigeration Test Room Conditioning
    The DOE test procedure for walk-in refrigeration systems has 
requirements for test chambers to be at specific temperature and/or 
humidity conditions. (See, e.g., Tables 3 through 16 of AHRI 1250-2009, 
which is incorporated by reference in the DOE test procedure) Section 
C6.2 of AHRI 1250-2009 appendix C requires that the environmental 
chambers ``be equipped with essential air handling units and 
controllers to process and maintain the enclosed air to any required 
test conditions.'' This same requirement is in Section C5.2.2 of AHRI 
1250-2020. However, DOE is aware that some test facilities rely on the 
test unit to cool and dehumidify the test room, in some cases without 
support from additional chamber conditioning systems. When unit coolers 
with hot gas defrost are tested and certified alone, these unit coolers 
may be paired with a condensing unit at a test facility that lacks hot 
gas capability and would be unable to remove the frost accumulated 
during pretest conditioning. Such frost would affect the results of the 
capacity test.
    DOE proposes to specify that for applicable system configurations 
(matched pairs, single-packaged systems, and unit coolers tested 
alone), the unit under test may be used to aid in achieving the 
required test chamber conditions prior to beginning any steady state 
test. However, the unit under test must be inspected and confirmed to 
be free from frost before initiating steady state testing. This 
additional instruction reflects DOE's understanding of the existing 
practice followed by manufacturers and third-party laboratories who use 
the unit under test to establish the required chamber conditions. The 
proposed inspection requirement would ensure that a steady state test 
is not started with frost on the coil. Starting a test with a frosted 
coil would likely lead to reduced-efficiency and non-representative 
test results, and DOE expects that test laboratories would have no 
incentive to conduct tests with a frosted coil.
    Issue 12: DOE requests comment on the proposed pretest coil 
inspection requirement. DOE requests comment on whether the proposed 
approach is inconsistent in any way with the way units under test are 
used to assist in chamber conditioning by testing facilities, and if 
so, in what way are the proposals inconsistent, and how could they be 
changed to align with this practice.
2. Temperature Measurement Requirements
    The current DOE test procedure requires all refrigerant temperature 
measurements entering or leaving the unit cooler be measured by a 
``temperature measuring instrument placed in a thermometer well and 
inserted into the refrigerant stream. These wells shall be filled with 
non-solidifying, thermal conducting liquid or paste to ensure the 
temperature sensing instrument is exposed to a representative 
temperature.'' AHRI 1250-2009 appendix C, Section C3.1.6. These 
temperature measurements are used to determine refrigerant enthalpy as 
part of the capacity measurement for matched pairs and unit coolers 
tested alone (see AHRI 1250-2009, Section C8.5.1, Equations C1 and C2). 
However, the capacity determination for dedicated condensing units 
tested alone is based on the refrigerant conditions leaving the 
condensing unit and standardized conditions leaving the unit cooler, as 
specified in section 3.4.2.1 of subpart R, appendix C. DOE believes 
that the added accuracy provided by immersing the temperature sensor in 
the refrigerant or by the thermometer wells should be applied for the 
temperature measurement used in the capacity calculation. Hence, DOE 
proposes that the test procedure provide clarification that when 
testing dedicated condensing units, the use of thermometer wells or 
immersed sensors be used only at the condensing unit liquid outlet. DOE 
believes this may reduce testing burden in cases where labs have been 
using two sets of refrigerant-immersed temperature measurements when 
testing dedicated condensing units alone.
    Issue 13: DOE requests comment on its proposal to require use of 
thermometer wells or sheathed sensors immersed in the refrigerant when 
measuring temperature at the liquid outlet of the condensing unit and 
to forego the requirement for this measurement technique for the 
suction line when testing a dedicated condensing unit alone.
    DOE has found that implementing the current thermometer well 
requirement for refrigerant lines with outer diameter \1/2\-inch or 
less can restrict the refrigerant flow and thus affect the 
measurements. To rectify this issue and to ensure that all walk-in 
refrigeration systems can be tested according to the DOE test 
procedure, DOE proposes allowing an alternative approach when the 
refrigerant line tubing diameter is \1/2\-inch or less in which the 
temperature measurement would be made using two surface-mounted 
measuring instruments with a minimum accuracy of <plus-minus>0.5 
[deg]F, which would be averaged to obtain the reading. DOE notes that 
when using the Dual Instrumentation method described in Section C8 of 
AHRI 1250-2009 appendix C, the two surface measurements described would 
constitute one temperature measurement, rather than the two 
measurements required for the test method. Additionally, DOE proposes 
that the two measuring instruments must be mounted on the pipe 
separated by 180-degrees around the refrigerant tube circumference. To 
ensure measurements are not affected by changes in ambient temperature, 
DOE proposes requiring use of 1-inch-thick insulation around the 
measuring instruments that extends 6-inches up- and down-stream of the 
measurement locations. Where this technique is used to measure 
temperature at the expansion valve inlet, i.e., where Section C3.16 of 
AHRI 1250-2009 requires the measurement to be within 6 pipe diameters 
of the control device, DOE proposes to relax this requirement and 
require instead that the measurement be within 6 inches of the device.
    Issue 14: DOE requests comment on its proposal to allow the use of 
two temperature measuring instruments, placed on the outside of 
refrigerant tubing that is less than or equal to \1/2\-inch, for the 
measurement of refrigerant temperature where the current test procedure 
requirement is to use thermometer wells or a sheathed sensor immersed 
in the refrigerant.

[[Page 23948]]

3. Hierarchy of Installation Instructions and Specified Refrigerant 
Conditions for Refrigerant Charging and Setting Refrigerant Conditions
    During testing, DOE has found that some refrigeration systems 
cannot be set up fully consistent with the refrigerant conditions 
specified in installation instructions. In some cases, there may be 
multiple installation instructions (e.g., instructions on labels 
affixed to the unit and instructions shipped with the unit), and 
different results could be obtained depending on which instructions are 
followed. To address this issue, DOE has developed a setup hierarchy 
for installation instructions and setup of refrigerant conditions to 
improve repeatability in testing by indicating which manufacturer-
specified conditions would be prioritized during test setup. DOE's 
proposed setup hierarchy is discussed in more detail in the following 
paragraphs.
    Setup conditions or instructions may be stamped on the unit 
nameplate or otherwise affixed to the unit, shipped with the unit, or 
available online. DOE has encountered walk-in refrigeration units for 
which these three sources of instruction provide different values or 
conflicting directions. To ensure consistent setup during testing, DOE 
proposes that instructions or conditions stamped on or adhered to a 
test unit take precedence, followed by instructions shipped with the 
unit. Additionally, since online instructions can be easily revised, 
DOE proposes that instructions or other setup information found online 
would not be used to set up the unit for test.
    Setting of refrigerant charge level or refrigerant conditions is a 
key aspect of setup of refrigeration systems, whether for field use or 
testing. DOE proposes that units be charged and set up at operating 
conditions specified in the test procedure (for outdoor refrigeration 
systems, DOE proposes use of operating condition A) based on the 
installation instructions, using the proposed hierarchy (i.e., 
prioritize instructions stamped or adhered to unit over instructions 
included in a manual shipped with the unit). In the case where 
instructions for refrigerant charging or refrigerant conditions are 
provided only in online instructions or not at all, DOE is proposing 
that a generic charging approach be used instead. If the installation 
instructions specify operating conditions to use to set up the 
refrigerant charge or refrigerant conditions, that operating condition 
would be used rather than the conditions specified in the test 
procedure.
    DOE often finds that in some cases, the manufacturer specifies a 
range of conditions for superheat,\28\ subcooling, and/or refrigerant 
pressure. If this is the case, DOE proposes to treat the midpoint of 
that range as the target temperature/pressure, and that a test 
condition tolerance would be applied to the parameter that is equal to 
half the range. For example, if a manufacturer specifies a target 
superheat of 5 to 10 [deg]F, the target for test would be 7.5 [deg]F 
and that the average value during operation at the setup operating 
conditions would have to be 7.5 [deg]F <plus-minus> 2.5 [deg]F. 
Alternatively, installation instructions may specify a refrigerant 
condition value without a range or without indicated tolerances. In 
such cases, DOE proposes that standardized tolerances be applied as 
indicated in Table III.6. These tolerances depend on the kind of 
refrigerant expansion device used.
---------------------------------------------------------------------------

    \28\ Superheat is the difference between vapor-phase refrigerant 
temperature and the dew point corresponding to the pressure level.
---------------------------------------------------------------------------

    DOE also notes that zeotropic \29\ refrigerants have become more 
common. When charging with such refrigerants (i.e., any 400 series 
refrigerant), DOE proposes that the refrigerant charged into the system 
must be in liquid form. This is standard practice for charging of such 
refrigerants since the concentrations of the components of the blend 
present in the vapor phase of the charging cylinder are often skewed 
from the intended concentrations of the refrigerant blend.
---------------------------------------------------------------------------

    \29\ A zeotropic refrigerant is a blend of two or more 
refrigerants that have different boiling points. Each refrigerant 
will evaporate and condense at different temperatures.
---------------------------------------------------------------------------

    If the installation instructions on the label affixed to (or 
shipped with) the unit do not provide instructions for setting 
subcooling or otherwise how to charge it with refrigerant for a 
condensing unit tested alone, or tested as part of a matched pair, DOE 
proposes requiring that the unit be tested in a way that is consistent 
with the DOE test procedure and the installation instructions and also 
does not cause the unit to stop operating during testing, e.g., by 
shutoff by the high pressure switch. DOE believes that such 
installation would be most representative of the way a technician would 
set up a system in the field if there were no refrigerant charge or 
subcooling instructions.
a. Dedicated Condensing Unit Charging Instructions
    For dedicated condensing units tested alone, subcooling is the 
primary setup condition. DOE is proposing that if the dedicated 
condensing unit includes a receiver and the subcooling target leaving 
the condensing unit provided in the installation instructions cannot be 
met without fully filling the receiver, the subcooling target would be 
ignored. Likewise, if the dedicated condensing unit does not include a 
receiver and the subcooling target leaving the condensing unit cannot 
be met without the unit cycling off on high pressure, the subcooling 
target would be ignored. Also, if no instructions for charging or for 
setting subcooling leaving the condensing unit are provided in the 
installation instructions, DOE is proposing that the refrigeration 
system would be set up with a charge quantity and/or exit subcooling 
such that the unit operates during testing without shutdown (e.g., on a 
high-pressure switch) and operation of the unit is otherwise consistent 
with the requirements of the test procedure and the installation 
instructions.
b. Unit Cooler Charging Instructions
    For unit coolers tested alone, superheat is the primary setup 
condition. Most WICF refrigeration systems use either thermostatic or 
electronic expansion valves that respond either mechanically or through 
a controller to adjust valve position to control for superheat leaving 
the unit cooler. If the unit under test is shipped with an adjustable 
expansion device, DOE proposes that this would be the primary method to 
adjust superheat. However, DOE has encountered units with expansion 
devices that are not adjustable or where the expansion device does not 
provide a sufficient range of adjustment to achieve the superheat 
target. If the expansion valve associated with the unit under test 
reaches its limit before the superheat target is met, the specified 
superheat may not be met within the specified tolerance. In this case, 
DOE proposes that the expansion valve should be left at the adjustment 
limit achieving the closest match to the superheat target.
    DOE has also encountered mis-matched expansion devices and unit 
coolers. In this situation, DOE proposes that any expansion device 
specified for use with the unit cooler in manufacturer literature may 
be used for the purposes of DOE testing.
    Also, DOE proposes that an operating tolerance would not apply to 
superheat. Hence, in the event that the expansion valve control of the 
systems is not steady, i.e., if so-called ``hunting'' occurs, in which 
the valve position, temperatures, and/or pressures are unsteady, this 
fluctuation would not

[[Page 23949]]

invalidate a test. However, if the fluctuations are so great that a 
valid test cannot be performed (i.e., any individual measurement of 
superheat during the test is zero or less, or if the operating 
tolerances for measurements that would be affected by expansion device 
hunting are exceeded (mass flow, pressure at the unit cooler exit, 
evaporator temperature difference),\30\ the test procedure would call 
for remedial action allowing deviation from the installation 
instructions. The remedial action would be, at the discretion of the 
test laboratory, replacing the expansion device with a different 
expansion device that does not need to be listed in installation 
instructions, adjusting the expansion device to provide an average 
superheat that is greater than the target superheat, or both.
---------------------------------------------------------------------------

    \30\ Evaporator Temperature Difference (TD) is the difference in 
temperature between the entering air and the refrigerant dew point 
of the exiting refrigerant.
---------------------------------------------------------------------------

    If the installation instructions on the label affixed to the unit 
or shipped with the unit do not provide instructions for setting 
superheat for a unit cooler tested alone or tested as part of a matched 
pair, DOE proposes that the target superheat would be 6.5 [deg]F, the 
same value required in such circumstances in AHRI 1250-2020 (see 
footnotes to Tables 16 and 17 of AHRI 1250-2020).
c. Single-Packaged Dedicated System Setup and Charging Instructions
    DOE has identified multiple setup issues while testing single-
packaged dedicated systems. Compared to split refrigeration 
systems,\31\ single-packaged dedicated systems have less adjustment 
flexibility due to lack of controls. Additionally, many single-packaged 
dedicated systems are marketed as ``fully charged''; therefore, it 
could be assumed that the charge would not need to be adjusted.
---------------------------------------------------------------------------

    \31\ ``Split refrigeration systems'' refer to systems made up of 
a condensing unit and a unit cooler that are connected by 
refrigerant lines and are not contained in a single housing. Split 
refrigeration systems could be field-matched condensing units and 
unit coolers or condensing units and unit coolers sold as matched 
pairs.
---------------------------------------------------------------------------

    DOE proposes that one or more pressure gauges, depending on the 
number of conditions which require a pressure measurement for 
validation, should be installed during the setup according to 
installation instructions to evaluate the charge of the unit under test 
and to accurately measure setup conditions. The location of the 
pressure gauge(s) would depend on the test setup conditions given in 
the installation instructions. If charging is based on subcooling or 
liquid pressure, DOE proposes that the pressure gauge would be 
installed at the service valve of the liquid line. If charging is based 
on superheat, low side pressure, or a corresponding saturation 
temperature/dew point temperature, DOE proposes that the pressure 
gauge(s) would be placed in the suction line.
    DOE is aware that installation instructions for some single-
packaged dedicated systems recommend against installing charging ports; 
however, DOE has observed through testing that some of these units do 
not operate once installed due to high- or low-pressure compressor cut 
off, which is often a symptom of under- or over-charging or refrigerant 
loss. These units are representative of what a contractor would 
encounter when installing a walk-in single-packaged unit in the field. 
Therefore, in cases where a unit under test is not operating due to 
high- or low-pressure compressor cut off, DOE proposes a charging port 
should be installed, the unit should be evacuated, and the nameplate 
charge should be added. This approach would eliminate under- or over-
charging of the unit which would address compressor cut off.
d. Hierarchy of Setup Conditions if Manufacturer-Specified Setup 
Conditions Cannot be Met
    In DOE's experience, even when all the previously discussed 
measures are implemented during test setup, some manufacturer specified 
setup conditions may not be met. If this is the case, DOE is proposing 
that the unit under test be set up according to a hierarchy of 
conditions similar to those used for central air-conditioning systems 
and heat pumps. First, the installation instruction hierarchy 
previously discussed would be applied. Specifically, if a refrigerant-
related setup instruction in the installation instructions affixed to 
the unit and a different instruction in the installation instructions 
shipped with the unit cannot both be achieved within tolerance, the 
instruction on the label takes precedence. Further, if multiple 
instructions within the relevant installation instructions cannot be 
met, the proposed hierarchy outlined in Table III.6 would be applied. 
The highest priority condition that can be satisfied, based on Table 
III.6, would need to be met, depending on what kind of expansion device 
the system uses. This approach would ensure that units are set up 
consistently across testing facilities, ensuring more consistent 
results.

    Table III.6--Test Condition Tolerances and Hierarchy for Refrigerant Charging and Setting of Refrigerant
                                                   Conditions
----------------------------------------------------------------------------------------------------------------
                Fixed orifice or capillary tube                                  Expansion valve
----------------------------------------------------------------------------------------------------------------
     Priority           Method               Tolerance             Priority          Method         Tolerance
----------------------------------------------------------------------------------------------------------------
1                  Superheat.......  <plus-minus>2.0 [deg]F...               1  Subcooling.....  10% of the
                                                                                                  Target Value;
                                                                                                  No less than
                                                                                                  <plus-
                                                                                                  minus>0.5
                                                                                                  [deg]F, No
                                                                                                  more than
                                                                                                  <plus-
                                                                                                  minus>2.0
                                                                                                  [deg]F.
2                  High Side         <plus-minus>4.0 psi or                  2  High Side        <plus-minus>4.0
                    Pressure or       <plus-minus>1.0 [deg]F.                    Pressure or      psi or <plus-
                    Saturation                                                   Saturation       minus>1.0
                    Temperature.                                                 Temperature.     [deg]F.
3                  Low Side          <plus-minus>2.0 psi or                  3  Superheat......  <plus-minus>2.0
                    Pressure or       <plus-minus>0.8 [deg]F.                                     [deg]F.
                    Saturation
                    Temperature.
4                  Low Side          <plus-minus>2.0 [deg]F...               4  Low Side         <plus-minus>2.0
                    Temperature.                                                 Pressure or      psi or <plus-
                                                                                 Saturation       minus>0.8
                                                                                 Temperature.     [deg]F.
5                  High Side         <plus-minus>2.0 [deg]F...               5  Approach         <plus-minus>1.0
                    Temperature.                                                 Temperature.     [deg]F.
6                  Charge Weight...  <plus-minus>2.0 oz.......               6  Charge Weight..  0.5% or 1.0 oz,
                                                                                                  whichever is
                                                                                                  greater.
----------------------------------------------------------------------------------------------------------------


[[Page 23950]]

    Issue 15: DOE requests comment on its proposals discussed in this 
section regarding set up of walk-in refrigeration systems for testing 
to achieve manufacturer-specified conditions for superheat, subcooling, 
high-side temperature, pressure or saturation temperature, low-side 
temperature, pressure or saturation temperature, and refrigerant charge 
weight. Additionally, DOE requests comment on the proposed hierarchy 
presented in Table III.6, if a laboratory has confirmed that the unit 
is properly charged.
4. Subcooling Requirement for Mass Flow Meters
    DOE has found that for testing dedicated condensing units alone an 
appropriate subcooling temperature ensures that the refrigerant is 
fully liquid at the mass flow meter, providing an accurate measurement. 
A mass flow meter may provide an inaccurate flow rate if the 
refrigerant is a mixture of vapor and liquid at the point of 
measurement. Section C3.4.5 of AHRI 1250-2009 appendix C requires that 
refrigerant be subcooled to at least 3 [deg]F and that bubbles not be 
visible in a sight glass immediately downstream of the mass flow meter. 
Section 3.2.3 of subpart R, appendix C, allows use of the sight glass 
and a temperature sensor located on the tube surface under the 
insulation to verify sufficient subcooling. DOE testing has also shown 
that even when the subcooling requirement is met downstream of the mass 
flow meters, the subcooling can be significantly lower upstream of the 
mass flow meters, resulting in questionable mass flow measurements that 
do not provide capacity determinations within the required tolerances, 
e.g., with 5 percent of each other as required by Section C8.5.3 of 
AHRI 1250-2009 (see EERE-2017-BT-TP-0010-0021, ``Development of Test 
Rating Conditions for Two-Capacity, Multiple-Capacity, and Variable-
Capacity Condensing Units''). DOE proposes to add further instruction 
to section 3.2.3 of subpart R, appendix C.
    First, DOE proposes that the 3 [deg]F subcooling requirement be 
applied at a location depending on location of the liquid-line mass 
flow meters. Specifically, the requirement would apply downstream of 
any mass flow meter located in the chamber in which the condensing unit 
under test is located, consistent with AHRI 1250-2009. However, for 
mass flow meters located in the chamber in which the unit cooler under 
test is located, the subcooling would have to be verified upstream of 
the mass flow meter. The latter requirement addresses observation in 
DOE testing that the upstream subcooling is less than the downstream 
subcooling when the mass flow meter is in the same chamber as the unit 
cooler. Id. This occurs because the unit cooler chamber is generally 
much cooler than the liquid refrigerant.\32\ Since mass flow meters are 
rarely insulated, the liquid refrigerant is cooled as it passes through 
the mass flow meter, which increases the refrigerant's subcooling. 
However, as the liquid refrigerant passes through the mass flow meter 
it also experiences a pressure drop which decreases the subcooling. The 
increase in subcooling that occurs across the mass flow meter is nearly 
always larger than the decrease in subcooling that occurs because of 
the pressure drop across the mass flow meter. Therefore, subcooling 
will nearly always be less at the inlet of a mass flow meter than at 
the outlet. This is in contrast to a mass flow meter located in the 
same chamber as the condensing unit, for which the air surrounding the 
mass flow meter, while typically cooler than the liquid, would be much 
closer in temperature to the liquid temperature.\33\ DOE also notes 
that the requirement for subcooling specified in ASHRAE 23.1-2010, 
which is incorporated by reference by the DOE test procedure for 
testing of condensing units alone, indicates in section 7.1.2 
(``Adequate subcooling shall be provided upstream of a liquid 
refrigerant flowmeter . . .'') suggesting that there is a lack of 
clarity regarding the best location for ensuring adequate subcooling. 
Based on DOE's experience and the prevailing air-liquid temperature 
differences during testing, DOE proposes to include the clarification 
above regarding the location of the subcooling verification.
---------------------------------------------------------------------------

    \32\ For example, when testing a matched pair refrigerator 
system under test condition A, the condensing unit chamber air 
temperature is at 95 [deg]F and the unit cooler chamber air is at 35 
[deg]F. The liquid refrigerant generally is warmer than the 
condensing unit ambient temperature. Hence, there is at least a 60 
[deg]F temperature difference between the unit cooler inlet air 
temperature and the liquid refrigerant temperature.
    \33\ For the same example, the liquid temperature may be in the 
range roughly from 95 [deg]F to 105 [deg]F, at most about 10 [deg]F 
warmer than the surrounding air.
---------------------------------------------------------------------------

    Second, DOE proposes to indicate that active cooling of the liquid 
line may be used to achieve the required subcooling, since the 
subcooling at the mass flow meter outlet may not meet the 3 [deg]F 
requirement when the subcooling at the condensing unit exit is within 
tolerance of its target. However, DOE also proposes requiring that if 
this is done when testing a matched pair (not including single-packaged 
dedicated systems), that the temperature also must be measured upstream 
of the location where cooling is provided, and that the temperature 
used to calculate the enthalpy of the refrigerant entering the unit 
cooler be increased by the difference between the upstream and 
downstream measurements. DOE is proposing this adjustment so that 
active cooling of the liquid to obtain a mass flow measurement does not 
provide a non-representative boost in calculated cooling capacity.
    DOE proposes to add these requirements to subpart R, appendix C, 
which would also carry over to the newly proposed subpart R, appendix 
C1.
    Issue 16: DOE requests comments on its proposal to clarify the 
location where the 3 [deg]F subcooling requirement would apply and to 
require active cooling of the liquid line in order to achieve the 
required 3 [deg]F subcooling at a refrigerant mass flow meter. DOE also 
seeks comment on its proposal to require, for matched pairs, adjustment 
of the measured unit cooler inlet temperature by the difference in 
temperatures measured upstream and downstream of the active cooling in 
order to calculate the inlet enthalpy in the capacity calculation.
5. Instrument Accuracy and Test Tolerances
    As discussed in section III.B.3.a, AHRI 1250-2020 has adopted 
language from the current DOE test procedure covering test tolerances 
and instrumentation accuracy. Additionally, as discussed in section 
III.B.3.d, some tolerances and instrumentation accuracy requirements in 
AHRI 1250-2020 are not consistent with the current DOE test procedure. 
DOE is proposing to adopt these changes from AHRI 1250-2020 into 
subpart R, appendix C, as DOE has tentatively determined these changes 
would not have an effect on measured values.
    AHRI 1250-2020 changes the measurement accuracy for the temperature 
of air entering or leaving either the evaporator or condenser to <plus-
minus> 0.25 [deg]F from <plus-minus> 0.2 [deg]F in AHRI 1250-2009. DOE 
notes that <plus-minus> 0.25 [deg]F is the standard minimum accuracy 
across many Heating, Ventilation and Air-Conditioning (``HVAC'') 
testing standards. Since AHRI 1250-2020 references AHSRAE 37-2009 for 
single-packaged testing, it simplifies the test procedure to have the 
same instrument accuracy requirements across both standards. In 
addition, providing a consistent minimum accuracy across test 
procedures reduces laboratory test burden and DOE expects it may 
benefit a laboratory's quality control. DOE is

[[Page 23951]]

proposing that the temperature measurement of air entering or leaving 
either the compressor or evaporator would have a minimum accuracy of 
<plus-minus> 0.25 [deg]F. DOE does not expect this modification to have 
a significant impact on measured values. Additionally, the proposed 
tolerance is greater than the current tolerance and therefore if 
adopted it would not require manufacturers to retest. DOE does not 
expect that the changed tolerance would impact the representativeness 
of the results. As noted, the proposed tolerance is that generally used 
for HVAC systems.
    As discussed in section III.B.3.d, AHRI 1250-2020 does not 
reference ASHRAE 23 or AHRI 420 for the testing of dedicated condensing 
units and unit coolers, respectively. As such, the ASHRAE 23 
refrigerant mass flow operating tolerance of <plus-minus> one percent 
of the quantity measured has been replaced in Table 2 of AHRI 1250-2020 
by an operating tolerance of 3 pounds per hour (``lb/h'') or 2 percent 
of the reading (whichever is greater). DOE notes that the requirement 
for a one percent mass flow tolerance posed challenges for test labs 
when at very low flow rates (near 0 lb/h). Specifically, as mass flow 
approaches 0 lb/h, the acceptable deviation from the average also 
approaches zero resulting in an unrealistic accuracy target. This issue 
would not occur with the minimum accuracy provided in AHRI 1250-2020 
because the acceptable deviation from the average must be within <plus-
minus> 3 lb/h if the variation is less than 2 percent of the mass flow 
reading. As such, DOE is proposing to adopt the mass flow tolerance 
specified in Table 2 of AHRI 1250-2020 into subpart R, appendix C. DOE 
does not expect that this modification would have a significant impact 
on capacity and AWEF values, and therefore would not require retesting 
or recertification.
6. CO<INF>2</INF> Unit Coolers
    All refrigerants have a ``critical pressure'' and an associated 
``critical temperature'' above which liquid and vapor phases cannot 
coexist. Above this critical point, the refrigerant will be a gas and 
its temperature will increase or decrease as heat is added or removed. 
For all conventional refrigerants, the critical pressure is so high 
that it is never exceeded in typical refrigeration cycles. For example, 
R404A is a common refrigerant used in refrigeration systems that has a 
critical pressure of 540.8 psia \34\ with an associated critical 
temperature of 161.7 [deg]F. However, CO<INF>2</INF> behaves 
differently, with a critical pressure of 1,072 psia associated with a 
lower critical temperature of 87.8 [deg]F. The refrigerant temperature 
must be somewhat higher than the ambient temperature in order to reject 
refrigeration cycle heat to the ambient environment. Ambient 
temperatures greater than 87.8 [deg]F are common and the performance of 
many refrigeration and air conditioning systems are tested using a 95 
[deg]F ambient temperature, as indicated by the A test condition in 
Section 5 of AHRI 1250-2009 (and AHRI 1250-2020). At temperatures 
greater than the critical temperature, the CO<INF>2</INF> refrigerant 
is in a supercritical state (i.e., a condition with pressure above the 
critical temperature). Since useful cooling is provided below the 
critical temperature, CO<INF>2</INF> cycles are said to be 
transcritical.
---------------------------------------------------------------------------

    \34\ Absolute pressure is the pressure measured relative to a 
complete vacuum; ``psia'' represents the absolute pressure in pounds 
per square inch.
---------------------------------------------------------------------------

    DOE has granted test procedure waivers to the manufacturers listed 
in Table III.1 for certain basic models of walk-in refrigeration 
systems that use CO<INF>2</INF> as a refrigerant. Manufacturers 
requesting a waiver from the DOE test procedure for CO<INF>2</INF> unit 
coolers stated that the test conditions described in Tables 15 and 16 
of AHRI 1250-2009, as incorporated by subpart R, appendix C, with 
modification, cannot be achieved by, and are not consistent with the 
operation of, CO<INF>2</INF> direct expansion unit coolers. These 
manufacturers also specified that CO<INF>2</INF> has a critical 
temperature of 87.8 [deg]F, and therefore the required liquid inlet 
saturation temperature of 105 [deg]F and the required liquid inlet 
subcooling temperature of 9 [deg]F as specified in the DOE test 
procedure are not achievable. The alternate test procedure provided in 
these waivers modifies the test condition values to reflect typical 
operating conditions for a transcritical CO<INF>2</INF> booster system. 
Specifically, the waiver test procedures require that CO<INF>2</INF> 
unit cooler testing is conducted at a liquid inlet saturation 
temperature of 38 [deg]F and a liquid inlet subcooling temperature of 5 
[deg]F. CO<INF>2</INF> that is cooled in the gas cooler of a 
transcritical booster system expands through a high-pressure control 
valve that delivers CO<INF>2</INF> to a subcritical-pressure flash 
tank, where liquid and vapor phases of the refrigerant are separated. 
The liquid is then split, and the unit cooler, regardless of 
refrigerated storage space temperature, receives the refrigerant at the 
same condition. This applies to both medium- and low-temperature 
systems.
    In the June 2021 RFI, DOE requested comment on whether the test 
conditions provided in the waivers are appropriate and if there are 
additional modifications that could more accurately evaluate the energy 
use of these systems while minimizing test burden. 86 FR 32332, 32346. 
Lennox, AHRI, National Refrigeration, and Hussmann recommended that DOE 
use the conditions provided in the waivers for CO<INF>2</INF> unit 
coolers. (Lennox, No. 9 at p. 7; AHRI, No. 11 at p. 12; National 
Refrigeration, No. 17 at p. 1; Hussmann, No. 18 at p. 14)
    In the June 2021 RFI, DOE also requested comment on the present and 
future expected use of CO<INF>2</INF> systems and information about 
such systems that would suggest a need to modify the DOE test 
procedure. 86 FR 32332, 32346. Lennox, AHRI, and Hussmann stated that 
some CO<INF>2</INF> units, not available in the U.S., may supply 
subcritical liquid or supercritical gas at the expansion valve, while 
some condensing units with integrated expansion valves supply two-phase 
CO<INF>2</INF> to evaporators. (Lennox, No. 9 at pp. 7-8; AHRI, No. 11 
at pp. 12-13; Hussmann, No. 18 at p. 14) For units where the 
CO<INF>2</INF> leaving the condensing unit is supercritical or two-
phase, Lennox, AHRI, and Hussmann recommended setting temperature and 
pressure conditions; for condensing units providing subcritical liquid 
to unit cooler expansion devices, these stakeholders suggested that the 
test method provided in the waivers should be used. (Lennox, No. 9 at 
p. 8; AHRI, No. 11 at p. 13; Hussmann, No. 18 at p. 14) Lennox, AHRI, 
and Hussmann additionally stated that while CO<INF>2</INF> condensing 
units with a single compression stage and conventional HFC units can be 
tested using the same method, an intermediate pressure that is the same 
as the liquid supply conditions in the waiver test procedures must be 
specified for units with two stages of compression. Id. Lennox 
recommended evaluating the potential energy savings of CO<INF>2</INF> 
units to see if additional changes are warranted. (Lennox, No. 9 at p. 
7) The CA IOUs suggested that DOE differentiate AWEF ratings of units 
using CO<INF>2</INF> and units using traditional refrigerants. (CA 
IOUs, No. 14 at p. 4) Additionally, the CA IOUs urged DOE to ensure 
that the walk-in test procedures and metrics continue to provide 
consumers with the information necessary to easily compare the 
performance of products with the same utility. Id.
    DOE acknowledges that a goal of its test procedures is to provide 
purchasers

[[Page 23952]]

with an energy use metric that is consistent across products that 
provide similar utility. In response to the comment by Lennox, DOE 
would evaluate the potential energy savings of CO<INF>2</INF> units as 
part of a separate, future energy conservation standards rulemaking. 
DOE investigation confirms that there are no known sales of 
CO<INF>2</INF> dedicated condensing units in the U.S. The only relevant 
CO<INF>2</INF> system architecture in the U.S. appears to be 
CO<INF>2</INF> booster systems using unit coolers operating with 
conditions consistent with the waivers.
    DOE also evaluated if the current AWEF calculation for unit coolers 
tested alone could be applied to CO<INF>2</INF> unit coolers. The 
current calculation uses an EER to determine the representative 
compressor power consumption. The EER values used are in Table 18 of 
AHRI 1250-2020 and are based on typical traditional refrigerant 
compressor efficiency. DOE has tentatively determined that the EER 
values used for the AWEF calculations of traditional unit coolers can 
also be used for CO<INF>2</INF> unit coolers. DOE research into the 
performance of different configurations of CO<INF>2</INF> booster 
systems shows that enhanced CO<INF>2</INF> cycles can match 
conventional refrigerants in average annual efficiency. These data and 
studies help to justify the use of the EER values in Table 18 of AHRI 
1250-2020 for determining the power consumption of CO<INF>2</INF> 
booster system unit coolers, even though these EER values were 
initially established for conventional refrigerants.
    In this NOPR, DOE is proposing to adopt in subpart R, appendix C 
(and also appendix C1), the alternate test conditions specified in the 
waivers that DOE granted for CO<INF>2</INF> transcritical unit coolers 
for all CO<INF>2</INF> unit coolers. Also, consistent with the waiver 
alternate test procedures, DOE proposes that the established EER values 
be used to determine compressor power found in Table 17 of AHRI 1250-
2009 (or Table 18 of AHRI 1250-2020 for appendix C1) would be used to 
determine the AWEF of all CO<INF>2</INF> unit coolers.
    Issue 17: DOE requests comment on the appropriateness of 
traditional refrigerant compressor EER values for use in CO2 unit 
cooler AWEF calculations.
7. High-Temperature Unit Coolers
    As discussed in the June 2021 RFI, DOE is aware of wine cellar 
(high-temperature) refrigeration systems that fall within the walk-in 
definition but that may be incapable of being tested in a manner that 
would yield representative performance results during a representative 
average use cycle under the current version of the walk-in test 
procedure. 86 FR 32332, 32344. For example, wine cellar refrigeration 
systems that may be installed in some commercial settings are designed 
to operate at a temperature range of 45 [deg]F to 65 [deg]F.
    High-temperature refrigeration systems are discussed generally in 
section III.G.6. Most of these refrigeration systems are either a 
single-packaged dedicated system or a matched pair. However, DOE has 
also received a petition for waiver for high-temperature unit coolers 
that are distributed into commerce without a paired condensing 
system.\35\ These unit cooler-only models would be tested according to 
the provisions in the test procedure for unit coolers tested alone, for 
which calculation of AWEF requires use of an appropriate EER based on 
the suction dew point temperature. Table 17 in AHRI 1250-2009 provides 
EER values for medium- and low-temperature unit coolers tested alone. 
However, DOE has tentatively determined that these values are not 
appropriate for calculating AWEF for high-temperature unit coolers 
because this equipment operates with a different suction dew point 
temperature and the counterpart dedicated condensing units likely use 
different compressor designs than those considered when developing the 
EER values included in AHRI 1250-2020.
---------------------------------------------------------------------------

    \35\ LRC Coil Company submitted a petition for waiver and 
interim waiver for specific basic models of unit cooler only walk-in 
wine cellar refrigeration systems. (LRC Coil, EERE-2020-BT-WAV-0040, 
No. 1) In reviewing another petition for waiver and interim waiver 
from Vinotheque for single-packaged system and matched pair system 
basic models (Vinotheque, EERE-2019-BT-WAV-0038, No. 6), DOE noted 
that the manufacturer also offered unit cooler-only systems 
distributed without a paired condensing system.
---------------------------------------------------------------------------

    In the June 2021 RFI, DOE requested data on appropriate EER values 
for use with high-temperature unit coolers and questioned how these 
values might depend on refrigerant or capacity. 86 FR 32332, 32345. 
AHRI stated that they did not have data to support EER values for use 
in determining AWEF for wine cellar unit coolers since most systems are 
sold as a matched pair. (AHRI, No. 11 at p. 11) In the June 2021 RFI, 
DOE also requested information on dedicated condensing units that would 
typically be paired with high-temperature unit coolers. 86 FR 32332, 
32345-32346. Lennox and AHRI stated that there are no definitive 
characteristics for unit coolers that are sold for use in wine cellar 
refrigeration applications, and that many units are sold to users as 
pairs matched by contractors. (Lennox, No. 9 at pp. 6-7; AHRI, No. 11 
at pp. 11-12)
    In its market evaluation, DOE has observed that a majority of high-
temperature refrigeration systems are sold as matched pairs or single-
packaged systems. While unit coolers sold for high-temperature walk-in 
cooler applications are sold separately, DOE was unable to find any 
dedicated condensing units marketed specifically for high-temperature 
walk-in applications. Thus, DOE could not use the performance data of 
such dedicated condensing unit models to provide an indication of the 
appropriate EER for dedicated condensing units paired with such high-
temperature unit coolers. Rather, consistent with the interim waiver 
granted to LRC, DOE is proposing EER values developed using compressor 
performance data from Emerson and Tecumseh product websites (EERE-2020-
BT-WAV-0040, No. 2 and No. 8, respectively) for high-temperature 
refrigeration compressor models within the applicable capacity range 
(2,900 Btu/h to 36,000 Btu/h). DOE expects that the dedicated 
condensing units paired with high-temperature walk-in unit coolers 
would use hermetic reciprocating compressors at lower capacities and 
hermetic scroll compressors at higher capacities. Also, DOE developed 
the EER values based on compressors rated for use with HFC-134a, R404A, 
or R407C refrigerants. Based on these compressor performance data, DOE 
calculated representative compressor EER levels for wine cellar walk-in 
unit coolers using the following parameters:
    <bullet> 38 [deg]F unit cooler exit dew point condition, as 
suggested by LRC (EERE-2020-BT-WAV-0040, No. 1 at p. 3).
    <bullet> 2 [deg]F equivalent suction line dew point pressure drop, 
consistent with AHRI 1250-2009 section 7.9.1.
    <bullet> 7 [deg]F evaporator exit superheat, rounding to whole 
number values of the 6.5 [deg]F superheat test condition prescribed in 
the footnote to Table 15 of subpart R, appendix C, in case a value is 
not provided in an installation manual.
    <bullet> 55 [deg]F refrigerant temperature entering the compressor, 
representing a 10 [deg]F refrigerant vapor temperature rise in the 
suction line, consistent with the temperature rise implied for medium-
temperature refrigeration system test conditions.\36\
---------------------------------------------------------------------------

    \36\ AHRI 1250-2009 Table 11 prescribes a return gas temperature 
(measured at the condensing unit inlet location) equal to 41 [deg]F 
for testing medium temperature dedicated condensing units. Also, 
Table 15 and section 3.3.1 of appendix C prescribe testing medium-
temperature unit coolers using 25 [deg]F saturated suction 
temperature (this is the same as unit cooler exit dew point 
temperature), and 6.5 [deg]F superheat (in case the installation 
manual doesn't provide superheat requirements). Thus, the unit 
cooler exit temperature would be 25 [deg]F + 6.5 [deg]F = 31.5 
[deg]F, and the implied suction line temperature rise is 41 [deg]F- 
31.5 [deg]F = 9.5 [deg]F. The analysis conducted for wine cellars 
rounds this to 10 [deg]F.

---------------------------------------------------------------------------

[[Page 23953]]

    <bullet> 90 [deg]F annual average condensing temperature. This 
assumes that the condensing unit serving the unit cooler would be 
located outdoors and that head pressure control would prevent 
excessively cold condensing operation at cold outdoor temperatures.\37\
---------------------------------------------------------------------------

    \37\ ``Head pressure control'' refers to the reduction of 
condenser heat transfer performance using fan cycling or other means 
when it is cold outside in order to avoid unusually low condensing 
temperature. Such low condensing temperatures are undesirable 
because they can reduce refrigeration system performance and/or 
increase risk of compressor damage. A typical minimum condensing 
temperature is 70 [deg]F, which may apply whenever outdoor 
temperature is lower than 50 [deg]F. DOE selected the 90 [deg]F 
annual average to be representative of operation that would involve 
condensing temperature ranging from 70 [deg]F to 120 [deg]F, since 
outdoor temperature varies.
---------------------------------------------------------------------------

    DOE plotted the calculated compressor EER values versus calculated 
unit cooler capacity and noted that the EER can significantly vary with 
capacity. (EERE-2020-BT-WAV-0040, No. 9) EER is generally lower for 
low-capacity compressors and higher for high-capacity compressors, with 
a transition region in between. Based on the plotted calculations, DOE 
determined for the purpose of the interim waiver that a representative 
value for EER should depend on capacity. As such, DOE developed 
different functions of EER for three distinct capacity ranges. Table 
III.7 summarizes these capacity ranges and EER functions for high-
temperature compressors.

 Table III.7--EER Values for High Temperature Compressors as a Function
         of Capacity for High-Temperature Refrigeration Systems
------------------------------------------------------------------------
             Capacity (Btu/hr)                      EER (Btu/Wh)
------------------------------------------------------------------------
<10,000...................................  11
10,000-19,999.............................  (0.0007 x Capacity) + 4
20,000-36,000.............................  18
------------------------------------------------------------------------

    The LRC interim waiver includes additional test procedure 
provisions to obtain representations that are representative for high-
temperature unit coolers, including both testing requirements and AWEF 
calculation requirements. These include provisions for setting ducted 
fan-coil unit evaporator systems.
    DOE proposes to include provisions for testing high-temperature 
unit coolers in subpart R, appendix C. These provisions, consistent 
with the LRC interim waiver, would include test conditions for testing 
these unit coolers at high-temperature refrigeration conditions, as 
well as EER values described previously for calculation of AWEF. DOE 
also proposes to include these provisions in appendix C1.
    Issue 18: DOE requests comment on its proposals to adopt test 
procedure provisions for high-temperature unit coolers in appendices C 
and C1 of 10 CFR part 431, subpart R.

G. Proposal To Establish Appendix C1

    In this NOPR, DOE is proposing to establish a new appendix C1 to 
subpart R of part 431, which would be required to demonstrate 
compliance coincident with the compliance date of any amended energy 
conservation standards that DOE may promulgate as part of a separate 
standards rulemaking. Certain proposed modifications to the test 
procedure are expected to alter measured values, and such changes are 
contained in the proposed appendix C1. DOE has tentatively determined 
that AHRI 1250-2020 improves representativeness of the walk-in 
refrigeration system test procedure by incorporating off-cycle 
measurement for components in addition to off-cycle fan power and 
providing test options for single-packaged dedicated systems, in 
addition to other changes. Therefore, DOE is proposing to incorporate 
AHRI 1250-2020 by reference into its proposed test procedure at 
appendix C1 for walk-in refrigeration systems.
    Lennox, AHRI, Keeprite, National Refrigeration, and Hussmann 
commented in response to the June 2021 RFI, that adopting the changes 
to AHRI 1250-2020 in the DOE test procedure would result in different 
energy consumption measurements. (Lennox, No. 9 at p. 2; AHRI, No. 11 
at p. 4; Keeprite, No. 12 at p. 1; National Refrigeration, No 17 at p. 
1; Hussmann, No. 18 at p. 6) DOE has tentatively determined that 
certain changes in AHRI 1250-2020, if adopted in DOE's test procedure, 
would impact measured values as compared to the current DOE test 
procedure. As discussed in the following paragraphs, DOE proposes to 
adopt such provisions in the newly proposed appendix C1 through refence 
to AHRI 1250-2020 and proposes that appendix C1 would not be required 
for testing until such time as compliance is required with amended 
energy conservation standards for walk-ins that are based on testing 
according to appendix C1, should DOE adopt such standards.
    The test procedure changes that DOE proposes to include in a newly 
proposed appendix C1 are discussed in the following sections. DOE 
expects these changes to improve the representativeness and 
applicability of the test procedure for walk-in refrigeration systems.
1. Off-Cycle Power Consumption
    For walk-in refrigeration systems, the term off-cycle refers to the 
period when the compressor is not running and defrost (if applicable) 
is not active. During off-cycle, unit cooler fans and other auxiliary 
equipment (i.e., crankcase heater, receiver heater, etc.) \38\ may 
typically run or cycle on and off, consuming energy. The DOE test 
procedure currently accounts for only unit cooler fan energy use during 
the off-cycle period. 10 CFR part 431, subpart R, appendix C, section 
3.3.3. Specifically, the current test procedure requires manufacturers 
to measure the integrated average off-cycle fan wattage \39\ for 
matched pair and unit coolers tested alone. Dedicated condensing units 
tested alone use default fan energy values rather than tested values. 
10 CFR part 431, subpart R, appendix C, section 3.4.2.2. When 
calculating AWEF, the unit cooler fans are assumed to run at this 
average integrated wattage throughout the entire off-cycle duration. 
Id.
---------------------------------------------------------------------------

    \38\ A crankcase heater prevents refrigerant migration and 
mixing with the crankcase oil when the compressor is off by heating 
the crankcase of the compressor. A receiver heater warms refrigerant 
in the receiver to prevent flooded starts of the compressor and 
cycling on low pressure to reduce the potential for compressor 
damage. They are used for outdoor dedicated condensing units in 
colder climates.
    \39\ Fans using periodic stir cycles are tested at the greater 
of a 50% duty cycle or the manufacturer default. Fans with two, 
multi-, or adjustable-speed controls are tested at the greater of 
50% fan speed or the manufacturer's default fan speed. Fans with no 
controls are tested at their single operating point. (See 10 CFR 
part 431, subpart R, appendix C, section 3.3.3).
---------------------------------------------------------------------------

    In the June 2021 RFI, DOE discussed the recommendations of the 
ASRAC Working Group (See Docket No. EERE-2015-BT-STD-0016, No. 56,\40\ 
Recommendation #6) to revise the off-cycle test procedure to account 
for all other components that consume energy during the off-cycle, such 
as pan heaters, crankcase heaters, and controls. 86 FR 32332, 32348. 
DOE noted that AHRI 1250-2020 includes a method for determining energy 
consumption during

[[Page 23954]]

off-cycle for many of these components and DOE discussed the 
possibility of incorporating the updated industry test method into a 
test procedure. In response to the June 2021 RFI, the CA IOUs supported 
the prioritization of ASRAC Term Sheet recommendation #6. (CA IOUs, No. 
14 at p. 1-2)
---------------------------------------------------------------------------

    \40\ Appliance Standards and Rulemaking Federal Advisory 
Committee Refrigeration Systems Walk-in Coolers and Freezers Term 
Sheet, available at www.regulations.gov/document?D=EERE-2015-BT-STD-0016-0056.
---------------------------------------------------------------------------

    DOE requested comment on the representativeness and repeatability 
of the off-cycle test procedure in AHRI 1250-2020. 86 FR 32332, 32348. 
Keeprite and National Refrigeration both stated that the off-cycle 
power measurement in AHRI 1250-2020 is accurate. (Keeprite, No. 12 at 
p. 2; National Refrigeration, No. 17 at p. 2) Lennox, AHRI, ASAP, and 
Hussmann supported using the off-cycle power measurements in AHRI 1250-
2020. (Lennox, No. 9 at p. 9; AHRI, No. 11 at p. 14; ASAP, No. 13 at p. 
2; Hussmann, No. 18 at p. 17) Keeprite and National Refrigeration 
asserted that adopting the off-cycle power measurements in AHRI 1250-
2020 would increase test burden without significant efficiency gains. 
(Keeprite, No. 12 at p. 3; National Refrigeration, No 17 at p. 2) NEEA 
commented that AHRI 1250-2020 captures off cycle energy consumption 
more fully but does not appear to account for start up or shutdown 
variation. (NEEA, No. 16 at p. 2)
    Also, in the June 2021 RFI, DOE sought feedback on whether there 
were additional walk-in refrigeration system components that consume 
energy while the unit is in off-cycle mode, which AHRI 1250-2020 does 
not address. 86 FR 32332, 32348. DOE did not receive comments on this 
topic.
    In the June 2021 RFI, DOE additionally requested comment on the 
magnitude of off-cycle energy use for each component. Id. DOE did not 
receive comments on this topic.
    DOE acknowledges that adopting the off-cycle power measurements in 
AHRI 1250-2020 may incrementally increase test time; however, obtaining 
off-cycle power measurements would account for less than 10 percent of 
the overall setup and test duration for walk-in refrigeration systems. 
In its testing, DOE has found that the additional energy use measured 
using the off-cycle power measurements in AHRI 1250-2020 can be up to 
60% more than the off-cycle power measurements in the current test 
procedure, indicating that the current test procedure does not fully 
represent off-cycle power use for walk-in refrigeration systems. 
Therefore, DOE proposes adopting the off-cycle procedure in sections 
C3.5, C4.2, and Table C3 in AHRI 1250-2020.
    In the following sections (III.F.1.a through III.F.1.d), DOE 
presents in more detail its proposals to modify the off-cycle test 
method and metric.
a. Off-Cycle Test Duration and Repetition
    DOE proposes revising the off-cycle test procedure to account for 
all other components (beyond evaporator fans) that consume energy 
during the off-cycle, including, but not limited to pan heaters, 
crankcase heaters, and controls (collectively, ``ancillary 
equipment''). To account for this energy, DOE proposes adopting the 
off-cycle power measurements in sections C3.5, C4.2, and Table C3 in 
AHRI 1250-2020. This method is generally consistent with the current 
DOE test method used to account for off-cycle evaporator fan power; 
however, DOE proposes adopting AHRI 1250-2020 in order to properly 
account for the energy use of ancillary equipment.
    Specifically, AHRI 1250-2020 includes two off-cycle test durations: 
One for evaporator fans and ancillary equipment with controls that are 
time-varying or respond to ambient or refrigerant temperatures (e.g., a 
crankcase heater or fan cycling control), and one for evaporator fans 
and ancillary equipment without such controls. For the former, AHRI 
1250-2020 requires a 30-minute test. DOE expects that 30 minutes is the 
shortest duration that can effectively capture the cyclic and time-
varying energy use that may occur for equipment with controls--thus, 
this duration balances the need to minimize test burden with the need 
for an accurate and representative test method. For units lacking such 
controls, AHRI 1250-2020 requires a test cycle duration of 5 minutes. 
In the absence of controls, DOE expects the off-cycle integrated power 
to be constant over time; consequently, DOE is proposing the shorter 5-
minute duration, which would minimize test burden, while still 
providing results representative of off-mode energy consumption.
    AHRI 1250-2020 also has two sets of test repetition requirements: 
One for evaporator fans and ancillary equipment with controls that are 
time-varying or respond to ambient or refrigerant temperatures (e.g., a 
crankcase heater or fan cycling control), and one for evaporator fans 
and ancillary equipment without such controls. For the former, AHRI 
1250-2020 requires that the off-cycle test for each applicable load 
point \41\ would consist of three initial test cycles, with the 
potential for three supplemental cycles. DOE anticipates that at least 
three cycles are needed to determine if the measured integrated off-
cycle power is representative of typical operation because the cyclic 
operation of evaporator fan and ancillary equipment controls has the 
potential to introduce a significant level of test-to-test variability. 
Specifically, AHRI 1250-2020 states that if the integrated power for 
each of the first three cycles is within 2 percent of the average of 
the first three cycles, then off-cycle power would be calculated as the 
average of the first three cycles. This requirement reduces test burden 
if the unit under test shows repeatable performance. If the 2 percent 
requirement is not met, DOE proposes running three supplemental cycles 
to provide an opportunity for the unit's controls to exhibit repeatable 
behavior. Specifically, AHRI 1250-2020 states that if the integrated 
power for each of the three supplemental cycles is within 2 percent of 
the average of the three supplemental cycles, then off-cycle power 
would be calculated as the average of the three supplemental cycles--
this follows the same rationale as the three initial test cycles. DOE 
expects that continuing to test the unit beyond a total of six cycles 
would be ineffectual and overly burdensome, as the previous two rounds 
of testing would show that stable test-to-test integrated power 
readings are unlikely. In the absence of stability, AHRI 1250-2020 
requires off-cycle power to be calculated as the maximum of all six 
integrated power readings. This requirement is appropriate since it 
provides a conservative estimate of integrated off-cycle.
---------------------------------------------------------------------------

    \41\ Off-cycle load points are discussed later in this section.
---------------------------------------------------------------------------

    Alternatively, for equipment lacking evaporator fans and ancillary 
equipment controls, AHRI 1250-2020 requires a single cycle to measure 
integrated power. In the absence of controls, DOE expects the off-cycle 
integrated power to be constant from cycle-to-cycle; consequently, DOE 
is proposing the single-cycle test for units without ancillary power 
controls. DOE has preliminarily determined that this approach would 
minimize test burden, while providing results representative of off-
mode energy consumption. A summary of test durations and fan settings 
based on fan control configuration and ancillary equipment control 
configuration is listed in Table III.8.

[[Page 23955]]



                           Table III.8--Proposed Off-Cycle Test Settings and Durations
----------------------------------------------------------------------------------------------------------------
                                         Ancillary equipment
      Fan control configuration         control configuration     Fan setting for test        Test duration
----------------------------------------------------------------------------------------------------------------
No Control...........................  No Control.............  Default setting, as      5 minutes.
                                                                 shipped.
No Control...........................  With Control...........  Default setting, as      30 minutes.
                                                                 shipped.
User-Adjustable Speed Controls.......  No Control.............  The greater of 50% fan   5 minutes.
                                                                 speed or the
                                                                 manufacturer's default
                                                                 fan speed.
User-Adjustable Speed Controls.......  With Control...........  The greater of 50% fan   30 minutes.
                                                                 speed or the
                                                                 manufacturer's default
                                                                 fan speed.
User-Adjustable Stir Cycles..........  With or Without Control  The greater of a 50%     The greater of 30
                                                                 duty cycle or the        minutes or three full
                                                                 manufacturer default.    ``stir cycles.''
Non-User Adjustable Controls.........  With or Without Control  Default setting, as      30 minutes.
                                                                 shipped.
----------------------------------------------------------------------------------------------------------------

b. Off-Cycle Operating Tolerances and Data Collection Rates
    DOE proposes to adopt the off-cycle power measurements in Section 
C3.5 of AHRI 1250-2020 to establish off-cycle-specific operating test 
tolerances. AHRI 1250-2020 excludes the first 10 minutes that follow 
the termination of the compressor on-cycle interval from the general 
operating tolerances (indoor/outdoor temperatures and power readings) 
established for the on-cycle steady state test. During this time 
period, the test room conditioning equipment is transitioning from 
steady state on-cycle operation into off-cycle operation and the 
evaporator coil will continue to remove heat from the inside room air 
until temperature equilibrium between the coil and the air is reached. 
This non-steady state operation following the on-cycle creates an 
environment that is temporarily difficult to control; consequently, DOE 
expects that the suspension of steady state tolerances during the 
transition period would not impact the representativeness of the test, 
since this non-steady state operation is representative of real-world 
performance during the transition period.
    DOE also proposes to establish off-cycle-specific data collection 
rates by adopting the off-cycle power measurements approach provided in 
Section C3.6 of AHRI 1250-2020. Specifically, AHRI 1250-2020 requires 
that the minimum data collection rate be increased (with respect to 
steady-state requirements) from 30 to 60 test readings per hour for 
temperature measurements and condensing unit electric power 
measurements, and from 3 to 60 test readings per hour for unit cooler 
electric power measurements. See Table C3 in Section C3.6.2 of AHRI 
1250-2020. DOE anticipates that the increased data collection rate is 
necessary since the off-cycle test time interval can be as low as five 
minutes whereas the steady-state test will typically run for at least 
60 minutes. AHRI 1250-2020 also requires that off-cycle power 
measurements be integrated and averaged over the recording interval 
with a sampling rate of no less than 1 second unless an integrating 
watt/hour meter is used. This requirement is necessary since power is 
anticipated to fluctuate during the off-cycle test. Increasing to a 1 
second sampling rate allows for an accurate software integration of 
power that would be comparable to an integrating watt/hour meter.
c. Off-Cycle Load Points
    Currently, the DOE test procedure specifies that off-cycle 
evaporator fan power is measured once with no specifications for 
ambient conditions. The current test procedure uses this approach 
because off-cycle fan power is not expected to vary significantly with 
ambient conditions. However, DOE expects the integrated power of 
ancillary equipment to potentially vary with ambient conditions, 
depending on the refrigeration system design. Consequently, DOE 
proposes that the off-cycle power test described in section III.G.1.a 
be run at each steady-state ambient test conditions as specified in 
Tables 4 through 17 of AHRI 1250-2020. Accordingly, refrigeration 
systems with dedicated condensing units located indoors would evaluate 
off-cycle power at a single outdoor ambient condition (90 [deg]F dry-
bulb), while systems with dedicated condensing units located outdoors 
would determine off-cycle power at three ambient conditions (95 [deg]F, 
59 [deg]F, and 35 [deg]F dry-bulb). The measured integrated off-cycle 
power results would then be used to calculate a revised AWEF metric, as 
described in the following section.
d. Modification to AWEF Calculations
    Walk-in cooler AWEF is calculated as a function of steady state 
capacity, steady state on-cycle power, and off-cycle unit cooler fan 
power in the current test procedure (see Section 7 of AHRI 1250-2009). 
10 CFR part 431, subpart R, appendix C, sections 3.3 and 3.4. AWEF for 
walk-in freezers considers defrost electrical energy consumption in 
addition to steady state gross capacity, steady state on-cycle power, 
and off-cycle fan power. Id. As discussed earlier, DOE proposes to 
update the AWEF calculation for refrigeration systems to account for 
off-cycle power more fully, not just off-cycle evaporator fan power. To 
do so, DOE proposes adopting the off-cycle calculations in AHRI 1250-
2020, which replace integrated off-cycle evaporator fan power with the 
combined integrated off-cycle power from the unit cooler and condensing 
unit in each equation. Additionally, for unit coolers tested alone, DOE 
proposes to update the AWEF calculation to account for all unit cooler 
off-cycle power--not just the evaporator fan power.\42\ To do so, DOE 
proposes adopting the off-cycle calculations in AHRI 1250-2020, which 
replace integrated off-cycle fan power with integrated off-cycle power 
in the unit cooler equation.
---------------------------------------------------------------------------

    \42\ DOE notes that under this proposal, condensing unit off-
cycle power is not explicitly accounted for unit coolers; rather, 
the total energy contribution from the condensing unit is based on a 
defined EER lookup table, which is currently found in Table 17 of 
AHRI 1250-2009 (incorporated by reference, 10 CFR 431.303(b)). This 
NOPR proposes changing that to Table 18 of AHRI 1250-2020. This 
aspect of the proposed unit cooler test method is consistent with 
the current method specified in appendix C to subpart R of 10 CFR 
part 431.
---------------------------------------------------------------------------

    DOE, however, proposes deviating from the AHRI 1250-2020 
calculations for off-cycle energy use for outdoor refrigeration 
systems. DOE notes that the AHRI 1250-2020 equations for average 
refrigeration system total power input for bin temperature 
T<INF>j</INF>, e.g., Equation 13, do not appear to use off-cycle power 
values for the unit cooler and/or the condensing unit that vary with 
T<INF>j</INF>. In fact, there are no equations providing the off-cycle 
power for either component as a function of T<INF>j</INF> in Section 7 
of AHRI 1250-2020, such as there are for net capacity and on-cycle 
power input (e.g., Equations 14 through 17). Since the off-cycle power 
may vary as a function of outdoor temperature as discussed previously, 
DOE proposes to

[[Page 23956]]

provide instructions for calculating off-cycle power as a function of 
outdoor temperature based on the measurements made at the three outdoor 
test condition temperatures.
    For condensing unit off-cycle power, DOE proposes to require that 
off-cycle power for T<INF>j</INF> less than or equal to 35 [deg]F would 
be equal to the power measured for the test condition C off-cycle power 
test. For T<INF>j</INF> higher than 95 [deg]F, DOE proposes that off-
cycle power would be equal to the power measured for the test condition 
A off-cycle power test. Between these two temperatures, DOE proposes 
that condensing unit off-cycle power would be determined based on the 
test condition B and C measurements when T<INF>j</INF> is below 59 
[deg]F, and based on the A and B measurements when it is above 59 
[deg]F, similar to equations 14 through 17 for on-cycle capacity and 
power.
    For unit cooler off-cycle power, it is unclear whether to apply a 
specific trend correlated to condensing unit outdoor air temperature. 
DOE notes that AHRI 1250-2020 did not establish tests for unit coolers 
tested alone for different condensing unit outdoor air temperatures, 
which supports the suggestion that there is no such trend. Hence, DOE 
is not proposing any equations for unit cooler off-cycle power that are 
based on the different bin temperatures, T<INF>j</INF>. Instead, DOE 
proposes that the three-unit cooler off-cycle power measurements that 
would be made when testing a matched pair or single-packaged dedicated 
system would be averaged, and that the resulting average, with no 
dependence on T<INF>j</INF>, would be used in the AWEF calculations.
    Issue 19: DOE requests comments on its proposals to align the test 
procedures for appendix C1 with AHRI 1250-2020, except for the use of 
off-cycle power measurements in the AWEF calculations for dedicated 
condensing units, matched pairs, or single-packaged dedicated systems 
intended for outdoor installation. DOE requests comments on its 
proposals for use in the AWEF calculations of the three sets of unit 
cooler and condensing unit off-cycle measurements made for outdoor 
refrigeration systems.
2. Single-Packaged Dedicated Systems
a. AHRI 1250-2020 Methods for Testing
    As discussed in section III.B.3.c, AHRI 1250-2020 expanded methods 
of test for single-packaged units to include air enthalpy, calorimetry, 
and compressor calibration. Specifically, AHRI 1250-2020 incorporates 
the following tests procedures by reference:
    (1) Air enthalpy method: ASHRAE 37 and ANSI/ASHRAE 41.6-2014 
(``ASHRAE 41.6''), ``Standard Method for Humidity Measurement'';
    (2) calorimeter methods: ASHRAE 16, ``Method of Testing for Rating 
Room Air Conditioners, Packaged Terminal Air Conditioners, and Packaged 
Terminal Heat Pumps for Cooling and Heating Capacity'';
    (3) compressor calibration methods: ASHRAE 37 and ANSI/ASHRAE 23.1-
2010.
    AHRI 1250-2020 requires two simultaneous measurements of system 
capacity (i.e., a primary and a secondary method) for single-packaged 
dedicated systems, and Section C9.2.1 of AHRI 1250-2020 requires that 
the measurements agree within 6 percent. Table C4 in AHRI 1250-2020 
specifies which of the test methods (calorimeter, air enthalpy, and 
compressor calibration) qualify as primary and/or secondary methods. 
However, as summarized in Table III.9, DOE is proposing to modify the 
method of test and test hierarchy table in AHRI 1250-2020 to include a 
single-packaged refrigerant enthalpy method--the addition of the 
Single-Packaged Refrigerant Enthalpy method is the only change to the 
hierarchy of test methods that DOE is proposing. The reasoning behind 
this addition is discussed in section III.G.2.d of this document.

                       Table III.9--Single-Packaged System Test Methods and Test Hierarchy
----------------------------------------------------------------------------------------------------------------
                      Method of test                                           Allowable use
----------------------------------------------------------------------------------------------------------------
Balanced Ambient Indoor Calorimeter......................  Primary.
Balanced Ambient Outdoor Calorimeter.....................  Primary or Secondary.
Indoor Air Enthalpy......................................  Primary or Secondary.
Indoor Room Calorimeter..................................  Primary or Secondary.
Single-packaged Refrigerant Enthalpy \43\................  Secondary.
Outdoor Room Calorimeter.................................  Secondary.
Outdoor Air Enthalpy.....................................  Secondary.
Compressor Calibration...................................  Secondary.
----------------------------------------------------------------------------------------------------------------

b. Waivers
---------------------------------------------------------------------------

    \43\ As described in section III.G.2.f, this does not apply to 
CO<INF>2</INF> single-packaged units.
---------------------------------------------------------------------------

    DOE granted a waiver to Store It Cold for single-packaged units on 
August 9, 2019. 84 FR 39286. Store It Cold petitioned for a waiver 
after determining that the refrigerant enthalpy method specified in 
AHRI 1250-2009 was not providing consistent capacity measurements for 
its single-packaged dedicated systems. 84 FR 39286, 39287. The 
alternate test procedure associated with this waiver requires that the 
specified single-packaged basic models shall be tested using the Indoor 
Air Enthalpy Method and the Outdoor Air Enthalpy Method in accordance 
with ASHRAE 37. 84 FR 39286, 39292. DOE also granted waivers to Air 
Innovations, CellarPro, Vinotemp, and Vinotheque for walk-in 
refrigeration systems used in wine cellar applications, where some of 
the basic models included in these waivers were single-packaged 
dedicated systems.\44\ Similar to the Store It Cold waiver, the 
alternate test methods included in these other waivers require the 
specified basic models to be tested in accordance with the air enthalpy 
methods specified in ASHRAE 37 for testing single-packaged dedicated 
systems, which is now referenced by AHRI 1250-2020. Use of air enthalpy 
methods for testing a single-packaged dedicated system captures the 
impact of thermal loss and the infiltration of warm air into the 
evaporator portion of these systems. As discussed, DOE proposes to 
reference in appendix C1 the methods of test for single-packaged 
dedicated systems in Section C9 of AHRI 1250-2020, with some 
modifications. Since DOE is proposing that appendix C1 would be 
required on the compliance date of any amended energy conservation 
standards, were such standards to be adopted, the current test 
procedure waivers for specified single-packaged basic models would 
expire on the compliance date of proposed appendix C1 if it should be 
adopted.
---------------------------------------------------------------------------

    \44\ Table III.2 lists the manufacturers that have received a 
test procedure waiver or interim waiver for walk-in refrigeration 
systems designed for wine cellar applications.

---------------------------------------------------------------------------

[[Page 23957]]

c. Suitability of the Single-Packaged Test Methods in AHRI 1250-2020
    In the June 2021 RFI, DOE requested data or comment on the 
additional thermal losses associated with single-packaged dedicated 
systems, and whether AHRI 1250-2020 fully accounts for these losses. 86 
FR 32332, 32344. Lennox, AHRI, and Hussmann stated that the AHRI 1250-
2020 single-packaged formulas account for additional thermal losses. 
(Lennox, No. 9 at p. 5; AHRI, No. 11 at p. 10; Hussmann, No. 18 at p. 
12) These stakeholders also asserted that the calorimeter test method 
should measure any minimal leakage. Id.
    In response to the June 2021 RFI, the CA IOUs commented that the 
room calorimeter and air enthalpy test methods in AHRI 1250-2020 would 
address single-packaged dedicated system test challenges that led to 
the Store It Cold waiver petition and subsequent granting of the 
waiver. (CA IOUs, No. 14 at p. 2) However, the comment did not 
specifically address the single-packaged heat loss or its magnitude.
    DOE requested comment on the representativeness of the single-
packaged dedicated test and calculation methods in AHRI 1250-2020 in 
the June 2021 RFI. DOE additionally invited comment on whether DOE 
should update its test procedure to incorporate AHRI 1250-2020 by 
reference. 86 FR 32332, 32343-32344. While Lennox, AHRI, and Hussmann 
each supported the AHRI 1250-2020 test methods for single-packaged 
dedicated systems, these stakeholders stated that these test procedures 
have not yet been fully evaluated and recommended against DOE updating 
its test procedure to incorporate single-packaged system-specific 
sections of AHRI 1250-2020. (Lennox, No. 9 at p. 5; AHRI, No. 11 at p. 
9; Hussmann, No. 18 at p. 12)
    The calorimeter tests mentioned previously were originally 
developed in ASHRAE 16 for testing room air conditioning units. In the 
June 2021 RFI, DOE noted that precise determination of the calorimeter 
chamber cooling fluid heat capacity is necessary for an accurate test. 
86 FR 32332, 32344. Since air conditioning units do not cool below 32 
[deg]F, the freezing temperature of pure water, ASHRAE 16 would not 
have encountered problems with this issue, as water can be used as the 
calorimetry fluid and the heat capacity of pure water is known. When 
testing walk-in refrigeration systems using this method, the fluid may 
have to be at a temperature lower than 32 [deg]F, which means that pure 
water would not be used. Precise determination of the heat capacity of 
glycol-water mixtures may present a challenge, since the concentration 
of the mixture must be determined. Therefore, in the June 2021 RFI, DOE 
requested feedback on what heat transfer liquids might be used to 
maintain test chamber temperature when testing single-packaged 
dedicated systems using the calorimeter method included in AHRI 1250-
2020. DOE additionally requested comment on whether the calorimetric 
procedure in AHRI 1250-2020 for testing single-packaged dedicated 
systems could be modified to enhance test accuracy or repeatability. 86 
FR 32332, 32344. Lennox, AHRI, and Hussmann stated that additional 
testing is necessary to fully evaluate each test method outlined for 
single-packaged units in AHRI 1250-2020. (Lennox, No. 9 at p. 5; AHRI, 
No. 11 at p. 10; Hussmann, No. 18 at p. 12) Daikin commented that 
standard EN 17432 uses a room calorimetry test for single-packaged 
units, with test conditions and a setup figure provided in the comment. 
(Daikin, No. 17 at p. 3) DOE notes the calorimetry room method 
suggested by Daikin does not appear to have a glycol loop and therefore 
does not provide a solution for heat transfer liquids that could be 
used when testing single-packaged dedicated systems using the 
calorimeter method included in AHRI 1250-2020. After consideration, DOE 
has tentatively determined that the comments provided do not 
conclusively indicate one way or the other that the AHSRAE 16 test 
method is unsuitable for walk-in refrigeration systems. Therefore, DOE 
is proposing to adopt the ASHRAE 16 calorimetry methods of test for 
single-packaged dedicated systems as referenced in AHRI 1250-2020. This 
approach would provide flexibility in selecting from one of the 
discussed testing methods even if these methods may be more challenging 
to implement for walk-in refrigeration systems than for room air 
conditioners. As the comments have not provided sufficient quantitative 
information, DOE will continue to consider this question and may take 
action at a later date.
    DOE also discussed the requirement for a pressure equalizer device 
for calorimetry chambers in ASHRAE 16 in the June 2021 RFI. DOE noted 
that since the calibrated box method (established in the current DOE 
test procedure) does not require such a device, this may increase 
testing burden. 86 FR 32332, 32344. DOE discussed two potential 
alternatives to this requirement; specifically, (1) no requirement to 
address transfer air or pressure equalization, or (2) require leak-free 
test facility chambers with no equalization requirement. Id. DOE 
requested comment on the requirement for a pressure equalizing device 
in ASHRAE 16 and solicited feedback on the expected cost and resource 
burdens associated with employing such a device. Id. Lennox, AHRI, and 
Hussmann stated that an equalizer device would not be necessary if the 
chamber were leak-free, that the addition of an equalizer device has 
not been fully evaluated and is expected to increase test burden. 
(Lennox, No. 9 at p. 5; AHRI, No. 11 at p. 10; Hussmann, No. 18 at p. 
13) Based on the single-packaged system testing conducted by DOE, DOE 
is not planning to propose an equalizer device for calorimeter room 
testing. DOE notes that a pressure equalizer is typically used when 
comfort cooling devices have a damper to bring fresh air into the 
cooled environment. Single-packaged dedicated systems do not include 
this functionality and therefore a pressure equalizing device is not 
necessary.
    Finally, DOE requested comment on any alternative test methods to 
measure single-packaged dedicated system capacity in the June 2021 RFI. 
86 FR 32332, 32344. Lennox, AHRI, and Hussmann confirmed that the test 
methods included in AHRI 1250-2020 for testing single-packaged 
dedicated systems are sufficient. (Lennox, No. 9 at p. 6; AHRI, No. 11 
at p. 10; Hussmann, No. 18 at p. 13)
    Testing conducted by DOE on single-packaged units using the room 
calorimeter and air enthalpy methods as described in AHRI 1250-2020 
suggest that these test methods appropriately account for the thermal 
losses experienced by this equipment. Therefore, DOE has tentatively 
determined that these methods are representative of single-packaged 
system energy use. As such, DOE proposes to adopt the single-packaged 
system test procedure in AHRI 1250-2020 with the modifications outlined 
in sections III.G.2.d and III.G.2.e of this document. DOE notes that 
while there may not be extensive experience applying these test methods 
to walk-in refrigeration systems, all the proposed test methods have 
been evaluated and are used extensively for testing other HVAC 
equipment. Additionally, DOE is required, as soon as practicable after 
the granting of any waiver, to publish in the Federal Register a notice 
of proposed rulemaking to amend its regulations so as to eliminate any 
need for the continuation of such a waiver. 10 CFR 431.401(l). Finally, 
DOE emphasizes

[[Page 23958]]

that testing according to proposed appendix C1 would not be required 
until such time as compliance is required with any amended energy 
conservation standards, should such standards be adopted. As such, were 
appendix C1 adopted, the existing waivers would remain in effect until 
such time as compliance would be required with appendix C1.
d. Single-Packaged Refrigerant Enthalpy Method
    As previously discussed, AHRI 1250-2020 includes 4 potential 
primary, and 6 potential secondary test methods for testing single-
packaged dedicated systems (see Table III.9). The refrigerant enthalpy 
method is not included in this list. Although the dual instrumentation 
test (i.e., two separate measurements using the refrigerant enthalpy 
method) is routinely used to evaluate the capacity of matched pair, 
dedicated condensing, and unit cooler systems, the DX dual 
instrumentation method is generally considered to be impractical for 
testing single-packaged dedicated systems. This is primarily because it 
requires breaking into the liquid refrigerant line within the packaged 
unit, routing the line outside of the unit to pass through two mass 
flow meters, and then routing the line back into the unit and through 
dual pressure and temperature measurements before it rejoins the 
original liquid line at the expansion device inlet. This is generally 
inappropriate for a single-packaged unit because the internal volume of 
the added liquid line and mass flow meters adds substantially to the 
required refrigerant charge, and the entire assembly adds substantial 
pressure drop.\45\ As discussed in section III.A.2.e, RSG submitted a 
request for waiver and interim waiver to use the refrigerant enthalpy 
method to test single-packaged dedicated systems with multiple 
refrigeration circuits, using only one mass flow meter per circuit and 
using added refrigerant liquid line no longer than 5 feet in 
length.\46\ DOE is proposing to adopt a single-packaged refrigerant 
enthalpy method that is similar to the alternate test procedure 
outlined in RSG's waiver request.
---------------------------------------------------------------------------

    \45\ These issues were the primary motivation for and are 
described in the Store-it-Cold petition for waiver--see the 
discussion in section III.G.2.b of this document.
    \46\ The RSG petition for waiver and interim waiver can be found 
at www.regulations.gov/docket/EERE-2022-BT-WAV-0010.
---------------------------------------------------------------------------

    The single-packaged refrigerant enthalpy method would be based 
using the refrigerant-side measurements of the DX Calibrated Box method 
in section C8 of AHRI 1250-2020 while simultaneously using one of the 
``Primary'' methods listed in the table for single-packaged methods of 
test as an air-side measurement. These primary test methods all measure 
the capacity delivered to the air passing through the evaporator 
section of the system, or to the air that is refrigerated by the 
system. Before disassembling the refrigeration system to set up the 
refrigerant-side mass flow measurement, a preliminary test at Condition 
A would be conducted using only the primary air-side measurement. For 
this test, surface-mounted temperature sensors would be installed on 
the evaporator and condenser coils, tubing entering and leaving the 
compressor, and tubing entering the expansion device. This preliminary 
test would be compared to the later test at Condition A using both 
airside and refrigerant-side measurements. To ensure that the 
refrigerant circuit modifications did not materially alter the system 
operation, the later test would be performed to confirm that (1) each 
on-coil temperature sensor indicates a reading that is within <plus-
minus>1.0 [deg]F of its initial-test measurement, (2) the temperatures 
of the refrigerant entering and leaving the compressor are within 
<plus-minus>4 [deg]F, and (3) the refrigerant temperature entering the 
expansion device is within <plus-minus>1 [deg]F. To limit the 
alteration of the refrigerant circuit, only 5 feet of tubing shall be 
added to the liquid refrigerant lines (not including the flow length 
associated with the mass flow meter).
    The heat balance applied to single-packaged dedicated systems using 
this method would involve comparison of the air-side net capacity to a 
net capacity determined based on the gross refrigerant-side capacity 
measurement that would include adjustment for the evaporator fan heat 
in addition to adjustment for the single-packaged dedicated system 
thermal loss. The thermal loss would be calculated similarly to the 
duct loss calculation of Section 7.3.3.3 of ASHRAE 37-2009, in which 
the heat losses associated with the insulated surface areas subject to 
heat transfer are summed based on their surface area, thermal 
resistance (which is based on known insulating material and insulation 
thickness), and the temperatures on either side of the surface.
    Issue 20: DOE requests comment on the proposed single-packaged 
refrigerant enthalpy test procedure for evaluating the performance of 
single-packaged dedicated systems.
e. Multi-Circuit Single-Packaged Dedicated Systems
    Multi-circuit single-packaged refrigeration systems provide a 
solution for flammable refrigerants, where safety standards limit the 
amount of refrigerant in a refrigeration circuit. Some flammable 
refrigerants, like propane, are efficient and have a very low global 
warming potential (``GWP''),\47\ making them advantageous design 
options for future refrigeration systems. Neither the current DOE test 
procedure nor AHRI 1250-2020, which DOE is proposing generally to adopt 
through reference in its updated test procedure for walk-in 
refrigeration systems, provides a method for testing single-packaged 
dedicated systems with multiple refrigeration circuits.
---------------------------------------------------------------------------

    \47\ Global warming potential is a measure of a substance's 
ability to warm the planet relative to CO<INF>2</INF>. 
CO<INF>2</INF> has a GWP of 1 while a traditional HFC refrigerant 
like R134a has a GWP of 3400, meaning a ton of R134a warms the 
planet 3400 times more than a ton of CO<INF>2</INF>.
---------------------------------------------------------------------------

    In its request for waiver and interim waiver, RSG provided an 
alternate test method for testing multi-circuit single-packaged 
dedicated systems. (EERE-2022-BT-WAV-0010-0001) This test procedure is 
based on the single-packaged refrigerant enthalpy method for single-
packaged units described in section III.G.2.d of this document. The 
procedure is duplicated for each refrigeration circuit contained in the 
unit such that each circuit returns mass flow, enthalpy in, and 
enthalpy out values. The resultant mass flow and enthalpy values are 
used to calculate the gross refrigeration capacity for each circuit. 
Each circuit's gross capacity is then summed to determine the total 
capacity of the system.
    DOE has tentatively determined that the alternate approach would 
generally provide a reasonable method for determining the capacity of 
multi-circuit single-packaged dedicated systems. However, this approach 
may not adequately capture the heat loss associated with single-
packaged dedicated systems; therefore, an indoor air refrigeration 
capacity test would need to be used to confirm the multiple 
refrigeration circuit capacity test. In sum, DOE proposes to adopt the 
previously described method for determining the capacity of single-
packaged dedicated systems with multiple refrigeration circuits, with 
the additional requirement that the primary test would be an indoor air 
refrigeration capacity test where the allowable refrigeration capacity 
heat balance is 6 percent.

[[Page 23959]]

    In summary, DOE is proposing to adopt the test procedures in 
section C8 of AHRI 1250-2020 for testing single-packaged dedicated 
systems with modifications to allow for secondary refrigerant enthalpy 
tests, and to accommodate multi-circuit single-packaged dedicated 
systems. The proposed test methods and their designation as primary or 
secondary tests are outlined in Table III.9 of this document.
f. CO<INF>2</INF> Single-Packaged Dedicated Systems
    The current DOE test procedure for single-packaged dedicated 
systems uses dual instrumentation refrigerant enthalpy methods. Using 
these methods, the current test procedure does not provide 
representative values for single-packaged dedicated systems that use 
CO<INF>2</INF> as a refrigerant because CO<INF>2</INF> remains in a 
gaseous state in those areas where mass flow meters are placed. The 
typical mass flow meters do not deliver accurate readings unless the 
medium being measured is in liquid form. However, the single-packaged 
dedicated system test methods in AHRI 1250-2020 use air enthalpy 
measurements and would not require any refrigerant mass flow 
measurements. This means single-packaged refrigeration systems that use 
CO<INF>2</INF> as a refrigerant can be tested using these methods with 
no issues. Therefore, DOE proposes that single-packaged refrigeration 
systems that use CO<INF>2</INF> as a refrigerant be tested using the 
test methods for single-packaged dedicated systems outlined in AHRI 
1250-2020.
3. Detachable Single-Packaged Dedicated Systems
    As discussed in section III.A.2.g DOE is aware of refrigeration 
systems that are installed with the evaporator unit through the wall of 
the walk-in, but with the condensing unit installed remotely and 
connected to the evaporator with refrigerant lines--DOE has defined 
this equipment as ``detachable single-packaged dedicated systems.'' 
Neither subpart R, appendix C, nor AHRI 1250-2020 contain provisions 
for testing these walk-in refrigeration systems. Detachable single-
packaged dedicated systems may be tested as either systems with the 
condensing unit and unit cooler in separate housings or as single-
packaged dedicated systems. Testing as the former is more typical of 
the walk-in industry and therefore may be less burdensome. However, 
testing as a single-packaged system using the indoor air enthalpy test 
would account for the heat loss of the evaporator installation. Since 
the single-packaged indoor air enthalpy method would be more 
representative of these separable single-packaged dedicated systems, 
DOE is proposing as part of new appendix C1 and 10 CFR 
429.53(a)(2)(i)(C) that detachable single-packaged dedicated systems 
would be tested using the test procedure for single-packaged dedicated 
systems.
    Issue 21: DOE requests comment on testing detachable single-
packaged dedicated systems using the test procedure for single-packaged 
dedicated systems.
4. Attached Split Systems
    As discussed in section III.A.2.f., DOE is aware of refrigeration 
systems that are sold as matched systems and permanently attached to 
each other with beams. These systems are mounted to the cooler box with 
the beams piercing the interior wall of the walk-in. As discussed in 
section III.A.2.f, DOE is proposing to classify these systems as 
``attached split systems.'' While thermal losses are expected to be 
lower for an attached split system than a single-packaged system since 
attached split systems have comparatively more insulation between the 
condenser and evaporator sides, DOE has preliminarily confirmed through 
testing that these systems still experience some heat leakage when 
compared to traditionally-installed systems that have the dedicated 
condensing unit and the unit cooler in separate housings. However, this 
heat leakage has not been studied extensively and DOE is aware that it 
may be difficult to calculate. Because of this issue, DOE is proposing 
in new appendix C1 and 10 CFR 429.53(a)(2)(i)(D) that attached split 
systems would be tested as a matched pair using refrigerant enthalpy 
methods.
    Issue 22: DOE requests comment on its proposal that attached split 
systems be tested using refrigerant enthalpy methods.
5. Systems for High-Temperature Freezer Applications
    As discussed in the December 2016 final rule, stakeholders 
commented that high-temperature freezer walk-ins, which have an 
enclosed storage (i.e., room) temperature range of 10 [deg]F to 32 
[deg]F, are typically refrigerated with medium-temperature dedicated 
condensing units. 81 FR 95758, 95790. Under the statutory definitions 
of ``walk-in cooler'' and ``walk-in freezer,'' this equipment would be 
considered a walk-in freezer because its room temperature is less than 
or equal to 32 [deg]F. (42 U.S.C. 6311(20))
    Accordingly, these refrigeration systems would be tested using a 
room temperature of -10 [deg]F, as specified in subpart R, appendix C. 
However, stakeholders commented that it is difficult for these medium-
temperature refrigeration systems to meet this temperature condition 
when using lower GWP refrigerants.\48\ 81 FR 95758, 95790. Lennox 
offered data suggesting that medium-temperature units generally perform 
more efficiently at the 10 [deg]F operating condition (i.e., the low 
end of the cited ``high-temperature freezer'' temperature range) than 
low-temperature systems. (Docket EERE-2015-BT-STD-0016, Lennox, No. 89 
\49\ at pp. 2-5) Lennox suggested that this ``high-temperature 
freezer'' application may justifiably represent a third class of walk-
in refrigeration systems, but also noted the reporting and testing 
burden that establishing an additional set of classes would incur. Id. 
In response, DOE noted that manufacturers of equipment that cannot be 
tested in a way that properly represents their performance 
characteristics may petition DOE for a test procedure waiver, as 
detailed in 10 CFR 431.401. DOE also indicated that it may consider 
amending its regulations by establishing new equipment classes and 
applicable test methods. 81 FR 95758, 95791.
---------------------------------------------------------------------------

    \48\ Lennox commented that the industry was moving to low-GWP 
refrigerants in response to the Environmental Protection Agency 
final rule under the Significant New Alternatives Policy (``SNAP'') 
program that prohibited the use of R-404A in certain retail food 
refrigeration applications, including WICF refrigeration systems 
starting July 20, 2016. (Docket EERE-2016-BT-TP-0030, Lennox, No. 13 
at p. 2) For further discussion of the SNAP rule, see section 
III.G.9 of this document.
    \49\ Available at www.regulations.gov/document?D=EERE-2015-BT-STD-0016-0089.
---------------------------------------------------------------------------

    In the June 2021 RFI, DOE presented three potential approaches for 
testing and certifying high-temperature freezers. One approach would 
provide for testing and certification based on the standardized 35 
[deg]F walk-in cooler temperature (or corresponding refrigerant suction 
conditions), if the walk-in refrigeration system is marketed at or 
above 10 [deg]F. By extension, the approach would also allow 
representations of performance (e.g., capacity, power input) of such 
medium-temperature refrigeration systems for walk-in temperatures at 10 
[deg]F and higher without requiring them to be tested and certified 
based on the -10 [deg]F low-temperature walk-in test condition. 86 FR 
32332, 32350.
    DOE could establish new definitions for the terms ``high-
temperature freezer system'' and ``medium-temperature refrigeration 
system,'' that implement this potential structure. For example, ``high-
temperature freezer system'' could be defined as ``a refrigeration

[[Page 23960]]

system used to cool the interior of walk-in freezers and maintain a 
room temperature of between 10 [deg]F and 32 [deg]F,'' while ``medium-
temperature refrigeration system'' could be defined as ``a 
refrigeration system used to cool the interior of a walk-in cooler or a 
walk-in freezer operating above 32 [deg]F.''
    A second alternative presented in the June 2021 RFI would be to 
require walk-in cooler refrigeration systems to be tested and certified 
at their lowest application temperature conditions. 86 FR 32332, 32350. 
This approach would be similar to that taken for commercial 
refrigerators, freezers, and refrigerator-freezers, where manufacturers 
report the lowest application product temperature, i.e., the lowest 
average compartment temperature at which the equipment can operate 
during testing (section 2.2 of appendix B to part 431, subpart C). For 
walk-ins, this concept could be based on the lowest evaporator return 
air temperature for matched pair refrigeration systems and the lowest 
saturated suction temperature (and a suitable corresponding return gas 
temperature) for dedicated condensing units tested alone. This approach 
would result in ratings for units used in high-temperature freezer 
applications that are representative of field performance, since the 
refrigeration system would be tested at a representative box 
temperature for such an application. Further, this approach would not 
presuppose what the optimal high-temperature freezer operating 
condition would be since it avoids selecting a standardized condition 
that may be unachievable by some units. However, AWEF ratings obtained 
from the lowest application temperature for different units, which 
would be rated for different box temperatures, would not be directly 
comparable. This approach would also add testing and reporting burden 
associated with the additional test condition.
    Finally, DOE presented a third approach in the June 2021 RFI, that 
would establish a single standardized test condition at which walk-in 
cooler refrigeration equipment would be tested. 86 FR 32332, 32350. 
This approach would result in AWEF ratings that are not as reflective 
of the expected field performance as compared with the lowest 
application temperature approach. Under a standardized test condition 
approach, all walk-in cooler refrigeration systems would be rated at 
the same condition, providing more directly comparable ratings for 
models that serve similar applications.
    In the June 2021 RFI, DOE requested comment on the three potential 
approaches for addressing high-temperature freezer walk-ins as well as 
any other potential approaches that DOE did not discuss. 86 FR 32332, 
32350. Lennox, AHRI, Keeprite, National Refrigeration, and Hussmann 
supported the first option presented by DOE, specifically, testing and 
rating high-temperature freezer systems at 35 [deg]F. (Lennox, No. 9 at 
p. 10; AHRI, No. 11 at p. 15; Keeprite, No. 12 at p. 3; National 
Refrigeration, No. 17 at p. 2; Hussmann, No. 18 at pp. 17-18) Keeprite 
and National Refrigeration both stated that this approach would 
eliminate the need to create a new class of equipment, and thus avoid 
additional testing. (Keeprite, No. 12 at p. 3; National Refrigeration, 
No. 17 at p. 2) Additionally, Keeprite stated that medium-temperature 
equipment design is no different from high-temperature freezer 
equipment design and therefore concluded that testing the same 
equipment twice would have no tangible benefit. (Keeprite, No. 12 at p. 
3) ASAP and the CA IOUs recommended the third option presented by DOE, 
which suggested establishing new, representative test conditions for 
high-temperature freezers irrespective of their lowest operating 
temperature. (ASAP, No. 13 at p. 3; CA IOUs, No. 14 at p. 4) 
Specifically, the CA IOUs stated that they support establishing 
additional equipment classes for refrigeration systems that are not 
well represented by the 35 [deg]F indoor test conditions in DOE's 
current test procedure. (CA IOUs, No. 14 at pp. 3-4) DOE understands 
the CA IOUs comment to infer that for systems not well represented by 
the 35 [deg]F indoor test conditions, this equipment should be included 
in a separate equipment class and energy use determined at a more 
representative temperature, with definitions and labelling that clearly 
identify that these units have different test conditions than 
`standard' walk-in refrigeration systems.
    In the June 2021 RFI, DOE also requested information to inform the 
development of test procedures for high-temperature freezer systems. 86 
FR 32332, 32350. Specifically, DOE sought comment on the test procedure 
parameters or calculations that would need to be modified to test 
medium-temperature refrigeration systems in the high-temperature 
freezer range. Id. Lennox, AHRI, Keeprite, National Refrigeration, and 
Hussmann stated that no new test procedures would be necessary if the 
DOE test procedure were to require testing and rating high-temperature 
freezers at 35 [deg]F. (Lennox, No. 9 at pp. 10-11; AHRI, No. 11 at pp. 
15-16; Keeprite, No. 12 at p. 3; National Refrigeration, No. 17 at p. 
2; Hussmann, No. 18 at pp. 18-19)
    As also discussed in the June 2021 RFI, if DOE were to pursue the 
lowest application temperature approach or the standardized high-
temperature freezer test condition approach, DOE would need to 
establish certain new default values to calculate the AWEF and net 
capacity of stand-alone high-temperature freezer dedicated condensing 
units. 86 FR 32332, 32350. Currently, the test procedure provides 
equations for determining evaporator fan power, defrost energy, and 
defrost heat load, all of which are used in lieu of matched unit cooler 
test data (section 3.4.2 of subpart R, appendix C).
    The current test procedure offers two separate equations that 
relate the cooling capacity to the evaporator fan power for medium- and 
low-temperature unit coolers (section 3.4.2.2 of subpart R, appendix 
C). Based on the condensing unit capacity at the medium-temperature 
test condition (35 [deg]F box temperature), using the medium-
temperature equation seems to be the most appropriate approach since 
the dedicated condensing units in question would also be certified as 
medium-temperature dedicated condensing units. This approach also 
assumes that fan energy use at high-temperature freezer conditions 
would be the same as fan energy use at medium-temperature conditions 
since it makes no adjustment in the calculated fan power for the high-
temperature freezer application. DOE requested comment on the 
appropriateness of using the current medium-temperature refrigeration 
system default fan input power equations (found at section 3.4.2.2 of 
subpart R, appendix C) to represent the fan input power of high-
temperature freezer refrigeration systems. 86 FR 32332, 32350. In 
response, Lennox, AHRI, and Hussmann recommended using the current low-
temperature default fan input power equation since medium-temperature 
dedicated condensing units are typically paired with low-temperature 
unit coolers for use in high-temperature freezer applications and low-
temperature unit coolers operate at higher suction temperatures than 
medium-temperature unit coolers. (Lennox, No. 9 at p. 11; AHRI, No. 11 
at p. 16; Hussmann, No. 18 at p. 19)
    In the current test procedure, defrost energy and defrost heat load 
for stand-alone dedicated condensing units are estimated based on the 
condenser capacity using an equation in section 3.4.2 of subpart R, 
appendix C. The calculations apply only to freezer models, since they 
assume that

[[Page 23961]]

refrigeration systems serving walk-in coolers are not equipped for 
defrost capability and thus have no defrost energy or heat load. 
However, medium- temperature refrigeration systems used for high-
temperature freezer applications require defrost capability because 
frost that collects on the evaporator during the compressor off-cycle 
will not melt in sub-freezing walk-in temperature conditions. The 
energy and heat load of these high-temperature freezer defrost systems 
may differ significantly from those of -10 [deg]F freezers. Therefore, 
proper accounting for defrost of high-temperature freezer refrigeration 
systems requires developing a modified calculation. The equation found 
in section 3.4.2.4 of subpart R, appendix C, calculates freezer 
equipment daily defrost energy use (``DF'') using the condenser 
capacity (``q<INF>mix,cd</INF>'') and the number of defrost cycles per 
day (``N<INF>DF</INF>''). The daily defrost heat load 
(``Q<INF>DF</INF>'') is directly dependent on DF (see relevant equation 
in section 3.4.2.5 of subpart R, appendix C). DOE anticipates 
calculating defrost impacts for high-temperature freezers, if adopted, 
would use similar equations with different magnitudes. In the June 2021 
RFI, DOE requested information or data to inform the use of potential 
modifications to the defrost equations for high-temperature freezers, 
and whether frost loads and/or defrost frequency are different for 
high-temperature freezers when compared to walk-in freezers that 
operate at a temperature of -10 [deg]F. 86 FR 32332, 32350. Lennox, 
AHRI, and Hussmann responded that modifications to defrost energy 
equations are unnecessary for high-temperature freezer applications 
since calculations for a freezer operating at -10 [deg]F, 0 [deg]F, and 
10 [deg]F would result in a negligible difference in defrost energy 
use. (Lennox, No. 9 at p. 11; AHRI, No. 11 at p. 16; Hussmann, No. 18 
at pp. 19-20)
    DOE recognizes that testing high-temperature freezer refrigeration 
systems at a consistent test condition is important to ensure test 
procedure consistency and to provide comparable performance values in 
the market. Additionally, DOE acknowledges that testing high-
temperature freezer refrigeration systems at a temperature less than 35 
[deg]F would be more representative of their actual energy use; 
however, it is not clear if the potential additional test burden 
justifies including an additional test condition for walk-in cooler 
refrigeration systems. Therefore, DOE has tentatively determined that 
medium-temperature dedicated condensing units used in high-temperature 
freezer applications would continue to be tested according to subpart 
R, appendix C; however, DOE may revisit its approach for this equipment 
in a future rulemaking.
6. Systems for High-Temperature Applications
    As discussed in the June 2021 RFI, DOE is aware of wine cellar 
(high-temperature) refrigeration systems that fall within the walk-in 
definition but that may be incapable of being tested in a manner that 
would yield representative performance results during a representative 
average use cycle under the current version of the walk-in test 
procedure. 86 FR 32332, 32344. For example, wine cellar refrigeration 
systems that may be installed in some commercial settings are designed 
to operate at a temperature range of 45 [deg]F to 65 [deg]F. Under the 
current walk-in test procedure, walk-in coolers must be tested while 
operating at 35 [deg]F--see Section 3.1.1 of subpart R, appendix C. To 
the extent that a wine cellar refrigeration system does not operate at 
35 [deg]F, applying the required 35 [deg]F testing temperature 
condition when evaluating the energy usage of this equipment would not 
produce results representative of an average use cycle.
    As discussed in section III.A.2.c, DOE has received requests for 
waiver and interim waiver from several manufacturers from the test 
procedure in subpart R, appendix C, for basic models of wine cellar 
refrigeration systems. DOE engaged with AHRI, the industry trade 
association, to discuss how to develop a consistent alternate testing 
approach for high-temperature refrigeration systems that would apply to 
all impacted manufacturers. Ultimately, AHRI submitted a memorandum on 
behalf of its wine cellar members supporting (1) a 45 [deg]F minimum 
operating temperature for high-temperature refrigeration systems, and 
(2) testing at 50 percent of maximum external static pressure, with 
manufacturers providing maximum external static pressure values to 
DOE.\50\ DOE has granted interim waivers or waivers to the 
manufacturers listed in Table III.2 for specified basic models of wine 
cellar refrigeration systems. These waivers provide an alternate test 
procedure for specific basic models of single-packaged dedicated 
systems, matched pair, and unit-cooler-only high-temperature 
refrigeration systems.
---------------------------------------------------------------------------

    \50\ Memorandum from AHRI, ``Department of Energy (DOE) Wine 
Cellar Cooling Systems Test Procedure Waiver Industry Comments from 
AHRI Membership,'' August 18, 2020. (EERE-2019-BT-WAV-0028, No. 5 
(CellarPro); EERE-2019-BT-WAV-0029, No. 5 (Air Innovations); EERE-
2019-BT-WAV-0038, No. 5(Vinotheque); EERE-2019-BT-WAV-022, No. 2 
(Vinotemp))
---------------------------------------------------------------------------

    In the June 2021 RFI, DOE requested comment on the alternative test 
procedure for high-temperature refrigeration systems, and if the 
procedure would be appropriate for basic models other than those 
specified in the waivers. 86 FR 32332, 32345. AHRI and Lennox both 
recommended that DOE adopt the test procedures outlined in the waivers. 
(Lennox, No. 9 at p. 6; AHRI, No. 11 at p. 11) AHRI and Lennox also 
stated that the ASHRAE 210P subcommittee is evaluating the inclusion of 
the waiver revisions into their test standard. Id.
    DOE is proposing to include a test procedure for testing and rating 
high-temperature matched-pair \51\ systems. The proposed test procedure 
specifies an air entering dry-bulb temperature of 55 [deg]F. DOE 
proposes that testing high-temperature refrigeration systems that are 
single-packaged systems be conducted using one of the following: The 
indoor air enthalpy method; the outdoor air enthalpy method; the 
compressor calibration method; the indoor room calorimeter method; the 
outdoor room calorimeter method; or the balanced ambient room 
calorimeter method as specified in AHRI 1250-2020.
---------------------------------------------------------------------------

    \51\ A ``matched refrigeration system'' is also called a 
``matched pair'' and is a refrigeration system where the condensing 
system is distributed into commerce with a specific unit cooler(s). 
See 10 CFR 431.302.
---------------------------------------------------------------------------

    As discussed in the June 2021 RFI, many refrigeration systems for 
wine cellars are designed for both ducted and non-ducted air delivery. 
86 FR 32332, 32345. The current DOE test procedure does not address the 
testing of ducted systems. In section III.A.1.d, DOE proposed including 
ducted single-packaged units in the scope of the walk-in test 
procedure. In section III.A.2.d, DOE proposed a definition for a ducted 
fan coil unit and proposed removing the restriction of ducts from the 
definition of a single-packaged unit. The alternate test approach in 
the waivers requires that testing of ducted units be conducted at 50 
percent of the maximum external static pressure (``ESP''), subject to a 
tolerance of -0.00/+0.05 in. wc.\52\ DOE requested feedback on its 
approach for testing ducted units, if testing at 50 percent of maximum 
ESP is representative, if there are other industry test methods that 
include testing of ducted. 86 FR 32332, 32345. Lennox and AHRI 
supported testing at 50 percent of the maximum ESP, stating

[[Page 23962]]

that it will provide representative performance values. (Lennox, No. 9 
at p. 6; AHRI, No. 11 at p. 11) The CA IOUs recommended that DOE 
require manufacturers to publish the maximum ESP to ensure that 
consumers do not exceed the maximum static pressure when they install 
these units so that the efficiency and operating capacity measured by 
the test procedure are representative of average use. (CA IOUs, No. 14 
at p. 4)
---------------------------------------------------------------------------

    \52\ Inches of water column (``in. wc'') is a unit of pressure 
conventionally used for measurement of pressure differentials.
---------------------------------------------------------------------------

    Consistent with the waivers that DOE has granted for high-
temperature refrigeration systems, DOE proposes to require that testing 
for ducted systems would be conducted with ducts fitted and at 50 
percent of the unit's maximum ESP, subject to a tolerance of -0.00/
+0.05 in. wc. DOE would include this provision to apply to any ducted 
units, not strictly high-temperature refrigeration systems. DOE 
proposes adding clarification on how to set ESP as follows. If testing 
using either the indoor or outdoor air enthalpy method, which includes 
a measurement of the air volume rate, the airflow measurement apparatus 
fan would be adjusted to set the external static pressure--otherwise, 
the external static pressure could be set by symmetrically restricting 
the outlet of the test duct.
    DOE has tentatively determined that requiring manufacturers to 
publish the maximum ESP could further ensure that the test conditions 
are representative of installation conditions. DOE intends to address 
in a future certification rulemaking the certification of the maximum 
ESP for each ducted unit. However, DOE proposes at this time to include 
a contingency in the test procedure for those cases where the maximum 
ESP is not listed in the installation instructions. DOE proposes that 
if the ESP is not provided, it would be set such that the air volume 
rate for the test is equal to two-thirds of the value that is measured 
for zero ESP operation. Making the measurements and adjustments 
required for this setup step would require use of an airflow 
measurement apparatus.
    Issue 23: DOE requests comment on provisions for setting ESP when 
testing ducted units.
    Finally, in the June 2021 RFI, DOE requested comment on any other 
issues regarding the testing of wine cellar (high-temperature) 
refrigeration systems. 86 FR 32332, 32346. Lennox and AHRI suggested 
that DOE work with wine cellar manufacturers to incorporate high-
temperature refrigeration systems adequately as a separate category. 
(Lennox, No. 9 at p. 7; AHRI, No. 11 at p. 12) Lennox and AHRI also 
both suggested that there may need to be a high medium temperature 
category of ducted indoor and outdoor units. Id. The same commenters 
noted the impact of HFC regulations on wine cellar refrigeration and 
recommended alternative refrigerants be evaluated. Id. DOE may evaluate 
equipment categories and refrigerant requirements for high-temperature 
refrigeration systems in a future energy conservation standards 
rulemaking. The CA IOUs recommended that definitions and labeling be 
developed to clearly differentiate high-temperature refrigeration units 
from medium temperature units. (CA IOUs, No. 14 at pp. 3-4) In response 
to the comment from the CA IOUs, DOE has proposed a high-temperature 
refrigeration system definition that differentiates these units from 
other refrigeration systems.
7. Variable-, Two-, and Multiple-Capacity Systems
    As discussed in the June 2021 RFI, DOE expected the majority of 
refrigeration equipment within the dedicated condensing class to be 
certified as dedicated condensing units tested alone, with a much 
smaller number of systems certified as matched pairs. 86 FR 32332, 
32348-32349. DOE's review of CCMS data has confirmed that most 
certified dedicated condensing unit basic models are dedicated 
condensing units tested and rated alone rather than matched pairs. This 
is consistent with comments made during the 2014 and 2016 rulemakings. 
However, the current DOE test procedure does not include a method for 
assessing stand-alone multiple- and variable-capacity systems. 
Similarly, AHRI 1250-2020 does not include test procedures or 
conditions for indoor variable- or two-capacity units. To address this 
gap, the ASRAC Working Group recommended that DOE amend its test 
procedure to allow for separate ratings of stand-alone variable-
capacity dedicated condensing units. (ASRAC Term Sheet Recommendation 
#6)
    Historically, refrigeration systems have been designed using a 
single-speed compressor, which operates at full cooling capacity while 
the compressor is on. To match the cooling load of the refrigerated 
space, which in most cases is less than the full cooling capacity of 
the compressor, a single-speed compressor cycles on and off. In 
contrast, variable-speed systems employ an inverter-driven compressor 
that can reduce its speed to match the cooling load. Accordingly, a 
variable-speed compressor can deliver cooling that more closely matches 
the load. This can reduce energy use by unloading the system's heat 
exchangers, allowing them to operate more effectively, and may also 
allow reduction of fan speeds, which can further enhance savings 
potential. Emerson's digital technology, used in scroll compressors, 
can also vary the average refrigerant flow by cycling the engagement of 
the scroll elements that make up the compressor--the duty cycle of this 
engagement within a cycle time on the order of 15 to 20 seconds can be 
varied to adjust average capacity. Similarly, a two- or multiple-
capacity compressor can reduce its displacement (volume intake per 
revolution), for example in a multiple-cylinder reciprocating 
compressor by ``unloading'' individual cylinders within the compressor. 
This allows the compressor to more closely match the required cooling 
load. Other staging technologies have been used, including multiple 
compressors and scroll compressors with a closable port that 
deactivates the outermost scroll wraps when open, thus reducing 
effective displacement. DOE is aware of some multiple- or variable-
capacity dedicated condensing units that are currently available on the 
market using such compressor technologies.\53\
---------------------------------------------------------------------------

    \53\ Multiple-capacity product information from one manufacturer 
can be found at www.regulations.gov under Docket EERE-2017-BT-TP-
0010, No. 4.
---------------------------------------------------------------------------

    The current DOE test procedure measures the performance of a walk-
in condensing unit while operating under a full cooling load at a fixed 
capacity; i.e., the compressor is operated continuously in its ``on'' 
state. See Tables 11 through 14 of AHRI 1250-2009, and section 3 of 
subpart R, appendix C, for further details. While AHRI 1250-2009 and 
AHRI 1250-2020 both include test methods for two-, multiple-, and 
variable-capacity matched pair refrigeration systems with outdoor 
dedicated condensing units, there is no test method for such dedicated 
condensing units when tested alone.
    In the June 2021 RFI DOE requested information on the development 
of test standards for, the efficiency gains of, and the market 
availability of multiple and variable-capacity systems. 86 FR 32332, 
32349. Lennox, AHRI, Keeprite, National Refrigeration, and Hussmann all 
stated that the market for variable capacity units is low and does not 
warrant test procedure changes. (Lennox, No. 9 at pp. 9-10; AHRI, No. 
11 at p. 14; Keeprite, No. 12 at p. 2; National Refrigeration, No 17 at 
p. 2; Hussmann, No. 18 at p. 17) Keeprite stated that variable capacity 
units are most often designed in tandem with the evaporator unit, and 
that AHRI 1250-

[[Page 23963]]

2020 tests were acceptable for all systems on the market. (Keeprite, 
No. 12 at p. 2) ASAP and NEEA recommended DOE develop a test method for 
dedicated condensing units tested alone. (ASAP, No. 13 at p. 2; NEEA, 
No. 16 at p. 2) NEEA notes that no matched systems are certified in 
CCMS indicating that the lack of test procedure may be limiting market 
adoption. (NEEA, No. 16 at p. 2) Similarly the CA IOUs stated that 
accurately measuring the field performance of variable capacity units 
is key for market adoption. (CA IOUs, No. 14 at p. 2) ASAP noted the 
ASRAC Working Group's recommendation to develop a test procedure for 
dedicated condensing units tested alone. (ASAP, No. 13 at pp. 2-3) 
ASAP, the CA IOUs, and NEEA all recommended that DOE evaluate whether 
AHRI 1250-2020 has the capability to measure real world cycling 
conditions of refrigeration systems. (ASAP, No. 13 at p. 2; CA IOUs, 
No. 14 at pp. 2-3; NEEA, No. 16 at p. 2) The CA IOUs note that this is 
important for more widespread adoption of variable capacity technology. 
(CA IOUs, No. 14 at p. 2) The CA IOUs recommended a potential 
alternative of testing variable capacity systems only as matched 
systems and having matching guidelines, similar to ASHRAE 29 or AHRI 
810. (CA IOUs, No. 14 at p. 3)
    DOE acknowledges the small market share of variable- and multiple-
capacity units but notes that the ASRAC Working Group agreed to the 
need for such test procedures for dedicated condensing units tested 
alone. Because of this, DOE proposes adding test procedures and 
conditions for variable-, two-, and multiple-capacity dedicated 
condensing units. DOE also proposes test methods for variable-, two-, 
and multiple-capacity matched pairs with indoor dedicated condensing 
units. To support these proposed additions, DOE also proposes to add a 
definition specifying that a ``multiple-capacity'' refrigeration system 
is one having three or more stages.
a. Dedicated Condensing Units
    As discussed, AHRI 1250-2020 specifies test conditions for matched 
variable- and multi-capacity refrigeration systems. Because matched 
pairs are complete refrigeration systems, the test conditions do not 
address refrigerant conditions in the refrigerant lines connecting the 
condensing unit and the unit cooler. Instead, the test specifies 
conditions for the air entering the unit cooler and the air entering 
the condensing unit. Test procedures for dedicated condensing units 
tested alone must address refrigerant conditions in the lines that 
would connect the condensing unit to a unit cooler. For example, Table 
12 of AHRI 1250-2020 provides test conditions for fixed capacity 
refrigerated indoor dedicated condensing units. The table specifies the 
refrigerant suction dew point return gas temperature at the condensing 
unit suction inlet--these conditions reflect the operation of a 
representative unit cooler as well as the temperature rise of 
refrigerant as it returns to the condensing unit in the suction line. 
In addition, the test procedure calculations also address the direct 
energy use of the unit cooler, specifically the unit cooler fan and 
(for freezer dedicated condensing units) the defrost heater energy 
input and heat impact. Section 7.9 of AHRI 1250-2020 includes equations 
providing representative values for some of these parameters--see, 
e.g., Equation 130 for on-cycle unit cooler power and Equation 118 for 
off-cycle unit cooler power. Section C10.2.2 in AHRI 1250-2020 includes 
equations providing representative values for the defrost parameters.
    To extend the test procedure to variable- and multiple-capacity 
dedicated condensing units, the test would need to specify how the 
parameters representing the unit cooler would change at part-load as 
compared to full-load. DOE is proposing new test conditions for such 
models, including values representing the unit cooler and suction line 
influence on operation at part-load. The proposed test conditions 
address condensing unit suction inlet refrigerant pressure (represented 
as dew point temperature) and temperature for the part-load conditions. 
The condenser air inlet conditions would be the same as for existing 
tests of dedicated condensing units: Tests only with 90 [deg]F dry bulb 
entering air temperature for indoor dedicated condensing units, and 
tests at 95 [deg]F, 59 [deg]F, and 35 [deg]F for outdoor dedicated 
condensing units. Also, the maximum-capacity test conditions would be 
the same as the test conditions for a single-capacity condensing unit 
since maximum-capacity operation of a multiple- or variable-capacity 
unit should match operation of a single-capacity unit. Specifically, 
for cooler dedicated condensing units the maximum-capacity suction 
connection dew point temperature would be 23 [deg]F and the refrigerant 
temperature would be 41 [deg]F--for freezers, these conditions would be 
-22 [deg]F and 5 [deg]F. These parameters would need to be defined for 
the part-load test conditions for variable-, multiple-, and two-
capacity dedicated condensing units. In addition, the unit cooler power 
levels at part-load would have to be specified, if they would be 
different than for full-load. Defrost parameters would not be expected 
to be changed for variable-, multiple-, or two-capacity dedicated 
condensing units as compared with single-capacity condensing units, 
because the defrost would occur when the dedicated condensing unit 
compressor is off, and the defrost energy and heat contribution depend 
primarily on the representative unit cooler.\54\
---------------------------------------------------------------------------

    \54\ Although the compressor would operate during hot gas 
defrost, the DOE test procedure calls for testing hot gas defrost 
dedicated condensing units using the electric defrost default 
parameters. Section 3.5 of appendix C to subpart R of 10 CFR part 
431.
---------------------------------------------------------------------------

    DOE developed representative values for the part-load refrigerant 
conditions at the condensing unit suction inlet based on testing of two 
variable-capacity systems. The testing and the development of the 
parameters is discussed in greater detail in document EERE-2017-BT-TP-
0010-0021, ``Development of Test Rating Conditions for Two-Capacity, 
Multiple-Capacity, and Variable-Capacity Condensing Units.'' The 
development is based on the expectation that the unit coolers with 
which such dedicated condensing units are paired in the field would 
have two-speed fans, either already installed or retrofitted as part of 
the condensing unit installation. The test work shows that this 
inclusion of two-speed fans would be necessary in order to achieve 
efficiency gains with part-load capacity near or lower than half of the 
full-load capacity.
(1) Dew Point Target Values for Part-Load Operation: Unit Cooler Exit
    As unit cooler-part-load capacity decreases, the suction dew point 
rises, approaching the temperature of the air entering the unit cooler 
(``air-entering temperature''). However, when a unit cooler fan 
switches to reduced speed, the suction dew point falls, in this case 
from the reduction in unit cooler evaporator effectiveness when 
operating with less airflow. Note that the unit cooler fan power 
reduces significantly at reduced speed, and this fan heat reduction can 
significantly increase net capacity and efficiency at part-load. DOE 
developed representative trendlines for approach of unit cooler exit 
evaporating (dew point) temperature to the unit cooler air-entering 
temperature for both full- and half-speed fan operation.
    However, in its development, DOE limited its approach to air-
entering temperature to account for the expected exit of superheat. 
Refrigerant flow

[[Page 23964]]

through unit coolers is controlled by expansion devices controlling for 
the presence of a certain refrigerant superheat level at the unit 
cooler exit. The test procedure for unit coolers calls for this value 
to be set at 6.5 [deg]F in case there is no manufacturer-specified 
level. For such operation, the temperature of the refrigerant leaving 
the unit cooler is 6.5 [deg]F warmer than the dew point temperature. 
However, the refrigerant leaving the unit cooler can be no warmer than 
the entering air. Thus, the approach of dew point temperature to 
entering air temperature can be no more than 6.5 [deg]F for a unit 
cooler operating with this level of superheat. Thus, in its 
development, DOE limited the approach to 7 [deg]F to account for this 
issue and to provide a 0.5 [deg]F margin.
    The selection of dew point temperature at the unit cooler exit for 
a given part-load operating condition thus depends on the capacity 
level and the unit cooler fan speed (full or half speed). While 
different compressor part-load technologies can provide different 
levels of capacity turndown, DOE developed representative dew point 
levels based on expectations of likely part-load capacity levels. 
Specifically, for variable- or multiple-stage dedicated condensing 
units, the expected minimum level is roughly \1/3\ of full capacity, 
and the expected intermediate level is roughly \2/3\ of full capacity. 
For two-capacity dedicated condensing units, DOE used a representative 
low-capacity level of roughly half the full-capacity level.
    As for unit cooler fan speed, DOE's testing showed that the optimum 
capacity level for switching between speeds is near \2/3\--this means 
that lower than this capacity level, the higher fan heat and power 
input associated with full fan operation outweighs the benefit of 
higher evaporator effectiveness. Hence, in determining the appropriate 
unit cooler exit condition, DOE assumed that low fan speed would be 
used if the compressor or compressors run at an operating level less 
than 65 percent. As mentioned, there are different ways that 
compressors can achieve part-load conditions. The operating level 
determination would be based on the compressor technology. 
Specifically, this would involve the speed ratio for a variable-speed 
compressor, scroll engagement duty cycle for a digital scroll 
compressor, or displacement ratio for a staged compressor system that 
changes displacement at part-load. Hence, for those part-load 
conditions where the operating level (determined as appropriate for the 
compressor technology) is less than or equal to 65 percent, the unit 
cooler exit condition would be based on the low fan trend measured in 
DOE's test series, and where the operating level is greater than 65 
percent, it would be based on the full fan trend. Correspondingly, the 
fan power used in calculating AWEF would be based on the operating 
level as well.
(2) Compressor Operating Levels During Testing
    In order to clarify the compressor operating level, DOE proposes to 
define specific terms appropriate for the compressor technologies 
expected to be used to achieve part-load operation. These terms would 
be ``duty cycle'' for digital scroll compressors, ``speed ratio'' for 
variable-speed compressors, and ``displacement ratio'' for compressors 
or compressor systems that vary the compressor inlet displacement 
volume to achieve capacity modulation.
    DOE proposes the following definitions:
    <bullet> Displacement Ratio, applicable for a staged positive 
displacement compressor system, means the swept volume rate, e.g., in 
cubic centimeters per second, of a given stage, divided by the swept 
volume rate at full capacity.
    <bullet> Duty Cycle, applicable for a digital compressor, means the 
fraction of time that the compressor is engaged and actively 
compressing refrigerant.
    <bullet> Speed Ratio, applicable for a variable-speed compressor, 
means the ratio of operating speed to the maximum speed.
    DOE is proposing to specify use of compressor operating levels 
during part-load testing that are consistent with the development of 
the representative unit cooler exit dew point targets. For two-capacity 
compressors, this is straightforward since there is only one part-load 
operating level. For variable-capacity and multiple-capacity 
compressors, DOE proposes that the part-load operating levels be the 
lowest level (e.g., speed, duty cycle, or stage) available for the 
compressor, and that the intermediate level be the nearest available 
level to the mean of the full-capacity and minimum-capacity levels. To 
clarify this proposal, DOE is proposing to define ``Minimum Speed'' and 
``Maximum Speed'' as set out in the regulatory text at the end of this 
document, proposed appendix C1 to subpart R of part 431.
(3) Dew Point Target Values for Part-Load Operation: Condensing Unit 
Inlet
    The previous section discussed the approach for development of 
appropriate unit representative cooler exit conditions for part-load 
operation of a condensing unit tested alone. However, performance 
depends on conditions at the condensing unit inlet. For full-load 
operation, the test procedure operating conditions are based on 
assuming that the pressure drop in the suction line is equivalent to a 
2 [deg]F reduction in dew point temperature. 81 FR 95758, 95792 
(December 28, 2016). For part-load operation, the suction line pressure 
drop would be lower, due to the reduced refrigerant flow rate. In its 
development of condensing unit test conditions, DOE assumed that the 
suction line pressure drop would be equivalent to a dew point reduction 
of 1 [deg]F when the part-load capacity is 50 percent of the full-load 
capacity or more and would be 0.5 [deg]F when the capacity is lower 
(see discussion in EERE-2017-BT-TP-0010-0021, ``Development of Test 
Rating Conditions for Two-Capacity, Multiple-Capacity, and Variable-
Capacity Condensing Units''). The suction dew point levels at the 
condensing unit inlet would then be as indicated in Table III.10 and 
Table III.11.

                     Table III.10--Two-Capacity Dedicated Condensing Unit Suction Dew Points
----------------------------------------------------------------------------------------------------------------
                                                                                   Low capacity,   Low capacity,
                                                                                     high unit       low unit
                                                                   High-capacity    cooler fan      cooler fan
                           Application                              suction dew   speed, suction  speed, suction
                                                                   point, [deg]F    dew point,      dew point,
                                                                                      [deg]F          [deg]F
----------------------------------------------------------------------------------------------------------------
Cooler..........................................................              23            25.5              23
Freezer.........................................................             -22           -19.5             -22
----------------------------------------------------------------------------------------------------------------


[[Page 23965]]


        Table III.11--Variable-Capacity or Multiple-Capacity Dedicated Condensing Unit Suction Dew Points
----------------------------------------------------------------------------------------------------------------
                                                                   Intermediate    Intermediate
                                                     Maximum-     capacity, high   capacity, low     Minimum-
                                                     capacity       unit cooler     unit cooler      capacity
                   Application                      suction dew     fan speed,      fan speed,      suction dew
                                                   point, [deg]F    suction dew     suction dew    point, [deg]F
                                                                   point, [deg]F   point, [deg]F
----------------------------------------------------------------------------------------------------------------
Cooler..........................................              23            25.5              22              26
Freezer.........................................             -22           -19.5             -23             -19
----------------------------------------------------------------------------------------------------------------

(4) Target Refrigerant Temperature at Condensing Unit Inlet
    As discussed previously, the refrigerant temperature at the exit of 
the representative unit cooler is equal to the unit cooler exit dew 
point temperature plus the superheat, assumed to be 6.5 [deg]F. The 
refrigerant warms up in the suction line as it returns to the 
condensing unit. For full-load operation, the test procedure specifies 
condensing unit inlet temperature conditions, i.e., 41 [deg]F for 
cooler dedicated condensing units and 5 [deg]F for freezer condensing 
units. In a cooler system operating at full-load in a 95 [deg]F outdoor 
condition, this means that the refrigerant is warmed from 31.5 [deg]F 
at the unit cooler exit to 41 [deg]F at the condensing unit inlet. Most 
of this warmup would be expected to occur where the suction line is 
exposed to 95 [deg]F outdoor conditions, since the cooler interior 
temperature at 35 [deg]F is only a few degrees warmer than the 
refrigerant exiting the unit cooler. The suction line exposed to 
outdoor air conditions can be seen as a heat exchanger with low 
effectiveness. For the purposes of determining the trend of suction 
line refrigerant temperature increase at part-load, DOE assumed that 
the suction line thermal resistance would remain the same as the 
capacity level changes. This means that when refrigerant flow is lower 
at part-load, the heat transfer effectiveness would be higher, and the 
refrigerant temperature rise would be greater. (See the more detailed 
discussion in EERE-2017-BT-TP-0010-0021, ``Development of Test Rating 
Conditions for Two-Capacity, Multiple-Capacity, and Variable-Capacity 
Condensing Units'') The document discusses in more detail how the 
suction line temperature rise was calculated for different operating 
conditions and related to the operating capacity level of the 
condensing unit. Note that for refrigerated outdoor dedicated 
condensing units using test condition C, no change in the condensing 
unit inlet temperature is assumed for different capacity levels, 
because the 41 [deg]F specified for single-capacity systems already 
suggests a suction line heat transfer effectiveness greater than 100 
percent. Hence, DOE proposes no change in condensing unit inlet 
temperature for cooler dedicated condensing units for condition C.

                   Table III.12--Two-Capacity Dedicated Condensing Unit Return Gas Conditions
----------------------------------------------------------------------------------------------------------------
                                                      Unit cooler fan level
                  Test title                       corresponding to compressor    Freezer return   Cooler return
                                                         operating level            gas, [deg]F     gas, [deg]F
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low Capacity...........  Low.............................            13.5            45.0
                                                High............................            12.0            42.5
Capacity, Condition A, High Capacity..........  High............................               5              41
Capacity, Condition B, Low Capacity...........  Low.............................            13.0            41.0
                                                High............................            11.5            41.5
Capacity, Condition B, High Capacity..........  High............................               5              41
Capacity, Condition C, Low Capacity...........  Low.............................            12.0            42.5
                                                High............................            10.5            41.0
Capacity, Condition C, High Capacity..........  High............................               5              41
----------------------------------------------------------------------------------------------------------------


                 Table III.13--Variable-Capacity Dedicated Condensing Unit Return Gas Conditions
----------------------------------------------------------------------------------------------------------------
                                                      Unit cooler fan level
                  Test title                       corresponding to compressor    Freezer return   Cooler return
                                                         operating level            gas, [deg]F     gas, [deg]F
----------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum Capacity.......  Low.............................            26.5            53.0
Capacity, Condition A, Intermediate Capacity..  Low.............................            10.5            43.0
                                                High............................            12.0            45.5
Capacity, Condition A, Maximum Capacity.......  High............................               5              41
Capacity, Condition B, Minimum Capacity.......  Low.............................            24.0            46.0
Capacity, Condition B, Intermediate Capacity..  Low.............................            10.0            40.0
                                                High............................            11.5            41.5
Capacity, Condition B, Maximum Capacity.......  High............................               5              41
Capacity, Condition C, Minimum Capacity.......  Low.............................            20.0            41.0
Capacity, Condition C, Intermediate Capacity..  Low.............................            10.0            41.0
                                                High............................            10.5            41.0
Capacity, Condition C, Maximum Capacity.......  High............................               5              41
----------------------------------------------------------------------------------------------------------------


[[Page 23966]]

(5) Unit Cooler Power To Use for AWEF Calculations
    As discussed previously, the proposed test for dedicated condensing 
units with more than one compressor capacity is based on the 
expectation that a representative unit cooler with which the condensing 
unit would be paired in the field will have or be fitted with during 
installation a two-speed or variable-speed fan, and that the fan would 
operate at half-speed as appropriate for part-load operation. Also 
discussed previously, the unit cooler dew point target for the test 
depends on the assumption for unit cooler fan operating condition, and 
DOE is proposing that half-speed would be used for compressor operating 
levels up to 65 percent. AHRI 1250-2020 already provides power input 
levels for a representative unit cooler with fans operating at full- 
and half-speed levels (for example, see Equations 118 and 130 of the 
test standard, providing representative wattages for off-cycle and on-
cycle wattages). DOE proposes that the half-speed off-cycle wattage 
would also be used for half-speed on-cycle operation when calculating 
AWEF.
(6) Other Aspects of AWEF Calculations
    DOE proposes that the calculations used to determine AWEF for 
dedicated condensing units with more than one capacity level would be 
essentially identical to the calculations for matched pair or single-
packaged dedicated systems once capacity and power input are determined 
for each standard operating condition at the different capacity levels. 
However, this proposal would adjust the calculation methods for 
variable- and multiple-capacity systems, consistent with the direction 
taken for calculating efficiency metrics for variable-capacity central 
air conditioners and heat pumps in the test procedure final rule 
published in 2016 for those products. These changes are described in 
section III.G.7.c of this document.
    Issue 24: DOE requests comments on its proposals for testing 
multiple-, variable-, and two-capacity dedicated condensing units 
tested alone. DOE specifically requests comments on (a) the expectation 
that a unit cooler with which such a condensing unit is paired in the 
field would have two-speed (or variable-speed) fans or be fitted with 
such fans during installation, (b) the proposed compressor operating 
levels to use for testing, (c) the proposed compressor operating level 
at which the unit cooler fan would be assumed to switch to half-speed, 
(d) the proposed targets for unit cooler exit and condensing unit inlet 
refrigerant temperatures and dew point target temperatures, and (e) the 
unit cooler half-fan-speed input wattage.
(7) Information Required for Testing
    Testing of dedicated condensing units with multiple capacity levels 
requires setting operating conditions for testing that are not required 
when testing single-capacity dedicated condensing units. DOE expects 
that some of this information may not be readily available in 
installation instructions and may consider whether certification of 
some of the required information may be needed in a separate rulemaking 
addressing certification.
(8) Potential Use of Equations Rather Than Tabulated Values for Target 
Test Conditions
    The proposed tabulated target values for suction dew point and 
suction temperature for part-load operation of dedicated condensing 
units shown in Table III.10 through Table III.13 were using 
correlations for the trends of unit cooler operation and suction line 
pressure drop and heat transfer developed based on test data (See the 
discussion in EERE-2017-BT-TP-0010-0021, ``Development of Test Rating 
Conditions for Two-Capacity, Multiple-Capacity, and Variable-Capacity 
Condensing Units'') The target values also consider likely compressor 
minimum operating levels and decisions regarding the unit cooler fan 
operating level corresponding to each compressor operating level. 
Rather than use a tabular approach to specifying target operating 
conditions, DOE could consider direct use of the correlations for 
determination of target test conditions. The approach would involve, 
for each part-load test, using (1) two correlations to calculate the 
target condensing unit suction inlet dew point, and (2) two equations 
to calculate target condensing unit suction inlet temperature. This 
approach would provide more flexibility in manufacturer decisions 
regarding the unit cooler fan level corresponding to any given 
compressor staging level and slightly better alignment of the test 
conditions to the compressor operating levels. However, it would 
require manufacturers to provide more information regarding selection 
of test conditions to clarify how models were tested and could be 
considered more burdensome by requiring calculation of test conditions. 
Depending on comments provided on this topic, DOE may consider adopting 
this approach of using the correlations for unit cooler and suction 
line trends instead of the tabulated values for setting target test 
conditions.
    Issue 25: DOE requests comment on whether DOE should set the target 
test conditions using correlations for unit cooler and suction line 
response to part-load operation rather than the proposed tabular 
approach.
b. Indoor Matched Pair and Single-Packaged Units
    As discussed previously, AHRI 1250-2020 does not include test 
procedures or conditions for indoor variable or multiple-capacity 
units. As with dedicated condensing units, DOE proposes to adopt test 
methods for indoor matched pair and single-packaged dedicated systems. 
Testing of these systems and calculating AWEF for them would require 
parallel testing and AWEF calculations for outdoor matched systems, 
except that there is only one test condition and the AWEF calculation 
would be based only on that one condition. The details for required 
test conditions and calculations are presented in section 4.5.6 and 
Table 17 and Table 18 of this document showing the proposed regulatory 
text revisions.
    Issue 26: DOE requests comment on its proposal to include in its 
test procedures instructions for testing and determining 
representations for indoor matched pair and single-packaged dedicated 
systems.
c. Revision to EER Calculation for Outdoor Variable-Capacity and 
Multiple-Capacity Refrigeration Systems
    AHRI 1250-2020 includes test conditions and calculations to 
determine representations, specifically AWEF, for refrigeration systems 
having variable-capacity capability. The calculations use a quadratic 
equation for determining system EER for intermediate-capacity operation 
(see, e.g., Equations 76 through 84 of AHRI 1250-2020). DOE moved from 
the same quadratic approach for central air conditioners and heat pumps 
(``CAC/HP'') to a linear interpolation method due to concerns about 
potential inaccuracies of this method. 82 FR 1426, 1440-1441 (January 
5, 2017). DOE proposes to make the same change when testing WICF 
refrigeration systems.
    Issue 27: DOE requests comment on its proposal to modify the 
approach for calculating intermediate-capacity EER for variable-speed 
refrigeration systems.
d. Digital Compressors
    Dedicated condensing units with digital compressors have been 
commercialized (see, e.g., EERE-2017-BT-TP-0010-0020). Digital 
compressor operation is discussed in the

[[Page 23967]]

introduction to section III.G.7 of this document. To clarify the 
proposed test procedure for digital compressors, DOE proposes to define 
the term ``digital compressor'' as a compressor that uses mechanical 
means for disengaging active compression on a cyclic basis to provide a 
reduced average refrigerant flow rate in response to an input signal.
    DOE testing has shown that operating tolerances specified in AHRI 
1250-2020 for certain parameters such as refrigerant pressure and mass 
flow can be exceeded when a digital compressor operates at part-load. 
Nevertheless, DOE testing has shown that the refrigerant enthalpy 
method for measuring capacity may still be quite accurate, as long as 
the liquid subcooling at the mass flow meter is sufficiently low, as 
required in Section C3.4.5 of AHRI 1250-2020. When conducting these 
tests, DOE used an integrating mass flow meter and measurement of 
temperature and pressure at a frequency of one measurement per second. 
DOE calculated capacity using refrigerant enthalpies determined based 
on test-period-average values of refrigerant temperature and pressure. 
When meeting the mass flow meter subcooling requirements, capacity 
balance with a separate calorimetric capacity measurement ranged from 
0.2 to 4.1 percent.
    Thus, DOE proposes that testing of refrigeration equipment with 
digital compressors operating at part-load may use the refrigerant 
enthalpy method as a secondary test method, with the following 
provisions and adjustments: (1) Pressure and temperature measurement 
would be at a frequency of once per second or faster, (2) the operating 
tolerances for pressure and temperature at both the inlet and outlet 
connections, and for mass flow would not apply, and (3) enthalpies 
determined for the capacity calculation would be based on test-period-
average pressure and temperature values.
    DOE proposes that the selection of the primary test method for 
measuring capacity would depend on the refrigeration system 
configuration. For single-packaged dedicated systems, the test methods 
proposed to be used as primary methods for any single-packaged 
dedicated system would be used (see discussion in section III.G.2of 
this document). For matched pairs, the same test methods allowed as 
primary methods for single-packaged dedicated systems would be used. 
For dedicated condensing units, the primary methods that would be used 
would include outdoor air enthalpy method, balanced ambient outdoor 
calorimeter, and outdoor room calorimeter measurements.
    Issue 28: DOE requests comments on its proposals to address part-
load testing for refrigeration systems with digital compressors.
8. Defrost
    The April 2011 final rule referenced AHRI 1250-2009 as DOE's WICF 
refrigeration system test procedure, including that standard's 
requirement that both frosted and dry coil defrost tests be conducted. 
81 FR 21580, 21597. DOE later noted in a supplemental notice of 
proposed rulemaking published on February 20, 2014 (``February 2014 
SNOPR'') that these tests may be overly burdensome for manufacturers to 
conduct due to the difficulty of maintaining the moist air infiltration 
conditions for the frosted coil test in a repeatable manner. 79 FR 
9818, 9831. Accordingly, in the May 2014 final rule, DOE adopted a set 
of nominal values for calculating defrost energy use for a frosted 
coil, number of defrosts per day if the unit has an adaptive defrost 
system, and daily contribution of heat load. 79 FR 27388, 27401. To 
address testing low-temperature dedicated condensing units alone, the 
May 2014 final rule established nominal values for the defrost energy 
use and thermal load. In addressing refrigeration systems with hot gas 
defrost, the May 2014 final rule established nominal values for 
calculating hot gas defrost energy use and heat load.\55\ Id.
---------------------------------------------------------------------------

    \55\ In a ``hot gas'' defrost system, high-temperature, high-
pressure hot refrigerant gas from the discharge side of the 
compressor is introduced into the evaporator, where it condenses, 
thereby releasing latent heat into the evaporator. This heat is used 
to melt the frost that has accumulated on the outside of the 
evaporator coil.
---------------------------------------------------------------------------

    The December 2016 final rule removed the method for calculating the 
defrost energy and defrost heat load of systems with hot gas defrost 
and established a new method to evaluate hot gas defrost refrigeration 
systems. That new method treated hot gas defrost refrigeration systems 
as if they used electric defrost rather than hot gas defrost. This 
method relied on the same nominal values for defrost energy use and 
thermal load that the test procedure prescribes for electric-defrost 
dedicated condensing units that are tested alone. 81 FR 95758, 95774-
95777. This approach was modified in the March 2021 final rule, which 
amended the DOE test procedure by rating hot gas defrost unit coolers 
using modified default values for energy use and heat load 
contributions that would make their ratings more consistent with those 
of electric defrost unit coolers. 86 FR 16027. The scope of the March 
2021 final rule is limited to unit coolers only. 86 FR 16027, 16030.
    In the June 2021 test procedure (``TP'') RFI, DOE stated that it 
was considering whether to include a test method for determining the 
energy use associated with defrost and/or a test method to assess and 
confirm defrost adequacy. 86 FR 32332, 32347. DOE observed that any 
test method for determining defrost energy use and adequacy would have 
to provide consistent, repeatable methods for (1) delivering a frost 
load to the test coil and (2) measuring the thermal load released into 
the refrigerated space during the defrost cycle, regardless of the 
method of defrost (e.g., electric or hot gas defrost), all while 
ensuring that the procedure provides results reflecting energy usage 
during a representative average use cycle and not be unduly burdensome 
to conduct. Id. DOE requested information on methods that might provide 
a measurable frost load and frost type to ensure repeatable defrost 
testing. Additionally, DOE requested data on typical frost loads and 
frost type, or information on the type and amount of testing that would 
be necessary to validate a method for evaluating frost loads and frost 
types during defrost testing. Id.
    In response to DOE's request for comment, Lennox, AHRI, National 
Refrigeration, and Hussmann recognized that although the injector 
system included in appendix E of AHRI 1250-2020 is an improvement, it 
remains a challenge to consistently build frost on an evaporator coil 
while minimizing interference with calorimeter systems. (Lennox No. 9 
at p. 8; AHRI No. 11 at p. 13; National Refrigeration No. 17 at p. 2; 
Hussmann No. 18 at p. 15 Keeprite reiterated the technical difficulties 
associated with a moist-air loading approach. (Keeprite No. 12 at p. 2) 
Each of these stakeholders urged DOE to wait for the completion of 
ASHRAE research project WS 1831, ``Validation of a Test Method for 
Applying a Standardized Frost Load on a Test Evaporator in a Test 
Chamber with an Operating Conditioning System'' (``WS 1831''), before 
modifying its defrost test procedure. (Lennox No. 9 at p. 8; AHRI No. 
11 at p. 13; National Refrigeration No. 17 at p. 2; Hussmann No. 18 at 
p. 15) ASAP also recognized the challenge associated with developing a 
test method to measure defrost energy (ASAP No. 13 at p. 2), while the 
CA IOUs agreed that AHRI 1250-2020 appendix E provides a good starting 
point for a universal defrost test but urged DOE to work with 
stakeholders to develop a test procedure for defrost that

[[Page 23968]]

could be used for all walk-in equipment. (CA IOUs No. 14 at p. 3) More 
specifically, the CA IOUs suggested that a test procedure for 
determining defrost energy consumption would vary the length and 
intensity of moisture injections to better represent field conditions. 
Id. Similarly, ASAP stressed that the ASRAC Working Group recommended 
incorporating a test method for measurement of defrost energy 
consumption and encouraged DOE to develop a future test method that 
better captures defrost energy use and performance for all defrost 
systems. (ASAP No. 13 at p. 2)
    DOE recognizes that it is challenging to consistently build frost 
on an evaporator coil to assess a unit's defrost performance. In 
Section C11 of AHRI 1250-2009, the moisture to provide a frost load is 
introduced through the infiltration of air at a 75.2 [deg]F dry-bulb 
temperature and a 64.4 [deg]F wet-bulb temperature into the walk-in 
freezer at a constant airflow rate that depends on the refrigeration 
capacity of the tested freezer unit (equations C11 and C12 in Section 
C11.1.1 of AHRI 1250-2009). A key issue with this approach is the 
difficulty in ensuring repeatable frost development on the unit under 
test, despite specifying the infiltration air dry-bulb and wet-bulb 
temperatures. For example, in addition to frost accumulating on the 
evaporator of the unit under test, frost may also accumulate on the 
evaporator of other cooling equipment used to condition the room, which 
could subsequently affect the rate of frost accumulation on the unit 
under test (by affecting the amount of moisture remaining in the air).
    In past ASHRAE-supported research, researchers created a frost load 
by introducing steam directly into the refrigerated space.\56\ However, 
as discussed in 1094-RP, this approach can result in the suspension of 
ice crystals in the saturated room air and the formation of snow-like 
frost on the test coils. The researchers found that this snow-like 
frost degrades refrigeration system performance more, and is more 
difficult to defrost, than the ice-like frost that forms in sub-
saturated air conditions. Both 622-RP and 1094-RP observed that a 
significant portion of the coil frost was converted to water vapor 
rather than melted during the defrost cycle. This finding suggests that 
measuring the quantity of frost melt water mass may be a poor indicator 
of the frost load, since a significant portion of the frost would not 
be captured as melt water.\61\
---------------------------------------------------------------------------

    \56\ Sherif, S.A., P.J. Mago, and R.S. Theen. A Study to 
Determine Heat Loads Due to Coil Defrosting. 1997. University of 
Florida: Gainesville, FL. ASHRAE Project No. 622-RP. Report No. 
UFME/SEECLSEE-9701 (``622-RP'') and Sherif, S.A., P.J. Mago, and 
R.S. Theen. A Study to Determine Heat Loads Due to Coil Defrosting-
Phase II. 2003. University of Florida: Gainesville, FL. ASHRAE 
Project No. 1094-RP. Report No. UFME/SEECLSEE-200201 (``1094-RP'').
---------------------------------------------------------------------------

    DOE is aware that ASHRAE initiated project WS 1831 on September 2, 
2021. The purpose of this research is to examine different approaches 
for applying a standardized, repeatable, full-frost accumulation (i.e., 
accumulation of a frost quantity that would typically accumulate 
between defrosts during system operation in moist conditions) on 
evaporator coils so that the subsequent defrost test provides a 
representative indication of energy use associated with defrosting a 
frosted coil. Indirect methods for determining full frost load might 
include air side temperature, humidity, or pressure drop, refrigerant-
side evaporation temperature or pressure, compressor or unit cooler fan 
power consumption, or the refrigerant-to-air or air-side inlet-to-
outlet temperature difference.
    Since the defrost test procedure in AHRI 1250-2009, section C11 has 
limitations, AHRI 1250-2020 does not include a frosted-coil test but 
does include provisions for a dry-coil defrost test.\57\ Industry is 
currently evaluating how to create and validate consistent evaporator 
coil frost loads; therefore, DOE proposes to maintain the current 
calculation-based approach for estimating defrost energy consumption. 
Specifically, DOE proposes to incorporate by reference Section C10 of 
AHRI 1250-2020 for unit coolers with either electric or hot gas 
defrost.
---------------------------------------------------------------------------

    \57\ AHRI 1250-2020 includes an adaptive defrost challenge test 
in appendix E (``Appendix E'') and a hot gas defrost challenge test 
in appendix F (``Appendix F'') that require a frosted coil. The 
tests in both of these appendices are labelled as ``informative,'' 
and were designed to evaluate adaptive defrost or hot gas defrost 
functionality, respectively, rather than to quantify defrost energy 
use.
---------------------------------------------------------------------------

    In the June 2021 RFI, DOE requested comment on whether these and 
other updates to AHRI 1250-2020 would, if incorporated by DOE, result 
in additional testing burden. 86 FR 32332, 32336. Lennox, AHRI, 
Keeprite, and Hussmann recommended that DOE omit Section C10.2.1.1 of 
AHRI 1250-2020 from its test procedure since it does little to make the 
test procedure more representative but introduces technical challenges 
associated with air conditions during the dry coil defrost test. 
(Lennox No. 9 at p. 3; AHRI No. 11 at p. 5; Keeprite No. 12 at p. 1-3; 
Hussmann No. 18 at p. 6-7) Section C10.2.1.1 of AHRI 1250-2020 
specifies that the general test condition tolerances are not applicable 
but does require that the indoor entering dry-blub temperature must be 
less than or equal to 4 [deg]F and that air velocity in the vicinity of 
the test unit must not exceed 500 feet per minute. At this time, DOE 
does not have sufficient data to fully evaluate how these test room 
condition requirements during the dry coil defrost test would impact 
the representativeness of the test procedure relative to any potential 
additional test burden. DOE has tentatively decided not to incorporate 
Section C10.2.1.1 of AHRI 1250-but will instead continue to investigate 
this issue and may decide to include dry coil defrost operating 
tolerances in a later rulemaking. While DOE will continue to evaluate 
the dry coil defrost test room conditions, DOE emphasizes that it is 
proposing to incorporate the entirety of Section C10 of AHRI 1250-2020, 
``Defrost Calculation and Test Methods,'' by reference, except for 
Section C10.2.1.1, ``Test Room Conditioning Equipment.''
    In the following sections, DOE discusses relevant stakeholder 
comments and additional proposals for adaptive defrost and hot gas 
defrost.
a. Adaptive Defrost
    Adaptive defrost refers to a factory-installed defrost control 
system that reduces defrost frequency by initiating defrosts or 
adjusting the number of defrosts per day in response to operating 
conditions rather than initiating defrost strictly based on compressor 
run time or clock time. 10 CFR 431.303. In the December 2016 final 
rule, DOE established an approach to address systems with adaptive 
defrost. 81 FR 95758, 95777. This approach requires that adaptive 
defrost features are deactivated during certification testing; i.e., 
for certification, units are tested as if they do not have adaptive 
defrost. See subpart R, appendix C, section 3.3.5. However, DOE's 
current approach also allows the energy saving benefits of adaptive 
defrost to be displayed in public representations and marketing 
material (but not for certification purposes). Id. To represent the 
benefits of adaptive defrost, a calculation method is provided that 
allows the unit under test to reduce its number of defrosts per day 
(``N<INF>DF</INF>'') to the average of its daily dry coil and frosted 
coil defrosts (typically 1 and 4, respectively, for an average of 2.5), 
rather than basing N<INF>DF</INF> on the number of frosted coil 
defrosts per day (typically 4). Id. DOE's current approach applies to 
all refrigeration system configurations (i.e., matched pairs, unit 
coolers tested alone, and dedicated condensing units tested alone).

[[Page 23969]]

    In the June 2021 TP RFI, DOE observed that a test method to 
evaluate the impact of adaptive defrost must evaluate (1) whether a 
system waits too long to defrost (i.e., too much frost builds up on the 
coils, which impacts on-cycle performance) and (2) if the system 
defrosts more than four times per day, which is typical for a 
conventional timed defrost. 86 FR 32332, 32348. DOE requested comment 
on how the performance of adaptive defrost systems should be accounted 
for in the walk-in test procedure and which refrigeration systems 
(i.e., matched pairs, unit coolers tested alone, and dedicated 
condensing units tested alone) should be eligible for a potential 
adaptive defrost test procedure. Lennox, AHRI, Keeprite, National 
Refrigeration, and Hussmann stated that adaptive defrost is most 
prevalent in matched pairs and that it would be necessary to match unit 
coolers and dedicated condensing units to realize adaptive defrost. 
(Lennox, No. 9 at p. 9; AHRI, No. 11 at p. 14; Keeprite, No. 12 at p. 
2; National Refrigeration, No. 17 at p. 2; Hussmann, No. 18 at p. 16) 
The CA IOUs encouraged DOE to develop a test to measure the performance 
benefits of adaptive defrost. (CA IOUs, No. 14 at p. 3) While the CA 
IOUs stated that Appendix E of AHRI 1250-2020 provides a good starting 
point for a defrost test, they suggested that the addition of moisture 
as a static load of 0.5 pounds per hour per 1,000 Btu per hour in 
Appendix E does not evaluate the full capability of most adaptive 
defrost systems and does not sufficiently differentiate between 
adaptive control strategies. (CA IOUs, No. 14 at p. 3)
    DOE also requested data showing the performance of adaptive defrost 
systems relative to non-controlled defrost systems, data showing the 
impact of adaptive defrost to on-cycle operation, and data 
demonstrating seasonal or daily frosting patterns for walk-in 
applications. 86 FR 32332, 32348. In response, the CA IOUs shared test 
results from adaptive defrost control systems installed in the field 
which show between 0 and 30 percent energy savings compared to baseline 
systems with no adaptive defrost control. (CA IOUs, No. 14 at p. 3) 
Accordingly, the CA IOUs encouraged DOE to consider varying the length 
and intensity of moisture injections to better represent in-field frost 
load and differentiate between control strategies. Id.
    DOE recognizes the need to develop a representative and repeatable 
test method for evaluating adaptive defrost performance, and notes that 
appendix E may be an appropriate starting point. DOE also acknowledges 
that industry is invested in developing an adaptive defrost test 
procedure and that the ASHRAE WS 1831 research project must be 
completed in order to understand how to best form a representative and 
uniform layer of frost on the defrost coil. DOE appreciates the 
information provided by the CA IOUs and will consider it in its 
development and/or evaluation of any newly developed test procedure for 
quantifying the energy use of adaptive defrost. After considering the 
stakeholder comments received, DOE proposes to maintain the current 
regulatory approach that reduces the number of defrosts per day in the 
AWEF calculation from 4.0 to 2.5, for adaptive defrost systems. DOE 
also proposes to maintain its approach where AWEF calculated using the 
adaptive defrost credit (i.e., using 2.5 defrosts per day, rather than 
4.0) may be used for representation purposes only, and may not be used 
when calculating AWEF for compliance with DOE energy conservation 
standards. DOE also proposes to maintain its current approach, in which 
the adaptive defrost calculation method is applicable to all 
refrigeration system configurations (i.e., matched pairs, unit coolers 
tested alone, and dedicated condensing units tested alone). Finally, 
DOE notes that use of the adaptive defrost credit for representation 
purposes only would continue to apply only to factory-installed defrost 
control systems. Overall, the optional adaptive defrost strategy that 
DOE is proposing for representation purposes can be summarized as 
follows:
    <bullet> The adaptive defrost calculation method (i.e., the 
adaptive defrost ``credit'') may be used only for representation 
purposes, and may not be used to calculate AWEF for compliance 
purposes.
    <bullet> All refrigeration system configurations (i.e., matched 
pairs, unit coolers tested alone, and dedicated condensing units tested 
alone) may use the adaptive defrost calculation method for 
representation purposes.
    <bullet> Refrigeration systems may use the adaptive defrost 
calculation method for representation purposes only if the adaptive 
defrost controller is distributed in commerce with the refrigeration 
system.
b. Hot Gas Defrost
    As discussed previously, the March 2021 final rule amended the test 
procedure to rate hot gas defrost unit coolers using modified default 
values for energy use and heat load contributions that would make their 
ratings more consistent with those of electric defrost unit coolers but 
is limited to unit coolers only. 86 FR 16027, 16030.
    In the June 2021 TP RFI, DOE discussed that it was interested in 
obtaining feedback on the most practicable method for measuring hot gas 
defrost performance. 86 FR 32332, 32347. DOE recognized that in order 
to assess the energy performance of a defrost cycle, the test procedure 
must measure both the energy consumed and the heat released into the 
refrigerated space by the defrost system. Id. DOE further discussed 
that for hot gas defrost systems, unlike electric resistance heating 
systems, the energy consumed and the heat released are not equivalent, 
which makes the current electric defrost test procedure outlined in 
AHRI 1250-2009 inappropriate for hot gas defrost systems. Id.
    DOE stated that it is not aware of a test method that can reliably 
be used to directly measure the thermal impact of hot gas defrost 
without a substantial increase in test burden and mentioned that it was 
therefore considering the use of a calculation method. Id. Rather than 
measure the energy used and heat released into the refrigerated space 
for the unit-under-test, the energy use and heat load could be 
calculated as a function of the refrigeration system's steady state 
capacity. Id. DOE further discussed that the energy use and heat load 
to capacity relationships could be defined based on test data from 
actual hot gas defrost systems. Id. DOE recognized that AHRI has 
developed a calculation method to represent hot gas defrost heat load 
and energy use contributions. Id. This method is provided in Section 
C10.1 of AHRI 1250-2020 and prescribes equations to represent energy 
use and heat addition associated with defrost for different system 
configurations (matched pair, single-packaged dedicated, unit cooler, 
condensing unit) and considers whether hot gas is used only to defrost 
the evaporator or whether it also maintains warm temperatures in the 
drip pan.
    Finally, DOE discussed that if it were to amend its walk-in 
refrigeration systems test procedure to account for hot gas defrost 
energy consumption and heat load, DOE would need to decide if all 
refrigeration system configurations (i.e., matched pairs, unit coolers 
tested alone, and dedicated condensing units tested alone) would be 
subject to a hot gas defrost-specific test procedure. Id.
    In their comments, AHRI, Lennox, Keeprite, Hussmann, and National 
Refrigeration each recommended that DOE utilize the AHRI 1250-2020 hot 
gas defrost calculations for all equipment

[[Page 23970]]

types, since matched pairs, unit coolers, and dedicated condensing 
units may be associated with hot gas defrost. (AHRI, No. 11 at pp. 13-
14; Lennox, No. 9 at pp. 8-9; Keeprite, No. 12 at p. 2; Hussmann, No. 
18 at pp. 15-16; National Refrigeration, No. 17 at p. 2) ASAP also 
supported the adoption of the hot gas defrost calculations in AHRI 
1250-2020 but did not specify for which equipment systems. (ASAP, No. 
13 at p. 2) NEEA observed that AHRI 1250-2020 provides both a 
calculation approach and a test method to account for hot gas defrost 
energy and recommended that DOE proceed with the hot gas defrost 
calculations in AHRI 1250-2020 in addition to including the hot gas 
defrost challenge test in Appendix F of AHRI 1250-2020. (NEEA, No. 16 
at p. 3) In spite of its inability to capture frost load conditions, 
the CA IOUs nevertheless supported the use of AHRI 1250-2020 Appendix F 
since it captures hot gas defrost energy use. (CA IOUs, No. 14 at p. 2) 
Both NEEA and the CA IOUs observed that additional work is needed to 
develop a robust test method to evaluate how hot gas defrost impacts 
equipment energy consumption and NEEA recommended that DOE continue to 
work with industry groups to develop such a procedure. (NEEA, No. 16 at 
p. 3; CA IOUs, No. 14 at p. 2)
    After reviewing the comments submitted by AHRI, Lennox, Keeprite, 
Hussmann and National Refrigeration, DOE has tentatively determined 
that all refrigeration system configurations (i.e., matched pairs, unit 
coolers tested alone, and dedicated condensing units tested alone) can 
benefit from hot gas defrost. For this reason, DOE proposes that all 
system configurations (when equipped with hot gas defrost) should be 
eligible for a hot gas defrost ``credit,'' which will be discussed in 
more detail in the following paragraphs.
    As discussed previously, there is currently no industry-accepted 
test method that can measure the heat load addition coming from hot gas 
defrost operation. In the absence of such a method, DOE is not able to 
propose a hot gas defrost testing-based method at this time. However, 
if the walk-in industry develops such a method in the future, DOE may 
evaluate that method's appropriateness in a future rulemaking.
    While all stakeholders support a calculation-based approach using 
the hot gas defrost equations in AHRI 1250-2020, DOE's goal in the 
December 2016 final rule was to provide calculations for rating hot gas 
defrost unit coolers using modified default values for energy use and 
heat load contributions that would make their ratings more consistent 
with those of electric defrost unit coolers. 81 FR 95758, 95776. The 
March 2021 final rule sought to maintain this consistency between units 
configured with hot gas defrost or electric defrost and ultimately 
included the equations in Section C10.2 of AHRI 1250-2020 for 
representing the defrost energy use and thermal load associated with 
hot gas defrost systems. 86 FR 16027, 16032. DOE proposes to maintain 
this calculation equivalence between hot gas defrost and electric 
defrost systems. Specifically, for rating and certification, all walk-
in refrigeration systems would utilize the default values for energy 
use and heat load for dedicated condensing units tested alone with 
electric defrost systems. AHRI 1250-2020, Section 10.2.2.
    However, like the approach discussed previously for adaptive 
defrost systems, DOE is proposing that manufacturers may account for a 
unit's potential improved performance with hot gas defrost in its 
market representations. In other words, DOE proposes that manufacturers 
may apply a hot gas defrost ``credit'' in their market representations 
but must certify hot gas defrost units using the default electric 
defrost equations. As mentioned previously, AHRI has developed specific 
equations for determining the defrost energy and heat load associated 
with hot gas defrost. AHRI 1250-2020, Section C10.1. DOE proposes that 
the hot gas defrost ``credit'' may be used in marketing materials for 
all refrigeration system configurations sold with hot gas defrost 
(i.e., matched pairs, unit coolers tested alone, and dedicated 
condensing units tested alone).
9. Refrigerant Glide
    In the June 2021 RFI, DOE discussed that it was considering 
changing its test procedure to a more refrigerant-neutral approach--
specifically, DOE discussed that it was considering approaches that 
would more accurately represent the performance of zero-, low-, and 
high-glide refrigerants. 86 FR 32332, 32351. Refrigerant glide refers 
to the increase in temperature at a fixed pressure as liquid 
refrigerant vaporizes during its conversion from saturated liquid (at 
its bubble point) to saturated vapor (at its dew point). R-404A--a 
common walk-in refrigerant--has very little glide, while R-407A--
another common walk-in refrigerant--can exhibit glide of up to 8 
[deg]F.\58\
---------------------------------------------------------------------------

    \58\ As noted in the June 2021 RFI, on July 20, 2015, the U.S. 
Environmental Protection Agency (``EPA'') published a final rule 
under the Significant New Alternatives Policy (``SNAP'') program 
listing the use of certain hydrofluorocarbons (``HFCs'') as 
unacceptable, including the use of R-404A in WICF refrigeration 
systems. 80 FR 42870 (``July 2015 EPA SNAP Rule''). On December 1, 
2016, EPA published a final rule (``December 2016 EPA SNAP Rule'') 
which listed a number of refrigerants, included R-407A, for use in 
certain refrigerant applications as unacceptable starting January 1, 
2023 for cold storage warehouse application, and January 1, 2021, 
for retail food refrigerant applications. 81 FR 86778. In August 
2017, the U.S. Court of Appeals for the District of Columbia Circuit 
vacated and remanded the July 2015 EPA SNAP Rule to the extent that 
it required manufacturers to replace HFCs with a substitute 
substance. (Mexichem Fluor, Inc. v. EPA, Case No. 15-1328 (D.C. Cir. 
August 8, 2017)) A petition for rehearing has been filed by a number 
of parties. (D.C. Cir., Consolidated Case Nos. 15-1328, 15-1329). 
That petition for rehearing was denied on January 26, 2018.
    Additionally, in October 2016, the 28th Meeting of the Parties 
to the Montreal Protocol adopted the Kigali Amendment on HFCs. The 
Kigali Amendment enters into force on January 1, 2019, and it 
requires parties to the protocol to reduce consumption and 
production of HFCs. DOE understands that, while the United States 
has not yet ratified the Kigali Amendment, a significant portion of 
WICFs currently use HFC-based refrigerants and may become affected 
by this Amendment to the Montreal Protocol.
    DOE plans to consider the potential impact of the court's 
decision and the Amendment to the Montreal Protocol in this 
rulemaking as appropriate.
---------------------------------------------------------------------------

    The current DOE test procedure specifies unit cooler test 
conditions based on the dew point at the evaporator exit. For zero-
glide refrigerants, the average evaporator temperature will typically 
be equivalent to the specified dew point. However, for high-glide 
refrigerants, the average evaporator temperature will be significantly 
lower than the dew point since the refrigerant temperature will 
increase (up to the dew point) as it travels through the evaporator. As 
a result, two identical unit coolers, one charged with R-404A and one 
with R-407A, will be tested at different evaporator-to-air temperature 
differences (``TD''), but with the same evaporator airflow. Measured 
capacity is directly correlated with the product of TD and airflow; 
therefore, the high-glide R-407A unit cooler would achieve a higher 
rated capacity than the R-404A unit cooler. However, this capacity 
difference is an artifact of the test procedure, which requires that 
unit coolers and dedicated condensing units be tested alone. In the 
field, a unit cooler will be paired with a dedicated condensing unit 
and R-407A unit coolers will not actually provide additional capacity 
when compared to their R-404A counterparts.
    For these reasons, the current test procedure is not refrigerant-
neutral. In the June 2021 RFI, DOE discussed the possibility of 
pursuing a modified midpoint approach, which DOE believed may be more 
refrigerant-neutral. 86 FR 32332, 32355. The modified midpoint approach 
attempts to standardize the average evaporator

[[Page 23971]]

temperature, rather than standardizing the evaporator dew point. In 
doing so, identical unit coolers using zero- and high-glide 
refrigerants would exhibit identical TDs, thus alleviating concerns of 
overstated capacity. DOE requested comment on the appropriateness of a 
modified midpoint approach and how such a method could be implemented 
in the June 2021 RFI. 86 FR 32332, 32355. Lennox, AHRI, Keeprite, 
National Refrigeration, and Hussmann recommended maintaining the 
current dew point approach since dewpoint is measurable and the 
approach is accepted in the industry. (Lennox, No. 9 at p. 11; AHRI, 
No. 11 at p. 16; Keeprite, No. 12 at p. 3; National Refrigeration, No. 
17 at p. 2; Hussmann, No. 18 at p. 20) Lennox, AHRI, and Hussmann also 
stated that dew point is a required reference for dual instrumentation 
evaporator superheat calculations and can be measured during 
installation and service. (Lennox, No. 9 at p. 11; AHRI, No. 11 at p. 
16; Hussmann, No. 18 at p. 20) Keeprite claimed that a midpoint or 
corrected midpoint approach is unproven and is not measurable. 
(Keeprite, No. 12 at p. 3) Keeprite additionally added that a change 
from dewpoint to midpoint may have large effects on unit cooler AWEF 
values. Id. Daikin stated that engineers use the mean value between dew 
point and bubble point when designing refrigeration systems since this 
approach simplifies energy calculations. (Daikin, No. 17 at p. 4)
    DOE acknowledges the potential increased testing burden highlighted 
by manufacturers if a modified midpoint were to be adopted. In response 
to these comments DOE proposes to continue to use dewpoint throughout 
the test procedure but will continue to evaluate the potential for 
using a midpoint in testing.
10. Refrigerant Temperature and Pressure Instrumentation Locations
    In the June 2021 RFI, DOE requested comment on changes between AHRI 
1250-2020 and AHRI 1250-2009 which may impact the determination of AWEF 
or increase the testing burden. 86 FR 32332, 32336. In response to this 
request AHRI, Lennox, and Hussmann stated that the test set-up for DX 
Dual instrumentation method for testing dedicated condensing units 
alone has changed, represented by Figure C1 in AHRI 1250-2009, and the 
new Figure C2 in AHRI 1250-2020. The commenters stated that this 
changes the location of the instrumentation for pressure and 
temperature measurement. Additionally, they stated that the new method 
removes the alternative location of the second mass flow meter and 
claim that both sets of changes necessitate changes in lab test stands. 
Further, the commenters claimed that AHRI 1250-2020 added a change to 
the refrigeration capacity calculation for dedicated condensing units, 
whereby the enthalpy representing the refrigerant at the evaporator 
exit condition has changed such that it is based on a pressure 
corresponding to a dew point 2 [deg]F higher than at the condensing 
unit inlet and a superheat of 6.5 [deg]F. (Lennox, No. 9 at p. 3; AHRI, 
No. 11 at p. 5; Hussmann, No. 18 at p. 7) The same group of commentors 
stated these locations are now different than those specified for 
matched pair testing, and the DX Calibrated Box method. Id.
    DOE notes first that AHRI 1250-2009 does not provide a test method 
for dedicated condensing units tested alone, other than incorporating 
by reference ASHRAE 23-2005 (see Section C12 of AHRI 1250-2009 appendix 
C). ASHRAE 23 calls for calculating capacity by multiplying the 
refrigerant mass flow rate by the difference in enthalpies. However, 
the current DOE test procedure clarifies which values of pressure and 
temperature are used to determine the enthalpies to use for this 
capacity calculation--this is specified in section 3.4.2.1 of subpart 
R, appendix C. The section indicates that, for enthalpy leaving the 
unit cooler, the calculation uses a pressure corresponding to a dew 
point temperature of 25 [deg]F and a temperature of 35 [deg]F for 
coolers, and a dew point of -20 [deg]F and temperature of -14 [deg]F 
for freezers. These dew points are identical to the dew points 
specified in AHRI 1250-2020.\59\ The temperatures represent superheat 
levels equal to 10 [deg]F for coolers and 6 [deg]F for freezers, which 
are different than the 6.5 [deg]F specified in Section C7.5.2 of AHRI 
1250-2020. Section 3.4.2.1 of subpart R, appendix C, also indicates 
that in the current DOE test procedure, the measured enthalpy at the 
condensing unit exit shall be used as the enthalpy entering the unit 
cooler. This is consistent with Figure C2 and Section C7.5.1.1.2 of 
AHRI 1250-2020. Thus, the only difference in AHRI 1250-2020 affecting 
the dedicated condensing unit efficiency calculations is the change in 
specified superheat, and there is no effective difference in the 
location of required pressure and temperature measurements. DOE will 
address the calculation change and other test procedure changes that 
can alter the measurement in an energy conservation standards 
rulemaking.
---------------------------------------------------------------------------

    \59\ For example, for coolers, Tables 12 and 13 of AHRI 1250-
2020 require that CDU suction dew point be 23 [deg]F, while section 
C7.5.2 indicates that the enthalpy to use in the calculation of 
capacity shall be for a pressure corresponding to dew point 2 [deg]F 
higher than for the recorded pressure at the inlet of the dedicated 
condensing unit.
---------------------------------------------------------------------------

    The comments of AHRI, Lennox, and Hussmann also address the test 
burden of not allowing the use of the alternative second location of 
the mass flow meter. (AHRI, No. 11 at pp. 5-6; Lennox, No. 9 at p. 3; 
Hussmann, No. 18 at p. 7 The comments provided no indication that use 
of a mass flow meter in the suction line should not be allowed. Hence, 
DOE proposes to clarify that the location of the second mass flow meter 
in the suction line would still be allowed. This proposal would 
eliminate the potential costs associated with Figure C2's suggestion 
that use of a suction line mass flow meter is not allowed.
    Issue 29: DOE requests comment on its proposal to clarify that the 
second mass flow measurement for the DX Dual Instrumentation method may 
be in the suction line upstream of the inlet to the condensing unit, as 
shown in Figure C1 of AHRI 1250-2009.
11. Updates to Default Values for Unit Cooler Parameters
    For dedicated condensing units tested alone, the current DOE test 
procedure calculates on-cycle evaporator fan power based on the cooling 
capacity of the condensing unit. This is necessary as a dedicated 
condensing unit tested alone will have no measured value for evaporator 
fan power. The on-cycle evaporator fan power is set equal to a fraction 
of the gross cooling capacity. The fraction is specified by a 
coefficient of .013 for medium temperature coolers and a coefficient of 
.016 for low temperature coolers. These coefficients were a product of 
the 2016 rulemaking negotiations. As discussed in section III.B.3.c, 
Sections 7.9.1 and 7.9.2 of AHRI 1250-2020 add new equations to 
calculate on-cycle evaporator fan power when testing a dedicated 
condensing unit alone. These equations are different from those in the 
current test procedure at subpart R, appendix C. The equations in AHRI 
1250-2020 are split based on low versus medium temperature dedicated 
condensing units, and the capacity of the dedicated condensing units. 
Those units over 50,000 Btu/h have one equation and those under 50,000 
Btu/h that capacity have another, resulting in 4 equations total. These 
equations are based on more test data and analysis than those currently 
in subpart R, appendix C. DOE has tentatively determined that these 
equations would be more representative, and do not pose a greater test 
burden. Therefore, DOE proposes to adopt the calculations for on-cycle 
evaporator fan

[[Page 23972]]

power for dedicated condensing units tested alone in AHRI 1250-2020.
    Issue 30: DOE requests comment on its proposal to adopt the 
calculations for evaporator fan power in AHRI 1250-2020.
12. Calculations and Rounding
    To ensure greater test procedure consistency, DOE is proposing to 
include rounding requirements for AWEF and capacity in the newly 
proposed appendix C1. DOE notes that AHRI 1250-2020 does not include 
requirements for rounding these values. DOE recognizes that the manner 
in which values are rounded can affect the resulting capacity and AWEF 
values. To ensure consistency in the manner in which capacity and AWEF 
values are calculated, DOE is proposing that raw measured data would be 
used in all capacity and AWEF calculations. DOE's current standards 
specify a minimum AWEF value in Btu/(W-h) to the hundredths place; 
therefore, DOE is proposing that AWEF values would be rounded to the 
nearest 0.05 Btu/(W-h). To round capacity, DOE is proposing to round to 
the nearest multiple as specified in Table III.14. The proposed 
capacity bins and multiples are consistent with other HVAC test 
procedures.\60\
---------------------------------------------------------------------------

    \60\ A version of Table III.9 can be found in AHRI Standard 390 
I-P (2021) ``Performance Rating of Single-packaged Vertical Air-
Conditioners and Heat Pumps.''

  Table III.14--Refrigeration Capacity Rating Ranges and Their Rounding
                                Multiples
------------------------------------------------------------------------
                                                          Multiples, Btu/
      Refrigeration capacity  ratings, 1,000 Btu/h               h
------------------------------------------------------------------------
<20.....................................................             100
>=20 and <38............................................             200
>=38 and <65............................................             500
>=65....................................................           1,000
------------------------------------------------------------------------

    Issue 31: DOE requests comment on its proposal for rounding AWEF to 
the nearest 0.05 Btu/(W-h) and rounding capacity values to the nearest 
multiple as presented in Table III.14.

H. Alternative Efficiency Determination Methods

    Pursuant to the requirements of 10 CFR 429.70, DOE may permit use 
of an alternative efficiency determination method (``AEDM'') in lieu of 
testing equipment for which testing burden may be considerable and for 
which that equipment's energy efficiency performance may be well 
predicted by such alternative methods. Although specific requirements 
vary by product or equipment, use of an AEDM entails development of a 
mathematical model that estimates energy efficiency or energy 
consumption characteristics of the basic model, as would be measured by 
the applicable DOE test procedure. The AEDM must be based on 
engineering or statistical analysis, computer simulation or modeling, 
or other analytic evaluation of performance data. A manufacturer must 
perform validation of an AEDM by demonstrating that the performance, as 
predicted by the AEDM, is in agreement with the performance as measured 
by actual testing in accordance with the applicable DOE test procedure. 
The validation procedure and requirements, including the statistical 
tolerance, number of basic models, and number of units tested vary by 
product or equipment.
    Once developed, an AEDM may be used to rate and certify the 
performance of untested basic models in lieu of physical testing. 
However, use of an AEDM for any basic model is always at the option of 
the manufacturer. One potential advantage of AEDM use is that it may 
free a manufacturer from the burden of physical testing. One potential 
risk is that the AEDM may not perfectly predict performance, and the 
manufacturer could be found responsible for having an invalid rating 
for the equipment in question or for having distributed a noncompliant 
basic model. The manufacturer, by using an AEDM, bears the 
responsibility and risk of the validity of the ratings. For walk-ins, 
DOE currently permits the use of AEDMs for refrigeration systems only. 
10 CFR 429.70(f).
    The following sections discuss DOE's proposal to allow walk-in door 
manufacturers to use AEDMs to rate both display and non-display doors, 
as well as proposed updates to the current AEDM provisions for 
refrigeration systems.
1. Doors
    DOE did not adopt provisions allowing for the use of AEDMs for 
walk-in doors in the May 2014 rule because DOE found that the modeling 
techniques approved for use in the NFRC 100 test procedure 
(incorporated by reference at 10 CFR 431.303) made a parallel AEDM 
provision for walk-in doors unnecessary. 79 FR 27388, 27394. Consistent 
with DOE's proposal to remove reference to NFRC 100 (and thus the 
computational method) for determining U-factor of doors, DOE is 
proposing to allow the use of AEDMs to determine the represented value 
of energy consumption of walk-in doors at 10 CFR 429.53(a)(3). 
Correspondingly, DOE is proposing to expand the AEDM provisions in 10 
CFR 429.70(f) to apply to walk-in doors. DOE is proposing to include a 
5 percent individual model tolerance, which aligns with the individual 
model tolerance applicable to walk-in refrigeration systems, to 
validate the energy consumption result of an AEDM with the appendix A 
test result at 10 CFR 429.70(f)(2)(ii). DOE also proposes that an AEDM 
for doors may not simulate or model components of the door that are not 
required to be tested by the DOE test procedure. If the test results 
used to validate the AEDM are for the U-factor test of the door, the 
AEDM must estimate the daily energy consumption--specifically, the 
conduction thermal load, and the direct and indirect electrical energy 
consumption, by using the nominal values (e.g., EER values used for 
coolers and freezers, PTO values) and calculation procedure specified 
in the DOE test procedure. Additionally, DOE is proposing to include 
walk-in door validation classes at 10 CFR 429.70(f)(2)(iv) and to 
require that two basic models per validation class be tested using the 
proposed test procedure in appendix A, which is consistent with the 
number of basic models required to be tested per validation class for 
walk-in refrigeration systems. Lastly, DOE is proposing to include a 5 
percent tolerance applicable to the maximum daily energy consumption 
metric for AEDM verification testing at 10 CFR 429.70(f)(5)(vi), which 
aligns with the tolerance applicable to AWEF of walk-in refrigeration 
systems.
    Issue 32: DOE seeks comment on its proposal to allow for the use of 
AEDMs to determine the energy consumption rating of walk-in doors. DOE 
requests specific feedback on the proposed 5 percent model tolerance 
for validating an AEDM, the proposed validation classes and number of 
basic models required to be tested per validation class, and the 
proposed 5 percent tolerance on the result from a DOE AEDM verification 
test.
2. Refrigeration Systems
    In the May 2014 final rule, DOE established that AEDMs can be used 
by manufacturers of refrigeration systems, once certain qualifications 
are met, to certify compliance and report ratings. 79 FR 27388, 27389. 
That rule established a uniform, systematic, and fair approach to the 
use of these types of modeling techniques that has enabled DOE to 
ensure that products in the marketplace are correctly rated--
irrespective of whether they are subject to actual physical testing or 
are rated using

[[Page 23973]]

modeling--without unnecessarily burdening regulated entities. Id.
    A minimum of two distinct models must be tested to validate an AEDM 
for each validation class. The May 2014 final rule established the 
following AEDM validation classes for walk-ins:
    <bullet> Dedicated condensing units, medium temperature, indoor 
system;
    <bullet> Dedicated condensing units, medium temperature, outdoor 
system;
    <bullet> Dedicated condensing units, low temperature, indoor 
system;
    <bullet> Dedicated condensing units, low temperature, outdoor 
system;
    <bullet> Unit cooler connected to a muliplex condensing unit, 
medium temperature;
    <bullet> Unit cooler connected to a multiplex condensing unit, low 
temperature;
    <bullet> Medium temperature, indoor condensing unit;
    <bullet> Medium temperature, outdoor condensing unit;
    <bullet> Low temperature, indoor condensing unit;
    <bullet> Low temperature, outdoor condensing unit.
    See 79 FR 27388, 27411 (codified at 10 CFR 429.70(f)(5)(iv)).
    In this NOPR, DOE is proposing new test procedures for single-
packaged refrigeration systems, high-temperature refrigeration systems, 
and CO<INF>2</INF> unit coolers. Temperature has a significant impact 
on equipment performance; therefore, DOE is proposing to incorporate 
new AEDM validation classes for all high-temperature refrigeration 
systems (dedicated condensing units, single-packaged dedicated systems, 
and matched pair systems). Additionally, single-packaged units are 
expected to perform differently than dedicated condensing units under 
the proposed test procedure which incorporates thermal losses. 
Therefore, DOE proposes to create new validation classes for low-
temperature, medium-temperature, and high-temperature single-packaged 
dedicated systems. To ensure that walk-in validation classes are 
consistent with DOE's current walk-in terminology, DOE proposes to 
rename the ``unit cooler connected to a multiplex condensing unit'' 
validation classes to ``unit cooler'' at either medium- or low-
temperature; however, the AEDM requirements for theses classes remain 
the same. Finally, DOE proposes to remove the medium/low temperature 
indoor/outdoor condensing unit validation classes, as these are 
redundant with the medium/low temperature indoor/outdoor dedicated 
condensing unit validation classes.
    As discussed, DOE proposes to reference in appendix C1 the methods 
of test for single-packaged dedicated systems in Section C9 of AHRI 
1250-2020, with some modifications. Implementation of appendix C1, if 
finalized, would require that all AEDMs for single-packaged dedicated 
systems are amended to be consistent with the test procedure proposed 
in appendix C1.
    In summary, DOE is proposing the following AEDM validation classes 
for walk-in refrigeration equipment:
    <bullet> Dedicated Condensing Unit, Medium Temperature, Indoor 
System
    <bullet> Dedicated Condensing Unit, Medium Temperature, Outdoor 
System
    <bullet> Dedicated Condensing Unit, Low Temperature, Indoor System
    <bullet> Dedicated Condensing Unit, Low Temperature, Outdoor System
    <bullet> Single-packaged Dedicated System, High-temperature, Indoor 
System
    <bullet> Single-packaged Dedicated System, High-temperature, 
Outdoor System
    <bullet> Single-packaged Dedicated System, Medium Temperature, 
Indoor System
    <bullet> Single-packaged Dedicated System, Medium Temperature, 
Outdoor System
    <bullet> Single-packaged Dedicated System, Low Temperature, Indoor 
System
    <bullet> Single-packaged Dedicated System, Low Temperature, Outdoor 
System
    <bullet> Matched Pair, High-temperature, Indoor Condensing Unit
    <bullet> Matched Pair, High-temperature, Outdoor Condensing Unit
    <bullet> Matched Pair, Medium Temperature, Indoor Condensing Unit
    <bullet> Matched Pair, Medium Temperature, Outdoor Condensing Unit
    <bullet> Matched Pair, Low Temperature, Indoor Condensing Unit
    <bullet> Matched Pair, Low Temperature, Outdoor Condensing Unit
    <bullet> Unit Cooler, High-temperature
    <bullet> Unit Cooler, Medium Temperature
    <bullet> Unit Cooler, Low Temperature
    DOE would maintain its provision that outdoor models that are 
within a given validation class may be used to determine represented 
values for the corresponding indoor class, and additional validation 
testing is not required. For example, two dedicated condensing unit, 
medium temperature, outdoor systems may be used to validate an AEDM for 
both the ``Dedicated Condensing Unit, Medium Temperature, Outdoor 
System'' class and the ``Dedicated Condensing Units, Medium 
Temperature, Indoor System'' class. If indoor models that fall within a 
given validation class are tested and used to validate an indoor AEDM, 
they may only be used for that validation class.
    DOE is proposing no additional modifications to the provisions 
within 10 CFR 429.70(f).
    Issue 33: DOE seeks comment on its proposal to modify and extend 
its AEDM validation classes for refrigeration systems, consistent with 
the test procedure revisions discussed in this document.

I. Sampling Plan for Enforcement Testing

    When DOE conducts enforcement testing of equipment, DOE uses one of 
the enforcement sampling plans in appendix A or B to subpart C of 10 
CFR part 429 to calculate upper control limits and lower control limits 
around the standard value based on the standard deviation of the test 
sample. These statistics are applied to the test results in the sample 
to determine compliance or non-compliance. DOE uses appendix B to 
subpart C of 10 CFR part 429 to assess compliance for walk-in 
refrigeration systems, which is specifically intended for use for 
covered equipment and certain low-volume covered products. 10 CFR 
429.110(e)(2). DOE does not specifically call out which appendix in 
subpart C of 10 CFR part 429 it uses for determination of compliance 
for walk-in doors or walk-in panels. In an Enforcement NOPR published 
on August 31, 2020 (``August 2020 Enforcement NOPR''), DOE proposed to 
add walk-in cooler and freezer doors and panels to the list of 
equipment subject to the low-volume enforcement sampling procedures in 
appendix B to subpart C of 10 CFR part 429. 85 FR 53691, 53696. DOE 
noted that this equipment is not currently included within DOE's list 
because when the current regulations were drafted, walk-in doors and 
walk-in panels did not have applicable performance standards, only 
design standards, and therefore sampling provisions were not necessary 
at the time. Id. DOE did not receive any comments in response to this 
proposal in the August 2020 Enforcement NOPR. DOE is therefore 
proposing in this document to include walk-in doors and walk-in panels 
in the list of low-volume products 10 CFR 429.110(e)(2).
    Issue 34: DOE requests comment on its proposal to apply the low-
volume sampling procedures in appendix B of subpart C of 10 CFR part 
429 to walk-in doors and panels.

J. Test Procedure Costs and Impact

    EPCA requires that test procedures proposed by DOE be reasonably 
designed to produce test results which reflect energy efficiency and 
energy use of a type of industrial equipment during a representative 
average use cycle and not be unduly burdensome to conduct. (42 U.S.C. 
6314(a)(2)) The following sections discuss DOE's evaluation of the 
estimated costs and savings associated

[[Page 23974]]

with the amendments proposed in this NOPR. The following sections 
outline the potential costs and savings differentiated by WICF 
component: Doors, panels, and refrigeration systems.
1. Doors
    In this NOPR, DOE proposes the following amendments to the test 
procedures for walk-in cooler and freezer doors:

    1. Referencing NFRC 102-2020 for the determination of U-factor;
    2. Including AEDM \61\ provisions for manufacturers to 
alternately determine the total energy consumption of display and 
non-display doors;
---------------------------------------------------------------------------

    \61\ As already noted elsewhere in this document, an AEDM is a 
computer modeling or mathematical tool that predicts the performance 
of non-tested basic models. These computer modeling and mathematical 
tools, when properly developed, can provide a means to predict the 
energy usage or efficiency characteristics of a basic model of a 
given covered product or equipment and reduce the burden and cost 
associated with testing.
---------------------------------------------------------------------------

    3. Providing additional detail for determining the area used to 
convert U-factor into conduction load, As, to differentiate it from 
the area used to determine compliance with the standards, Add or 
And; and
    4. Specifying a PTO value of 97 percent for door motors.

    Items 1 and 3, referencing NFRC 102-2020 and additional detail on 
the area used to convert U-factor into a conduction load, improves the 
consistency, reproducibility, and representativeness of test procedure 
results. Item 2, including AEDM provisions, intends to provide 
manufacturers with the flexibility to use an alternative method that 
gives the best agreement for their doors. Item 4, by proposing to 
include a PTO value of 97 percent, intends to provide a more 
representative and consistent means for comparison of walk-in door 
performance for doors with motors.
    DOE has tentatively determined that these proposed amendments would 
improve the representativeness, accuracy, and reproducibility of the 
test results, and would not be unduly burdensome for door manufacturers 
to conduct. DOE has also tentatively determined that these proposed 
amendments would not increase testing costs per basic model relative to 
the current DOE test procedure in appendix A, which DOE estimates to be 
$10,000 for third-party labs to determine energy consumption of a walk-
in door, including physical U-factor testing per NFRC 102-2020.\62\ DOE 
has tentatively determined that manufacturers would not be required to 
redesign any of the covered equipment or change how the equipment is 
manufactured, solely as result of the proposed amendments, if 
finalized.
---------------------------------------------------------------------------

    \62\ DOE estimates the cost of one test to determine energy 
consumption of a walk-in door, including one physical U-factor test 
per NFRC 102-2020 to be $5,000. Per the sampling requirements 
specified at 10 CFR 429.53(a)(3)(ii) and 10 CFR 429.11(b), 
manufacturers are required to test at least two units to determine 
the rating for a basic model, except where only one unit of the 
basic model is produced.
---------------------------------------------------------------------------

    The cost impact to manufacturers as a result of the reference to 
NFRC 102-2020 and inclusion of AEDM provisions is dependent on the 
agreement between tested and simulated values as specified in Section 
4.7.1 of NFRC 100 \63\ as referenced in the current test procedure. For 
manufacturers of doors that have been able to achieve the specified 
agreement between U-factors simulated using the method in NFRC 100 and 
U-factors tested using NFRC 102, manufacturers would be able to 
continue using the simulation method in NFRC 100, provided that the 
simulation method also meets the basic requirements proposed for an 
AEDM in 10 CFR 429.53 and 10 CFR 429.70(f).
---------------------------------------------------------------------------

    \63\ Section 4.7.1 of NFRC 100 requires that the accepted 
difference between the tested U-factor and the simulated U-factor be 
(a) 0.03 Btu/(h-ft2 [deg]F) for simulated U-factors that are 0.3 
Btu/(h-ft\2\-[deg]F) or less, or (b) 10 percent of the simulated U-
factor for simulated U-factors greater than 0.3 Btu/(h-ft\2\-
[deg]F). This agreement must match for the baseline product in a 
product line. Per NFRC 100, the baseline product is the individual 
product selected for validation; it is not synonymous with ``basic 
model'' as defined in 10 CFR 431.302.
---------------------------------------------------------------------------

    For manufacturers of doors that have not been able to achieve the 
specified agreement between U-factors simulated using the method in 
NFRC 100 and U-factors tested using NFRC 102, DOE estimates that the 
test burden would decrease. Under the current requirements, 
manufacturers may be required to determine U-factor through physical 
testing of every basic model. If the proposed test procedure were to be 
adopted, manufacturers who would have otherwise been required to 
physically test every walk-in door basic model could develop an AEDM 
for rating their basic models of walk-in doors consistent with the 
proposed provisions in 10 CFR 429.53 and 10 CFR 429.70(f). DOE 
estimates the per-manufacturer cost to develop and validate an AEDM for 
a single validation class of walk-in doors to be $11,100. DOE estimates 
an additional cost to determine energy consumption of a walk-in door 
using an AEDM to be $46 per basic model.\64\
---------------------------------------------------------------------------

    \64\ DOE estimated initial costs to validate an AEDM assuming 24 
hours of general time to develop and validate an AEDM based on 
existing simulation tools. DOE estimated the cost of an engineering 
calibration technician fully burdened wage of $46 per hour plus the 
cost of third-party physical testing of two basic models per 
proposed validation class. DOE estimated the additional per basic 
model cost to determine efficiency using an AEDM assuming 1 hour per 
basic model at the cost of an engineering calibration technician 
wage of $46 per hour.
---------------------------------------------------------------------------

    DOE expects that the additional detail provided for determining the 
area used to convert U-factor into conduction load, As, would either 
result in a reduced energy consumption or have no impact. To the extent 
that this change to the test procedure would amend the energy 
consumption attributable to a door, such changes would either not 
change the calculated energy consumption or result in a lower energy 
consumption value as compared to how manufacturers may currently be 
rating given that the current test procedure does not provide specific 
details on measurement of Add or And. As such, DOE expects that 
manufacturers would be able to rely on data generated under the current 
test procedure. While manufacturers must submit a report annually to 
certify a basic model's represented values, basic models do not need to 
be retested annually. The initial test results used to generate a 
certified rating for a basic model remain valid as long as the basic 
model has not been modified from the tested design in a way that makes 
it less efficient or more consumptive, which would require a change to 
the certified rating. If a manufacturer has modified a basic model in a 
way that makes it more efficient or less consumptive, new testing is 
only required if the manufacturer wishes to make claims of the new, 
more efficient rating.\65\
---------------------------------------------------------------------------

    \65\ See guidance issued by DOE at: www1.eere.energy.gov/buildings/appliance_standards/pdfs/cert_faq_2012-04-17.pdf.
---------------------------------------------------------------------------

    For doors without motors, DOE has tentatively concluded that the 
proposed test procedure would not change energy consumption ratings, 
and therefore would not require re-rating solely as result of DOE's 
adoption of this proposed amendment to the test procedure. Therefore, 
DOE has determined the proposed amendments either decrease or result in 
no additional testing costs to manufacturers of walk-in doors.
    To the extent that changes to the test procedure would amend the 
energy consumption attributable to a door motor, such changes would 
either not change the calculated energy consumption or result in a 
lower energy consumption value as compared to the currently granted 
waivers addressing door motors. As such, DOE expects that manufacturers 
would be able to rely on data generated under the current test 
procedure and current waivers. While manufacturers must submit a report 
annually to certify a basic model's represented values, basic models do 
not

[[Page 23975]]

need to be retested annually. The initial test results used to generate 
a certified rating for a basic model remain valid as long as the basic 
model has not been modified from the tested design in a way that makes 
it less efficient or more consumptive, which would require a change to 
the certified rating. If a manufacturer has modified a basic model in a 
way that makes it more efficient or less consumptive, new testing is 
only required if the manufacturer wishes to make claims of the new, 
more efficient rating.\66\
---------------------------------------------------------------------------

    \66\ See guidance issued by DOE at: www1.eere.energy.gov/buildings/appliance_standards/pdfs/cert_faq_2012-04-17.pdf.
---------------------------------------------------------------------------

    Issue 35: DOE requests comment on its tentative understanding of 
the impact of the test procedure proposals for appendix A in this 
NOPR--specifically, whether the proposed test procedure amendments, if 
finalized, would either not impact or decrease the testing burden for 
walk-in door manufacturers when compared to the current DOE test 
procedure in appendix A.
2. Panels
    In this NOPR, DOE proposes to amend the existing test procedure in 
appendix B for measuring the R-value of insulation of panels by:
    1. Incorporating by reference the updated version of the applicable 
industry test method, ASTM C518-17;
    2. Including provisions specific to measurement of test specimen 
and total insulation thickness; and
    3. Providing guidance on determining the parallelism and flatness 
of the test specimen.
    Item 1 incorporates by reference the most up to date version of the 
industry standards currently referenced in the DOE test procedure. 
Items 2 and 3 include additional instructions intended to improve 
consistency and reproducibility of test procedure results. DOE has 
tentatively determined that these proposed amendments would improve the 
accuracy and reproducibility of the test results and would not be 
unduly burdensome for manufacturers to conduct, nor would they be 
expected to increase the testing burden.
    DOE expects that the proposed test procedure in appendix B for 
measuring the R-value of insulation would not increase testing costs 
per basic model relative to the current DOE test procedure, which DOE 
estimates to be $1,200 for third-party lab testing.\67\ Additionally, 
DOE has tentatively determined that the proposed test procedure in 
appendix B would not result in manufacturers having to redesign any of 
the covered equipment or change how the equipment is manufactured. 
Further DOE has tentatively determined that, if finalized, the proposed 
amendments would not impact the utility of the equipment.
---------------------------------------------------------------------------

    \67\ DOE estimates the cost of one test to determine R-value to 
be $600. Per the sampling requirements specified at 10 CFR 
429.53(a)(3)(ii) and 10 CFR 429.11(b), manufacturers are required to 
test at least two units to determine the rating for a basic model, 
except where only one unit of the basic model is produced.
---------------------------------------------------------------------------

    Issue 36: DOE requests comment on its tentative understanding of 
the impact of the test procedure proposals for appendix B in this 
NOPR--specifically, that the proposed test procedure amendments, if 
finalized, would not increase testing burden on panel manufacturers 
when compared to the current DOE test procedure in appendix B.
3. Refrigeration Systems
    In this NOPR, DOE proposes certain changes to subpart R, appendix 
C, that DOE has tentatively determined would improve the accuracy and 
reproducibility of the test results and would not be unduly burdensome 
for manufacturers to conduct. DOE has tentatively determined that these 
proposed changes would not impact testing cost. Additionally, the 
proposed amended subpart R, appendix C, measuring AWEF per AHRI 1250-
2009, does not contain any changes that would require retesting or 
rerating if it were to be adopted. DOE's tentative assessment of the 
impacts of the proposed amendments of subpart R, appendix C, to include 
new test procedures for high-temperature refrigeration systems and 
CO<INF>2</INF> unit coolers are discussed in more detail below.
    DOE also proposes to adopt certain changes in the newly proposed 
appendix C1 that would amend the existing test procedure for walk-in 
coolers and freezers by:
    1. Expanding the off-cycle refrigeration system power measurements;
    2. Adding methods of test for single-packaged dedicated systems; 
and
    3. Including a method for testing ducted systems.
    DOE has tentatively determined that these proposed amendments would 
improve the representativeness, accuracy, and reproducibility of the 
test results, and would not be unduly burdensome for manufacturers to 
conduct. DOE has also tentatively determined that these proposed 
amendments would impact testing costs by equipment type. DOE does not 
anticipate that the remainder of the amendments proposed in this NOPR 
would impact test costs or test burden.
    DOE estimates third-party test costs for testing to the current DOE 
test procedure to be:
    <bullet> $10,000 for outdoor low-temperature and medium-temperature 
dedicated condensing units tested alone
    <bullet> $6,500 for indoor low temperature and medium temperature 
dedicated condensing units tested alone
    <bullet> $6,500 for low-temperature unit coolers tested alone
    <bullet> $6,000 for medium-temperature unit coolers tested alone
    <bullet> $10,000 for single-packaged dedicated systems
    <bullet> $10,000 for high-temperature matched pairs
    As discussed previously in section III.G.1 of this document, DOE is 
proposing to adopt off-cycle test provisions in AHRI 1250-2020 for 
walk-in cooler and freezer refrigeration systems. The current test 
procedure requires off-cycle power to be measured at the 95 [deg]F 
ambient condition. The proposed test procedure requires off-cycle to be 
measured at 95 [deg]F, 59 [deg]F, and 35 [deg]F ambient conditions for 
outdoor dedicated condensing units, outdoor matched pair systems, and 
outdoor dedicated systems. The matched pair and single-packaged 
dedicated systems include high-temperature refrigeration systems. When 
the waivers for these high-temperature refrigeration systems were 
granted, only one off-cycle test was required; therefore, manufacturers 
with waivers would be required to conduct additional testing as 
compared to the alternate test procedure currently required. DOE 
estimates that measuring off-cycle power at these additional ambient 
conditions may increase per-unit third-party lab test cost by $1,000 
per unit to a total cost of $11,000 per unit for outdoor dedicated 
condensing units, outdoor matched pair systems, and outdoor single-
packaged dedicated systems.
    Manufacturers are not required to perform laboratory testing on all 
basic models. In accordance with 10 CFR 429.53, WICF refrigeration 
system manufacturers may elect to use AEDMs. DOE estimates the per-
manufacturer cost to develop and validate an AEDM for outdoor dedicated 
condensing units and outdoor matched pair systems to be $24,580.\68\ 
DOE estimates an additional

[[Page 23976]]

cost of approximately $46 per basic model \69\ for determining energy 
efficiency of a given basic model using the validated AEDM.
---------------------------------------------------------------------------

    \68\ Outdoor single-packaged systems are also impacted by the 
proposed adoption of AHRI 1250-2020 single-packaged test procedure 
for walk-in cooler and freezer refrigeration systems. The combined 
potential cost increase for outdoor single-packaged systems is 
presented in the next paragraph.
    \69\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    As discussed previously in section III.G.2, DOE is proposing to 
adopt the single-packaged dedicated system test procedure for walk-ins 
in AHRI 1250-2020. The proposed procedure requires air enthalpy tests 
to be used as the primary test method. In the current test procedure, 
single-packaged dedicated systems use refrigerant enthalpy as the 
primary test method. DOE does not estimate a difference in physical 
testing costs between air and refrigerant enthalpy testing of single-
packaged units. DOE estimates the per-unit third-party lab test cost to 
be $11,000 for outdoor single-packaged units and $6,500 for indoor 
single-packaged units. However, should a manufacturer choose to use an 
AEDM, they may incur additional costs regarding the development and 
validation of new AEDMs for single-packaged dedicated systems. DOE 
estimates the per-manufacturer cost to develop and validate an AEDM to 
be $24,580 for outdoor single-packaged units and $15,580 for indoor 
single-packaged units. DOE estimates an additional cost of 
approximately $46 per basic model \70\ for determining energy 
efficiency using the validated AEDM.
---------------------------------------------------------------------------

    \70\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    As discussed in sections III.F.6 and III.G.6, DOE is proposing test 
procedures for CO<INF>2</INF> unit coolers and high-temperature 
refrigeration systems. DOE tentatively estimates that the average 
third-party lab per unit test cost would be $11,000 for a high-
temperature matched pair or single-packaged system, $6,000 for a high-
temperature unit cooler tested alone, $6,500 for a low temperature 
CO<INF>2</INF> unit cooler, and $6,000 for a medium temperature 
CO<INF>2</INF> unit cooler. As discussed previously, DOE has granted 
waivers to certain manufacturers for both high-temperature 
refrigeration systems and CO<INF>2</INF> unit coolers. The test 
procedures proposed in this NOPR are consistent with the alternate test 
procedures included in the granted waivers. For those manufacturers who 
have been granted a test procedure waiver for this equipment, DOE 
expects that there would be no additional test burden. However, DOE 
expects that there would be additional testing costs for any 
manufacturers of these products who have not submitted or been granted 
a test procedure waiver at the time this proposed test procedure is 
finalized. Such companies may incur an additional per unit test cost 
of:
    <bullet> $11,000 for a high-temperature matched pair or single-
packaged system;
    <bullet> $6,000 for a high-temperature unit cooler tested alone;
    <bullet> $6,500 for a low temperature CO<INF>2</INF> unit cooler 
tested alone; and
    <bullet> $6,000 for a medium temperature CO<INF>2</INF> unit cooler 
tested alone.
    Issue 37: DOE requests comment on its tentative understanding of 
the impact of the test procedure proposals for refrigeration systems--
specifically, whether DOE's initial conclusion that the proposed DOE 
test procedure amendments, if finalized, would increase testing burden.

K. Compliance Date and Waivers

    EPCA prescribes that, if DOE amends a test procedure, all 
representations of energy efficiency and energy use, including those 
made on marketing materials and product labels, must be made in 
accordance with that amended test procedure, beginning 180 days after 
publication of such a test procedure final rule in the Federal 
Register. (42 U.S.C. 6314(d)(1)) To the extent the modified test 
procedure proposed in this document is required only for the evaluation 
and issuance of updated efficiency standards, use of the modified test 
procedure, if finalized, would not be required until the implementation 
date of updated standards. 10 CFR 431.4; section 8(e) of appendix A 10 
CFR part 430 subpart C.
    If DOE were to publish an amended test procedure, EPCA provides an 
allowance for individual manufacturers to petition DOE for an extension 
of the 180-day period if the manufacturer may experience undue hardship 
in meeting the deadline. (42 U.S.C. 6314(d)(2)) To receive such an 
extension, petitions must be filed with DOE no later than 60 days 
before the end of the 180-day period and must detail how the 
manufacturer will experience undue hardship. Id.
    Upon the compliance date of any provisions of an amended test 
procedure, any waivers that are currently in effect pertaining to 
issues addressed by such provisions are terminated. 10 CFR 
431.401(h)(3). Recipients of any such waivers would be required to test 
the products subject to the waiver according to the amended test 
procedure as of the compliance date of the amended test procedure. The 
amendments proposed in this document pertain to issues addressed by 
waivers and interim waivers granted to the manufacturers listed in 
Table III.15. The proposed amendments also address issues identified in 
a pending waiver for RSG (Case No. 2022-004).\71\
---------------------------------------------------------------------------

    \71\ The RSG waiver docket can be found at www.regulations.gov/docket/EERE-2022-BT-WAV-0010.

                         Table III.15--Manufacturers Granted Waivers and Interim Waivers
----------------------------------------------------------------------------------------------------------------
                                                                                                Proposed test
           Manufacturer                  Subject           Case No.        Relevant test          procedure
                                                                             procedure         compliance date
----------------------------------------------------------------------------------------------------------------
Jamison Door Company.............  PTO for Door Motors        2017-009  Appendix A.........  180 days after test
                                                                                              procedure final
                                                                                              rule publication.
HH Technologies..................  PTO for Door Motors        2018-001  Appendix A.........  180 days after test
                                                                                              procedure final
                                                                                              rule publication.
Senneca Holdings.................  PTO for Door Motors        2020-002  Appendix A.........  180 days after test
                                                                                              procedure final
                                                                                              rule publication.
Hercules.........................  PTO for Door Motors        2020-013  Appendix A.........  180 days after test
                                                                                              procedure final
                                                                                              rule publication.

[[Page 23977]]

 
HTPG.............................  CO2 Unit Coolers...        2020-009  Appendix C.........  180 days after test
                                                                                              procedure final
                                                                                              rule publication.
Hussmann.........................  CO2 Unit Coolers...        2020-010  Appendix C.........  180 days after test
                                                                                              procedure final
                                                                                              rule publication.
Keeprite.........................  CO2 Unit Coolers...        2020-014  Appendix C.........  180 days after test
                                                                                              procedure final
                                                                                              rule publication.
RefPlus, Inc.....................  CO2 Unit Coolers...        2021-006  Appendix C.........  180 days after test
                                                                                              procedure final
                                                                                              rule publication.
RSG..............................  Multi-Circuit              2022-004  Appendix C.........  180 days after test
                                    Single-Package                                            procedure final
                                    Dedicated Systems.                                        rule publication.
Store It Cold....................  Single-Package             2018-002  Appendix C1........  Compliance date of
                                    Dedicated Systems.                                        updated standards.
CellarPro........................  Wine Cellar                2019-009  Appendix C1........  Compliance date of
                                    Refrigeration                                             updated standards.
                                    Systems.
Air Innovations..................  Wine Cellar                2019-010  Appendix C1........  Compliance date of
                                    Refrigeration                                             updated standards.
                                    Systems.
Vinotheque.......................  Wine Cellar                2019-011  Appendix C1........  Compliance date of
                                    Refrigeration                                             updated standards.
                                    Systems.
Vinotemp.........................  Wine Cellar                2020-005  Appendix C1........  Compliance date of
                                    Refrigeration                                             updated standards.
                                    Systems.
LRC Coil.........................  Wine Cellar                2020-024  Appendix C1........  Compliance date of
                                    Refrigeration                                             updated standards.
                                    Systems.
----------------------------------------------------------------------------------------------------------------

L. Organizational Changes

    DOE is also proposing a number of non-substantive organizational 
changes. As discussed previously, DOE is proposing to reorganize 
appendices A and B so that they are easier for stakeholders to follow 
as a step-by-step test procedure. Additionally, DOE is proposing to 
remove the specifications at 10 CFR 429.53(a)(2)(i) regarding specific 
test procedure provisions and instead include these provisions in the 
uniform test method section at 10 CFR 431.304. The intent of this 
proposed change is to move provisions of the applicable test procedure 
to the appropriate place in subpart R, rather than keeping them under 
the provisions for determining represented values for certification. 
However, DOE is proposing to keep the additional detail regarding the 
represented values of various configurations of refrigeration systems 
(e.g., outdoor and indoor dedicated condensing units, matched 
refrigeration systems, etc.) at 10 CFR 429.53(a)(2)(i).

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866 and 13563

    Executive Order (``E.O.'') 12866, ``Regulatory Planning and 
Review,'' as supplemented and reaffirmed by E.O. 13563, ``Improving 
Regulation and Regulatory Review,'' 76 FR 3821 (Jan. 21, 2011), 
requires agencies, to the extent permitted by law, to (1) propose or 
adopt a regulation only upon a reasoned determination that its benefits 
justify its costs (recognizing that some benefits and costs are 
difficult to quantify); (2) tailor regulations to impose the least 
burden on society, consistent with obtaining regulatory objectives, 
taking into account, among other things, and to the extent practicable, 
the costs of cumulative regulations; (3) select, in choosing among 
alternative regulatory approaches, those approaches that maximize net 
benefits (including potential economic, environmental, public health 
and safety, and other advantages; distributive impacts; and equity); 
(4) to the extent feasible, specify performance objectives, rather than 
specifying the behavior or manner of compliance that regulated entities 
must adopt; and (5) identify and assess available alternatives to 
direct regulation, including providing economic incentives to encourage 
the desired behavior, such as user fees or marketable permits, or 
providing information upon which choices can be made by the public. DOE 
emphasizes as well that E.O. 13563 requires agencies to use the best 
available techniques to quantify anticipated present and future 
benefits and costs as accurately as possible. In its guidance, the 
Office of Information and Regulatory Affairs (``OIRA'') has emphasized 
that such techniques may include identifying changing future compliance 
costs that might result from technological innovation or anticipated 
behavioral changes. For the reasons stated in the preamble, this 
proposed regulatory action is consistent with these principles.
    Section 6(a) of E.O. 12866 also requires agencies to submit 
``significant regulatory actions'' to OIRA for review. OIRA has 
determined that this proposed regulatory action does not constitute a 
``significant regulatory action'' under section 3(f) of E.O. 12866. 
Accordingly, this action was not submitted to OIRA for review under 
E.O. 12866.

B. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires 
preparation of an initial regulatory flexibility analysis (``IRFA'') 
for any rule that by law must be proposed for public comment, unless 
the agency certifies that the rule, if promulgated, will not have a 
significant economic impact on a substantial number of small entities. 
As required by Executive Order 13272, ``Proper Consideration of Small 
Entities in Agency Rulemaking,'' 67 FR 53461 (Aug. 16, 2002), DOE 
published procedures and policies on February 19, 2003, to ensure that 
the potential impacts of its rules on small entities are properly 
considered during the DOE rulemaking process. 68 FR 7990. DOE has made 
its procedures and policies available on the Office of the General 
Counsel's website: www.energy.gov/gc/office-general-counsel.
    The following sections detail DOE's IRFA for this test procedure 
proposed rulemaking.

[[Page 23978]]

1. Description of Why Action Is Being Considered
    The Energy Policy and Conservation Act, as amended (``EPCA''),\72\ 
authorizes DOE to regulate the energy efficiency of a number of 
consumer products and certain industrial equipment. (42 U.S.C. 6291-
6317) Title III, Part C \73\ of EPCA, added by Public Law 95-619, Title 
IV, section 441(a), established the Energy Conservation Program for 
Certain Industrial Equipment, which sets forth a variety of provisions 
designed to improve energy efficiency. This covered equipment includes 
walk-in coolers and walk-in freezers, the subject of this document. (42 
U.S.C. 6311(1)(G)) DOE is publishing this NOPR in satisfaction of the 
7-year review requirement specified in EPCA. (42 U.S.C. 6314(a)(1))
---------------------------------------------------------------------------

    \72\ All references to EPCA in this document refer to the 
statute as amended through the Energy Act of 2020, Public Law 116-
260 (Dec. 27, 2020).
    \73\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
---------------------------------------------------------------------------

2. Objective of, and Legal Basis for, Rule
    The Energy Policy and Conservation Act, as amended (``EPCA''),\74\ 
authorizes DOE to regulate the energy efficiency of a number of 
consumer products and certain industrial equipment. (42 U.S.C. 6291-
6317) Title III, Part C \75\ of EPCA, added by Public Law 95-619, Title 
IV, section 441(a), established the Energy Conservation Program for 
Certain Industrial Equipment, which sets forth a variety of provisions 
designed to improve energy efficiency. This covered equipment includes 
walk-in coolers and walk-in freezers, the subject of this document. (42 
U.S.C. 6311(1)(G))
---------------------------------------------------------------------------

    \74\ All references to EPCA in this document refer to the 
statute as amended through the Energy Act of 2020, Public Law 116-
260 (Dec. 27, 2020).
    \75\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
---------------------------------------------------------------------------

    Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures 
DOE must follow when prescribing or amending test procedures for 
covered equipment. EPCA requires that any test procedures prescribed or 
amended under this section must be reasonably designed to produce test 
results which reflect energy efficiency, energy use or estimated annual 
operating cost of a given type of covered equipment during a 
representative average use cycle and requires that test procedures not 
be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))
    EPCA also requires that, at least once every 7 years, DOE evaluate 
test procedures for each type of covered equipment including WICFs, to 
determine whether amended test procedures would more accurately or 
fully comply with the requirements for the test procedures to not be 
unduly burdensome to conduct and be reasonably designed to produce test 
results that reflect energy efficiency, energy use, and estimated 
operating costs during a representative average use cycle. (42 U.S.C. 
614(a)(1)(A))
3. Description and Estimate of Small Entities Regulated
    For manufacturers of WICFs, the Small Business Administration 
(``SBA'') has set a size threshold, which defines those entities 
classified as ``small businesses'' for the purposes of the statute. DOE 
used the SBA's small business size standards to determine whether any 
small entities would be subject to the requirements of the rule. See 13 
CFR part 121. The equipment covered by this rule are classified under 
North American Industry Classification System (``NAICS'') code 
333415,\76\ ``Air-Conditioning and Warm Air Heating Equipment and 
Commercial and Industrial Refrigeration Equipment Manufacturing.'' In 
13 CFR 121.201, the SBA sets a threshold of 1,250 employees or fewer 
for an entity to be considered as a small business for this category.
---------------------------------------------------------------------------

    \76\ The size standards are listed by NAICS code and industry 
description and are available at: www.sba.gov/document/support--table-size-standards (Last accessed on November 1, 2021).
---------------------------------------------------------------------------

    DOE reviewed the test procedures proposed in this NOPR under the 
provisions of the Regulatory Flexibility Act and the procedures and 
policies published on February 19, 2003. DOE used publicly available 
information to identify potential small businesses that manufacture 
WICFs covered in this rulemaking. DOE's analysis relied on publicly 
available databases to identify potential small businesses that 
manufacture equipment covered in this rulemaking. DOE utilized the 
DOE's Certification Compliance Database (``CCD'') \77\ and the 
California Energy Commission's Modernized Appliance Efficiency Database 
System (``MAEDbS'') \78\ in identifying manufacturers. DOE also used 
subscription-based business information tools to determine headcount 
and revenue of the small businesses.
---------------------------------------------------------------------------

    \77\ Certified equipment in the CCD are listed by product class 
and can be accessed at www.regulations.doe.gov/certification-data/#q=Product_Group_s%3A* (Last accessed July 15th, 2021).
    \78\ MAEDbS can be accessed at 
www.cacertappliances.energy.ca.gov/Pages/Search/AdvancedSearch.aspx 
(Last accessed Nov. 1, 2021).
---------------------------------------------------------------------------

    Using these data sources, DOE identified 79 original equipment 
manufacturers (``OEMs'') of WICFs that could be potentially affected by 
this rulemaking. DOE screened out companies that do not meet the 
definition of a ``small business'' or are foreign-owned and operated. 
Of these 79 OEMs, 60 are small, domestic manufacturers. DOE notes that 
some manufacturers may produce more than one of the principal 
components of WICFs: Panels, doors, and refrigeration systems. Eighteen 
of the small, domestic OEMs manufacture refrigeration systems; 38 of 
the small, domestic OEMs manufacture panels; and 43 of the small, 
domestic OEMs manufacture doors. To better reflect the impact on 
manufacturers, DOE evaluated the impacts of test procedure changes to 
panels, doors, and refrigeration systems separately.
    Of these small businesses, not all were impacted by the proposed 
changes. The following section further details the impact to 
manufacturers by principal component and proposed test procedure 
amendment.
    Issue 38: DOE invites comment on the number of small, domestic OEMs 
producing the three principal components of WICFs: Panels, doors, and 
refrigeration systems.
4. Description and Estimate of Compliance Requirements
    The potential regulatory costs of the proposed test procedure are 
differentiated by WICF component: Panels, doors, and refrigeration 
systems. The following sub-sections outline these changes and potential 
burden.
a. Doors
    In this NOPR, DOE proposes the following amendments to the test 
procedures for walk-in cooler and freezer doors:
    1. Referencing NFRC 102-2020 for the determination of U-factor;
    2. Including AEDM \79\ provisions for manufacturers to alternately 
determine the total energy consumption of display and non-display 
doors;
---------------------------------------------------------------------------

    \79\ An AEDM is a computer modeling or mathematical tool that 
predicts the performance of non-tested basic models. These computer 
modeling and mathematical tools, when properly developed, can 
provide a means to predict the energy usage or efficiency 
characteristics of a basic model of a given covered product or 
equipment and reduce the burden and cost associated with testing.
---------------------------------------------------------------------------

    3. Providing additional detail for determining the area used to 
convert U-factor into conduction load, As, to differentiate it from the 
area used to determine compliance with the standards, Add or And; and
    4. Specifying a percent time off (``PTO'') value of 97 percent for 
door motors.
    Items 1 and 3, referencing NFRC 102-2020 and additional detail on 
the area used to convert U-factor into a

[[Page 23979]]

conduction load, would improve the consistency, reproducibility, and 
representativeness of test procedure results. Item 2, including AEDM 
provisions, would provide manufacturers with the flexibility to use an 
alternative method that gives the best agreement for their doors. Item 
4, specifying a PTO value of 97 percent for door motors, would provide 
a more representative and consistent means for comparison of walk-in 
door performance for doors with motors. DOE has tentatively determined 
that these proposed amendments as a whole would improve the 
representativeness, accuracy, and reproducibility of the test results, 
and would not be unduly burdensome for door manufacturers to conduct. 
DOE has also tentatively determined that these proposed amendments 
would not increase physical testing costs per basic model relative to 
the current DOE test procedure in appendix A, which DOE estimates to be 
$10,000 for third-party labs to determine energy consumption of a walk-
in door, including physical U-factor testing per NFRC 102-2020.\80\ DOE 
has tentatively determined that manufacturers would not be required 
redesign any of the covered equipment or change how the equipment is 
manufactured, solely as result of the proposed amendments.
---------------------------------------------------------------------------

    \80\ DOE estimates the cost of one test to determine energy 
consumption of a walk-in door, including one physical U-factor test 
per NFRC 102-2020, to be $5,000. Per the sampling requirements 
specified at 10 CFR 429.53(a)(3)(ii) and 10 CFR 429.11(b), 
manufacturers are required to test at least two units to determine 
the rating for a basic model, except where only one unit of the 
basic model is produced.
---------------------------------------------------------------------------

    DOE is also proposing to permit manufacturers to use AEDMs. Using 
AEDMs when evaluating the energy efficiency of their equipment may 
enable some manufacturers to reduce costs to rate models. AEDMs can 
require an upfront investment but lower overall testing costs. The cost 
impact to manufacturers as result of the reference to NFRC 102-2020 and 
inclusion of AEDM provisions is dependent on the agreement specified in 
Section 4.7.1 of NFRC 100 \81\ between U-factors simulated using the 
method in NFRC 100 and U-factors tested using NFRC 102. For 
manufacturers of doors that have been able to achieve the specified 
agreement between U-factors simulated using the method in NFRC 100 and 
U-factors tested using NFRC 102, manufacturers would be able to 
continue using the simulation method in NFRC 100, provided that the 
simulation method also meets the basic requirements proposed for an 
AEDM in 10 CFR 429.53 and 10 CFR 429.70(f).
---------------------------------------------------------------------------

    \81\ Section 4.7.1 of NFRC 100 requires that the accepted 
difference between the tested U-factor and the simulated U-factor be 
(a) 0.03 Btu/(h-ft\2\-[deg]F) for simulated U-factors that are 0.3 
Btu/(h-ft\2\-[deg]F) or less, or 10 percent of the simulated U-
factor for simulated U-factors greater than 0.3 Btu/(h-ft\2\-
[deg]F). This agreement must match for the baseline product in a 
product line. Per NFRC 100, the baseline product is the individual 
product selected for validation; it is not synonymous with ``basic 
model'' as defined in 10 CFR 431.302.
---------------------------------------------------------------------------

    For manufacturers of doors that have not been able to achieve the 
specified agreement between U-factors simulated using the method in 
NFRC 100 and U-factors tested using NFRC 102, DOE estimates that the 
test burden could decrease. Under the current requirements, 
manufacturers may be required to physically test every model to meet 
the basic model definition since these models are highly customizable. 
If the proposed test procedure is adopted, manufacturers who would 
otherwise physically test every walk-in door basic model could develop 
an AEDM for rating. DOE estimates the per-manufacturer cost to develop 
and validate an AEDM for a single validation class of walk-in doors to 
be $11,100. DOE estimates the cost to determine energy consumption of a 
walk-in door using an AEDM to be $46 per basic model.
    DOE expects that the additional detail provided for determining the 
area used to convert U-factor into conduction load, As, would either 
result in a reduced energy consumption or have no impact. To the extent 
that this change to the test procedure would amend the energy 
consumption attributable to a door, such changes would either not 
change the calculated energy consumption or result in a lower energy 
consumption value as compared to how manufacturers may currently be 
rating. As such, DOE expects that manufacturers would be able to rely 
on data generated under the current test procedure. While manufacturers 
must submit a report annually to certify a basic model's represented 
values, basic models do not need to be retested annually. The initial 
test results used to generate a certified rating for a basic model 
remain valid as long as the basic model has not been modified from the 
tested design in a way that makes it less efficient or more 
consumptive, which would require a change to the certified rating. If a 
manufacturer has modified a basic model in a way that makes it more 
efficient or less consumptive, new testing is only required if the 
manufacturer wishes to make claims of the new, more efficient 
rating.\82\
---------------------------------------------------------------------------

    \82\ See guidance issued by DOE at: www1.eere.energy.gov/buildings/appliance_standards/pdfs/cert_faq_2012-04-17.pdf.
---------------------------------------------------------------------------

    For doors without motors, DOE has tentatively concluded that the 
proposed test procedure would not change energy consumption ratings, 
and therefore would not require re-rating as a result this proposed 
test procedure. Therefore, DOE has determined the proposed amendments 
would either decrease or result in no additional testing costs to small 
business manufacturers of walk-in doors.
    To the extent that changes to the test procedure would amend the 
energy consumption attributable to a door motor, such changes would 
either not change the calculated energy consumption or result in a 
lower energy consumption value as compared to the currently granted 
waivers addressing door motors. As such, DOE expects that manufacturers 
would be able to rely on data generated under the current test 
procedure and current waivers. While manufacturers must submit a report 
annually to certify a basic model's represented values, basic models 
would not need to be retested annually. The initial test results used 
to generate a certified rating for a basic model would remain valid as 
long as the basic model has not been modified from the tested design in 
a way that makes it less efficient or more consumptive, which would 
require a change to the certified rating. If a manufacturer has 
modified a basic model in a way that makes it more efficient or less 
consumptive, new testing would be required only if the manufacturer 
wishes to make claims of the new, more efficient rating.\83\
---------------------------------------------------------------------------

    \83\ See guidance issued by DOE at: www1.eere.energy.gov/buildings/appliance_standards/pdfs/cert_faq_2012-04-17.pdf.
---------------------------------------------------------------------------

    Issue 39: DOE requests comment on its cost estimate of impacts on 
small, domestic OEMs of doors.
b. Panels
    DOE proposes to amend the existing test procedure in appendix B for 
measuring the R-value of insulation of walk-in panels by:
    1. Incorporating by reference the updated version of the applicable 
industry test method, ASTM C518-17;
    2. Including provisions specific to the measurement of test 
specimen and total insulation thickness; and
    3. Providing guidance on determining the parallelism and flatness 
of the test specimen.
    Item 1 incorporates by reference the most up to date version of the 
industry standards currently referenced in the DOE test procedure. 
Items 2 and 3 includes additional instructions that would improve the 
consistency and reproducibility of test procedure results.

[[Page 23980]]

DOE has tentatively determined that these proposed amendments would 
improve the accuracy and reproducibility of the test results and would 
not be unduly burdensome for manufacturers to conduct, nor would they 
be expected to increase the testing burden.
    DOE expects that the proposed test procedure in appendix B for the 
measuring R-value of insulation would not increase testing costs per 
basic model relative to the current DOE test procedure, which DOE 
estimates to be $1,200 for third-party lab testing.\84\ Additionally, 
DOE has tentatively determined that manufacturers would not be required 
to redesign any of the covered equipment or change how the equipment is 
manufactured, solely as result of the proposed amendments. Further, DOE 
has tentatively determined that the proposed amendments would not 
impact the utility of the equipment.
---------------------------------------------------------------------------

    \84\ DOE estimates the cost of one test to determine R-value to 
be $600. Per the sampling requirements specified at 10 CFR 
429.53(a)(3)(ii) and 10 CFR 429.11(b), manufacturers are required to 
test at least two units to determine the rating for a basic model, 
except where only one unit of the basic model is produced.
---------------------------------------------------------------------------

    DOE has tentatively concluded that the proposed test procedure 
would not change efficiency ratings for walk-in panels, and therefore 
would not require re-rating as result of DOE's adoption of this 
proposed amendment to the test procedure. Therefore, DOE has determined 
the proposed amendments would not add any additional testing costs to 
small business manufacturers of walk-in doors.
    Issue 40: DOE requests comment on its cost estimate of impacts on 
small, domestic OEMs of panels.
c. Refrigeration Systems
    In this NOPR, DOE proposes certain changes to subpart R, appendix 
C, that DOE has tentatively determined would improve the accuracy and 
reproducibility of the test results and would not be unduly burdensome 
for manufacturers to conduct. DOE has tentatively determined that these 
proposed changes would not impact testing cost. Additionally, the 
proposed amended subpart R, appendix C, measuring AWEF per AHRI 1250-
2009, does not contain any changes that would require retesting or 
rerating if it were to be adopted.
    DOE also proposes to adopt through incorporations by reference 
certain provisions of AHRI 1250-2020 in appendix C1 that would amend 
the existing test procedure for walk-in cooler and freezer 
refrigeration systems. Additionally, DOE proposes amendments to the 
current DOE test procedure to accommodate high-temperature 
refrigeration systems and CO<INF>2</INF> unit coolers. A summary of the 
proposed changes are as follows:
    1. Expanding the off-cycle refrigeration system power measurements;
    2. Adding air enthalpy methods for single-packaged dedicated 
systems;
    3. Including new test procedures for high-temperature refrigeration 
systems; and
    4. Including new test procedures for CO<INF>2</INF> unit coolers.
    DOE has tentatively determined that these proposed amendments would 
improve the representativeness, accuracy, and reproducibility of the 
test results, and would not be unduly burdensome for manufacturers to 
conduct. DOE has also tentatively determined that these proposed 
amendments may impact testing costs. The following paragraphs outline 
the proposed changes and the potential costs to manufacturers. Because 
DOE's proposal of off-cycle refrigeration power measurements and 
single-packaged dedicated system air enthalpy test methods requirements 
impact both high-temperature and CO<INF>2</INF> units, all potential 
cost impacts to high-temperature and CO<INF>2</INF> units are discussed 
separately in the third and fourth sections.
(1) Small Business Impacts as a Result of Off-Cycle Refrigeration 
System Power Requirements
    DOE is proposing to adopt the off-cycle testing for walk-ins in 
AHRI 1250-2020. The current test procedure requires off-cycle power to 
be measured at the 95 [deg]F ambient condition. The proposed test 
procedure requires off-cycle to be measured at 95 [deg]F, 59 [deg]F, 
and 35 [deg]F ambient conditions for outdoor dedicated condensing 
units, outdoor matched pair systems, and outdoor single-packaged 
dedicated systems. These proposed amendments would not increase testing 
costs or require manufacturers to re-rate models, as DOE energy 
conservation standards do not currently require off-cycle requirements 
to be measured at 95 [deg]F, 59 [deg]F, and 35 [deg]F ambient 
conditions for outdoor dedicated condensing units, outdoor matched pair 
systems, and outdoor single-packaged systems. However, should DOE adopt 
energy conservation standards that require these off-cycle 
requirements, DOE estimates that measuring off-cycle power at these 
additional ambient conditions may increase per-unit third-party lab 
test cost by $1,000 per unit to a total cost of $11,000 per unit for 
outdoor dedicated condensing units and outdoor matched pair 
systems.\85\ The physical testing cost, according to the proposed 
amendments, would be $22,000 per basic model for outdoor dedicated 
condensing units and outdoor matched pair systems.\86\
---------------------------------------------------------------------------

    \85\ Outdoor single-packaged systems are also impacted by the 
proposed adoption of AHRI 1250-2020 single-packaged test procedure 
for walk-in cooler and freezer refrigeration systems. The combined 
potential cost increase for outdoor single-packaged systems is 
presented in the following section.
    \86\ The cost to test one unit is $11,000. Per the sampling 
requirements specified at 10 CFR 429.53(a)(2)(ii) and 10 CFR 
429.11(b), manufacturers are required to test at least two units to 
determine the rating for a basic model, except where only one unit 
of the basic model is produced.
---------------------------------------------------------------------------

    However, manufacturers are not required to perform laboratory 
testing on all basic models. In accordance with 10 CFR 429.53, WICF 
refrigeration system manufacturers may elect to use AEDMs. DOE 
estimates the per-manufacturer cost to develop and validate an AEDM for 
outdoor dedicated condensing units and outdoor matched pair systems to 
be $24,580 per validation class. DOE estimates an additional cost of 
approximately $46 per basic model \87\ for determining energy 
efficiency using the validated AEDM.
---------------------------------------------------------------------------

    \87\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    DOE estimates the range of potential costs for the five small OEMs 
that manufacture outdoor dedicated condensing units and outdoor matched 
pair systems. When developing cost estimates for the small OEMs, DOE 
considers the cost to update the existing AEDM simulation tool, the 
costs to validate the AEDM through physical testing, and the cost to 
rate basic models using the AEDM. DOE assumes a high-cost scenario 
where manufacturers would be required to develop AEDMs for six 
validation classes.
    DOE estimates the impacts based on basic model counts and company 
revenue. Table IV.1 summarizes DOE's estimates for the five identified 
small businesses. On average, testing costs represent less than 1 
percent of annual revenue for a typical small business.

[[Page 23981]]



Table IV.1--Estimated Small Business Re-Rating Costs (2022$) as a Result of Off-Cycle Refrigeration System Power
                                                  Requirements
----------------------------------------------------------------------------------------------------------------
                                                                     Re-rating    Annual revenue    Percent of
                          Manufacturer                            estimate ($mm)  estimate ($mm)    revenue (%)
----------------------------------------------------------------------------------------------------------------
Manufacturer A..................................................           0.151              12            1.25
Manufacturer B..................................................           0.148              19            0.78
Manufacturer C..................................................           0.214              77            0.28
Manufacturer D..................................................           0.148              86            0.17
Manufacturer E..................................................           0.159             147            0.10
----------------------------------------------------------------------------------------------------------------

(2) Small Business Impacts as a Result of Requiring Single-Packaged 
Dedicated Systems To Test Using Air Enthalpy Methods
    DOE is also proposing to adopt the single-packaged dedicated system 
test procedure in AHRI 1250-2020 for walk-in cooler and freezer 
refrigeration systems. The proposed procedure requires air enthalpy 
tests to be used as the primary test method. In the current test 
procedure, single-packaged dedicated systems use refrigerant enthalpy 
as the primary test method. DOE estimates no difference in costs 
between air and refrigerant enthalpy testing of single-packaged 
dedicated systems. DOE estimates the per-unit third-party lab test cost 
to be $11,000 for outdoor single-packaged dedicated systems and $6,500 
for indoor single-packaged dedicated systems. The physical testing 
cost, according to the proposed amendments, would be $22,000 per basic 
model for outdoor single-packaged dedicated systems and $13,000 per 
basic model for indoor package systems.\88\ However, manufacturers of 
single-packaged dedicated systems may elect to use AEDMs. DOE estimates 
the per-manufacturer cost to develop and validate an AEDM per 
validation class to be $24,580 for outdoor single-packaged dedicated 
systems and $15,580 for indoor single-packaged dedicated systems. DOE 
estimates an additional cost of approximately $46 per basic model \89\ 
for determining energy efficiency using the validated AEDM.
---------------------------------------------------------------------------

    \88\ Per the sampling requirements specified at 10 CFR 
429.53(a)(2)(ii) and 10 CFR 429.11(b), manufacturers are required to 
test at least two units to determine the rating for a basic model, 
except where only one unit of the basic model is produced.
    \89\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    DOE estimated the range of potential costs for the two domestic, 
small OEMs that manufacture single-packaged dedicated systems. When 
developing cost estimates for the small OEMs, DOE considered the cost 
to update the existing AEDM simulation tool, the costs to validate the 
AEDM through physical testing, and the cost to rate basic models using 
the AEDM.
    Both small businesses manufacture indoor and outdoor, low and 
medium temperature, single-packaged dedicated systems. One small 
business manufactures 28 basic models of single-packaged dedicated 
systems with an estimated annual revenue of $19 million. Therefore, DOE 
estimates that the associated re-rating costs for this manufacturer to 
be approximately $81,650 when making use of AEDMs. The cost for this 
manufacturer represents less than 1 percent of annual revenue.
    The second small business manufactures 38 basic models of single-
packaged dedicated systems with an estimated annual revenue of $147 
million. Therefore, DOE estimates that the associated re-rating costs 
for this manufacturer to be approximately $82,100 when making use of 
AEDMs. The cost for this manufacturer represents less than 1 percent of 
annual revenue.
(3) Small Business Impacts as a Result of New Test Procedures for High-
Temperature Refrigeration Systems
    DOE is proposing test procedures for high-temperature refrigeration 
systems. DOE has granted waivers to certain manufacturers for high-
temperature refrigeration systems. The test procedures proposed in this 
NOPR are consistent with the alternate test procedures included in the 
granted waivers, excluding the changes discussed previously about off-
cycle power measurements. For those manufacturers who have been granted 
a test procedure waiver for this equipment, DOE expects the only test 
burden incurred would be that related to off-cycle requirements. 
However, DOE expects that there would be additional testing costs for 
any manufacturers of these products who have not submitted or been 
granted a test procedure waiver at the time this proposed test 
procedure is finalized.
    For manufacturers that have been granted waivers, DOE estimates 
that measuring off-cycle power at these additional ambient conditions 
may increase per-unit third-party lab test cost by $1,000 to a total 
per-unit cost of $11,000 for high-temperature outdoor dedicated 
condensing units, outdoor matched pair systems, and outdoor single-
packaged dedicated systems. The physical testing cost, according to the 
proposed amendments, would be $22,000 per basic model for outdoor 
dedicated condensing units and outdoor matched pair systems.\90\
---------------------------------------------------------------------------

    \90\ Per the sampling requirements specified at 10 CFR 
429.53(a)(2)(ii) and 10 CFR 429.11(b), manufacturers are required to 
test at least two units to determine the rating for a basic model, 
except where only one unit of the basic model is produced.
---------------------------------------------------------------------------

    However, manufacturers are not required to perform laboratory 
testing on all basic models. In accordance with 10 CFR 429.53, WICF 
refrigeration system manufacturers may elect to use AEDMs. DOE 
estimates the per-manufacturer cost to develop and validate an AEDM for 
outdoor dedicated condensing units and outdoor matched pair systems to 
be $24,580 per validation class. DOE estimates an additional cost of 
approximately $46 per basic model \91\ for determining energy 
efficiency using the validated AEDM.
---------------------------------------------------------------------------

    \91\ DOE estimated initial costs to validate an AEDM assuming 40 
hours of general time to develop an AEDM based on existing 
simulation tools and 16 hours to validate two basic models within 
that AEDM at the cost of an engineering calibration technician fully 
burdened wage of $46 per hour plus the cost of third-party physical 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.

---------------------------------------------------------------------------

[[Page 23982]]

    DOE estimated the potential costs to manufacturers of high-
temperature units as a result of off-cycle requirements using an AEDM. 
Specifically, DOE estimated the range of potential costs for the five 
identified domestic, small OEMs that manufacture high-temperature 
units. When developing cost estimates for the small OEMs, DOE considers 
the cost to develop the AEDM simulation tool, the costs to validate the 
AEDM through physical testing, and the cost to rate basic models using 
the AEDM. DOE assumes a scenario where manufacturers would be required 
to develop AEDMs for three validation classes.
    DOE estimated the impacts based on basic model counts and company 
revenue. Table IV.2 summarizes DOE's estimates for the five identified 
small businesses. On average, testing costs represent approximately 1.5 
percent of annual revenue for a typical small business.

     Table IV.2--Estimated Small Business Re-Rating Costs (2022$) for High-Temperature Refrigeration Systems
----------------------------------------------------------------------------------------------------------------
                                                                     Re-rating    Annual revenue    Percent of
                          Manufacturer                            estimate ($mm)  estimate ($mm)    revenue (%)
----------------------------------------------------------------------------------------------------------------
Manufacturer A..................................................           0.075             2.1            3.57
Manufacturer B..................................................           0.074             3.6            2.06
Manufacturer C..................................................           0.074             8.9            0.84
Manufacturer D..................................................           0.076              11            0.70
Manufacturer E..................................................           0.075              14            0.53
----------------------------------------------------------------------------------------------------------------

    For manufacturers that have not been granted waivers, manufacturers 
of high-temperature equipment may incur first-time rating expenses. DOE 
estimates these manufacturers may incur rating expenses up to $22,000 
per basic model for a high-temperature matched pair, $22,000 per basic 
model for a single-packaged dedicated system, and $12,000 per basic 
model for a high-temperature unit cooler.\92\
---------------------------------------------------------------------------

    \92\ Per the sampling requirements specified at 10 CFR 
429.53(a)(2)(ii) and 10 CFR 429.11(b), manufacturers are required to 
test at least two units to determine the rating for a basic model, 
except where only one unit of the basic model is produced.
---------------------------------------------------------------------------

(4) Small Business Impacts as a Result of New Test Procedures for 
CO<INF>2</INF> Unit Coolers
    Lastly, DOE is proposing test procedures for CO<INF>2</INF> unit 
coolers. DOE has granted waivers to certain manufacturers for 
CO<INF>2</INF> unit coolers. In this proposal, DOE is proposing that 
CO<INF>2</INF> refrigeration systems, as DOE proposed to define in 
section III.A.2.h of this NOPR, meet the definition of a walk-in, but 
that the DOE test procedure is applicable only to single-packaged 
dedicated and to unit cooler variants of CO<INF>2</INF> refrigeration 
systems. All CO<INF>2</INF> refrigerant waiver petitions DOE has thus 
far received address unit coolers. 86 FR 32332, 32346.
    The test procedures proposed in this NOPR are consistent with the 
alternate test procedures included in the granted waivers. For those 
manufacturers who have been granted a test procedure waiver for this 
equipment, DOE expects no change in test burden. However, DOE expects 
that there would be additional testing costs for any manufacturers of 
these products who have not submitted or been granted a test procedure 
waiver at the time this proposed test procedure is finalized. This 
additional cost is partially offset because, without a method of test, 
manufacturers of these products would not be able to sell them in the 
U.S. since there would be no way of certifying their energy use as 
required EPCA.
    For manufacturers that have not been granted waivers, manufacturers 
of CO<INF>2</INF> equipment may incur first-time rating expenses. DOE 
estimates these manufacturers may incur rating expenses up to $13,000 
per-unit for a low temperature CO<INF>2</INF> unit cooler and $12,000 
per-unit for a medium temperature CO<INF>2</INF> unit cooler.\93\ 
However, manufacturers of CO<INF>2</INF> unit coolers may choose to 
utilize an AEDM. Furthermore, AEDM unit cooler validation classes do 
not distinguish between CO<INF>2</INF> unit coolers and non-
CO<INF>2</INF> unit coolers. Therefore, manufacturers of CO<INF>2</INF> 
unit coolers may use the same validation classes as non-CO<INF>2</INF> 
unit coolers.
---------------------------------------------------------------------------

    \93\ Per the sampling requirements specified at 10 CFR 
429.53(a)(2)(ii) and 10 CFR 429.11(b), manufacturers are required to 
test at least two units to determine the rating for a basic model, 
except where only one unit of the basic model is produced.
---------------------------------------------------------------------------

    Issue 41: DOE requests comment on its cost estimate of impacts on 
small, domestic OEMs of refrigeration systems.
5. Duplication, Overlap, and Conflict With Other Rules and Regulations
    DOE is not aware of any rules or regulations that duplicate, 
overlap, or conflict with the rule being considered in this document.
6. Significant Alternatives to the Rule
    DOE proposes to reduce burden on manufacturers, including small 
businesses, by allowing AEDMs in lieu of physically testing all basic 
models. The use of an AEDM is less costly than physical testing WICF 
components. For doors, DOE's proposed inclusion of AEDM provisions 
would allow manufacturers to develop an AEDM for rating their models. 
Without an AEDM, DOE estimates physical testing would cost door 
manufacturers $10,000 per basic model. With the use of an AEDM, DOE 
estimates the costs of $11,100 to develop and validate a single 
validation class plus an additional $46 per basic model yielding 
savings to manufacturers that produce more than one basic model of 
door. For refrigeration systems, DOE estimates $24,580 at the high-end 
of the range to develop and validate an AEDM with an additional cost of 
$46 per basic model. With a high-end cost of approximately $22,000 per 
basic model to physically test refrigeration models, manufacturers of 
three or more basic models could yield cost savings.
    Additional compliance flexibilities may be available through other 
means. For example, manufacturers subject to DOE's energy efficiency 
standards may apply to DOE's Office of Hearings and Appeals for 
exception relief under certain circumstances. Manufacturers should 
refer to 10 CFR part 1003 for additional details.

C. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of walk-ins must certify to DOE that their products 
comply with any applicable energy conservation standards. To certify

[[Page 23983]]

compliance, manufacturers must first obtain test data for their 
products according to the DOE test procedures, including any amendments 
adopted for those test procedures. DOE has established regulations for 
the certification and recordkeeping requirements for all covered 
consumer products and commercial equipment, including walk-ins. See 
generally 10 CFR part 429. The collection-of-information requirement 
for the certification and recordkeeping is subject to review and 
approval by the Office of Management and Budget (``OMB'') under the 
Paperwork Reduction Act (``PRA''). This requirement has been approved 
by OMB under OMB control number 1910-1400. Public reporting burden for 
the certification is estimated to average 35 hours per response, 
including the time for reviewing instructions, searching existing data 
sources, gathering and maintaining the data needed, and completing and 
reviewing the collection of information.
    DOE is not proposing to amend the certification or reporting 
requirements for walk-ins in this NOPR. Instead, DOE may consider 
proposals to amend the certification requirements and reporting for 
walk-ins under a separate rulemaking regarding appliance and equipment 
certification. DOE will address changes to OMB Control Number 1910-1400 
at that time, as necessary.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply with, a collection of information subject to the 
requirements of the PRA, unless that collection of information displays 
a currently valid OMB Control Number.

D. Review Under the National Environmental Policy Act of 1969

    In this NOPR, DOE proposes test procedure amendments that it 
expects would be used to develop and implement future energy 
conservation standards for walk-in coolers and freezers. DOE has 
determined that this rule falls into a class of actions that are 
categorically excluded from review under the National Environmental 
Policy Act of 1969 (42 U.S.C. 4321 et seq.) and DOE's implementing 
regulations at 10 CFR part 1021. Specifically, DOE has tentatively 
determined that adopting test procedures for measuring energy 
efficiency of consumer products and industrial equipment is consistent 
with activities identified in 10 CFR part 1021, appendix A to subpart 
D, A5 and A6. See also 10 CFR 1021.410. DOE will complete its NEPA 
review before issuing the final rule.

E. Review Under Executive Order 13132

    Executive Order 13132, ``Federalism,'' 64 FR 43255 (Aug. 4, 1999), 
imposes certain requirements on agencies formulating and implementing 
policies or regulations that preempt State law or that have federalism 
implications. The Executive order requires agencies to examine the 
constitutional and statutory authority supporting any action that would 
limit the policymaking discretion of the States and to carefully assess 
the necessity for such actions. The Executive order also requires 
agencies to have an accountable process to ensure meaningful and timely 
input by State and local officials in the development of regulatory 
policies that have federalism implications. On March 14, 2000, DOE 
published a statement of policy describing the intergovernmental 
consultation process it will follow in the development of such 
regulations. 65 FR 13735. DOE has examined this proposed rule and has 
tentatively determined that it would not have a substantial direct 
effect on the States, on the relationship between the National 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of government. EPCA governs 
and prescribes Federal preemption of State regulations as to energy 
conservation for the products that are the subject of this proposed 
rule. States can petition DOE for exemption from such preemption to the 
extent, and based on criteria, set forth in EPCA. (42 U.S.C. 6297(d)) 
No further action is required by Executive Order 13132.

F. Review Under Executive Order 12988

    Regarding the review of existing regulations and the promulgation 
of new regulations, section 3(a) of Executive Order 12988, ``Civil 
Justice Reform,'' 61 FR 4729 (Feb. 7, 1996), imposes on Federal 
agencies the general duty to adhere to the following requirements: (1) 
Eliminate drafting errors and ambiguity, (2) write regulations to 
minimize litigation, (3) provide a clear legal standard for affected 
conduct rather than a general standard, and (4) promote simplification 
and burden reduction. Section 3(b) of Executive Order 12988 
specifically requires that executive agencies make every reasonable 
effort to ensure that the regulation (1) clearly specifies the 
preemptive effect, if any, (2) clearly specifies any effect on existing 
Federal law or regulation, (3) provides a clear legal standard for 
affected conduct while promoting simplification and burden reduction, 
(4) specifies the retroactive effect, if any, (5) adequately defines 
key terms, and (6) addresses other important issues affecting clarity 
and general draftsmanship under any guidelines issued by the Attorney 
General. Section 3(c) of Executive Order 12988 requires executive 
agencies to review regulations in light of applicable standards in 
sections 3(a) and 3(b) to determine whether they are met, or it is 
unreasonable to meet one or more of them. DOE has completed the 
required review and determined that, to the extent permitted by law, 
the proposed rule meets the relevant standards of Executive Order 
12988.

G. Review Under the Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (``UMRA'') 
requires each Federal agency to assess the effects of Federal 
regulatory actions on State, local, and Tribal governments, and the 
private sector. Public Law 104-4, sec. 201 (codified at 2 U.S.C. 1531). 
For a proposed regulatory action likely to result in a rule that may 
cause the expenditure by State, local, and Tribal governments, in the 
aggregate, or by the private sector of $100 million or more in any one 
year (adjusted annually for inflation), section 202 of UMRA requires a 
Federal agency to publish a written statement that estimates the 
resulting costs, benefits, and other effects on the national economy. 
(2 U.S.C. 1532(a), (b)) The UMRA also requires a Federal agency to 
develop an effective process to permit timely input by elected officers 
of State, local, and Tribal governments on a proposed ``significant 
intergovernmental mandate,'' and requires an agency plan for giving 
notice and opportunity for timely input to potentially affected small 
governments before establishing any requirements that might 
significantly or uniquely affect small governments. On March 18, 1997, 
DOE published a statement of policy on its process for 
intergovernmental consultation under UMRA. 62 FR 12820; also available 
at energy.gov/gc/office-general-counsel. DOE examined this proposed 
rule according to UMRA and its statement of policy and determined that 
the rule contains neither an intergovernmental mandate, nor a mandate 
that may result in the expenditure of $100 million or more in any year, 
so these requirements do not apply.

H. Review Under the Treasury and General Government Appropriations Act, 
1999

    Section 654 of the Treasury and General Government Appropriations

[[Page 23984]]

Act, 1999 (Pub. L. 105-277), requires Federal agencies to issue a 
Family Policymaking Assessment for any rule that may affect family 
well-being. This proposed rule would not have any impact on the 
autonomy or integrity of the family as an institution. Accordingly, DOE 
has concluded that it is not necessary to prepare a Family Policymaking 
Assessment.

I. Review Under Executive Order 12630

    DOE has determined, under Executive Order 12630, ``Governmental 
Actions and Interference with Constitutionally Protected Property 
Rights,'' 53 FR 8859 (March 18, 1988), that this proposed regulation 
would not result in any takings that might require compensation under 
the Fifth Amendment to the U.S. Constitution.

J. Review Under Treasury and General Government Appropriations Act, 
2001

    Section 515 of the Treasury and General Government Appropriations 
Act, 2001 (44 U.S.C. 3516 note), provides for agencies to review most 
disseminations of information to the public under guidelines 
established by each agency pursuant to general guidelines issued by 
OMB. OMB's guidelines were published at 67 FR 8452 (Feb. 22, 2002), and 
DOE's guidelines were published at 67 FR 62446 (Oct. 7, 2002). Pursuant 
to OMB Memorandum M-19-15, Improving Implementation of the Information 
Quality Act (April 24, 2019), DOE published updated guidelines which 
are available at www.energy.gov/sites/prod/files/2019/12/f70/DOE%20Final%20Updated%20IQA%20Guidelines%20Dec%202019.pdf. DOE has 
reviewed this proposed rule under the OMB and DOE guidelines and has 
concluded that it is consistent with applicable policies in those 
guidelines.

K. Review Under Executive Order 13211

    Executive Order 13211, ``Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355 
(May 22, 2001), requires Federal agencies to prepare and submit to OMB, 
a Statement of Energy Effects for any proposed significant energy 
action. A ``significant energy action'' is defined as any action by an 
agency that promulgated or is expected to lead to promulgation of a 
final rule, and that (1) is a significant regulatory action under 
Executive Order 12866, or any successor order; and (2) is likely to 
have a significant adverse effect on the supply, distribution, or use 
of energy; or (3) is designated by the Administrator of OIRA as a 
significant energy action. For any proposed significant energy action, 
the agency must give a detailed statement of any adverse effects on 
energy supply, distribution, or use should the proposal be implemented, 
and of reasonable alternatives to the action and their expected 
benefits on energy supply, distribution, and use.
    The proposed regulatory action to amend the test procedure for 
measuring the energy efficiency of walk-ins is not a significant 
regulatory action under Executive Order 12866. Moreover, it would not 
have a significant adverse effect on the supply, distribution, or use 
of energy, nor has it been designated as a significant energy action by 
the Administrator of OIRA. Therefore, it is not a significant energy 
action, and, accordingly, DOE has not prepared a Statement of Energy 
Effects.

L. Review Under Section 32 of the Federal Energy Administration Act of 
1974

    Under section 301 of the Department of Energy Organization Act 
(Pub. L. 95-91; 42 U.S.C. 7101), DOE must comply with section 32 of the 
Federal Energy Administration Act of 1974, as amended by the Federal 
Energy Administration Authorization Act of 1977. (15 U.S.C. 788; 
``FEAA'') Section 32 essentially provides in relevant part that, where 
a proposed rule authorizes or requires use of commercial standards, the 
notice of proposed rulemaking must inform the public of the use and 
background of such standards. In addition, section 32(c) requires DOE 
to consult with the Attorney General and the Chairman of the Federal 
Trade Commission (``FTC'') concerning the impact of the commercial or 
industry standards on competition.
    The proposed modifications to the test procedure for walk-ins would 
incorporate testing methods contained in certain sections of the 
following commercial standards: NFRC 102-2020, ASTM C1199-14, ASTM 
C518-17, AHRI 1250-2020, ASHRAE 37-2009, AHRI 1250-2020, ANSI/ASHRAE 
37-2009, and ANSI/ASHRAE 16-2016. DOE has evaluated these standards and 
is unable to conclude whether they fully comply with the requirements 
of section 32(b) of the FEAA (i.e., whether they were developed in a 
manner that fully provides for public participation, comment, and 
review). DOE will consult with both the Attorney General and the 
Chairman of the FTC concerning the impact of these test procedures on 
competition, prior to prescribing a final rule.

M. Description of Materials Incorporated by Reference

    In this NOPR, DOE proposes to incorporate by reference the 
following industry test standards into 10 CFR part 431:
    (1) AHRI Standard 1250-2020, ``Standard for Performane Rating of 
Walk-in Coolers and Freezers,'' copyright 2020.
    AHRI 1250-2020 is an industry-accepted test procedure for measuring 
the performance of walk-in cooler and walk-in freezer refrigeration 
systems. AHRI 1250-2020 is available on AHRI's website at 
www.ahrinet.org/search-standards.
    (2) ANSI/ASHRAE Standard 16-2016, ``Method of Testing for Rating 
Room Air Conditioners, Packaged Terminal Air Conditioners, and Packaged 
Terminal Heat Pumps for Cooling and Heating Capacity,'' approved 
October 31, 2016.
    ANSI/ASHRAE 16 is an industry-accepted test procedure for measuring 
cooling and heating capacity of room air conditioners, packaged 
terminal air conditioners, and packaged terminal heat pumps referenced 
by AHRI 1250-2020. ANSI/ASHRAE 16 includes test provisions related to 
the measuring of the capacity of single-packaged dedicated systems for 
the proposed appendix C1 test procedure. ANSI/ASHRAE 16 is available on 
ASHRAE's website at www.ashrae.org.
    (3) ANSI/ASHRAE Standard 37-2009, ``Methods of Testing for Rating 
Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment,'' 
approved June 24, 2009.
    ANSI/ASHRAE 37 is an industry-accepted test procedure for testing 
and rating air-conditioning and heat pump equipment referenced by AHRI 
1250-2020. ANSI/ASHRAE 37 includes test provisions related to the 
measuring of the capacity of single-packaged dedicated systems for the 
proposed appendix C1 test procedure. ANSI/ASHRAE 37 is available on 
ASHRAE's website at www.ashrae.org.
    (4) ASTM C518-17, ``Standard Test Method for Steady state Thermal 
Transmission Properties by Means of the Heat Flow Meter Apparatus,'' 
approved May 1, 2017.
    ASTM C518-17 is an industry-accepted test procedure for measuring 
thermal transmission properties using a heat flow meter apparatus. ASTM 
C518-17 is available on ASTM's website at www.astm.org.
    (5) ASTM C1199-14, ``Standard Test Method for Measuring the Steady 
state Thermal Transmittance of Fenestration Systems Using Hot Box 
Methods,'' approved February 1, 2014.

[[Page 23985]]

    ASTM C1199-14 is an industry-accepted test procedure for measuring 
the steady state thermal transmittance of fenestration systems 
referenced by NFRC 102-2020. ASTM C1199-14 is available on ASTM's 
website at www.astm.org.
    (6) NFRC 102-2020 [E0A0], ``Procedure for Measuring the Steady-
State Thermal Transmittance of Fenestration Systems.''
    NFRC 102-2020 is an industry-accepted test procedure for measuring 
the steady state thermal transmittance of fenestration systems. NFRC 
102-2020 is available on NFRC's website at www.nfrc.org/.
    The following standards were approved on December 28, 2016, for IBR 
into the provisions where they appear in this document and no change in 
use is proposed: ANSI/AHRI Standard 420-2008, AHRI Standard 1250 (I-P)-
2009, and ANSI/ASHRAE Standard 23.1-2010.

V. Public Participation

A. Participation in the Webinar

    The time and date of the webinar are listed in the DATES section at 
the beginning of this document. Webinar registration information, 
participant instructions, and information about the capabilities 
available to webinar participants will be published on DOE's website: 
www.energy.gov/eere/buildings/public-meetings-and-comment-deadlines. 
Participants are responsible for ensuring their systems are compatible 
with the webinar software.

B. Procedure for Submitting Prepared General Statements for 
Distribution

    Any person who has an interest in the topics addressed in this 
document, or who is representative of a group or class of persons that 
has an interest in these issues, may request an opportunity to make an 
oral presentation at the webinar. Such persons may submit to 
<a href="/cdn-cgi/l/email-protection#78390808141119161b1d2b0c19161c190a1c0b290d1d0b0c1117160b381d1d561c171d561f170e"><span class="__cf_email__" data-cfemail="b1f0c1c1ddd8d0dfd2d4e2c5d0dfd5d0c3d5c2e0c4d4c2c5d8dedfc2f1d4d49fd5ded49fd6dec7">[email protected]</span></a>. Persons who wish to speak 
should include with their request a computer file in WordPerfect, 
Microsoft Word, PDF, or text (ASCII) file format that briefly describes 
the nature of their interest in this proposed rulemaking and the topics 
they wish to discuss. Such persons should also provide a daytime 
telephone number where they can be reached.
    Persons requesting to speak should briefly describe the nature of 
their interest in this rulemaking and provide a telephone number for 
contact. DOE requests persons selected to make an oral presentation to 
submit an advance copy of their statements at least two weeks before 
the webinar. At its discretion, DOE may permit persons who cannot 
supply an advance copy of their statement to participate, if those 
persons have made advance alternative arrangements with the Building 
Technologies Office. As necessary, requests to give an oral 
presentation should ask for such alternative arrangements.

C. Conduct of the Webinar

    DOE will designate a DOE official to preside at the webinar/public 
meeting and may also use a professional facilitator to aid discussion. 
The meeting will not be a judicial or evidentiary-type public hearing, 
but DOE will conduct it in accordance with section 336 of EPCA (42 
U.S.C. 6306). A court reporter will be present to record the 
proceedings and prepare a transcript. DOE reserves the right to 
schedule the order of presentations and to establish the procedures 
governing the conduct of the webinar/public meeting. There shall not be 
discussion of proprietary information, costs or prices, market share, 
or other commercial matters regulated by U.S. anti-trust laws. After 
the webinar/public meeting and until the end of the comment period, 
interested parties may submit further comments on the proceedings and 
any aspect of the proposed rulemaking.
    The webinar/public meeting will be conducted in an informal, 
conference style. DOE will present a general overview of the topics 
addressed in this proposed rulemaking, allow time for prepared general 
statements by participants, and encourage all interested parties to 
share their views on issues affecting this proposed rulemaking. Each 
participant will be allowed to make a general statement (within time 
limits determined by DOE), before the discussion of specific topics. 
DOE will permit, as time permits, other participants to comment briefly 
on any general statements.
    At the end of all prepared statements on a topic, DOE will permit 
participants to clarify their statements briefly. Participants should 
be prepared to answer questions by DOE and by other participants 
concerning these issues. DOE representatives may also ask questions of 
participants concerning other matters relevant to this proposed 
rulemaking. The official conducting the webinar/public meeting will 
accept additional comments or questions from those attending, as time 
permits. The presiding official will announce any further procedural 
rules or modification of the procedures that may be needed for the 
proper conduct of the webinar/public meeting.
    A transcript of the webinar/public meeting will be included in the 
docket, which can be viewed as described in the Docket section at the 
beginning of this proposed rule. In addition, any person may buy a copy 
of the transcript from the transcribing reporter.

D. Submission of Comments

    DOE will accept comments, data, and information regarding this 
proposed rule no later than the date provided in the DATES section at 
the beginning of this proposed rule.\94\ Interested parties may submit 
comments using any of the methods described in the ADDRESSES section at 
the beginning of this document.
---------------------------------------------------------------------------

    \94\ DOE has historically provided a 75-day comment period for 
test procedure NOPRs pursuant to the North American Free Trade 
Agreement, U.S.-Canada-Mexico (``NAFTA''), Dec. 17, 1992, 32 I.L.M. 
289 (1993); the North American Free Trade Agreement Implementation 
Act, Public Law 103-182, 107 Stat. 2057 (1993) (codified as amended 
at 10 U.S.C.A. 2576) (1993) (``NAFTA Implementation Act''); and 
Executive Order 12889, ``Implementation of the North American Free 
Trade Agreement,'' 58 FR 69681 (Dec. 30, 1993). However, on July 1, 
2020, the Agreement between the United States of America, the United 
Mexican States, and the United Canadian States (``USMCA''), Nov. 30, 
2018, 134 Stat. 11 (i.e., the successor to NAFTA), went into effect, 
and Congress's action in replacing NAFTA through the USMCA 
Implementation Act, 19 U.S.C. 4501 et seq. (2020), implies the 
repeal of E.O. 12889 and its 75-day comment period requirement for 
technical regulations. Thus, the controlling laws are EPCA and the 
USMCA Implementation Act. Consistent with EPCA's public comment 
period requirements for consumer products, the USMCA only requires a 
minimum comment period of 60 days. Consequently, DOE now provides a 
60-day public comment period for test procedure NOPRs.
---------------------------------------------------------------------------

    Submitting comments via www.regulations.gov. The 
www.regulations.gov web page will require you to provide your name and 
contact information. Your contact information will be viewable to DOE 
Building Technologies staff only. Your contact information will not be 
publicly viewable except for your first and last names, organization 
name (if any), and submitter representative name (if any). If your 
comment is not processed properly because of technical difficulties, 
DOE will use this information to contact you. If DOE cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, DOE may not be able to consider your comment.
    However, your contact information will be publicly viewable if you 
include it in the comment or in any documents attached to your comment. 
Any information that you do not want to be publicly viewable should not 
be included in your comment, nor in any document attached to your 
comment.

[[Page 23986]]

Persons viewing comments will see only first and last names, 
organization names, correspondence containing comments, and any 
documents submitted with the comments.
    Do not submit to www.regulations.gov information for which 
disclosure is restricted by statute, such as trade secrets and 
commercial or financial information (hereinafter referred to as 
Confidential Business Information (``CBI'')). Comments submitted 
through www.regulations.gov cannot be claimed as CBI. Comments received 
through the website will waive any CBI claims for the information 
submitted. For information on submitting CBI, see the Confidential 
Business Information section.
    DOE processes submissions made through www.regulations.gov before 
posting. Normally, comments will be posted within a few days of being 
submitted. However, if large volumes of comments are being processed 
simultaneously, your comment may not be viewable for up to several 
weeks. Please keep the comment tracking number that www.regulations.gov 
provides after you have successfully uploaded your comment.
    Submitting comments via email. Comments and documents submitted via 
email also will be posted to www.regulations.gov. If you do not want 
your personal contact information to be publicly viewable, do not 
include it in your comment or any accompanying documents. Instead, 
provide your contact information on a cover letter. Include your first 
and last names, email address, telephone number, and optional mailing 
address. The cover letter will not be publicly viewable as long as it 
does not include any comments.
    Include contact information each time you submit comments, data, 
documents, and other information to DOE. No faxes will be accepted.
    Comments, data, and other information submitted to DOE 
electronically should be provided in PDF (preferred), Microsoft Word or 
Excel, WordPerfect, or text (ASCII) file format. Provide documents that 
are not secured, written in English and free of any defects or viruses. 
Documents should not contain special characters or any form of 
encryption and, if possible, they should carry the electronic signature 
of the author.
    Campaign form letters. Please submit campaign form letters by the 
originating organization in batches of between 50 to 500 form letters 
per PDF or as one form letter with a list of supporters' names compiled 
into one or more PDFs. This reduces comment processing and posting 
time.
    Confidential Business Information. Pursuant to 10 CFR 1004.11, any 
person submitting information that he or she believes to be 
confidential and exempt by law from public disclosure should submit via 
email two well-marked copies: One copy of the document marked 
confidential including all the information believed to be confidential, 
and one copy of the document marked non-confidential with the 
information believed to be confidential deleted. DOE will make its own 
determination about the confidential status of the information and 
treat it according to its determination.
    It is DOE's policy that all comments may be included in the public 
docket, without change and as received, including any personal 
information provided in the comments (except information deemed to be 
exempt from public disclosure).

E. Issues on Which DOE Seeks Comment

    Although DOE welcomes comments on any aspect of this proposal, DOE 
is particularly interested in receiving comments and views of 
interested parties concerning the following issues:
    Issue 1: DOE requests comment on its proposed changes to the 
definition for walk-in cooler and walk-in freezer.
    Issue 2: DOE requests feedback on the proposed changes to the 
definition of ``door'' and the newly proposed definition for ``door 
leaf.'' DOE also seeks comment on the newly proposed definitions for 
certain door opening characteristics: ``hinged vertical door,'' ``roll-
up door,'' and ``sliding door.''
    Issue 3: DOE requests comment on the proposed definition of 
``ducted fan coil unit'' and on the proposed modification to the 
``single-packaged dedicated system'' definition.
    Issue 4: DOE requests comment on the proposed definition for multi-
circuit single-packaged dedicated refrigeration systems.
    Issue 5: DOE requests comment on the proposed definition for 
attached split system.
    Issue 6: DOE requests comment on the proposed definition for 
detachable single-packaged dedicated system.
    Issue 7: DOE requests comment on the proposed definition of 
CO<INF>2</INF> unit coolers. DOE also requests comment on whether any 
distinguishing features of CO<INF>2</INF> unit coolers exist that could 
reliably be used as an alternative approach that can differentiate them 
from those unit coolers intended for use with conventional 
refrigerants.
    Issue 8: DOE requests comment on the proposed definition for hot 
gas defrost. Specifically, DOE requests comment on if this proposed 
definition is sufficient to identify which equipment is sold with hot 
gas defrost capability installed and which is not.
    Issue 9: DOE requests feedback on the proposed provisions relating 
to test specimen and total insulation thickness and test specimen 
preparation prior to conducting the ASTM C518-17 test.
    Issue 10: DOE requests feedback on the proposed provisions relating 
to determining parallelism and flatness of the test specimen.
    Issue 11: DOE seeks comment on other comparable data or studies of 
aging of foam panels that are representative of the foam insulation, 
blowing agents, and panel construction currently used in the 
manufacture of walk-in panels. DOE also requests comment on whether 
manufacturers have been certifying R-value at time of manufacture or 
after a period of aging.
    Issue 12: DOE requests comment on the proposed pretest coil 
inspection requirement. DOE requests comment on whether the proposed 
approach is inconsistent in any way with the way units under test are 
used to assist in chamber conditioning by testing facilities, and if 
so, in what way are the proposals inconsistent, and how could they be 
changed to align with this practice.
    Issue 13: DOE requests comment on its proposal to require use of 
thermometer wells or sheathed sensors immersed in the refrigerant when 
measuring temperature at the liquid outlet of the condensing unit and 
to forego the requirement for this measurement technique for the 
suction line when testing a dedicated condensing unit alone.
    Issue 14: DOE requests comment on its proposal to allow the use of 
two temperature measuring instruments, placed on the outside of 
refrigerant tubing that is less than or equal to \1/2\-inch, for the 
measurement of refrigerant temperature where the current test procedure 
requirement is to use thermometer wells or a sheathed sensor immersed 
in the refrigerant.
    Issue 15: DOE requests comment on its proposals discussed in this 
section regarding set up of walk-in refrigeration systems for testing 
to achieve manufacturer-specified conditions for superheat, subcooling, 
high-side temperature, pressure or saturation temperature, low-side 
temperature, pressure or saturation temperature, and refrigerant charge 
weight. Additionally, DOE requests comment on the proposed hierarchy 
presented in Table III.6, if a laboratory has confirmed that the unit 
is properly charged.

[[Page 23987]]

    Issue 16: DOE requests comments on its proposal to clarify the 
location where the 3 [deg]F subcooling requirement would apply and to 
require active cooling of the liquid line in order to achieve the 
required 3 [deg]F subcooling at a refrigerant mass flow meter. DOE also 
seeks comment on its proposal to require, for matched pairs, adjustment 
of the measured unit cooler inlet temperature by the difference in 
temperatures measured upstream and downstream of the active cooling in 
order to calculate the inlet enthalpy in the capacity calculation.
    Issue 17: DOE requests comment on the appropriateness of 
traditional refrigerant compressor EER values for use in CO<INF>2</INF> 
unit cooler AWEF calculations.
    Issue 18: DOE requests comment on its proposals to adopt test 
procedure provisions for high-temperature unit coolers in appendices C 
and C1 of 10 CFR part 431, subpart R.
    Issue 19: DOE requests comments on its proposals to align the test 
procedures for appendix C1 with AHRI 1250-2020, except for the use of 
off-cycle power measurements in the AWEF calculations for dedicated 
condensing units, matched pairs, or single-packaged dedicated systems 
intended for outdoor installation. DOE requests comments on its 
proposals for use in the AWEF calculations of the three sets of unit 
cooler and condensing unit off-cycle measurements made for outdoor 
refrigeration systems.
    Issue 20: DOE requests comment on the proposed single-packaged 
refrigerant enthalpy test procedure for evaluating the performance of 
single-packaged dedicated systems.
    Issue 21: DOE requests comment on testing detachable single-
packaged dedicated systems using the test procedure for single-packaged 
dedicated systems.
    Issue 22: DOE requests comment on its proposal that attached split 
systems be tested using refrigerant enthalpy methods.
    Issue 23: DOE requests comment on provisions for setting ESP when 
testing ducted units.
    Issue 24: DOE requests comments on its proposals for testing 
multiple-, variable-, and two-capacity dedicated condensing units 
tested alone. DOE specifically requests comments on (a) the expectation 
that a unit cooler with which such a condensing unit is paired in the 
field would have two-speed (or variable-speed) fans or be fitted with 
such fans during installation, (b) the proposed compressor operating 
levels to use for testing, (c) the proposed compressor operating level 
at which the unit cooler fan would be assumed to switch to half-speed, 
(d) the proposed targets for unit cooler exit and condensing unit inlet 
refrigerant temperatures and dew point target temperatures, and (e) the 
unit cooler half-fan-speed input wattage.
    Issue 25: DOE requests comment on whether DOE should set the target 
test conditions using correlations for unit cooler and suction line 
response to part-load operation rather than the proposed tabular 
approach.
    Issue 26: DOE requests comment on its proposal to include in its 
test procedures instructions for testing and determining 
representations for indoor matched pair and single-packaged dedicated 
systems.
    Issue 27: DOE requests comment on its proposal to modify the 
approach for calculating intermediate-capacity EER for variable-speed 
refrigeration systems.
    Issue 28: DOE requests comments on its proposals to address part-
load testing for refrigeration systems with digital compressors.
    Issue 29: DOE requests comment on its proposal to clarify that the 
second mass flow measurement for the DX Dual Instrumentation method may 
be in the suction line upstream of the inlet to the condensing unit, as 
shown in Figure C1 of AHRI 1250-2009.
    Issue 30: DOE requests comment on its proposal to adopt the 
calculations for evaporator fan power in AHRI 1250-2020.
    Issue 31: DOE requests comment on its proposal for rounding AWEF to 
the nearest 0.05 Btu/(W-h) and rounding capacity values to the nearest 
multiple as presented in Table III.14.
    Issue 32: DOE seeks comment on its proposal to allow for the use of 
AEDMs to determine the energy consumption rating of walk-in doors. DOE 
requests specific feedback on the proposed 5 percent model tolerance 
for validating an AEDM, the proposed validation classes and number of 
basic models required to be tested per validation class, and the 
proposed 5 percent tolerance on the result from a DOE AEDM verification 
test.
    Issue 33: DOE seeks comment on its proposal to modify and extend 
its AEDM validation classes for refrigeration systems, consistent with 
the test procedure revisions discussed in this document.
    Issue 34: DOE requests comment on its proposal to apply the low-
volume sampling procedures in appendix B of subpart C of 10 CFR part 
429 to walk-in doors and panels.
    Issue 35: DOE requests comment on its tentative understanding of 
the impact of the test procedure proposals for appendix A in this 
NOPR--specifically, whether the proposed test procedure amendments, if 
finalized, would either not impact or decrease the testing burden for 
walk-in door manufacturers when compared to the current DOE test 
procedure in appendix A.
    Issue 36: DOE requests comment on its tentative understanding of 
the impact of the test procedure proposals for appendix B in this 
NOPR--specifically, that the proposed test procedure amendments, if 
finalized, would not increase testing burden on panel manufacturers 
when compared to the current DOE test procedure in appendix B.
    Issue 37: DOE requests comment on its tentative understanding of 
the impact of the test procedure proposals for refrigeration systems--
specifically, whether DOE's initial conclusion that the proposed DOE 
test procedure amendments, if finalized, would increase testing burden.
    Issue 38: DOE invites comment on the number of small, domestic OEMs 
producing the three principal components of WICFs: Panels, doors, and 
refrigeration systems.
    Issue 39: DOE requests comment on its cost estimate of impacts on 
small, domestic OEMs of doors.
    Issue 40: DOE requests comment on its cost estimate of impacts on 
small, domestic OEMs of panels.
    Issue 41: DOE requests comment on its cost estimate of impacts on 
small, domestic OEMs of refrigeration systems.

VI. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this notice of 
proposed rulemaking and announcement of public webinar.

List of Subjects

10 CFR Part 429

    Administrative practice and procedure, Confidential business 
information, Energy conservation, Household appliances, Reporting and 
recordkeeping requirements.

10 CFR Part 431

    Administrative practice and procedure, Confidential business 
information, Energy conservation test procedures, Incorporation by 
reference, and Reporting and recordkeeping requirements.

Signing Authority

    This document of the Department of Energy was signed on March 18, 
2022, by Kelly J. Speakes-Backman, Principal Deputy Assistant Secretary 
for Energy Efficiency and Renewable Energy,

[[Page 23988]]

pursuant to delegated authority from the Secretary of Energy. That 
document with the original signature and date is maintained by DOE. For 
administrative purposes only, and in compliance with requirements of 
the Office of the Federal Register, the undersigned DOE Federal 
Register Liaison Officer has been authorized to sign and submit the 
document in electronic format for publication, as an official document 
of the Department of Energy. This administrative process in no way 
alters the legal effect of this document upon publication in the 
Federal Register.

    Signed in Washington, DC, on March 23, 2022.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.

    For the reasons stated in the preamble, DOE is proposing to amend 
parts 429 and 431 of chapter II of title 10, Code of Federal 
Regulations as set forth below:

PART 429--CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR CONSUMER 
PRODUCTS AND COMMERCIAL AND INDUSTRIAL EQUIPMENT

0
1. The authority citation for part 429 continues to read as follows:

    Authority:  42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.

0
2. Amend Sec.  429.53 by:
0
a. Revising paragraphs (a)(2)(i) and (a)(3); and
0
b. Adding paragraph (a)(4).
    The revisions and addition read as follows:


Sec.  429.53  Walk-in coolers and walk-in freezers.

    (a) * * *
    (2) * * *
    (i) Applicable test procedure. If the AWEF is determined by 
testing, test according to the applicable provisions of Sec.  
431.304(b) of this chapter with the equipment specific provisions in 
paragraphs (a)(2)(i)(A) through (D) of this section.
    (A) Dedicated condensing units. Outdoor dedicated condensing 
refrigeration systems that are also designated for use in indoor 
applications must be tested and rated as both an outdoor dedicated 
condensing refrigeration system and an indoor dedicated refrigeration 
system.
    (B) Matched refrigeration systems. A matched refrigeration system 
is not required to be rated if the constituent unit cooler(s) and 
dedicated condensing unit have been tested as specified in Sec.  
431.304(b)(4) of this chapter. However, if a manufacturer wishes to 
represent the efficiency of the matched refrigeration system as 
distinct from the efficiency of either constituent component, or if the 
manufacturer cannot rate one or both of the constituent components 
using the specified method, the manufacturer must test and rate the 
matched refrigeration system as specified in Sec.  431.304(b)(4) of 
this chapter.
    (C) Detachable single-packaged dedicated systems. Detachable 
single-packaged dedicated systems must be tested and rated as a single-
packaged dedicated systems using the test procedure in Sec.  
431.304(b)(4) of this chapter.
    (D) Attached split systems. Attached split systems must be tested 
and rated as dedicated condensing units and unit coolers using the test 
procedure in Sec.  431.304(b)(4) of this chapter.
* * * * *
    (3) For each basic model of walk-in cooler and walk-in freezer 
display and non-display door, the daily energy consumption must be 
determined by testing, in accordance with Sec.  431.304 of this chapter 
and the provisions of this section, or by application of an alternative 
efficiency determination method (AEDM) that meets the requirements of 
Sec.  429.70 and the provisions of this section.
    (i) Applicable test procedure. Prior to [180 days after publication 
of final rule], use the test procedure for walk-ins as it appeared in 
10 CFR part 431, subpart R, appendix A, revised as of January 1, 2021, 
to determine daily energy consumption. Beginning [180 days after 
publication of final rule], use the test procedure in part 431, subpart 
R, appendix A, of this chapter to determine daily energy consumption.
    (ii) Units to be tested. For each basic model, a sample of 
sufficient size shall be randomly selected and tested to ensure that 
any represented value of daily energy consumption of a basic model or 
other measure of energy use for which consumers would favor lower 
values shall be greater than or equal to the higher of:
    (A) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.000
    
    And x is the sample mean, n is the number of samples, and xi is the 
i\th\ sample; or,
    (B) The upper 95 percent confidence limit (UCL) of the true mean 
divided by 1.05, where:
[GRAPHIC] [TIFF OMITTED] TP21AP22.001

    And x is the sample mean, s is the sample standard deviation; n is 
the number of samples, and t<INF>0.95</INF> is the statistic for a 95% 
one-tailed confidence interval with n-1 degrees of freedom (from 
appendix A to this subpart).
    (4) For each basic model of walk-in cooler and walk-in freezer 
panel and non-display door, the R-value must be determined by testing, 
in accordance with Sec.  431.304 of this chapter and the provisions of 
this section.
    (i) Applicable test procedure. Prior to [date 180 days after 
publication of final rule], use the test procedure for walk-ins as it 
appeared in 10 CFR part 431, subpart R, appendix B, revised as of 
January 1, 2021, to determine R-value. Beginning [date 180 days after 
publication of final rule], use the test procedure in part 431, subpart 
R, appendix B, of this chapter to determine R-value.
    (ii) Units to be tested. For each basic model, a sample of 
sufficient size shall be randomly selected and tested to ensure that 
any represented value of R-value or other measure of efficiency of a 
basic model for which consumers would favor higher values shall be less 
than or equal to the lower of:
    (A) The mean of the sample, where:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.002
    
    And x is the sample mean, n is the number of samples, and xi is the 
i\th\ sample; or,
    (B) The lower 95 percent confidence limit (LCL) of the true mean 
divided by 0.95, where:
[GRAPHIC] [TIFF OMITTED] TP21AP22.003

    And x is the sample mean, s is the sample standard deviation; n is 
the number of samples, and t<INF>0.95</INF> is the statistic for a 95% 
one-tailed confidence interval with n-1 degree of freedom (from 
appendix A to this subpart).
* * * * *
0
3. Amend Sec.  429.70 by:
0
a. Revising paragraphs (f) heading and (f)(2)(ii)(A) and (B);
0
b. Adding paragraph (f)(2)(ii)(C);
0
c. Removing the word ``and'' at the end of paragraphs (f)(2)(iii)(A) 
and (C);
0
d. Removing the period at the end of paragraph (f)(2)(iii)(D) and 
adding ``; and'' in its place;
0
e. Adding paragraph (f)(2)(iii)(E); and
0
f. Revising paragraphs (f)(2)(iv) and (f)(5)(vi).

[[Page 23989]]

    The revisions and additions read as follows:


Sec.  429.70  Alternative methods for determining energy efficiency and 
energy use.

* * * * *
    (f) Alternative efficiency determination method (AEDM) for walk-in 
refrigeration systems and doors-- * * *
    (2) * * *
    (ii) * * *
    (A) For refrigeration systems, which are subject to an energy 
efficiency metric, the predicted efficiency for each model calculated 
by applying the AEDM may not be more than five percent greater than the 
efficiency determined from the corresponding test of the model.
    (B) For doors, which are subject to an energy consumption metric 
the predicted daily energy consumption for each model calculated by 
applying the AEDM may not be more than five percent less than the daily 
energy consumption determined from the corresponding test of the model.
    (C) The predicted energy efficiency or energy consumption for each 
model calculated by applying the AEDM must meet or exceed the 
applicable Federal energy conservation standard.
    (iii) * * *
    (E) For rating doors, an AEDM may not simulate or model components 
of the door that are not required to be tested by the DOE test 
procedure. That is, if the test results used to validate the AEDM are 
for the U-factor test of the door, the AEDM must estimate the daily 
energy consumption, specifically the conduction thermal load, and the 
direct and indirect electrical energy consumption, using the nominal 
values and calculation procedure specified in the DOE test procedure.
    (iv) Walk-in coolers and freezers (WICF) validation classes--(A) 
Doors.

                   Table 1 to Paragraph (f)(2)(iv)(A)
------------------------------------------------------------------------
                                            Minimum number of distinct
            Validation class                models that must be  tested
------------------------------------------------------------------------
Display Doors, Medium Temperature.......  2 Basic Models.
Display Doors, Low Temperature..........  2 Basic Models.
Non-display Doors, Medium Temperature...  2 Basic Models.
Non-display Doors, Low Temperature......  2 Basic Models.
------------------------------------------------------------------------

    (B) Refrigeration systems. (1) For representations made prior to 
the compliance date of revised energy conservation standards for walk-
in cooler and walk-in freezer refrigeration systems, use the following 
validation classes.

                  Table 2 to Paragraph (f)(2)(iv)(B)(1)
------------------------------------------------------------------------
                                            Minimum number of distinct
            Validation class                models that must be  tested
------------------------------------------------------------------------
Dedicated Condensing, Medium              2 Basic Models.
 Temperature, Matched Pair Indoor System.
Dedicated Condensing, Medium              2 Basic Models.
 Temperature, Matched Pair Outdoor
 System.\1\
Dedicated Condensing, Low Temperature,    2 Basic Models.
 Matched Pair Indoor System.
Dedicated Condensing, Low Temperature,    2 Basic Models.
 Matched Pair Outdoor System.\1\
Unit Cooler, High-temperature...........  2 Basic Models.
Unit Cooler, Medium Temperature.........  2 Basic Models.
Unit Cooler, Low Temperature............  2 Basic Models.
Medium Temperature, Indoor Condensing     2 Basic Models.
 Unit.
Medium Temperature, Outdoor Condensing    2 Basic Models.
 Unit.\1\
Low Temperature, Indoor Condensing Unit.  2 Basic Models.
Low Temperature, Outdoor Condensing       2 Basic Models.
 Unit.\1\
------------------------------------------------------------------------
\1\ AEDMs validated for an outdoor class by testing only outdoor models
  of that class may be used to determine representative values for the
  corresponding indoor class, and additional validation testing is not
  required. AEDMs validated only for a given indoor class by testing
  indoor models or a mix of indoor and outdoor models may not be used to
  determine representative values for the corresponding outdoor class.

    (2) For representations made on or after the compliance date of 
revised energy conservation standards for walk-in cooler and walk-in 
freezer refrigeration systems, use the following validation classes.

                  Table 3 to Paragraph (f)(2)(iv)(B)(2)
------------------------------------------------------------------------
                                            Minimum number of distinct
            Validation class                models that must be  tested
------------------------------------------------------------------------
Dedicated Condensing Unit, Medium         2 Basic Models.
 Temperature, Indoor System.
Dedicated Condensing Unit, Medium         2 Basic Models.
 Temperature, Outdoor System.\1\
Dedicated Condensing Unit, Low            2 Basic Models.
 Temperature, Indoor System.
Dedicated Condensing Unit, Low            2 Basic Models.
 Temperature, Outdoor System.\1\
Single-packaged Dedicated Condensing,     2 Basic Models.
 High-temperature, Indoor System.

[[Page 23990]]

 
Single-packaged Dedicated Condensing,     2 Basic Models.
 High-temperature, Outdoor System.\1\
Single-packaged Dedicated Condensing,     2 Basic Models.
 Medium Temperature, Indoor System.
Single-packaged Dedicated Condensing,     2 Basic Models.
 Medium Temperature, Outdoor System.\1\
Single-packaged Dedicated Condensing,     2 Basic Models.
 Low Temperature, Indoor System.
Single-packaged Dedicated Condensing,     2 Basic Models.
 Low Temperature, Indoor System.\1\
Matched Pair, High-temperature, Indoor    2 Basic Models.
 Condensing Unit.
Matched Pair, High-temperature, Outdoor   2 Basic Models.
 Condensing Unit.\1\
Matched Pair, Medium Temperature, Indoor  2 Basic Models.
 Condensing Unit.
Matched Pair, Medium Temperature,         2 Basic Models.
 Outdoor Condensing Unit.\1\
Matched Pair, Low Temperature, Indoor     2 Basic Models.
 Condensing Unit.
Matched Pair, Low Temperature, Outdoor    2 Basic Models.
 Condensing Unit.\1\
Unit Cooler, High-temperature...........  2 Basic Models.
Unit Cooler, Medium Temperature.........  2 Basic Models.
Unit Cooler, Low Temperature............  2 Basic Models.
------------------------------------------------------------------------
\1\ AEDMs validated for an outdoor class by testing only outdoor models
  of that class may be used to determine representative values for the
  corresponding indoor class, and additional validation testing is not
  required. AEDMs validated only for a given indoor class by testing
  indoor models or a mix of indoor and outdoor models may not be used to
  determine representative values for the corresponding outdoor class.

* * * * *
    (5) * * *
    (vi) Tolerances. For efficiency metrics, the result from a DOE 
verification test must be greater than or equal to the certified rating 
x (1 - the applicable tolerance). For energy consumption metrics, the 
result from a DOE verification test must be less than or equal to the 
certified rating x (1 + the applicable tolerance).

                     Table 4 to Paragraph (f)(5)(vi)
------------------------------------------------------------------------
                                                            Applicable
             Equipment                     Metric            tolerance
------------------------------------------------------------------------
Refrigeration systems (including    AWEF................              5%
 components).
Doors.............................  Daily Energy                      5%
                                     Consumption.
------------------------------------------------------------------------

* * * * *
0
4. Amend Sec.  429.110 by revising paragraph (e)(2) to read as follows:


Sec.  429.110  Enforcement testing.

* * * * *
    (e) * * *
    (2) For automatic commercial ice makers; commercial refrigerators, 
freezers, and refrigerator-freezers; refrigerated bottled or canned 
vending machines; commercial air conditioners and heat pumps; 
commercial packaged boilers; commercial warm air furnaces; commercial 
water heating equipment; and walk-in cooler and walk-in freezer doors, 
panels, and refrigeration systems, DOE will use an initial sample size 
of not more than four units and follow the sampling plans in appendix B 
of this subpart (Sampling Plan for Enforcement Testing of Covered 
Equipment and Certain Low-Volume Covered Products).
* * * * *
0
5. Amend Sec.  429.134 by:
0
a. Adding paragraph (q) introductory text; and
0
b. Revising paragraphs (q)(2) and (4).
    The addition and revisions read as follows:


Sec.  429.134  Product-specific enforcement provisions.

* * * * *
    (q) * * * Prior to [date 180 days after final rule publication], 
the provisions in 10 CFR 429.134, revised as of January 1, 2021, are 
applicable. On and after [date 180 days after final rule publication], 
the provisions in paragraphs (q)(1) through (4) of this section apply.
* * * * *
    (2) Verification of refrigeration system net capacity. The net 
capacity of the refrigeration system basic model will be measured 
pursuant to the test requirements of part 431, subpart R, appendix C, 
of this chapter for each unit tested on and after [date 180 days after 
final rule publication] but before the compliance date of revised 
energy conservation standards for walk-in cooler and walk-in freezer 
refrigeration systems. The net capacity of the refrigeration system 
basic model will be measured pursuant to the test requirements of part 
431, subpart R, appendix C1, of this chapter for each unit tested on 
and after the compliance date of revised energy conservation standards 
for walk-in cooler and walk-in freezer refrigeration systems. The 
results of the measurement(s) will be averaged and compared to the 
value of net capacity certified by the manufacturer. The certified net 
capacity will be considered valid only if the average measured net 
capacity is within plus or minus five percent of the certified net 
capacity.
* * * * *
    (4) Verification of door electricity-consuming device power. For 
each basic model of walk-in cooler and walk-in freezer door, DOE will 
calculate the door's energy consumption using the input power listed on 
the nameplate of each electricity-consuming device shipped with the 
door. If an electricity-consuming device shipped with a walk-in door 
does not have a nameplate or the nameplate does not list the device's 
input power, then DOE will use the device's rated input power included 
in the door's certification report. If the door is not certified or if 
the certification does not include a rated input power for an 
electricity-consuming device shipped with a walk-in door, DOE will use 
the measured input power. DOE also may validate the power listed on the 
nameplate or the rated input power by measuring it when

[[Page 23991]]

energized using a power supply that provides power within the allowable 
voltage range listed on the component nameplate or the door nameplate, 
whichever is available. If the measured input power is more than 10 
percent higher than the input power listed on the nameplate or the 
rated input power, as appropriate, then the measured input power shall 
be used in the door's energy consumption calculation.
    (i) For electricity-consuming devices with controls, the maximum 
input wattage observed while energizing the device and activating the 
control shall be considered the measured input power. For anti-sweat 
heaters that are controlled based on humidity levels, the control may 
be activated by increasing relative humidity in the region of the 
controls without damaging the sensor. For lighting fixtures that are 
controlled with motion sensors, the control may be activated by 
simulating motion in the vicinity of the sensor. Other kinds of 
controls may be activated based on the functions of their sensor.
    (ii) [Reserved]
* * * * *

PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND 
INDUSTRIAL EQUIPMENT

0
6. The authority citation for part 431 continues to read as follows:

    Authority: 42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.

0
7. Amend Sec.  431.302 by:
0
a. Adding, in alphabetical order, definitions for ``Attached split 
system,'' ``CO<INF>2</INF> unit cooler,'' and ``Detachable single-
packaged dedicated system'';
0
b. Revising the definition for ``Door'';
0
c. Adding, in alphabetical order, definitions for ``Door leaf,'' ``Door 
surface area,'' ``Ducted fan coil unit,'' ``High-temperature 
refrigeration system,'' ``Hinged vertical door,'' ``Hot gas defrost,'' 
``Multi-circuit single-packaged dedicated system,'' ``Non-display 
door,'' and ``Roll-up door'';
0
d. Revising the definition of ``Single-packaged dedicated system'';
0
e. Adding, in alphabetical order, the definition for ``Sliding door''; 
and
0
f. Revising the definition of ``Walk-in cooler and walk-in freezer'';
    The additions and revisions read as follows:


Sec.  431.302  Definitions concerning walk-in coolers and walk-in 
freezers.

* * * * *
    Attached split system means a matched pair refrigeration system 
which is designed to be installed with the evaporator entirely inside 
the walk-in enclosure and the condenser entirely outside the walk-in 
enclosure, and the evaporator and condenser are permanently connected 
with structural members extending through the walk-in wall.
* * * * *
    CO<INF>2</INF> unit cooler means a unit cooler that includes a 
nameplate listing only CO<INF>2</INF> as an approved refrigerant.
* * * * *
    Detachable single-packaged dedicated system means a system 
consisting of a dedicated condensing unit and an insulated evaporator 
section in which the evaporator section is designed to be installed 
external to the walk-in enclosure and circulating air through the 
enclosure wall, and the condensing unit is designed to be installed 
either attached to the evaporator section or mounted remotely with a 
set of refrigerant lines connecting the two components.
* * * * *
    Door means an assembly installed in an opening of an interior or 
exterior wall that is used to allow access or close off the opening and 
that is movable in a sliding, pivoting, hinged, or revolving manner of 
movement. For walk-in coolers and walk-in freezers, a door includes the 
frame (including mullions), the door leaf or multiple leaves (including 
glass) within the frame, and any other elements that form the assembly 
or part of its connection to the wall.
    Door leaf means the pivoting, rolling, sliding, or swinging portion 
of a door.
    Door surface area means the product of the height and width of a 
walk-in door measured external to the walk-in. The height and width 
dimensions shall be perpendicular to each other and parallel to the 
wall or panel of the walk-in to which the door is affixed. The height 
and width measurements extend to the edge of the frame and frame flange 
(as applicable) to which the door is affixed. The surface area of a 
display door is represented as Add and the surface area of a non-
display door is represented as And.
    Ducted fan coil unit means an assembly, including means for forced 
air circulation capable of moving air against both internal and non-
zero external flow resistance, and elements by which heat is 
transferred from air to refrigerant to cool the air, with provision for 
ducted installation.
* * * * *
    High-temperature refrigeration system means a refrigeration system 
which is not designed to operate below 45 [deg]F.
    Hinged vertical door means a door with a leaf (or leaves) with a 
hinge (or hinges) connecting one vertical edge of the leaf (or leaves) 
to a frame or mullion of the door. This includes doors that swing open 
in one direction (i.e., into or out of the walk-in) and free-swinging 
doors that open both into and out of the walk-in.
    Hot gas defrost means a factory-installed system where refrigerant 
is used to transfer heat from ambient outside air, to the compressor, 
and/or a thermal storage component that stores heat when the compressor 
is running and uses this stored heat to defrost the evaporator coils.
* * * * *
    Multi-circuit single-packaged dedicated system means a single-
packaged dedicated system (as defined in this section) that contains 
two or more refrigeration circuits that refrigerate a single stream of 
circulated air.
    Non-display door means a door that is not a display door.
* * * * *
    Roll-up door means a door that bi-directionally rolls open and 
closed in a vertical and horizontal manner and includes vertical jamb 
tracks.
    Single-packaged dedicated system means a refrigeration system (as 
defined in this section) that is a single-packaged assembly that 
includes one or more compressors, a condenser, a means for forced 
circulation of refrigerated air, and elements by which heat is 
transferred from air to refrigerant.
    Sliding door means a door having one or more manually-operated or 
motorized leaves within a common frame that slide horizontally or 
vertically.
* * * * *
    Walk-in cooler and walk-in freezer means an enclosed storage space 
including, but not limited to, panels, doors, and refrigeration system, 
refrigerated to temperatures, respectively, above, and at or below 32 
degrees Fahrenheit that can be walked into, and has a total chilled 
storage area of less than 3,000 square feet; however, the terms do not 
include products designed and marketed exclusively for medical, 
scientific, or research purposes.
* * * * *
0
8. Amend Sec.  431.303 by:
0
a. Revising paragraph (a);
0
b. Adding paragraph (b)(3);
0
c. Revising paragraphs (c), (d), and (e)(1).
    The revisions and additions read as follows:


Sec.  431.303  Materials incorporated by reference.

    (a) Certain material is incorporated by reference into this subpart 
with the

[[Page 23992]]

approval of the Director of the Federal Register in accordance with 5 
U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that 
specified in this section, DOE must publish a document in the Federal 
Register and the material must be available to the public. All approved 
material is available for inspection at DOE, and at the National 
Archives and Records Administration (``NARA''). Contact DOE at the U.S. 
Department of Energy, Office of Energy Efficiency and Renewable Energy, 
Building Technologies Program, Sixth Floor, 950 L'Enfant Plaza SW, 
Washington, DC 20024, (202) 586-9127, <a href="/cdn-cgi/l/email-protection#c280b7abaea6abaca5b182a7a7eca6ada7eca5adb4"><span class="__cf_email__" data-cfemail="ce8cbba7a2aaa7a0a9bd8eababe0aaa1abe0a9a1b8">[email protected]</span></a>, 
www.energy.gov/eere/buildings/building-technologies-office. For 
information on the availability of this material at NARA, email: 
<a href="/cdn-cgi/l/email-protection#a6c0d488cfc8d5d6c3c5d2cfc9c8e6c8c7d4c788c1c9d0"><span class="__cf_email__" data-cfemail="bddbcf93d4d3cecdd8dec9d4d2d3fdd3dccfdc93dad2cb">[email protected]</span></a>, or go to: www.archives.gov/federal-register/cfr/ibr-locations.html. The material may be obtained from the sources 
in the following paragraphs of this section.
    (b) * * *
    (3) AHRI Standard 1250-2020 (``AHRI 1250-2020''), ``Standard for 
Performance Rating of Walk-in Coolers and Freezers,'' copyright 2020. 
IBR approved for appendix C1 to subpart R.
    (c) ASHRAE. American Society of Heating, Refrigerating and Air-
Conditioning Engineers, 180 Technology Parkway, Peachtree Corners, GA 
30092; (404) 636-8400; www.ashrae.org.
    (1) ANSI/ASHRAE Standard 16-2016, (``ANSI/ASHRAE 16''), ``Method of 
Testing for Rating Room Air Conditioners, Packaged Terminal Air 
Conditioners, and Packaged Terminal Heat Pumps for Cooling and Heating 
Capacity,'' approved October 31, 2016, IBR approved for appendix C1 to 
subpart R.
    (2) ANSI/ASHRAE Standard 23.1-2010, (``ASHRAE 23.1-2010''), 
``Methods of Testing for Rating the Performance of Positive 
Displacement Refrigerant Compressors and Condensing Units that Operate 
at Subcritical Temperatures of the Refrigerant,'' ANSI approved January 
28, 2010, IBR approved for appendix C to subpart R of part 431.
    (3) ANSI/ASHRAE Standard 37-2009, (``ANSI/ASHRAE 37''), ``Methods 
of Testing for Rating Electrically Driven Unitary Air-Conditioning and 
Heat Pump Equipment,'' ASHRAE approved June 24, 2009, IBR approved for 
appendices C and C1 to subpart R.
    (d) ASTM. ASTM, International, 100 Barr Harbor Drive, West 
Conshohocken, PA 19428-2959; (610) 832-9500; www.astm.org.
    (1) ASTM C518-17, (``ASTM C518-17''), ``Standard Test Method for 
Steady-State Thermal Transmission Properties by Means of the Heat Flow 
Meter Apparatus,'' approved May 1, 2017, IBR approved for appendix B to 
subpart R.
    (2) ASTM C1199-14, (``ASTM C1199-14''), ``Standard Test Method for 
Measuring the Steady-State Thermal Transmittance of Fenestration 
Systems Using Hot Box Methods,'' approved February 1, 2014, IBR 
approved for appendix A to subpart R.
    (e) * * *
    (1) NFRC 102-2020 [E0A0], (``NFRC 102-2020''), ``Procedure for 
Measuring the Steady-State Thermal Transmittance of Fenestration 
Systems,'' IBR approved for appendix A to subpart R.
* * * * *
0
9. Amend Sec.  431.304 by revising paragraph (b) to read as follows:


Sec.  431.304  Uniform test method for the measurement of energy 
consumption of walk-in coolers and walk-in freezers.

* * * * *
    (b) Testing and Calculations. Determine the energy efficiency and/
or energy consumption of the specified walk-in cooler and walk-in 
freezer components by conducting the appropriate test procedure as 
follows:
    (1) Display panels. Determine the energy use of walk-in cooler and 
walk-in freezer display panels by conducting the test procedure set 
forth in appendix A to this subpart.
    (2) Display doors and non-display doors. Determine the energy use 
of walk-in cooler and walk-in freezer display doors and non-display 
doors by conducting the test procedure set forth in appendix A to this 
subpart.
    (3) Non-display panels and non-display doors. Determine the R-value 
of insulation of walk-in cooler and walk-in freezer non-display panels 
and non-display doors by conducting the test procedure set forth in 
appendix B to this subpart.
    (4) Refrigeration systems. Determine the Annual Walk-in Energy 
Factor (AWEF) and net capacity of walk-in cooler and walk-in freezer 
refrigeration systems by conducting the test procedures set forth in 
appendix C or C1 to this subpart, as applicable. Refer to the notes at 
the beginning of those appendices to determine the applicable appendix 
to use for testing.
    (i) For unit coolers: Follow the general testing provisions in 
sections 3.1 and 3.2 of appendices C or C1 to this subpart, and the 
equipment-specific provisions in section 3.3 of appendix C or sections 
4.5 through 4.8 of appendix C1.
    (ii) For dedicated condensing units: Follow the general testing 
provisions in sections 3.1 and 3.2 of appendices C or C1 to this 
subpart, and the product-specific provisions in section 3.4 of appendix 
C or sections 4.5 through 4.8 of appendix C1.
    (iii) For single-packaged dedicated systems: Follow the general 
testing provisions in sections 3.1 and 3.2 of appendices C or C1 to 
this subpart, and the product-specific provisions in section 3.3 of 
appendix C or sections 4.5 through 4.8 of appendix C1.
0
10. Revise appendix A to subpart R of part 431 to read as follows:

Appendix A to Subpart R of Part 431--Uniform Test Method for the 
Measurement of Energy Consumption of the Components of Envelopes of 
Walk-in Coolers and Walk-in Freezers

    Note: Prior to [date 180 days after publication of final rule], 
representations with respect to the energy use of envelope 
components of walk-in coolers and walk-in freezers, including 
compliance certifications, must be based on testing conducted in 
accordance with the applicable provisions of 10 CFR part 431, 
subpart R, appendix A, revised as of January 1, 2022. Beginning 
[date 180 days after publication of final rule], representations 
with respect to energy use of envelope components of walk-in coolers 
and walk-in freezers, including compliance certifications, must be 
based on testing conducted in accordance with this appendix.

Incorporation by Reference

    DOE incorporated by reference in Sec.  431.303 the entire 
standards for NFRC 102-2020, and ASTM C1199-14. However, certain 
enumerated provisions of these standards, as set forth in sections 
0.1 and 0.2 of this appendix are inapplicable. To the extent that 
there is a conflict between the terms or provisions of a referenced 
industry standard and the CFR, the CFR provisions control.

0.1 NFRC 102-2020

    0.1.1 Section 1 Scope, is inapplicable as specified in section 
5.1.1.1 of this appendix,
    0.1.2 Section 4 Significance and Use, is inapplicable as 
specified in section 5.1.1.2 of this appendix,
    0.1.3 Section 7.3 Test Conditions, is inapplicable as specified 
in section 5.1.1.3 of this appendix,
    0.1.4 Section 10 Report, is inapplicable as specified in section 
5.1.1.4 of this appendix,
    0.1.5 Section 11 Precision and Bias, is inapplicable as 
specified in section 5.1.1.5 of this appendix,
    0.1.6 Annex A3 Standard Test Method for Determining the Thermal 
Transmittance of Tubular Daylighting Devices, is inapplicable as 
specified in section 5.1.1.6 of this appendix, and
    0.1.7 Annex A5 Tables and Figures, is inapplicable as specified 
in section 5.1.1.7 of this appendix.

0.2 ASTM C1199-14

    0.2.1 Section 1 Scope, is inapplicable as specified in section 
5.1.2.1 of this appendix,
    0.2.2 Section 4 Significance and Use is inapplicable as 
specified in section 5.1.2.2 of this appendix,

[[Page 23993]]

    0.2.3 Section 7.3 Test Conditions, is inapplicable as specified 
in section 5.1.2.3 of this appendix,
    0.2.4 Section 10 Report, is inapplicable as specified in section 
5.1.2.4 of this appendix, and
    0.2.5 Section 11 Precision and Bias, is inapplicable as 
specified in section 5.1.2.5 of this appendix.
    1. General. The following sections of this appendix provide 
additional instructions for testing. In cases where there is a 
conflict, the language of this appendix takes highest precedence, 
followed by NFRC 102-2020, followed by ASTM C1199-14. Any subsequent 
amendment to a referenced document by the standard-setting 
organization will not affect the test procedure in this appendix, 
unless and until the test procedure is amended by DOE. Material is 
incorporated as it exists on the date of the approval, and a 
notification of any change in the incorporation will be published in 
the Federal Register.
    2. Scope.
    This appendix covers the test requirements used to measure the 
energy consumption of the components that make up the envelope of a 
walk-in cooler or walk-in freezer.
    3. Definitions.
    The definitions contained in Sec.  431.302 are applicable to 
this appendix.
    4. Additional Definitions.
    4.1 Automatic door opener/closer means a device or control 
system that ``automatically'' opens and closes doors without direct 
user contact, such as a motion sensor that senses when a forklift is 
approaching the entrance to a door and opens it, and then closes the 
door after the forklift has passed.
    4.2 Percent time off (PTO) means the percent of time that an 
electrical device is assumed to be off.
    4.3 Rated power means the input power of an electricity-
consuming device as specified on the device's nameplate. If the 
device does not have a nameplate or such nameplate does not list the 
device's input power, then the rated power must be determined from 
the device's product data sheet, literature, or installation 
instructions that come with the device or are available online.
    4.4 Rating conditions means, unless explicitly stated otherwise, 
all conditions shown in Table A.1 of this appendix.

                    Table A.1--Temperature Conditions
------------------------------------------------------------------------
 
------------------------------------------------------------------------
        Internal Temperatures (cooled space within the envelope)
------------------------------------------------------------------------
Cooler Dry Bulb Temperature...............  35 [deg]F.
Freezer Dry Bulb Temperature..............  -10 [deg]F.
------------------------------------------------------------------------
         External Temperatures (space external to the envelope)
------------------------------------------------------------------------
Freezer and Cooler Dry Bulb Temperatures..  75 [deg]F.
------------------------------------------------------------------------

    5. Test Methods and Measurements.
    5.1 U-factor Test of Doors and Display Panels.
    Determine the U-factor of the entire door or display panel, 
including the frame, in accordance with the specified sections of 
NFRC 1022020 and ASTM C1199-14 at the temperature conditions listed 
in Table A.1 of this appendix; however, the following enumerated 
provisions of NFRC 102-2020 and ASTM C1199-14 are not applicable, as 
set forth in sections 5.1.1 and 5.1.2 of this appendix.
    5.1.1 Excepted sections of NFRC 102-2020.
    5.1.1.1 Section 1 Scope,
    5.1.1.2 Section 4 Significance and Use,
    5.1.1.3 Section 7.3 Test Conditions,
    5.1.1.4 Section 10 Report,
    5.1.1.5 Section 11 Precision and Bias,
    5.1.1.6 Annex A3 Standard Test Method for Determining the 
Thermal Transmittance of Tubular Daylighting Devices, and
    5.1.1.7 Annex A5 Tables and Figures.
    5.1.2 Excepted sections of ASTM C1199-14.
    5.1.2.1 Section 1 Scope,
    5.1.2.2 Section 4 Significance and Use,
    5.1.2.3 Section 7.3 Test Conditions,
    5.1.2.4 Section 10 Report, and
    5.1.2.5 Section 11 Precision and Bias.
    5.2 Required Test Measurements.
    5.2.1 For display doors and display panels, thermal 
transmittance, U<INF>dd</INF> or U<INF>dp</INF>, respectively, shall 
be the standardized thermal transmittance, U<INF>ST</INF>, 
determined per section 5.1.1 of this appendix.
    5.2.2 For non-display doors, thermal transmittance, 
U<INF>nd</INF>, shall be the standardized thermal transmittance, 
U<INF>ST</INF>, determined per section 5.1 of this appendix.
    5.2.3 Projected area of the test specimen, As, in ft\2\, as 
referenced in ASTM C1199-14.
    6. Calculations.
    6.1 Display Panels.
    6.1.1 Determine the U-factor of the display panel in accordance 
with section 5.1 of this appendix, in units of Btu/(h-ft\2\-[deg]F).
    6.1.2 Calculate the temperature differential, 
[Delta]T<INF>dp</INF>, [deg]F, for the display panel, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.004

Where:

T<INF>DB,ext,dp</INF> = dry-bulb air external temperature, [deg]F, 
as prescribed in Table A.1 of this appendix; and
T<INF>DB,int,dp</INF> = dry-bulb air temperature internal to the 
cooler or freezer, [deg]F, as prescribed in Table A.1 of this 
appendix.

    6.1.3 Calculate the conduction load through the display panel, 
Q<INF>cond-dp</INF>, Btu/h, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.005

Where:

A<INF>s</INF> = projected area of the test specimen (same as the 
test specimen aperture in the surround panel) or the area used to 
determine the U-factor in section 5.1 of this appendix, ft\2\;
[Delta]T<INF>dp</INF> = temperature differential between 
refrigerated and adjacent zones, [deg]F; and
U<INF>dp</INF> = thermal transmittance, U-factor, of the display 
panel in accordance with section 5.1 of this appendix, Btu/(h-ft\2\-
[deg]F).

    6.1.4 Calculate the total daily energy consumption, 
E<INF>dp</INF>, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.006

Where:

Q<INF>cond,dp</INF> = the conduction load through the display panel, 
Btu/h; and
EER = Energy Efficiency Ratio of walk-in (cooler or freezer), Btu/W-
h. For coolers, use EER = 12.4 Btu/W-h. For freezers, use EER = 6.3 
Btu/W-h.

    6.2 Display Doors.
    6.2.1 Conduction Through Display Doors.
    6.2.1.1 Determine the U-factor of the display door in accordance 
with section 5.1 of this appendix, in units of Btu/(h-ft\2\-[deg]F).
    6.2.1.2 Calculate the temperature differential, 
[Delta]T<INF>dd</INF>, [deg]F, for the display door as follows:

[[Page 23994]]

[GRAPHIC] [TIFF OMITTED] TP21AP22.007

Where:

T<INF>DB,ext,dd</INF> = dry-bulb air temperature external to the 
display door, [deg]F, as prescribed in Table A.1 of this appendix; 
and
T<INF>DB,int,dd</INF> = dry-bulb air temperature internal to the 
display door, [deg]F, as prescribed in Table A.1 of this appendix.

    6.2.1.3 Calculate the conduction load through the display doors, 
Q<INF>cond,dd</INF>, Btu/h, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.008

Where:

A<INF>s</INF> = projected area of the test specimen (same as the 
test specimen aperture in the surround panel) or the area used to 
determine the U-factor in section 5.1 of this appendix, ft\2\;
[Delta]T<INF>dd</INF> = temperature differential between 
refrigerated and adjacent zones, [deg]F; and
U<INF>dd</INF> = thermal transmittance, U-factor of the door, in 
accordance with section 5.1 of this appendix, Btu/(h-ft\2\-[deg]F).

    6.2.1.4 Calculate the total daily energy consumption due to 
conduction thermal load, E<INF>dd,thermal</INF>, kWh/day, as 
follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.009

Where:

Q<INF>cond,dd</INF> = the conduction load through the display door, 
Btu/h; and
EER = EER of walk-in (cooler or freezer), Btu/W-h. For coolers, use 
EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).

    6.2.2 Direct Energy Consumption of Electrical Component(s) of 
Display Doors.
    Electrical components associated with display doors could 
include but are not limited to: Heater wire (for anti-sweat or anti-
freeze application); lights; door motors; control system units; and 
sensors.
    6.2.2.1 Select the required value for percent time off (PTO) for 
each type of electricity-consuming device per Table A.2 of this 
appendix, PTO<INF>t</INF> (%).

                                       Table A.2--Percent Time Off Values
----------------------------------------------------------------------------------------------------------------
                                                                                                   Percent time
                 Device                      Temperature condition             Controls            off value (%)
----------------------------------------------------------------------------------------------------------------
Lights..................................  All.......................  Without...................              25
                                                                      With......................              50
Anti-sweat heaters......................  All.......................  Without...................               0
                                          Coolers...................  With......................              75
                                          Freezers..................  With......................              50
Door motors.............................  All.......................  ..........................              97
All other electricity-consuming devices.  All.......................  Without...................               0
                                                                      With......................              25
----------------------------------------------------------------------------------------------------------------

    6.2.2.2 Calculate the power usage for each type of electricity-
consuming device, P<INF>dd,comp,u,t</INF>, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.010

Where:

u = the index for each of type of electricity-consuming device 
located on either (1) the interior facing side of the display door 
or within the inside portion of the display door, (2) the exterior 
facing side of the display door, or (3) any combination of (1) and 
(2). For purposes of this calculation, the interior index is 
represented by u = int and the exterior index is represented by u = 
ext. If the electrical component is both on the interior and 
exterior side of the display door then use u = int. For anti-sweat 
heaters sited anywhere in the display door, 75 percent of the total 
power is be attributed to u = int and 25 percent of the total power 
is attributed to u = ext;
t = index for each type of electricity-consuming device with 
identical rated power;
P<INF>rated,u,t</INF> = rated input power of each component, of type 
t, kW;
PTO<INF>u,t</INF> = percent time off, for device of type t, %; and
n<INF>u,t</INF> = number of devices at the rated input power of type 
t, unitless.
    6.2.2.3 Calculate the total electrical energy consumption for 
interior and exterior power, P<INF>dd,tot,int</INF> (kWh/day) and 
P<INF>dd,tot,ext</INF> (kWh/day), respectively, as follows:

[[Page 23995]]

[GRAPHIC] [TIFF OMITTED] TP21AP22.011

Where:

t = index for each type of electricity-consuming device with 
identical rated input power;
P<INF>dd,comp,int,t</INF> = the energy usage for an electricity-
consuming device sited on the interior facing side of or in the 
display door, of type t, kWh/day; and
P<INF>dd,comp,ext,t</INF> = the energy usage for an electricity-
consuming device sited on the external facing side of the display 
door, of type t, kWh/day.

    6.2.2.4 Calculate the total electrical energy consumption, 
P<INF>dd,tot</INF>, (kWh/day), as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.012

Where:

P<INF>dd,tot,int</INF> = the total interior electrical energy usage 
for the display door, kWh/day; and
P<INF>dd,tot,ext</INF> = the total exterior electrical energy usage 
for the display door, kWh/day.
    6.2.3 Total Indirect Electricity Consumption Due to Electrical 
Devices.
    Calculate the additional refrigeration energy consumption due to 
thermal output from electrical components sited inside the display 
door, C<INF>dd,load</INF>, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.013

Where:

P<INF>dd,tot,int</INF> = The total internal electrical energy 
consumption due for the display door, kWh/day; and
EER = EER of walk-in cooler or walk-in freezer, Btu/W-h. For 
coolers, use EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/
(W-h).

    6.2.4 Total Display Door Energy Consumption.
    Calculate the total energy, E<INF>dd,tot</INF>, kWh/day,
    [GRAPHIC] [TIFF OMITTED] TP21AP22.014
    
Where:

E<INF>dd,thermal</INF> = the total daily energy consumption due to 
thermal load for the display door, kWh/day;
P<INF>dd,tot</INF> = the total electrical load, kWh/day; and
C<INF>dd,load</INF> = additional refrigeration load due to thermal 
output from electrical components contained within the display door, 
kWh/day.

    6.3 Non-Display Doors.
    6.3.1 Conduction Through Non-Display Doors.
    6.3.1.1 Determine the U-factor of the non-display door in 
accordance with section 5.1 of this appendix, in units of Btu/(h-
ft\2\-[deg]F).
    6.3.1.2 Calculate the temperature differential of the non-
display door, [Delta]T<INF>nd</INF>, [deg]F, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.015

Where:

T<INF>DB,ext,nd</INF> = dry-bulb air external temperature, [deg]F, 
as prescribed by Table A.1 of this appendix; and
T<INF>DB,int,nd</INF> = dry-bulb air internal temperature, [deg]F, 
as prescribed by Table A.1 of this appendix. If the component spans 
both cooler and freezer spaces, the freezer temperature must be 
used.

    6.3.1.3 Calculate the conduction load through the non-display 
door: Q<INF>cond,nd</INF>, Btu/h,
[GRAPHIC] [TIFF OMITTED] TP21AP22.016

Where:

A<INF>s</INF> = projected area of the test specimen (same as the 
test specimen aperture in the surround panel) or the area used to 
determine the U-factor in section 5.1 of this appendix, ft\2\;
[Delta]T<INF>nd</INF> = temperature differential across the non-
display door, [deg]F; and
U<INF>nd</INF> = thermal transmittance, U-factor of the door, in 
accordance with section 5.1 of this appendix, Btu/(h-ft\2\-[deg]F).

    6.3.1.4 Calculate the total daily energy consumption due to 
thermal load, E<INF>nd,thermal</INF>, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.017


[[Page 23996]]


Where:

Q<INF>cond,nd</INF> = the conduction load through the non-display 
door, Btu/h; and
EER = EER of walk-in (cooler or freezer), Btu/W-h. For coolers, use 
EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).

    6.3.2 Direct Energy Consumption of Electrical Components of Non-
Display Doors.
    Electrical components associated with non-display doors comprise 
could include, but are not limited to: Heater wire (for anti-sweat 
or anti-freeze application), lights, door motors, control system 
units, and sensors.
    6.3.2.1 Select the required value for percent time off for each 
type of electricity-consuming device per Table A.2 of this appendix, 
PTO<INF>t</INF> (%).
    6.3.2.2 Calculate the power usage for each type of electricity-
consuming device, P<INF>nd,comp,u,t</INF>, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.018

Where:

u = the index for each of type of electricity-consuming device 
located on either (1) the interior facing side of the non-display 
door or within the inside portion of the non-display door, (2) the 
exterior facing side of the non-display door, or (3) any combination 
of (1) and (2). For purposes of this calculation, the interior index 
is represented by u = int and the exterior index is represented by u 
= ext. If the electrical component is both on the interior and 
exterior side of the non-display door then use u = int. For anti-
sweat heaters sited anywhere in the non-display door, 75 percent of 
the total power is be attributed to u = int and 25 percent of the 
total power is attributed to u = ext;
t = index for each type of electricity-consuming device with 
identical rated input power;
P<INF>rated,u,t</INF> = rated input power of each component, of type 
t, kW;
PTO<INF>u,t</INF> = percent time off, for device of type t, %; and
n<INF>u,t</INF> = number of devices at the rated input power of type 
t, unitless.

    6.3.2.3 Calculate the total electrical energy consumption for 
interior and exterior power, P<INF>nd,tot,int</INF>, kWh/day, and 
P<INF>nd,tot,ext</INF>, kWh/day, respectively, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.019

Where:

t = index for each type of electricity-consuming device with 
identical rated input power;
P<INF>nd,comp,int,t</INF> = the energy usage for an electricity-
consuming device sited on the internal facing side or internal to 
the non-display door, of type t, kWh/day; and
P<INF>nd,comp,ext,t</INF> = the energy usage for an electricity-
consuming device sited on the external facing side of the non-
display door, of type t, kWh/day. For anti-sweat heaters,

    6.3.2.4 Calculate the total electrical energy consumption, 
P<INF>nd,tot</INF>, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.020

Where:

P<INF>nd,tot,int</INF> = the total interior electrical energy usage 
for the non-display door, of type t, kWh/day; and
P<INF>nd,tot,ext</INF> = the total exterior electrical energy usage 
for the non-display door, of type t, kWh/day.

    6.3.3 Total Indirect Electricity Consumption Due to Electrical 
Devices.
    Calculate the additional refrigeration energy consumption due to 
thermal output from electrical components associated with the non-
display door, C<INF>nd,load</INF>, kWh/day, as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.021

Where:

P<INF>nd,tot,int</INF> = the total interior electrical energy 
consumption for the non-display door, kWh/day; and
EER = EER of walk-in cooler or freezer, Btu/W-h. For coolers, use 
EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).
    6.3.4 Total Non-Display Door Energy Consumption.
    Calculate the total energy, E<INF>nd,tot</INF>, kWh/day, as 
follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.022

Where:

E<INF>nd,thermal</INF> = the total daily energy consumption due to 
thermal load for the non-display door, kWh/day;
P<INF>nd,tot</INF> = the total electrical energy consumption, kWh/
day; and
C<INF>nd,load</INF> = additional refrigeration load due to thermal 
output from electrical components contained on the inside face of 
the non-display door, kWh/day.

[[Page 23997]]

0
11. Revise appendix B to subpart R of part 431 to read as follows:

Appendix B to Subpart R of Part 431--Uniform Test Method for the 
Measurement of R-Value of Insulation for Envelope Components of Walk-In 
Coolers and Walk-In Freezers

    Note: Prior to [date 180 days after publication of final rule], 
representations with respect to the R-value for insulation of 
envelope components of walk-in coolers and walk-in freezers, 
including compliance certifications, must be based on testing 
conducted in accordance with the applicable provisions of 10 CFR 
part 431, subpart R, appendix B, revised as of January 1, 2022. 
Beginning [date 180 days after publication of final rule], 
representations with respect to R-value for insulation of envelope 
components of walk-in coolers and walk-in freezers, including 
compliance certifications, must be based on testing conducted in 
accordance with this appendix.


    0. Incorporation by Reference.
    DOE incorporated by reference in Sec.  431.303 the entire 
standard for ASTM C518-17. However, certain enumerated provisions of 
ASTM C518-17, as set forth in section 0.1 of this appendix, are 
inapplicable. To the extent there is a conflict between the terms or 
provisions of a referenced industry standard and the CFR, the CFR 
provisions control.

0.1 ASTM C518-17

    0.1.1 Section 1 Scope, is inapplicable as specified in section 
5.3.1.1 of this appendix,
    0.1.2 Section 4 Significance and Use, is inapplicable as 
specified in section 5.3.1.2 of this appendix,
    0.1.3 Section 7.3 Specimen Conditioning, is inapplicable as 
specified in section 5.3.1.3 of this appendix,
    0.1.4 Section 9 Report, is inapplicable as specified in section 
5.3.1.4 of this appendix,
    0.1.5 Section 10 Precision and Bias, is inapplicable as 
specified in section 5.3.1.5 of this appendix,
    0.1.6 Section 11 Keywords, is inapplicable as specified in 
section 5.3.1.6 of this appendix,
    0.1.7 Annex A2 Equipment Error Analysis, is inapplicable as 
specified in section 5.3.1.7 of this appendix,
    0.1.8 Appendix X1 is inapplicable as specified in section 
5.3.1.8 of this appendix,
    0.1.9 Appendix X2 Response of Heat Flux Transducers, is 
inapplicable as specified in section 5.3.1.9 of this appendix, and
    0.1.10 Appendix X3 Proven Performance of a Heat Flow Apparatus, 
is inapplicable as specified in section 5.3.1.10 of this appendix.
    1. General.
    The following sections of this appendix provide additional 
instructions for testing. In cases where there is a conflict, the 
language of this appendix takes highest precedence, followed by ASTM 
C518-17. Any subsequent amendment to a referenced document by the 
standard-setting organization will not affect the test procedure in 
this appendix, unless and until the test procedure is amended by 
DOE. Material is incorporated as it exists on the date of the 
approval, and a notification of any change in the incorporation will 
be published in the Federal Register.
    2. Scope.
    This appendix covers the test requirements used to measure the 
R-value of non-display panels and non-display doors of a walk-in 
cooler or walk-in freezer.
    3. Definitions.
    The definitions contained in Sec.  431.302 apply to this 
appendix.
    4. Additional Definitions.
    4.1 Edge region means a region of the envelope component that is 
wide enough to encompass any framing members. If the envelope 
component contains framing members (e.g., a wood frame) then the 
width of the edge region must be as wide as any framing member plus 
an additional 2 in. <plus-minus>0.25 in.
    5. Test Methods, Measurements, and Calculations.
    5.1 General. Foam shall be tested after it is produced in its 
final chemical form. For foam produced inside of an envelope 
component (``foam-in-place''), ``final chemical form'' means the 
foam is cured as intended and ready for use as a finished envelope 
component. For foam produced as board stock (e.g., polystyrene), 
``final chemical form'' means after extrusion and ready for assembly 
into an envelope component or after assembly into an envelope 
component. Foam must not include any structural members or non-foam 
materials during testing in accordance with ASTM C518-17. When 
preparing the specimen for test, a high-speed bandsaw or a meat 
slicer are two types of recommended cutting tools. Hot wire cutters 
or other heated tools shall not be used for cutting foam test 
specimens.
    5.2 Specimen Preparation.
    5.2.1 Determining the thickness around the perimeter of the 
envelope component, tp. The full thickness of an envelope component 
around the perimeter, which may include facers on one or both sides, 
shall be determined as follows:
    5.2.1.1 At least 8 thickness measurements shall be taken around 
the perimeter of the envelope component, at least 2 inches from the 
edge region, and avoiding any regions with hardware or fixtures.
    5.2.1.2 The average of the thickness measurements taken around 
the perimeter of the envelope component shall be the thickness 
around the perimeter of the envelope component, tp.
    5.2.1.3 Measure and record the width, wp, and height, hp, of the 
envelope component. The surface area of the envelope component, Ap, 
shall be determined as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.023

Where:

wp = width of the envelope component, in.; and
hp = height of the envelope component, in.
    5.2.2. Removing the sample from the envelope component.
    5.2.2.1. Determine the center of the envelope component relative 
to its height and its width.
    5.2.2.2. Cut a sample from the envelope component that is at 
least the length and width dimensions of the heat flow meter, and 
where the marked center of the sample is at least 3 inches from any 
cut edge.
    5.2.2.3. If the center of the envelope component contains any 
non-foam components (excluding facers), additional samples may be 
cut adjacent to the previous cut that is at least the length and 
width dimensions of the heat flow meter and is greater than 12 
inches from the edge region.
    5.2.3. Determining the thickness at the center of the envelope 
component, tc. The full thickness of an envelope component at the 
center, which may include facers on one or both sides, shall be 
determined as follows:
    5.2.3.1. At least 2 thickness measurements shall be taken in 
each quadrant of the cut sample removed from the envelope component 
per section 5.2.2 of this appendix, for a total of at least 8 
measurements.
    5.2.3.2. The average of the thickness measurements of the cut 
sample removed from the envelope component shall be the overall 
thickness of the cut sample, tc.
    5.2.3.3. Measure and record the width and height of the cut 
sample removed from the envelope component. The surface area of the 
cut sample removed from the envelope component, Ac., shall be 
determined as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.024

Where:

wc = width of the cut sample removed from the envelope component, 
in.; and
hc = height of the cut sample removed from the envelope component, 
in.

    5.2.4. Determining the total thickness of the foam within the 
envelope component, tfoam. The average total thickness of the foam

[[Page 23998]]

sample, without facers, shall be determined as follows:
    5.2.4.1. Remove the facers on the envelope component sample, 
while minimally disturbing the foam.
    5.2.4.2. Measure the thickness of each facer in 4 locations for 
a total of 4 measurements if 1 facer is removed, and a total of 8 
measurements if 2 facers are removed. The average of all facer 
measurements shall be the thickness of the facers, tfacers, in.
    5.2.4.3. The average total thickness of the foam, tfoam, in., 
shall be determined as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.025

Where:

tc = the average thickness of the center of the envelope component, 
in., as determined per sections 5.2.3.1 and 5.2.3.2 of this 
appendix;
Ac = the surface area of the center of the envelope component, 
in\2\., as determined per section 5.2.3.3 of this appendix;
tp = the average thickness of the perimeter of the envelope 
component, in., as determined per sections 5.2.1.1 and 5.2.1.2 of 
this appendix;
Ap = the average thickness of the center of the envelope component, 
in\2\, as determined per section 5.2.1.3 of this appendix;
tfacers = the average thickness of the facers of the envelope 
component, in., as determined per section 5.2.4.2 of this appendix.

    5.2.5 Cutting, measuring, and determining parallelism and 
flatness of a 1-inch-thick specimen for test from the center of the 
cut envelope component sample.
    5.2.5.1 Cut a 1 <plus-minus>0.1-inch-thick specimen from the 
center of the cut envelope sample. The 1-inch-thick test specimen 
shall be cut from the point that is equidistant from both edges of 
the sample (i.e., shall be cut from the center point that would be 
directly between the interior and exterior space of the walk-in).
    5.2.5.2 Document through measurement or photographs with 
measurement indicators that the specimen was taken from the center 
of the sample.
    5.2.5.3 After the 1-inch specimen has been cut, and prior to 
testing, place the specimen on a flat surface and allow gravity to 
determine the specimen's position on the surface. This will be side 
1.
    5.2.5.4 To determine the flatness of side 1, take at least nine 
height measurements at equidistant positions on the specimen (i.e., 
the specimen would be divided into 9 regions and height measurements 
taken at the center of each of these nine regions). Contact with the 
measurement indicator shall not indent the foam surface. From the 
height measurements taken, determine the least squares plane for 
side 1. For each measurement location, calculate the theoretical 
height from the least squares plane for side 1. Then, calculate the 
difference between the measured height and the theoretical least 
squares plane height at each location. The maximum difference minus 
the minimum difference out of the nine measurement locations is the 
flatness of side 1. For side 1 of the specimen to be considered 
flat, this shall be less than or equal to 0.03 inches.
    5.2.5.5 To determine the flatness of side 2, turn the specimen 
over and allow gravity to determine the specimen's position on the 
surface. Repeat section 5.2.5.4 to determine the flatness of side 2.
    5.2.5.6 To determine the parallelism of the specimen for side 1, 
calculate the theoretical height of the least squares plane at the 
furthest corners (i.e., at points (0,0), (0,12), (12,0), and 
(12,12)) of the 12-inch by 12-inch test specimen. The difference 
between the maximum theoretical height and the minimum theoretical 
height shall be less than or equal to 0.03 inches for each side in 
order for side 1 to be considered parallel.
    5.2.5.7 To determine the parallelism of the specimen for side 2, 
repeat section
    5.2.5.8 The average thickness of the test specimen, L, shall be 
1 <plus-minus>0.1-inches determined using a minimum of 18 thickness 
measurements (i.e., a minimum of 9 measurements on side 1 of the 
specimen and a minimum of 9 on side 2 of the specimen). This average 
thickness shall be used to determine the thermal conductivity, or K-
factor.
    5.3 K-factor Test. Determine the thermal conductivity, or K-
factor, of the 1-inch-thick specimen in accordance with the 
specified sections of ASTM C518-17; however, the following 
enumerated provisions of ASTM C518-17 are not applicable, as set 
forth in section 5.3.1 of this appendix. Testing must be completed 
within 24 hours of the specimen being cut for testing per section 
5.2.5 of this appendix.
    5.3.1 Excepted sections of ASTM C518-17.
    5.3.1.1 Section 1 Scope,
    5.3.1.2 Section 4 Significance and Use,
    5.3.1.3 Section 7.3 Specimen Conditioning,
    5.3.1.4 Section 9 Report,
    5.3.1.5 Section 10 Precision and Bias,
    5.3.1.6 Section 11 Keywords,
    5.3.1.7 Annex A2 Equipment Error Analysis,
    5.3.1.8 Appendix X1,
    5.3.1.9 Appendix X2 Response of Heat Flux Transducers, and
    5.3.1.10 Appendix X3 Proven Performance of a Heat Flow 
Apparatus.
    5.3.2 Test Conditions.
    5.3.2.1 For freezer envelope components, the K-factor of the 
specimen shall be determined at an average specimen temperature of 
20 <plus-minus>1 degrees Fahrenheit.
    5.3.2.2 For cooler envelope components, the K-factor of the 
specimen shall be determined at an average specimen temperature of 
55 <plus-minus>1 degrees Fahrenheit.
    5.4 R-value Calculation.
    5.4.1 For envelope components consisting of one homogeneous 
layer of insulation, calculate the R-value, h-ft\2\-[deg]F/Btu, as 
follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.026

Where:

tfoam = the total thickness of the foam, in., as determined in 
section 5.2.4 of this appendix; and
[lgr] = K-factor, Btu-in/(h-ft\2\-[deg]F), as determined in section 
5.3 of this appendix.

    5.4.2 For envelope components consisting of two or more layers 
of dissimilar insulating materials (excluding facers or protective 
skins), determine the K-factor of each material as described in 
sections 5.1 through 5.3 of this appendix. For an envelope component 
with N layers of insulating material, the overall R-value shall be 
calculated as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.027

Where:

ti is the thickness of the ith material that appears in the envelope 
component, inches, as determined in section 5.2.4 of this appendix;
[lgr]i is the k factor of the ith material, Btu-in/(h-ft\2\-[deg]F), 
as determined in section 5.3 of this appendix; and

[[Page 23999]]

N is the total number of material layers that appears in the 
envelope component.

    5.4.3 K-factor test results from a test sample 1 <plus-
minus>0.1-inches in thickness may be used to determine the R-value 
of envelope components with various foam thicknesses as long as the 
foam throughout the panel depth is of the same final chemical form 
and the test was completed at the same test conditions that the 
other envelope components would be used at. For example, a K-factor 
test result conducted at cooler conditions cannot be used to 
determine R-value of a freezer envelope component.
0
12. Amend appendix C to subpart R of part 431 by:
0
a. Adding a note to the beginning of the appendix;
0
b. Revising sections 2.0 and 3.1.1;
0
c. Adding sections 3.1.6 and 3.1.7;
0
d. Revising sections 3.2.1 and 3.2.3;
0
e. Adding sections 3.2.6, 3.2.7, 3.2.7.1, 3.2.7.2, 3.2.7.3, and 3.2.8;
0
f. Revising sections 3.3.1 and 3.3.3;
0
g. Adding sections 3.3.3.1, 3.3.3.2, 3.3.3.3, 3.3.3.3.1, and 3.3.3.3.2;
0
h. Revising sections 3.3.7, 3.3.7.1, and 3.3.7.2;
0
i. Adding sections 3.3.7.3, 3.3.7.3.1, and 3.3.7.3.2; and
0
j. Revising section 3.4.2.1.
    The additions and revisions read as follows:

Appendix C to Subpart R of Part 431--Uniform Test Method for the 
Measurement of Net Capacity and AWEF of Walk-In Cooler and Walk-In 
Freezer Refrigeration Systems

    Note: Prior to [date 180 days after publication of final rule], 
representations with respect to the energy use of refrigeration 
components of walk-in coolers and walk-in freezers, including 
compliance certifications, must be based on testing conducted in 
accordance with the applicable provisions of this appendix as they 
appeared in 10 CFR part 431, subpart R, appendix C, revised as of 
January 1, 2022. Beginning [date 180 days after publication of final 
rule], representations with respect to energy use of refrigeration 
components of walk-in coolers and walk-in freezers, including 
compliance certifications, must be based on testing conducted in 
accordance with this appendix.


    For any amended standards for walk-in coolers and freezers 
published after January 1, 2022, manufacturers must use the results 
of testing under appendix C1 of this part to determine compliance. 
Representations related to energy consumption must be made in 
accordance with appendix C1 of this part when determining compliance 
with the relevant standard. Manufacturers may also use appendix C1 
of this part to certify compliance with any amended standards prior 
to the applicable compliance date for those standards.
* * * * *
    2.0 Definitions.
    The definitions contained in Sec.  431.302 and AHRI 1250-2009 
(incorporated by reference; see Sec.  431.303) apply to this 
appendix. When definitions contained in the standards DOE has 
incorporated by reference are in conflict or when they conflict with 
this section, the hierarchy of precedence shall be in the following 
order: Sec.  431.302, AHRI 1250-2009, and then either AHRI 420-2008 
(incorporated by reference; see Sec.  431.303) for unit coolers or 
ASHRAE 23.1-2010 (incorporated by reference; see Sec.  431.303) for 
dedicated condensing units.
    The term ``unit cooler'' used in AHRI 1250-2009, AHRI 420-2008, 
and this subpart shall be considered to address both ``unit 
coolers'' and ``ducted fan-coil units,'' as appropriate.
    3.0 * * *
    3.1. * * *
    3.1.1. In Table 1, Instrumentation Accuracy, refrigerant 
temperature measurements shall have an accuracy of +/-0.5 [deg]F for 
unit cooler in/out. When testing high-temperature refrigeration 
systems, measurements used to determine temperature or water vapor 
content of the air (i.e. wet bulb or dew point) shall be accurate to 
within +/-0.25 [deg]F; all other temperature measurements shall be 
accurate to within +/-1.0 [deg]F.
* * * * *
    3.1.6. Test Operating Conditions for CO<INF>2</INF> Unit 
Coolers.
    For medium-temperature CO<INF>2</INF> unit coolers, conduct 
tests using the test conditions specified in Table 17 of this 
appendix. For low-temperature CO<INF>2</INF> unit coolers, conduct 
tests using the test conditions specified in Table 18 of this 
appendix.

                                       Table 17--Test Operating Conditions for Medium-Temperature CO2 Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                  Unit cooler     Unit cooler                    Liquid inlet
                                 air entering    air entering     Suction dew    bubble point    Liquid inlet
       Test description            dry-bulb,       relative       point temp,    temperature,     subcooling,     Compressor capacity    Test objective
                                    [deg]F        humidity, %       [deg]F          [deg]F          [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power...............              35             <50  ..............  ..............  ..............  Compressor On.........  Measure fan
                                                                                                                                         input power
                                                                                                                                         during
                                                                                                                                         compressor off
                                                                                                                                         cycle.
Refrigeration Capacity,                     35             <50              25              38               5  Compressor Off........  Determine Net
 Ambient Condition A.                                                                                                                    Refrigeration
                                                                                                                                         Capacity of
                                                                                                                                         Unit Cooler.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1. Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.


                                        Table 18--Test Operating Conditions for Low-Temperature CO2 Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                  Unit cooler     Unit cooler                    Liquid inlet
                                 air entering    air entering     Suction dew    bubble point    Liquid inlet
       Test description            dry-bulb,       relative       point temp,     temperature     subcooling,     Compressor capacity    Test objective
                                    [deg]F        humidity, %       [deg]F          [deg]F          [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power...............             -10             <50  ..............  ..............  ..............  Compressor Off........  Measure fan
                                                                                                                                         input power
                                                                                                                                         during
                                                                                                                                         compressor off
                                                                                                                                         cycle.
Refrigeration Capacity,                    -10             <50             -20              38               5  Compressor On.........  Determine Net
 Ambient Condition A.                                                                                                                    Refrigeration
                                                                                                                                         Capacity of
                                                                                                                                         Unit Cooler.
Defrost.......................             -10             <50  ..............  ..............  ..............  Compressor Off........  Test according
                                                                                                                                         to Appendix C
                                                                                                                                         Section C11 of
                                                                                                                                         AHRI 1250-2009.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1. Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.


[[Page 24000]]

    3.1.7. Test Operating Conditions for High-Temperature Unit 
Coolers.
    For high temperature cooler unit coolers, conduct tests using 
the test conditions specified in Table 19 of this appendix.

                                          Table 19--Test Operating Conditions for High-Temperature Unit Coolers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Unit cooler
                                  Unit cooler    air entering     Suction dew    Liquid inlet    Liquid inlet
       Test description          air entering      relative       point temp,    bubble point     subcooling,     Compressor capacity    Test objective
                                   dry-bulb,     humidity, % 1    [deg]F 2 3     temperature,       [deg]F
                                    [deg]F                                          [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle.....................              55              55  ..............             105               9  Compressor Off........  Measure fan
                                                                                                                                         input power.
Refrigeration Capacity Suction              55              55              38             105               9  Compressor On.........  Determine Net
 A.                                                                                                                                      Refrigeration
                                                                                                                                         Capacity of
                                                                                                                                         Unit Cooler.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1. The test condition tolerance (maximum permissible variation of the average value of the measurement from the specified test condition) for relative
  humidity is 3%.
2. Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.
3. Suction Dew Point shall be measured at the Unit Cooler Exit.

    3.2. * * *
    3.2.1. Refrigerant Temperature Measurements.
    In AHRI 1250-2009 appendix C, section C3.1.6, any refrigerant 
temperature measurements entering and leaving the unit cooler may 
use sheathed sensors immersed in the flowing refrigerant instead of 
thermometer wells. When testing a condensing unit alone, measure 
refrigerant liquid temperature leaving the condensing unit using 
thermometer wells as described in AHRI 1250-2009 appendix C, section 
C3.1.6 or sheathed sensors immersed in the flowing refrigerant. For 
all of these cases, if the refrigerant tube outer diameter is less 
than \1/2\ inch, the refrigerant temperature may be measured using 
the average of two temperature measuring instruments with a minimum 
accuracy of <plus-minus>0.5 [deg]F placed on opposite sides of the 
refrigerant tube surface--resulting in a total of up to 8 
temperature measurement devices used for the DX Dual Instrumentation 
method. In this case, the refrigerant tube shall be insulated with 
1-inch thick insulation from a point 6 inches upstream of the 
measurement location to a point 6 inches downstream of the 
measurement location. Also, to comply with this requirement, the 
unit cooler entering measurement location may be moved to a location 
6 inches upstream of the expansion device and, when testing a 
condensing unit alone, the entering and leaving measurement 
locations may be moved to locations 6 inches from the respective 
service valves.
* * * * *
    3.2.3. Subcooling at Refrigerant Mass Flow Meter.
    In appendix C, Section C3.4.5 of AHRI 1250-2009 (incorporated by 
reference; see Sec.  431.303), and in Section 7.1.2 of ASHRAE 23.1-
2010 (incorporated by reference; see Sec.  431.303) when verifying 
sub-cooling at the mass flow meters, only the sight glass and a 
temperature sensor located on the tube surface under the insulation 
are required. Subcooling shall be verified to be within the 3 
[ordm]F requirement downstream of flow meters located in the same 
chamber as a condensing unit under test and upstream of flow meters 
located in the same chamber as a unit cooler under test, rather than 
always downstream as indicated in AHRI 1250-2009, Section C3.4.5 or 
always upstream as indicated in Section 7.1.2 of ASHRAE 23.1-2010. 
If the subcooling is less than 3 [ordm]F, cool the line between the 
condensing unit outlet and this location to achieve the required 
subcooling. When providing such cooling while testing a matched 
pair, also measure the refrigerant temperature upstream of the 
location at which the line is being cooled, and increase the 
temperature used to calculate unit cooler entering enthalpy by the 
difference between the upstream and downstream temperatures.
* * * * *
    3.2.6. Installation Instructions.
    Manufacturer installation instructions or installation 
instructions described in this section refer to the instructions 
that come packaged with or appear on the labels applied to the unit. 
This does not include online manuals or materials.
    Installation Instruction Hierarchy: If a given installation 
instruction provided on the label(s) applied to the unit conflicts 
with the installation instructions that are shipped with the unit, 
the label takes precedence. For testing of matched pairs, the 
installation instructions for the dedicated condensing unit shall 
take precedence. Setup shall be in accordance with the field 
installation instructions (laboratory installation instructions 
shall not be used). Achieving test conditions shall always take 
precedence over installation instructions.
    3.2.7. Refrigerant Charging and Adjustment of Superheat and 
Subcooling.
    All test samples shall be charged, and superheat and/or 
subcooling shall be set, at Refrigeration A test conditions unless 
otherwise specified in the installation instructions. If the 
installation instructions give a specified range for superheat, sub-
cooling, or refrigerant pressure, the average of the range shall be 
used as the refrigerant charging parameter target and the test 
condition tolerance shall be <plus-minus>50 percent of the range. 
Perform charging of near-azeotropic and zeotropic refrigerants only 
with refrigerant in the liquid state. Once the correct refrigerant 
charge is determined, all tests shall run until completion without 
further modification.
    3.2.7.1. When charging or adjusting superheat/subcooling, use 
all pertinent instructions contained in the installation 
instructions to achieve charging parameters within the tolerances. 
However, in the event of conflicting charging information between 
installation instructions, follow the installation instruction 
hierarchy listed in section 3.2.6. of this appendix. Conflicting 
information is defined as multiple conditions given for charge 
adjustment where all conditions specified cannot be met. In the 
event of conflicting information within the same set of charging 
instructions (e.g., the installation instructions shipped with the 
dedicated condensing unit), follow the hierarchy in Table 1 of this 
section for priority. Unless the installation instructions specify a 
different charging tolerance, the tolerances identified in Table 1 
of this section shall be used.

 Table 1--Test Condition Tolerances and Hierarchy for Refrigerant Charging and Setting of Refrigerant Conditions
----------------------------------------------------------------------------------------------------------------
                                 Fixed orifice                                  Expansion valve
                 -----------------------------------------------------------------------------------------------
    Priority           Parameter with                                Parameter with
                        installation            Tolerance      installation  instruction         Tolerance
                     instruction target                                  target
----------------------------------------------------------------------------------------------------------------
1...............  Super-heat.............  <plus-minus> 2.0    Sub-cooling..............  10% of the Target
                                            [deg]F.                                        Value; No less than
                                                                                           <plus-minus>0.5
                                                                                           [deg]F, No more than
                                                                                           <plus-minus>2.0
                                                                                           [deg]F.

[[Page 24001]]

 
2...............  High Side Pressure or    <plus-minus>4.0     High Side Pressure or      <plus-minus>4.0 psi or
                   Saturation Temperature.  psi or <plus-       Saturation Temperature.    <plus-minus>1.0
                                            minus>1.0 [deg]F.                              [deg]F.
3...............  Low Side Pressure or     <plus-minus>2.0     Super-heat...............  <plus-minus>2.0
                   Saturation Temperature.  psi or <plus-                                  [deg]F.
                                            minus>0.8 [deg]F.
4...............  Low Side Temperature...  <plus-minus>2.0     Low Side Pressure or       <plus-minus>2.0 psi or
                                            [deg]F.             Saturation Temperature.    <plus-minus>0.8
                                                                                           [deg]F.
5...............  High Side Temperature..  <plus-minus>2.0     Approach Temperature.....  <plus-minus>1.0
                                            [deg]F.                                        [deg]F.
6...............  Charge Weight..........  <plus-minus>2.0 oz  Charge Weight............  0.5% or 1.0 oz,
                                                                                           whichever is greater.
----------------------------------------------------------------------------------------------------------------

    3.2.7.2. Dedicated Condensing Unit. If the Dedicated Condensing 
Unit includes a receiver and the subcooling target leaving the 
condensing unit provided in installation instructions cannot be met 
without fully filling the receiver, the subcooling target shall be 
ignored. Likewise, if the Dedicated Condensing unit does not include 
a receiver and the subcooling target leaving the condensing unit 
cannot be met without the unit cycling off on high pressure, the 
subcooling target can be ignored. Also, if no instructions for 
charging or for setting subcooling leaving the condensing unit are 
provided in the installation instructions, the refrigeration system 
shall be set up with a charge quantity and/or exit subcooling such 
that the unit operates during testing without shutdown (e.g., on a 
high-pressure switch) and operation of the unit is otherwise 
consistent with the requirements of the test procedure of this 
appendix and the installation instructions.
    3.2.7.3. Unit Cooler. Use the shipped expansion device for 
testing. Otherwise, use the expansion device specified in the 
installation instructions. If the installation instructions specify 
multiple options for the expansion device, any specified expansion 
device may be used. The supplied expansion device shall be adjusted 
until either the superheat target is met, or the device reaches the 
end of its adjustable range. In the event the device reaches the end 
of its adjustable range and the super heat target is not met, test 
with the adjustment at the end of its range providing the closest 
match to the superheat target, and the test condition tolerance for 
super heat target shall be ignored. The measured superheat is not 
subject to a test operating tolerance. However, if the evaporator 
exit condition is used to determine capacity using the DX dual-
instrumentation method or the refrigerant enthalpy method, 
individual superheat value measurements may not be equal to or less 
than zero. If this occurs, or if the operating tolerances of 
measurements affected by expansion device fluctuation are exceeded, 
the expansion device shall be replaced, operated at an average 
superheat value higher than the target, or both, in order to avoid 
individual superheat value measurements less than zero and/or to 
meet the required operating tolerances.
    3.2.8. Chamber Conditioning using the Unit Under Test.
    In appendix C, Section C6.2 of AHRI 1250-2009, for applicable 
system configurations (matched pairs, single-packaged refrigeration 
systems, and standalone unit coolers), the unit under test may be 
used to aid in achieving the required test chamber conditions prior 
to beginning any steady state test. However, the unit under test 
must be inspected and confirmed to be free from frost before 
initiating steady state testing.
    3.3. * * *
    3.3.1. For unit coolers tested alone, use test procedures 
described in AHRI 1250-2009 for testing unit coolers for use in mix-
match system ratings, except that for the test conditions in Tables 
15 and 16 of this appendix, use the Suction A saturation condition 
test points only. Also for unit coolers tested alone, other than 
high-temperature unit coolers, use the calculations in section 7.9 
to determine AWEF and net capacity described in AHRI 1250-2009 for 
unit coolers matched to parallel rack systems.
* * * * *
    3.3.3. Evaporator Fan Power.
    3.3.3.1. Ducted Evaporator Air.
    For ducted fan-coil units with ducted evaporator air, or that 
can be installed with or without ducted evaporator air: Connect 
ductwork on both the inlet and outlet connections and determine 
external static pressure as described in ASHRAE 37-2009 
(incorporated by reference; see Sec.  431.303), Sections 6.4 and 
6.5. Use pressure measurement instrumentation as described in ASHRAE 
37-2009, Section 5.3.2. Test at the fan speed specified in 
manufacturer installation instructions--if there is more than one 
fan speed setting and the installation instructions do not specify 
which speed to use, test at the highest speed. Conduct tests with 
the external static pressure equal to 50 percent of the maximum 
external static pressure allowed by the manufacturer for system 
installation within a tolerance of -0.00/+0.05 in. wc. Set the 
external static pressure by symmetrically restricting the outlet of 
the test duct. Alternatively, if using the indoor air enthalpy 
method to measure capacity, set external static pressure by 
adjusting the fan of the airflow measurement apparatus. In case of 
conflict, these requirements for setting evaporator airflow take 
precedence over airflow values specified in manufacturer 
installation instructions or product literature.
    3.3.3.2. Unit Coolers or Single-Packaged Systems that are not 
High-Temperature Refrigeration Systems.
    Use appendix C, Section C10 of AHRI 1250-2009 for off-cycle 
evaporator fan testing, with the exception that evaporator fan 
controls using periodic stir cycles shall be adjusted so that the 
greater of a 50% duty cycle (rather than a 25% duty cycle) or the 
manufacturer default is used for measuring off-cycle fan energy. For 
adjustable-speed controls, the greater of 50% fan speed (rather than 
25% fan speed) or the manufacturer's default fan speed shall be used 
for measuring off-cycle fan energy. Also, a two-speed or multi-speed 
fan control may be used as the qualifying evaporator fan control. 
For such a control, a fan speed no less than 50% of the speed used 
in the maximum capacity tests shall be used for measuring off-cycle 
fan energy.
    3.3.3.3. High-Temperature Refrigeration Systems.
    3.3.3.3.1. The evaporator fan power consumption shall be 
measured in accordance with the requirements in Section C3.5 of AHRI 
1250-2009. This measurement shall be made with the fan operating at 
full speed, either measuring unit cooler or total system power input 
upon the completion of the steady state test when the compressor and 
the condenser fan of the walk-in system are turned off, or by 
submetered measurement of the evaporator fan power during the steady 
state test.
    Section C3.5 of AHRI 1250-2009 is revised to read:
    Evaporator Fan Power Measurement.
    The following shall be measured and recorded during a fan power 
test.

EF<INF>comp,on</INF> Total electrical power input to fan motor(s) of 
Unit Cooler, W
FS Fan speed(s), rpm
N Number of motors
P<INF>b</INF> Barometric pressure, in. Hg
T<INF>db</INF> Dry-bulb temperature of air at inlet, [deg]F

[[Page 24002]]

T<INF>wb</INF> Wet-bulb temperature of air at inlet, [deg]F
V Voltage of each phase

    For a given motor winding configuration, the total power input 
shall be measured at the highest nameplate voltage. For three-phase 
power, voltage imbalance shall be no more than 2%.
    3.3.3.3.2. Evaporator fan power for the off-cycle is equal to 
the on-cycle evaporator fan power with a run time of ten percent of 
the off-cycle time.

EFcomp,off = 0.1 x EFcomp,on
* * * * *
    3.3.7. Calculations for Unit Coolers Tested Alone.
    3.3.7.1. Unit Coolers that are not High-Temperature Unit 
Coolers.
    Calculate the AWEF and net capacity using the calculations in 
AHRI 1250-2009, Section 7.9.
    3.3.7.2. High-Temperature Unit Coolers.
    Calculate AWEF on the basis that walk-in box load is equal to 
half of the system net capacity, without variation according to high 
and low load periods, and with EER set according to tested 
evaporator capacity, as follows:
    The net capacity, qmix,evap, is determined from the test data 
for the unit cooler at the 38 [deg]F suction dewpoint.
[GRAPHIC] [TIFF OMITTED] TP21AP22.028

[GRAPHIC] [TIFF OMITTED] TP21AP22.029

Where:

BL is the non-equipment-related box load;
LF is the load factor; and
Other symbols are as defined in Section 8 of AHRI 1250-2009.

    3.3.7.3. If the unit cooler has variable-speed evaporator fans 
that vary fan speed in response to load, then:
    3.3.7.3.1. When testing to certify compliance with the energy 
conservation standards in Sec.  431.306, fans shall operate at full 
speed during on-cycle operation. Do not conduct the calculations in 
AHRI 1250-2009, Section 7.9.3. Instead, use AHRI 1250-2009, Section 
7.9.2 to determine the system's AWEF.
    3.3.7.3.2. When calculating the benefit for the inclusion of 
variable-speed evaporator fans that modulate fan speed in response 
to load for the purpose of making representations of efficiency, use 
AHRI 1250-2009, Section 7.9.3 to determine the system A WEF.
    3.4. * * *
    3.4.2. * * *
    3.4.2.1. For calculating enthalpy leaving the unit cooler to 
calculate gross capacity, (a) the saturated refrigerant temperature 
(dew point) at the unit cooler coil exit, T<INF>evap</INF>, shall be 
25 [deg]F for medium-temperature systems (coolers) and -20 [deg]F 
for low-temperature systems (freezers), and (b) the refrigerant 
temperature at the unit cooler exit shall be 35 [deg]F for medium-
temperature systems (coolers) and -14 [deg]F for low-temperature 
systems (freezers). For calculating gross capacity, the measured 
enthalpy at the condensing unit exit shall be used as the enthalpy 
entering the unit cooler. The temperature measurement requirements 
of appendix C, Section C3.1.6 of AHRI 1250-2009 and modified by 
section 3.2.1 of this appendix shall apply only to the condensing 
unit exit rather than to the unit cooler inlet and outlet, and they 
shall be applied for two measurements when using the DX Dual 
Instrumentation test method.
* * * * *
0
13. Add appendix C1 to subpart R of part 431 to read as follows:

Appendix C1 to Subpart R of Part 431--Uniform Test Method for the 
Measurement of Net Capacity and AWEF of Walk-In Cooler and Walk-In 
Freezer Refrigeration Systems

    Note: Prior to [date 180 days after publication of final rule], 
representations with respect to the energy use of refrigeration 
components of walk-in coolers and walk-in freezers, including 
compliance certifications, must be based on testing conducted in 
accordance with the applicable provisions for 10 CFR part 431, 
subpart R, appendix C,

[[Page 24003]]

revised as of January 1, 2022. Beginning [date 180 days after 
publication of final rule], representations with respect to energy 
use of refrigeration components of walk-in coolers and walk-in 
freezers, including compliance certifications, must be based on 
testing conducted in accordance with appendix C of this subpart.

    For any amended standards for walk-in coolers and walk-in 
freezers published after January 1, 2022, manufacturers must use the 
results of testing under this appendix to determine compliance. 
Representations related to energy consumption must be made in 
accordance with this appendix when determining compliance with the 
relevant standard. Manufacturers may also use this appendix to 
certify compliance with any amended standards prior to the 
applicable compliance date for those standards.
    1. Incorporation by Reference
    DOE incorporated by reference in Sec.  431.303, the entire 
standards for AHRI 1250-2020, ANSI/ASHRAE 16, and ANSI/ASHRAE 37. 
However, certain enumerated provisions of these standards, as set 
forth in sections 1.1, 1.2, and 1.3 of this appendix are 
inapplicable. To the extent there is a conflict between the terms or 
provisions of a referenced industry standard and the CFR, the CFR 
provisions control. To the extent there is a conflict between the 
terms or provisions of AHRI 1250-2020, ANSI/ASHRAE 16, and ANSI/
ASHRAE 37, the AHRI 1250-2020 provisions control.

1.1 AHRI 1250-2020
    1.1.1 Section 1 Purpose, is inapplicable as specified in section 
4.1.1 of this appendix.
    1.1.2 Section 2 Scope, is inapplicable as specified in section 
4.1.2 of this appendix.
    1.1.3 Section 9 Minimum Data Requirements for Published Rating, 
is inapplicable as specified in section 4.1.3 of this appendix.
    1.1.4 Section 10 Marking and Nameplate Data, is inapplicable as 
specified in section 4.1.4 of this appendix.
    1.1.5 Section 11 Conformance Conditions, is inapplicable as 
specified in section 4.1.5 of this appendix.

1.2 ANSI/ASHRAE 16

    1.2.1 Section 1 Purpose, is inapplicable as specified in section 
4.2.1 of this appendix.
    1.2.2 Section 2 Scope, is inapplicable as specified in section 
4.2.2 of this appendix.
    1.2.3 Section 4 Classifications, is inapplicable as specified in 
section 4.2.3 of this appendix.
    1.2.4 Normative Appendices E-M, are inapplicable as specified in 
section 4.2.4 of this appendix.
    1.2.5 Informative Appendices N-R, are inapplicable as specified 
in section 4.2.5 of this appendix.

1.3 ANSI/ASHRAE 37

    1.3.1 Section 1 Purpose, is inapplicable as specified in section 
4.3.1 of this appendix.
    1.3.2 Section 2 Scope, is inapplicable as specified in section 
4.3.2 of this appendix.
    1.3.3 Section 4 Classifications, is inapplicable as specified in 
section 4.3.3 of this appendix.
    1.3.4 Informative Appendix A Classifications of Unitary Air-
conditioners and Heat Pumps, is inapplicable as specified in section 
4.3.4 of this appendix.
    2. Scope.
    This appendix covers the test requirements used to determine the 
net capacity and the AWEF of the refrigeration system of a walk-in 
cooler or walk-in freezer.
    3. Definitions.
    3.1. Applicable Definitions.
    The definitions contained in Sec.  431.302, AHRI 1250-2020, 
ANSI/ASHRAE 37, and ANSI/ASHRAE 16 apply to this appendix. When 
definitions in standards incorporated by reference are in conflict 
or when they conflict with this section, the hierarchy of precedence 
shall be in the following order: Sec.  431.302, AHRI 1250-2020, and 
then either ANSI/ASHRAE 37 or ANSI/ASHRAE 16.
    The term ``unit cooler'' used in AHRI 1250-2020 and this subpart 
shall be considered to address both ``unit coolers'' and ``ducted 
fan-coil units,'' as appropriate.
    3.2. Additional Definitions.
    3.2.1. Digital Compressor means a compressor that uses 
mechanical means for disengaging active compression on a cyclic 
basis to provide a reduced average refrigerant flow rate in response 
to a control system input signal.
    3.2.2. Displacement Ratio, applicable to staged positive 
displacement compressor systems, means the swept volume rate, e.g., 
in cubic centimeters per second, of a given stage, divided by the 
swept volume rate at full capacity.
    3.2.3. Duty Cycle, applicable to digital compressors, means the 
fraction of time that the compressor is engaged and actively 
compressing refrigerant.
    3.2.4. Maximum Speed, applicable to variable-speed compressors, 
means the maximum speed at which the compressor will operate under 
the control of the dedicated condensing system control system for 
extended periods of time, i.e., not including short-duration boost-
mode operation.
    3.2.5. Minimum Speed, applicable to variable-speed compressors, 
means the minimum compressor speed at which the compressor will 
operate under the control of the dedicated condensing system control 
system.
    3.2.6. Multiple-Capacity, applicable for describing a 
refrigeration system, indicates that it has three or more stages 
(levels) of capacity.
    3.2.7. Speed Ratio, applicable to variable-speed compressors, 
means the ratio of operating speed to the maximum speed.
    4. Test Methods, Measurements, and Calculations.
    Determine the Annual Walk-in Energy Factor (AWEF) and net 
capacity of walk-in cooler and walk-in freezer refrigeration systems 
by conducting the test procedure set forth in AHRI 1250-2020, with 
the modifications to that test procedure provided in this section. 
However, certain sections of AHRI 1250-2020, ANSI/ASHRAE 37, and 
ANSI/ASHRAE 16 are not applicable, as set forth in sections 4.1, 
4.2, and 4.3 of this appendix. Round AWEF measurements to the 
nearest 0.05 Btu/Wh. Round net capacity measurements as indicated in 
Table 1 of this appendix.

         Table 1--Rounding of Refrigeration System Net Capacity
------------------------------------------------------------------------
                                                             Rounding
                Net capacity range, Btu/h                 multiple, Btu/
                                                                 h
------------------------------------------------------------------------
<20,000.................................................             100
>=20,000 and <38,000....................................             200
>=38,000 and <65,000....................................             500
>=65,000................................................           1,000
------------------------------------------------------------------------

    The following sections of this appendix provide additional 
instructions for testing. In cases where there is a conflict, the 
language of this appendix takes highest precedence, followed by AHRI 
1250-2020, then ANSI/ASHRAE 37 or ANSI/ASHRAE 16. Any subsequent 
amendment to a referenced document by the standard-setting 
organization will not affect the test procedure in this appendix, 
unless and until the test procedure is amended by DOE. Material is 
incorporated as it exists on the date of the approval, and a notice 
of any change in the incorporation will be published in the Federal 
Register.
    4.1 Excepted sections of AHRI 1250-2020.
    (a) Section 1 Purpose,
    (b) Section 2 Scope,
    (c) Section 9 Minimum Data Requirements for Published Ratings,
    (d) Section 10 Marking and Nameplate Data, and
    (e) Section 11 Conformance Conditions.
    4.2 Excepted sections of ANSI/ASHRAE 16.
    (a) Section 1 Purpose,
    (b) Section 2 Scope,
    (c) Section 4 Classifications,
    (d) Normative Appendices E-M,
    (e) Informative Appendices N-R.
    4.3 Excepted sections of ANSI/ASHRAE 37.
    (a) Section 1 Purpose,
    (b) Section 2 Scope,
    (c) Section 4 Classifications,
    (d) Informative Appendix A Classifications of Unitary Air-
conditioners and Heat Pumps.
    4.4. Instrumentation Accuracy and Test Tolerances.
    Use measuring instruments as described in Section 4.1 of AHRI 
1250-2020, with the following additional requirement.
    4.4.1. Electrical Energy Input measured in Wh with a minimum 
accuracy of <plus-minus>0.5% of reading (for Off-Cycle tests per 
footnote 5 of Table C3 in Section C3.6.2 of AHRI 1250-2020).
    4.5. Test Operating Conditions.
    Test conditions used to determine AWEF shall be as specified in 
Tables 4 through 17 of AHRI 1250-2020. Tables 7 and 11 of AHRI 1250-
2020, labeled to apply to variable-speed outdoor matched-pair 
refrigeration systems, shall also be used for testing variable-
capacity single-packaged outdoor refrigeration systems, and also for 
testing multiple-capacity matched-pair or single-packaged outdoor 
refrigeration systems. Test conditions used to determine AWEF for 
refrigeration systems not specifically identified in AHRI 1250-2020 
are as enumerated in sections 4.5.1 through 4.5.6 of this appendix.

[[Page 24004]]

    4.5.1 Test Operating Conditions for High-Temperature 
Refrigeration Systems.
    For fixed-capacity high-temperature matched-pair or single-
packaged refrigeration systems with indoor condensing units, conduct 
tests using the test conditions specified in Table 2 of this 
appendix. For fixed-capacity high-temperature matched-pair or 
single-packaged refrigeration systems with outdoor condensing units, 
conduct tests using the test conditions specified in Table 3 of this 
appendix. For high-temperature unit coolers tested alone, conduct 
tests using the test conditions specified in Table 4 of this 
appendix.

           Table 2--Test Operating Conditions for Fixed-Capacity High-Temperature Indoor Matched Pair or Single-Packaged Refrigeration Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Unit cooler
                                       Unit cooler    air entering    Condenser air   Condenser air
          Test description            air entering      relative     entering  dry-  entering  wet-       Compressor status           Test objective
                                        dry-bulb,      humidity, %    bulb, [deg]F    bulb, [deg]F
                                         [deg]F            \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power....................              55              55  ..............  ..............  Compressor Off.............  Measure total input
                                                                                                                                   wattage during
                                                                                                                                   compressor off cycle,
                                                                                                                                   (Ecu,off +
                                                                                                                                   EFcomp,off) \2\.
Refrigeration Capacity A...........              55              55              90   75,\3\ 65 \4\  Compressor On..............  Determine Net
                                                                                                                                   Refrigeration
                                                                                                                                   Capacity of Unit
                                                                                                                                   Cooler, input power,
                                                                                                                                   and EER at Test
                                                                                                                                   Condition.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1 The test condition tolerance (maximum permissible variation of the average value of the measurement from the specified test condition) for relative
  humidity is 3%.
2 Measure off-cycle power as described in Sections C3 and C4.2 of AHRI 1250-2020.
3 Required only for evaporative condensing units (e.g., incorporates a slinger ring).
4 Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units, where all or part of the equipment is
  located in the outdoor room.


          Table 3--Test Operating Conditions for Fixed-Capacity High-Temperature Outdoor Matched-Pair or Single-Packaged Refrigeration Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Unit cooler
                                       Unit cooler    air entering    Condenser air   Condenser air
          Test description            air entering      relative     entering  dry-  entering  wet-       Compressor status           Test objective
                                        dry-bulb,      humidity, %    bulb, [deg]F    bulb, [deg]F
                                         [deg]F            \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Refrigeration Capacity A...........              55              55              95   75,\3\ 68 \4\  Compressor On..............  Determine Net
                                                                                                                                   Refrigeration
                                                                                                                                   Capacity of Unit
                                                                                                                                   Cooler, input power,
                                                                                                                                   and EER at Test
                                                                                                                                   Condition.
Off-Cycle Power, Capacity A........              55              55              95   75,\3\ 68 \4\  Compressor Off.............  Measure total input
                                                                                                                                   wattage during
                                                                                                                                   compressor off cycle,
                                                                                                                                   (Ecu,off +
                                                                                                                                   EFcomp,off) \2\.
Refrigeration Capacity B...........              55              55              59   54,\3\ 46 \4\  Compressor On..............  Determine Net
                                                                                                                                   Refrigeration
                                                                                                                                   Capacity of Unit
                                                                                                                                   Cooler and system
                                                                                                                                   input power at
                                                                                                                                   moderate condition.
Off-Cycle Power, Capacity B........              55              55              59   54,\3\ 46 \4\  Compressor Off.............  Measure total input
                                                                                                                                   wattage during
                                                                                                                                   compressor off cycle,
                                                                                                                                   (Ecu,off +
                                                                                                                                   EFcomp,off) \2\.
Refrigeration Capacity C...........              55              55              35   34,\3\ 29 \4\  Compressor On..............  Determine Net
                                                                                                                                   Refrigeration
                                                                                                                                   Capacity of Unit
                                                                                                                                   Cooler and system
                                                                                                                                   input power at cold
                                                                                                                                   condition.
Off-Cycle Power, Capacity C........              55              55              35   34,\3\ 29 \4\  Compressor Off.............  Measure total input
                                                                                                                                   wattage during
                                                                                                                                   compressor off cycle,
                                                                                                                                   (Ecu,off +
                                                                                                                                   EFcomp,off) \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1 The test condition tolerance (maximum permissible variation of the average value of the measurement from the specified test condition) for relative
  humidity is 3%.
2 Measure off-cycle power as described in Sections C3 and C4.2 of AHRI 1250-2020.
3 Required only for evaporative condensing units (e.g., incorporates a slinger ring).
4 Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units, where all or part of the equipment is
  located in the outdoor room.


                                                              Table 4--Test Operating Conditions for High-Temperature Unit Coolers
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Unit cooler
                                          Unit cooler    air entering     Suction dew    Liquid inlet    Liquid inlet
           Test description              air entering      relative       point temp,    bubble point     subcooling,          Compressor status                     Test objective
                                           dry-bulb,      humidity, %   [deg]F \3\ \4\   temperature,       [deg]F
                                            [deg]F            \1\                           [deg]F
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle.............................              55              55  ..............             105               9  Compressor Off................  Measure unit cooler input wattage during
                                                                                                                                                         compressor off cycle, EF \2\.
Refrigeration Capacity................              55              55              38             105               9  Compressor On.................  Determine Net Refrigeration Capacity of
                                                                                                                                                         Unit Cooler, input power, and EER at
                                                                                                                                                         Test Condition.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1 The test condition tolerance (maximum permissible variation of the average value of the measurement from the specified test condition) for relative humidity is 3%.
2 Measure off-cycle power as described in Sections C3 and C4.2 of AHRI 1250-2020.
3 Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F shall be used.
4 Suction Dew Point shall be measured at the Unit Cooler Exit.

    4.5.2 Test Operating Conditions for CO<INF>2</INF> Unit Coolers.
    For medium-temperature CO<INF>2</INF> Unit Coolers, conduct 
tests using the test conditions specified in Table 5 of this 
appendix. For low-temperature CO<INF>2</INF> Unit Coolers, conduct 
tests using the test conditions specified in Table 6 of this 
appendix.

[[Page 24005]]



                                     Table 5--Test Operating Conditions for Medium-Temperature CO2 Unit Coolers \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                  Unit cooler     Unit cooler                    Liquid inlet
                                 air entering    air entering     Suction dew    bubble point    Liquid inlet    Compressor operating
          Test title               dry-bulb,       relative     point temp,\3\   temperature,     subcooling,            mode            Test objective
                                    [deg]F        humidity, %       [deg]F          [deg]F          [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power...............              35             <50  ..............  ..............  ..............  Compressor On.........  Measure unit
                                                                                                                                         cooler input
                                                                                                                                         wattage during
                                                                                                                                         compressor off
                                                                                                                                         cycle,
                                                                                                                                         EBFcomp,off.\2\
Refrigeration Capacity,                     35             <50              25              38               5  Compressor Off........  Determine Net
 Ambient Condition A.                                                                                                                    Refrigeration
                                                                                                                                         Capacity of
                                                                                                                                         Unit Cooler,
                                                                                                                                         qmix,rack.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.
\2\ Measure off-cycle power as described in Sections C3 and C4.2 of AHRI 1250-2020.
\3\ Suction Dew Point shall be measured at the Unit Cooler Exit conditions.


                                       Table 6--Test Operating Conditions for Low-Temperature CO2 Unit Coolers \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                  Unit cooler     Unit cooler                    Liquid inlet
                                 air entering    air entering     Suction dew    bubble point    Liquid inlet    Compressor operating
          Test Title               dry-bulb,       relative     point temp,\3\   temperature,     subcooling,            mode            Test objective
                                    [deg]F        humidity, %       [deg]F          [deg]F          [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Off-Cycle Power...............             -10             <50  ..............  ..............  ..............  Compressor Off........  Measure unit
                                                                                                                                         cooler input
                                                                                                                                         wattage during
                                                                                                                                         compressor off
                                                                                                                                         cycle,
                                                                                                                                         EBFcomp,off.\2\
Refrigeration Capacity,                    -10             <50             -20              38               5  Compressor On.........  Determine Net
 Ambient Condition A.                                                                                                                    Refrigeration
                                                                                                                                         Capacity of
                                                                                                                                         Unit Cooler,
                                                                                                                                         qmix,rack.
Defrost.......................             -10             <50  ..............  ..............  ..............  Compressor Off........  Test according
                                                                                                                                         to Appendix C
                                                                                                                                         Section C10 of
                                                                                                                                         AHRI 1250-2020,
                                                                                                                                         DBF,QBDF.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Superheat shall be set as indicated in the installation instructions. If no superheat specification is given a default superheat value of 6.5 [deg]F
  shall be used.
\2\ Measure off-cycle power as described in Sections C3 and C4.2 of AHRI 1250-2020.
\3\ Suction Dew Point shall be measured at the Unit Cooler Exit conditions.

    4.5.3 Test Operating Conditions for Two-Capacity Condensing 
Units Tested Alone.
    For two-capacity medium-temperature outdoor condensing units 
tested alone, conduct tests using the test conditions specified in 
Table 7 of this appendix. For two-capacity medium-temperature indoor 
condensing units tested alone, conduct tests using the test 
conditions specified in Table 8 of this appendix. For two-capacity 
low-temperature outdoor condensing units tested alone, conduct tests 
using the test conditions specified in Table 9 of this appendix. For 
two-capacity low-temperature indoor condensing units tested alone, 
conduct tests using the test conditions specified in Table 10 of 
this appendix.

                        Table 7--Test Operating Conditions for Two-Capacity Medium-Temperature Outdoor Dedicated Condensing Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Condenser air
                                          Suction dew point,       Return gas,    Condenser air   entering wet-
           Test description                     [deg]F               [deg]F       entering dry-   bulb, [deg]F              Compressor status
                                                                                  bulb, [deg]F         \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low Capacity..  Unit Cooler Low Fan: \2\              49              95              75  Low Capacity, k=1.
                                        24.5.                                46
                                       Unit Cooler High Fan:
                                        \2\ 25.5.
Capacity, Condition A, High Capacity.  23......................              41              95              75  High Capacity, k=2.
Off Cycle, Condition A...............  ........................  ..............              95              75  Off.
Capacity, Condition B, Low Capacity..  Unit Cooler Low Fan: \2\              47              59              54  Low Capacity, k=1.
                                        24.5.                                45
                                       Unit Cooler High Fan:
                                        \2\ 25.5.
Capacity, Condition B, High Capacity.  23......................  ..............              59              54  High Capacity, k=2.
Off Cycle, Condition B...............  ........................  ..............              59              54  Off.
Capacity, Condition C, Low Capacity..  Unit Cooler Low Fan: \2\              41              35              34  Low Capacity, k=1.
                                        22.5.                                41
                                       Unit Cooler High Fan:
                                        \2\ 25.5.
Capacity, Condition C, High Capacity.  23......................              41              35              34  High Capacity, k=2.
Off Cycle, Condition C...............  ........................  ..............              35              34  Off.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ When Staged compressor displacement ratio for low capacity is 65% or less, use the Unit Cooler Low Fan condition, otherwise use the Unit cooler High
  Fan condition.


[[Page 24006]]


                        Table 8--Test Operating Conditions for Two-Capacity Medium-Temperature Indoor Dedicated Condensing Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Condenser air
                                          Suction dew point,       Return gas,    Condenser air   entering wet-
           Test description                     [deg]F               [deg]F       entering dry-   bulb, [deg]F              Compressor status
                                                                                  bulb, [deg]F         \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low Capacity..  Unit Cooler Low Fan: \2\              49              90              75  Low Capacity, k=1.
                                        24.5.                                46
                                       Unit Cooler High Fan:
                                        \2\ 25.5.
Capacity, Condition A, High Capacity.  23......................              41              90              75  High Capacity, k=2.
Off Cycle, Condition A...............  ........................  ..............              90              75  Off.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ When staged compressor displacement ratio for low capacity is 65% or less, use the Unit Cooler Low Fan condition, otherwise use the Unit cooler High
  Fan condition.


                         Table 9--Test Operating Conditions for Two-Capacity Low-Temperature Outdoor Dedicated Condensing Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                              Condenser air
                                                                               Return gas,    Condenser air   entering wet-
                Test title                     Suction dew point, [deg]F         [deg]F       entering dry-   bulb, [deg]F    Compressor operating  mode
                                                                                              bulb, [deg]F         \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low Capacity......  Unit Cooler Low Fan: \2\ -20.5..              21              95              75  Low Capacity, k=1.
                                           Unit Cooler High Fan: \2\ -19.5.              13
Capacity, Condition A, High Capacity.....  -22.............................               5              95              75  High Capacity, k=2.
Off Cycle, Condition A...................  ................................  ..............              95              75  Compressor Off.
Capacity, Condition B, Low Capacity......  Unit Cooler Low Fan: \2\ -20.5..              19              59              54  Low Capacity, k=1.
                                           Unit Cooler High Fan: \2\ -19.5.              13
Capacity, Condition B, High Capacity.....  -22.............................               5              59              54  High Capacity, k=2.
Off Cycle, Condition B...................  ................................  ..............              59              54  Compressor Off.
Capacity, Condition C, Low Capacity......  Unit Cooler Low Fan: \2\ -20.5..              17              35              34  Low Capacity, k=1.
                                           Unit Cooler High Fan: \2\ -19.5.              12
Capacity, Condition C, High Capacity.....  -22.............................               5              35              34  Maximum Capacity, k=2.
Off Cycle, Condition C...................  ................................  ..............              35              34  Compressor Off.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ When staged compressor displacement ratio for low capacity is 65% or less, use the Unit Cooler Low Fan condition, otherwise use the Unit cooler High
  Fan condition.


                         Table 10--Test Operating Conditions for Two-Capacity Low-Temperature Indoor Dedicated Condensing Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Condenser air
                                          Suction dew point,       Return gas,    Condenser air   entering wet-
              Test title                        [deg]F               [deg]F       entering dry-   bulb, [deg]F          Compressor operating  mode
                                                                                  bulb, [deg]F         \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low Capacity..  Unit Cooler Low Fan: \2\              21              90              75  Low Capacity, k=1.
                                        -20.5.                               13
                                       Unit Cooler High Fan:
                                        \2\-19.5.
Capacity, Condition A, High Capacity.  -22.....................               5              90              75  High Capacity, k=2.
Off Cycle, Condition A...............  ........................  ..............              90              75  Compressor Off.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ When staged compressor displacement ratio for low capacity is 65% or less, use the Unit Cooler Low Fan condition, otherwise use the Unit cooler High
  Fan condition.

    4.5.4 Test Operating Conditions for Variable- or Multiple-
Capacity Condensing Units Tested Alone.
    For variable-capacity or multiple-capacity outdoor medium-
temperature condensing units tested alone, conduct tests using the 
test conditions specified in Table 11 of this appendix. For 
variable-capacity or multiple-capacity indoor medium-temperature 
condensing units tested alone, conduct tests using the test 
conditions specified in Table 12 of this appendix. For variable-
capacity or multiple-capacity outdoor low-temperature condensing 
units tested alone, conduct tests using the test conditions 
specified in Table 13 of this appendix. For variable-capacity or 
multiple-capacity indoor low-temperature condensing units tested 
alone, conduct tests using the test conditions specified in Table 14 
of this appendix.

[[Page 24007]]



              Table 11--Test Operating Conditions for Variable- or Multiple-Capacity Medium-Temperature Outdoor Dedicated Condensing Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Condenser air
                                          Suction dew point,       Return gas,    Condenser air  entering  wet-
           Test description                     [deg]F               [deg]F      entering  dry-   bulb, [deg]F              Compressor status
                                                                                  bulb, [deg]F         \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum         26......................              56              95              75  Minimum Capacity, k=1.
 Capacity.
Capacity, Condition A, Intermediate    Unit Cooler Low Fan: \2\              44              95              75  Intermediate Capacity, k=i.
 Capacity.                              22.5.                                46
                                       Unit Cooler High Fan:
                                        \2\ 25.5.
Capacity, Condition A, Maximum         23......................              41              95              75  Maximum Capacity, k=2.
 Capacity.
Off Cycle, Condition A...............  ........................  ..............              95              75  Off.
Capacity, Condition B, Minimum         26......................              51              59              54  Minimum Capacity, k=1.
 Capacity.
Capacity, Condition B, Intermediate    Unit Cooler Low Fan: \2\              44              59              54  Intermediate Capacity, k=i.
 Capacity.                              22.5.                                45
                                       Unit Cooler High Fan:
                                        \2\ 25.5.
Capacity, Condition B, Maximum         23......................              41              59              54  Maximum Capacity, k=2.
 Capacity.
Off Cycle, Condition B...............  ........................  ..............              59              54  Off.
Capacity, Condition C, Minimum         26......................              41              35              34  Minimum Capacity, k=1.
 Capacity.
Capacity, Condition C, Intermediate    Unit Cooler Low Fan: \2\              41              35              34  Intermediate Capacity, k=i.
 Capacity.                              22.5.                                41
                                       Unit Cooler High Fan:
                                        \2\ 25.5.
Capacity, Condition C, Maximum         23......................              41              35              34  Maximum Capacity, k=2.
 Capacity.
Off Cycle, Condition C...............  ........................  ..............              35              34  Off
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ When Digital Compressor duty cycle, variable-speed speed ratio, or staged compressor displacement ratio for intermediate capacity is 65% or less,
  use the Unit Cooler Low Fan condition, otherwise use the Unit cooler High Fan condition.


               Table 12--Test Operating Conditions for Variable- or Multiple-Capacity Medium-Temperature Indoor Dedicated Condensing Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Condenser air
                                          Suction dew point,       Return gas,    Condenser air  entering  wet-
           Test description                     [deg]F               [deg]F      entering  dry-   bulb, [deg]F              Compressor status
                                                                                  bulb, [deg]F         \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum         26......................              56              90              75  Minimum Capacity, k=1.
 Capacity.
Capacity, Condition A, Intermediate    Unit Cooler Low Fan: \2\              44              90              75  Intermediate Capacity, k=i,
 Capacity.                              22.5.                                46
                                       Unit Cooler High Fan:
                                        \2\ 25.5.
Capacity, Condition A, Maximum         23......................              41              90              75  Maximum Capacity, k=2.
 Capacity.
Off Cycle, Condition A...............  ........................  ..............              90              75  Off.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ When Digital Compressor duty cycle, variable-speed speed ratio, or staged compressor displacement ratio for intermediate capacity is 65% or less,
  use the Unit Cooler Low Fan condition, otherwise use the Unit cooler High Fan condition.


                Table 13--Test Operating Conditions for Variable- or Multiple-Capacity Low-Temperature Outdoor Dedicated Condensing Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Condenser air
                                          Suction dew point,       Return gas,    Condenser air  entering  wet-
              Test title                        [deg]F               [deg]F      entering  dry-   bulb, [deg]F          Compressor operating mode
                                                                                  bulb, [deg]F         \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum         -19.....................              32              95              75  Minimum Capacity, k=1.
 Capacity.
Capacity, Condition A, Intermediate    Unit Cooler Low Fan: \2\              13              95              75  Minimum Capacity, k=i.
 Capacity.                              -22.5.                               13
                                       Unit Cooler High Fan:
                                        \2\ -19.5.
Capacity, Condition A, Maximum         -22.....................               5              95              75  Maximum Capacity, k=2.
 Capacity.
Off Cycle, Condition A...............  ........................  ..............              95              75  Compressor Off.

[[Page 24008]]

 
Capacity, Condition B, Minimum         -19.....................              28              59              54  Minimum Capacity, k=1.
 Capacity.
Capacity, Condition B, Intermediate    Unit Cooler Low Fan: \2\              12              59              54  Minimum Capacity, k=i.
 Capacity.                              -22.5.                               13
                                       Unit Cooler High Fan:
                                        \2\ -19.5.
Capacity, Condition B, Maximum         -22.....................               5              59              54  Maximum Capacity, k=2.
 Capacity.
Off Cycle, Condition B...............  ........................  ..............              59              54  Compressor Off.
Capacity, Condition C, Minimum         -19.....................              23              35              34  Minimum Capacity, k=1.
 Capacity.
Capacity, Condition C, Intermediate    Unit Cooler Low Fan: \2\              11              35              34  Minimum Capacity, k=i.
 Capacity.                              -22.5.                               12
                                       Unit Cooler High Fan:
                                        \2\ -19.5.
Capacity, Condition C, Maximum         -22.....................               5              35              34  Maximum Capacity, k=2.
 Capacity.
Off Cycle, Condition C...............  ........................  ..............              35              34  Compressor Off.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ When Digital Compressor duty cycle, variable-speed speed ratio, or staged compressor displacement ratio for intermediate capacity is 65% or less,
  use the Unit Cooler Low Fan condition, otherwise use the Unit cooler High Fan condition.


                Table 14--Test Operating Conditions for Variable- or Multiple-Capacity Low-Temperature Indoor Dedicated Condensing Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                  Condenser air
                                          Suction dew point,       Return gas,    Condenser air   entering wet-
              Test title                        [deg]F               [deg]F       entering dry-   bulb, [deg]F          Compressor operating mode
                                                                                  bulb, [deg]F         \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum         -19.....................              32              90              75  Minimum Capacity, k=1.
 Capacity.
Capacity, Condition A, Intermediate    Unit Cooler Low Fan: \2\              13              90              75  Minimum Capacity, k=i.
 Capacity.                              -22.5.                               13
                                       Unit Cooler High Fan:
                                        \2\ -19.5.
Capacity, Condition A, Maximum         -22.....................               5              90              75  Maximum Capacity, k=2.
 Capacity.
Off Cycle, Condition A...............  ........................  ..............              90              75  Compressor Off.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ When Digital Compressor duty cycle, variable-speed speed ratio, or staged compressor displacement ratio for intermediate capacity is 65% or less,
  use the Unit Cooler Low Fan condition, otherwise use the Unit cooler High Fan condition.

    4.5.5 Test Operating Conditions for Two-Capacity Indoor Matched-
Pair or Single-Packaged Refrigeration Systems.
    For two-capacity indoor medium-temperature matched-pair or 
single-packaged refrigeration systems, conduct tests using the test 
conditions specified in Table 15 of this appendix. For two-capacity 
indoor low-temperature matched-pair or single-packaged refrigeration 
systems, conduct tests using the test conditions specified in Table 
16 of this appendix.

          Table 15--Test Operating Conditions for Two-Capacity Medium-Temperature Indoor Matched-Pair or Single-Packaged Refrigeration Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                        Unit cooler     Unit cooler
                                       air entering    air entering    Condenser air  Condenser air entering wet-
          Test description               dry-bulb,       relative      entering dry-         bulb, [deg]F                    Compressor status
                                          [deg]F        humidity, %    bulb, [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low Capacity.              35             <50              90  75,\1\ 65 \2\.............  Low Capacity.
Capacity, Condition A, High Capacity              35             <50              90  75,\1\ 65 \2\.............  High Capacity.
Off Cycle,..........................              35             <50              90  75,\1\ 65 \2\.............  Off.
Condition A.........................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units, where all or part of the equipment is
  located in the outdoor room.


[[Page 24009]]


            Table 16--Test Operating Conditions for Two Capacity Low-Temperature Indoor Matched-Pair or Single-Packaged Refrigeration Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                        Unit cooler     Unit cooler
                                       air entering    air entering    Condenser air     Maximum condenser air
          Test description               dry-bulb,       relative      entering dry-   entering wet-bulb, [deg]F             Compressor status
                                          [deg]F        humidity, %    bulb, [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Low Capacity.             -10             <50              90  75,\1\ 65 \2\.............  Low Capacity.
Capacity, Condition A, High Capacity             -10             <50              90  75,\1\ 65 \2\.............  High Capacity.
Off Cycle, Condition A..............             -10             <50              90  75,\1\ 65 \2\.............  Off.
Defrost.............................             -10             <50  ..............  ..........................  System Dependent.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units, where all or part of the equipment is
  located in the outdoor room.

    4.5.6 Test Conditions for Variable- or Multiple-Capacity Indoor 
Matched Pair or Single-Packaged Refrigeration Systems.
    For variable- or multiple-capacity indoor medium-temperature 
matched-pair or single-packaged refrigeration systems, conduct tests 
using the test conditions specified in Table 17 of this appendix. 
For variable- or multiple-capacity indoor low-temperature matched-
pair or single-packaged refrigeration systems, conduct tests using 
the test conditions specified in Table 18 of this appendix.

 Table 17--Test Operating Conditions for Variable- or Multiple-Capacity Medium-Temperature Indoor Matched-Pair or Single-Packaged Refrigeration Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                        Unit cooler     Unit cooler
                                       air entering    air entering    Condenser air  Condenser air entering wet-
          Test description               dry-bulb,       relative      entering dry-         bulb, [deg]F                    Compressor status
                                          [deg]F        humidity, %    bulb, [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum                    35             <50              90  75,\1\ 65 \2\.............  Minimum Capacity.
 Capacity.
Capacity, Condition A, Intermediate               35             <50              90  75,\1\ 65 \2\.............  Intermediate Capacity.
 Capacity.
Capacity, Condition A, High Capacity              35             <50              90  75,\1\ 65 \2\.............  Maximum Capacity.
Off Cycle, Condition A..............              35             <50              90  75,\1\ 65 \2\.............  Off.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units, where all or part of the equipment is
  located in the outdoor room.


   Table 18--Test Operating Conditions for Variable- or Multiple-Capacity Low-Temperature Indoor Matched-Pair or Single-Packaged Refrigeration Systems
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                        Unit cooler     Unit cooler
                                       air entering    air entering    Condenser air     Maximum condenser air
          Test description               dry-bulb,       relative      entering dry-   entering wet-bulb, [deg]F             Compressor status
                                          [deg]F        humidity, %    bulb, [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Capacity, Condition A, Minimum                   -10             <50              90  75,\1\ 65 \2\.............  Minimum Capacity.
 Capacity.
Capacity, Condition A, Intermediate              -10             <50              90  75,\1\ 65 \2\.............  Intermediate Capacity.
 Capacity.
Capacity, Condition A, Maximum                   -10             <50              90  75,\1\ 65 \2\.............  Maximum Capacity.
 Capacity.
Off Cycle, Condition A..............             -10             <50              90  75,\1\ 65 \2\.............  Off.
Defrost.............................             -10             <50  ..............  ..........................  System Dependent.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Required only for evaporative condensing units (e.g., incorporates a slinger ring).
\2\ Maximum allowable value for Single-Packaged Systems that do not use evaporative Dedicated Condensing Units, where all or part of the equipment is
  located in the outdoor room.


[[Page 24010]]

    4.6. Calculation for Walk-in Box Load.
    4.6.1 For medium- and low-temperature refrigeration systems with 
indoor condensing units, calculate walk-in box loads for high and 
low load periods as a function of net capacity as described in 
Section 6.2.1 of AHRI 1250-2020.
    4.6.2 For medium- and low-temperature refrigeration systems with 
outdoor condensing units, calculate walk-in box loads for high and 
low load periods as a function of net capacity and outdoor 
temperature as described in Section 6.2.2 of AHRI 1250-2020.
    4.6.3 For high-temperature refrigeration systems, calculate 
walk-in box load as follows.

BBL = [middot] qss,A

Where qss,A is the measured net capacity for Test Condition A.

    4.7. Calculation for Annual Walk-in Energy Factor (AWEF).
    Calculations used to determine AWEF based on performance data 
obtained for testing shall be as specified in Section 7 of AHRI 
1250-2020 with modifications as indicated in sections 4.7.7 through 
4.7.10 of this appendix. Calculations used to determine AWEF for 
refrigeration systems not specifically identified in Sections 7.1.1 
through 7.1.6 of AHRI 1250-2020 are enumerated in sections 4.7.1 
through 4.7.6 and sections 4.7.11 through 4.7.14 of this appendix.
    4.7.1 Two-Capacity Condensing Units Tested Alone, Indoor.
    4.7.1.1 Unit Cooler Power.
    Calculate maximum-capacity unit cooler power during the 
compressor on period EBFcomp,on, in Watts, using Equation 130 of 
AHRI 1250-2020 for medium-temperature refrigeration systems and 
using Equation 173 of AHRI 1250-2020 for low-temperature 
refrigeration systems.
    Calculate unit cooler power during the compressor off period 
EBFcomp,off, in Watts, as 20 percent of the maximum-capacity unit 
cooler power during the compressor on period.
    4.7.1.2 Defrost.
    For freezer refrigeration systems, calculate defrost heat 
contribution QBDF in Btu/h and the defrost average power consumption 
DBF in W as a function of steady-state maximum gross refrigeration 
capacity QBj, as specified in Section C10.2.2 of Appendix C of AHRI 
1250-2020.
    4.7.1.3 Net Capacity.
    Calculate steady-state maximum net capacity, qZ, and minimum net 
capacity, qF as follows:

qZ = QBj-3.412 [middot] EBFcomp,on
qF = QBj-3.412 [middot] 0.2 [middot] EBFcomp,on

Where:

QBj, and QBq, represent gross refrigeration capacity at maximum and 
minimum capacity, respectively.

    4.7.1.4 Calculate average power input during the low load period 
as follows.
    If the low load period box load, BLBL, plus defrost heat 
contribution, QBDF (only applicable for freezers), is less than the 
minimum net capacity qF:
[GRAPHIC] [TIFF OMITTED] TP21AP22.030

Where:

EBF is the steady state condensing unit power input for minimum-
capacity operation.
EBcu,off is the condensing unit off-cycle power input, measured as 
described in Section C3.5 of AHRI 1250-2020.

    If the low load period box load, BLBL, plus defrost heat 
contribution, QBDF , (only applicable for freezers) is greater than 
the minimum net capacity qF:
[GRAPHIC] [TIFF OMITTED] TP21AP22.031

    4.1.7.5 Calculate average power input during the high load 
period as follows.

[[Page 24011]]

[GRAPHIC] [TIFF OMITTED] TP21AP22.032

    4.1.7.6 Calculate the AWEF as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.033
    
    4.7.2 Variable-Capacity or Multistage Condensing Units Tested 
Alone, Indoor.
    4.7.2.1 Unit Cooler Power.
    Calculate maximum-capacity unit cooler power during the 
compressor on period EBFcomp,on as described in section 4.7.1.1 of 
this appendix.
    Calculate unit cooler power during the compressor off period 
EBFcomp,off, in Watts, as 20 percent of the maximum-capacity unit 
cooler power during the compressor on period.
    4.7.2.2 Defrost.
    Calculate Defrost parameters as described in section 4.7.1.2 of 
this appendix.
    4.7.2.3 Net Capacity.
    Calculate steady-state maximum net capacity, qBZ, intermediate 
net capacity, qBF, and minimum net capacity, qBE, as follows:

qBZ = QBj - 3.412 [middot] EBF<INF>comp,on</INF>

qBZ = QBj - 3.412 [middot] K<INF>f</INF> EBF<INF>comp,on</INF>

qBF = QBi - 3.412 [middot] 0.2 [middot] EBF<INF>comp,on</INF>

Where:

QBj, QBm, QBq, and represent gross refrigeration capacity at 
maximum, intermediate, and minimum capacity, respectively.

    K<INF>f</INF> is the unit cooler power coefficient for 
intermediate capacity operation, set equal to 0.2 to represent low-
speed fan operation if the Duty Cycle for a Digital Compressor, the 
Speed Ratio for a Variable-Speed Compressor, or the Displacement 
Ratio for a Multi-Stage Compressor at Intermediate Capacity is 65% 
or less, and otherwise set equal to 1.0.
    4.7.2.4 Calculate average power input during the low load period 
as follows.
    If the low load period box load, BLBL, plus defrost heat 
contribution QBDF (only applicable for freezers) is less than the 
minimum net capacity:
[GRAPHIC] [TIFF OMITTED] TP21AP22.034

    Where EBcu,off, in W, is the condensing unit off-mode power 
consumption, measured as described in Section C3.5 of AHRI 1250-
2020.
    If the low load period box load BLBL plus defrost heat 
contribution QBDF (only applicable for freezers) is greater than the 
minimum net capacity and less than the intermediate net capacity 
qBE:
[GRAPHIC] [TIFF OMITTED] TP21AP22.035

Where:

EER\k=1\ is the minimum-capacity energy efficiency ratio, equal to 
qBF divided by EBF + EBF<INF>comp,on</INF>; and
EER\k=i\ is the intermediate-capacity energy efficiency ratio, equal 
to qBE divided by EBE + EBF<INF>comp,on</INF>.
    4.7.2.5 Calculate average power input during the high load 
period as follows:
    If the high load period box load, BLBH, plus defrost heat 
contribution, QBDF (only applicable for freezers), is greater than 
the minimum net capacity qBF and less than the intermediate net 
capacity qBE:

[[Page 24012]]

[GRAPHIC] [TIFF OMITTED] TP21AP22.036

    If the high load period box load, BLBH, plus defrost heat 
contribution, QBDF (only applicable for freezers), is greater than 
the intermediate net capacity qBE and less than the maximum net 
capacity, qBZ:
[GRAPHIC] [TIFF OMITTED] TP21AP22.037

Where:

EER\k=2\ is the maximum-capacity energy efficiency ratio, equal to 
qBZ divided by EBZ + EBF<INF>comp,on</INF>

    4.7.2.6 Calculate the AWEF as follows.
    [GRAPHIC] [TIFF OMITTED] TP21AP22.038
    
    4.7.3 Two-Capacity Condensing Units Tested Alone, Outdoor.
    4.7.3.1 Unit Cooler Power.
    Calculate maximum-capacity unit cooler power during the 
compressor on period EBFcomp,on, in Watts, using Equation 153 of 
AHRI 1250-2020 for medium-temperature refrigeration systems and 
using Equation 196 of AHRI 1250-2020 for low-temperature 
refrigeration systems.
    Calculate unit cooler power during the compressor off period 
EBFcomp,off, in Watts, as 20 percent of the maximum-capacity unit 
cooler power during the compressor on period.
    4.7.3.2 Defrost.
    Calculate Defrost parameters as described in section 4.7.1.2.
    4.7.3.3 Condensing Unit Off-Cycle Power.
    Calculate Condensing Unit Off-Cycle Power for temperature 
t<INF>j</INF> as follows.
[GRAPHIC] [TIFF OMITTED] TP21AP22.039

    Where EBcu,off,A and EBcu,off,C are the Condensing Unit off-
cycle power measurements for test conditions A and C, respectively, 
measured as described in Section C3.5 of AHRI 1250-2020. If 
t<INF>j</INF> is greater than 35 [deg]F and less than 59 [deg]F, use 
Equation 157 of AHRI 1250-2020, and if t<INF>j</INF> is greater than 
or equal to 59 [deg]F and less than 95 [deg]F, use Equation 159.
    4.7.3.4 Net Capacity and Condensing Unit Power Input.
    Calculate steady-state maximum net capacity, qBZ(t<INF>j</INF>), 
and minimum net capacity, qBZ(t<INF>j</INF>), and corresponding 
condensing unit power input levels EBZ(t<INF>j</INF>) and 
EBF(t<INF>j</INF>) as a function of outdoor temperature 
t<INF>j</INF> as follows:

[[Page 24013]]

[GRAPHIC] [TIFF OMITTED] TP21AP22.040

Where:

The capacity level k can equal 1 or 2;
QBs and QBw represent gross refrigeration capacity at maximum and 
minimum capacity, respectively, for test condition X, which can take 
on values A, B, or C;
EBb and EBg represent condensing unit power input at maximum and 
minimum capacity, respectively for test condition X.

    4.7.3.5 Calculate average power input during the low load period 
as follows.
    Calculate the temperature, t<INF>IL</INF>, below which the low 
load period box load, BLBL(tj), plus defrost heat contribution, QBDF 
(only applicable for freezers), is less than the minimum net 
capacity, qF(tj), by solving the following equation for 
t<INF>IL</INF>:

BLBL(tIL) + QBDF = qF(tIL)

    For t<INF>j</INF> < t<INF>IL</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.041
    
    Where EBcu,off(tj), in W, is the condensing unit off-mode power 
consumption for temperature t<INF>j</INF>, determined as indicated 
in section 4.7.3.3 of this appendix.
    For t<INF>j</INF> >= t<INF>IL</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.042
    
    4.7.3.6 Calculate average power input during the high load 
period as follows.
    Calculate the temperature, t<INF>IH</INF>, below which the high 
load period box load, BLBH(tj), plus defrost heat contribution, QBDF 
(only applicable for freezers), is less than the

[[Page 24014]]

minimum net capacity, qF(tj), by solving the following equation for 
t<INF>IH</INF>:

BLBH(tIH) + QBDF = qF(tIH)

    Calculate the temperature, t<INF>IIH</INF>, below which the high 
load period box load BLBH(tj) plus defrost heat contribution QBDF 
(only applicable for freezers) is less than the maximum net capacity 
qZ(tj), by solving the following equation for t<INF>IIH</INF>:

BLBH(tIH) + QBDF = qF(tIIH)

    For t<INF>j</INF> < t<INF>IH</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.043
    
    For t<INF>IH</INF> <= t<INF>j</INF> < t<INF>IIH</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.044
    
    For t<INF>IIH</INF> <= t<INF>j</INF>:

EBH(tj) + (EBZ(tj) + EBFcomp,on

    4.7.3.7 Calculate the AWEF as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.045
    
    4.7.4 Variable-Capacity or Multistage Condensing Units Tested 
Alone, Outdoor.
    4.7.4.1 Unit Cooler Power.
    Calculate maximum-capacity unit cooler power during the 
compressor on period EBFcomp,on as described in section 4.7.1.1 of 
this appendix.
    Calculate unit cooler power during the compressor off period 
EBFcomp,off, in Watts, as 20 percent of the maximum-capacity unit 
cooler power during the compressor on period.
    4.7.4.2 Defrost.
    Calculate Defrost parameters as described in section 4.7.1.2.
    4.7.4.3 Condensing Unit Off-Cycle Power.
    Calculate Condensing Unit Off-Cycle Power for temperature, 
t<INF>j</INF>, as described in section 4.7.3.3 of this appendix.
    4.7.4.4 Net Capacity and Condensing Unit Power Input.
    Calculate steady-state maximum net capacity, qZ(tj), 
intermediate net capacity, qF(tj), and minimum net capacity, qF(tj), 
and corresponding condensing unit power input levels EBZ(tj), 
EBF(tj), and EBF(tj) as a function of outdoor temperature, 
t<INF>j</INF>, as follows:
    If 35 [deg]F > t<INF>j</INF> >= 59 [deg]F:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.046
    
    If 59 [deg]F >= t<INF>j</INF> > 95 [deg]F:

[[Page 24015]]

[GRAPHIC] [TIFF OMITTED] TP21AP22.047

Where:

The capacity level k can equal 1, i, or 2;
QBs, QBt and QBt represent gross refrigeration capacity at maximum, 
intermediate, and minimum capacity, respectively, for test condition 
X, which can take on values A, B, or C;
EBb and EBa represent condensing unit power input at maximum and 
minimum capacity, respectively for test condition X; and
K<INF>f</INF> is the unit cooler power coefficient for intermediate 
capacity operation, set equal to 0.2 to represent low-speed fan 
operation if the Duty Cycle for a Digital Compressor, the Speed 
Ratio for a Variable-Speed Compressor, or the Displacement Ratio for 
a Multi-Stage Compressor at Intermediate Capacity is 65% or less, 
and otherwise set equal to 1.0.

    4.7.4.5 Calculate average power input during the low load period 
as follows.
    Calculate the temperature, t<INF>IL</INF>, below which the low 
load period box load BLBL(tj) plus defrost heat contribution, QBDF 
(only applicable for freezers), is less than the minimum net 
capacity, qF(tj), by solving the following equation for 
t<INF>IL</INF>:
BLBL(tIL) + qF(tIL)

    Calculate the temperature, t<INF>VL</INF>, below which the low 
load period box load, BLBL(tj), plus defrost heat contribution, QBDF 
(only applicable for freezers), is less than the intermediate net 
capacity, qF(tj), by solving the following equation for 
t<INF>VL</INF>:

BLBL(tVL) + QBDF = qE(tVL)

    For t<INF>j</INF> < t<INF>IL</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.048
    
    Where EBcu,off(tj), in W, is the condensing unit off-mode power 
consumption for temperature, t<INF>j</INF>, determined as indicated 
in section 4.7.3.3 of this appendix.
    For t<INF>IL</INF> <= t<INF>j</INF> < t<INF>VL</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.049
    
    For t<INF>VL</INF> <= t<INF>j</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.050
    

[[Page 24016]]


Where:

EER\k=1\(t<INF>j</INF>) is the minimum-capacity energy efficiency 
ratio, equal to qF(tj) divided by EBF(tj) + 0.2 [middot] EBFcomp,on;
EER\k=i\(t<INF>j</INF>) is the intermediate-capacity energy 
efficiency ratio, equal to qE(tj) divided by EBssk=i(tj) + Kf 
[middot] EBFcomp,on; and
EER\k=2\(t<INF>j</INF>) is the maximum-capacity energy efficiency 
ratio, equal to qZ(tj) divided by EBZ(tj) + EBFcomp,on

    4.7.4.6 Calculate average power input during the high load 
period as follows.
    Calculate the temperature t<INF>VH</INF> below which the high 
load period box load BLBH(tj) plus defrost heat contribution QBDF 
(only applicable for freezers) is less than the intermediate net 
capacity qE(tj), by solving the following equation for 
t<INF>VH</INF>:

BLBH(tVH) + QBDF = qssk=i(tVH)

    Calculate the temperature t<INF>IIH</INF> below which the high 
load period box load BLBH(tj) plus defrost heat contribution QBDF 
(only applicable for freezers) is less than the maximum net capacity 
qZ(tj), by solving the following equation for t<INF>IIH</INF>:

BLBH(tIIH) + QBDF = qZs(tIIH)

    For t<INF>j</INF> < t<INF>VH</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.051
    
    For t<INF>VH</INF> <= t<INF>j</INF> < t<INF>IIH</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.052
    
    For t<INF>IIH</INF> <= t<INF>j</INF>:

EBH(tj) = (EBZ(tj) + EBFcomp,on)

    4.7.4.7 Calculate the AWEF as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.053
    
    4.7.5 Two-Capacity Indoor Matched Pairs or Single-Packaged 
Refrigeration Systems Other than High-Temperature.
    4.7.5.1 Defrost.
    For freezer refrigeration systems, defrost heat contribution 
QBDF in Btu/h and the defrost average power consumption DBF in W 
shall be as measured in accordance with Section C10.2.1 of Appendix 
C of AHRI 1250-2020.
    4.7.5.2 Calculate average power input during the low load period 
as follows.
    If the low load period box load BLBL plus defrost heat 
contribution QBDF (only applicable for freezers) is less than the 
minimum net capacity qF:
[GRAPHIC] [TIFF OMITTED] TP21AP22.054

Where:

qF and EBF> are the steady state refrigeration system minimum net 
capacity, in Btu/h, and associated refrigeration system power input, 
in W, respectively, for minimum-capacity operation, measured as 
described in AHRI 1250-2020.
EBFcomp,off and EBcu,off, both in W, are the unit cooler and 
condensing unit, respectively, off-mode power consumption, measured 
as described in Section C3.5 of AHRI 1250-2020.

    If the low load period box load BLBL plus defrost heat 
contribution QBDF (only applicable for freezers) is greater than the 
minimum net capacity qF:

[[Page 24017]]

[GRAPHIC] [TIFF OMITTED] TP21AP22.055

    Where qZ and EBZ are the steady state refrigeration system 
maximum net capacity, in Btu/h, and associated refrigeration system 
power input, in W, respectively, for maximum-capacity operation, 
measured as described in AHRI 1250-2020.
    4.7.5.3 Calculate average power input during the high load 
period as follows.
[GRAPHIC] [TIFF OMITTED] TP21AP22.056

    4.7.5.4 Calculate the AWEF as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.057
    
    4.7.6 Variable-Capacity or Multistage Indoor Matched Pairs or 
Single-Packaged Refrigeration Systems Other than High-Temperature.
    4.7.6.1 Defrost.
    For freezer refrigeration systems, defrost heat contribution in 
Btu/h and the defrost average power consumption in W shall be as 
measured in accordance with Section C10.2.1 of Appendix C of AHRI 
1250-2020.
    4.7.6.2 Calculate average power input during the low load period 
as follows.
    If the low load period box load BLBL plus defrost heat 
contribution QBDF (only applicable for freezers) is less than the 
minimum net capacity qF
[GRAPHIC] [TIFF OMITTED] TP21AP22.058

Where:

qF and EBF are the steady state refrigeration system minimum net 
capacity, in Btu/h, and associated refrigeration system power input, 
in W, respectively, for minimum-capacity operation, measured as 
described in AHRI 1250-2020; and
 EBFcomp,off and EBcu,off, both in W, are the unit cooler and 
condensing unit, respectively, off-mode power consumption, measured 
as described in Section C3.5 of AHRI 1250-2020.

    If the low load period box load BLBL plus defrost heat 
contribution QBDF (only applicable for freezers) is greater than the 
minimum net capacity qF and less than the intermediate net capacity 
qE:
[GRAPHIC] [TIFF OMITTED] TP21AP22.059

[GRAPHIC] [TIFF OMITTED] TP21AP22.060


[[Page 24018]]


Where:

EER\k=1\ is the minimum-capacity energy efficiency ratio, equal to 
qF divided by EBF;
qF and EBF are the steady state refrigeration system intermediate 
net capacity, in Btu/h, and associated refrigeration system power 
input, in W, respectively, for intermediate-capacity operation, 
measured as described in AHRI 1250-2020.
EER\k=i\ is the intermediate-capacity energy efficiency ratio, equal 
to qE divided by EBF.

    4.7.6.3 Calculate average power input during the high load 
period as follows.
    If the high load period box load BLBH plus defrost heat 
contribution QBDF (only applicable for freezers) is greater than the 
minimum net capacity qF and less than the intermediate net capacity 
qE:
[GRAPHIC] [TIFF OMITTED] TP21AP22.061

    If the high load period box load BLBH plus defrost heat 
contribution QBDF (only applicable for freezers) is greater than the 
intermediate net capacity qE and less than the maximum net capacity 
qZ:
[GRAPHIC] [TIFF OMITTED] TP21AP22.062

Where:

qZ and EBZ are the steady state refrigeration system maximum net 
capacity, in Btu/h, and associated refrigeration system power input, 
in W, respectively, for maximum-capacity operation, measured as 
described in AHRI 1250-2020; and
EER\k=2\ is the maximum-capacity energy efficiency ratio, equal toqZ 
divided by EBZ.

    4.7.6.4 Calculate the AWEF as follows.
    [GRAPHIC] [TIFF OMITTED] TP21AP22.063
    
    4.7.7 Variable-Capacity or Multistage Outdoor Matched Pairs or 
Single-Packaged Refrigeration Systems Other than High-Temperature.
    Calculate AWEF as described in Section 7.6 of AHRI 1250-2020, 
with the following revisions.
    4.7.7.1 Condensing Unit Off-Cycle Power.
    Calculate condensing unit off-cycle power for temperature 
t<INF>j</INF> as indicated in section 4.7.3.3 of this appendix. 
Replace the constant value EBCU,off in Equations 55 and 70 of AHRI 
1250-2020 with the values EBCU,off(tj), which vary with outdoor 
temperature t<INF>j</INF>.
    4.7.7.2 Unit Cooler Off-Cycle Power.
    Set unit cooler Off-Cycle power EBFcomp,off equal to the average 
of the unit cooler off-cycle power measurements made for test 
conditions A, B, and C.
    4.7.7.3 Average Power During the Low Load Period.
    Calculate average power for intermediate-capacity compressor 
operation during the low load period EBss,Lk=v(tj) as described in 
Section 7.6 of AHRI 1250-2020, except that, instead of calculating 
intermediate-capacity compressor EER using Equation 77, calculate 
EER as follows.
    For t<INF>j</INF> < t<INF>VL</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.064
    
    For t<INF>VL</INF> <= t<INF>j</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.065
    

[[Page 24019]]


Where:

EER\k=1\(t<INF>j</INF>) is the minimum-capacity energy efficiency 
ratio, equal to qF(tj) divided by EBFk=1(tj);
EER\k=i\(t<INF>j</INF>) is the intermediate-capacity energy 
efficiency ratio, equal to qF(tj) divided by EBF(tj); and
EER\k=2\(t<INF>j</INF>) is the maximum-capacity energy efficiency 
ratio, equal to qF(tj) divided by EBZ(tj)

    4.7.7.4 Average Power During the High Load Period.
    Calculate average power for intermediate-capacity compressor 
operation during the high load period EBS(tj) as described in 
Section 7.6 of AHRI 1250-2020, except that, instead of calculating 
intermediate-capacity compressor EER using Equation 61, calculate 
EER as follows:
    For t<INF>j</INF> < t<INF>VH</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.066
    
    For t<INF>VH</INF> <= t<INF>j</INF>:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.067
    
    4.7.8 Two-Capacity Outdoor Matched Pairs or Single-Packaged 
Refrigeration Systems Other than High-Temperature.
    Calculate AWEF as described in Section 7.5 of AHRI 1250-2020, 
with the following revisions for Condensing Unit Off-Cycle Power and 
Unit Cooler Off-Cycle Power. Calculate condensing unit off-cycle 
power for temperature t<INF>j</INF> as indicated in section 4.7.3.3 
of this appendix. Replace the constant value EBCU,off in Equations 
13 and 29 of AHRI 1250-2020 with the values EBCU,off(tj), which vary 
with outdoor temperature (t<INF>j</INF>. Set unit cooler Off-Cycle 
power EBFcomp,off equal to the average of the unit cooler off-cycle 
power measurements made for test conditions A, B, and C.
    4.7.9 Single-capacity Outdoor Matched Pairs or Single-Packaged 
Refrigeration Systems Other than High-Temperature.
    Calculate AWEF as described in Section 7.4 of AHRI 1250-2020, 
with the following revision for Condensing Unit Off-Cycle Power and 
Unit Cooler Off-cycle Power. Calculate condensing unit off-cycle 
power for temperature t<INF>j</INF> as indicated in section 4.7.3.3 
of this appendix. Replace the constant value EBCU,off in Equations 
13 of AHRI 1250-2020 with the values EBCU,off(tj), which vary with 
outdoor temperature t<INF>j</INF>. Set unit cooler Off-Cycle power 
EBFcomp,off equal to the average of the unit cooler off-cycle power 
measurements made for test conditions A, B, and C.
    4.7.10 Single-capacity Condensing Units, Outdoor.
    Calculate AWEF as described in Section 7.9 of AHRI 1250-2020, 
with the following revision for Condensing Unit Off-Cycle Power. 
Calculate condensing unit off-cycle power for temperature 
t<INF>j</INF> as indicated in section 4.7.3.3 of this appendix 
rather than as indicated in equations 157, 159, 202, and 204 of AHRI 
1250-2020.
    4.7.11 High-Temperature Matched Pairs or Single-Packaged 
Refrigeration Systems, Indoor.
    4.7.11.1 Calculate Load Factor LF as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.068
    
Where:

BBL, in Btu/h is the non-equipment-related box load calculated as 
described in section 4.6.3 of this appendix;
EBFcomp,off, in W, is the unit cooler off-cycle power consumption, 
equal to 0.1 times the unit cooler on-cycle power consumption; and
qBss,A, in Btu/h is the measured net capacity for test condition A.

    4.7.11.2 Calculate the AWEF as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.069
    
Where:

EBss,A, in W, is the measured system power input for test condition 
A; and
EBcu,off, in W, is the condensing unit off-cycle power consumption, 
measured as described in Section C3.5 of AHRI 1250-2020.

    4.7.12 High-Temperature Matched Pairs or Single-Packaged 
Refrigeration Systems, Outdoor.
    4.7.12.1 Calculate Load Factor LF(t<INF>j</INF>) for outdoor 
temperature t<INF>j</INF> as follows:
[GRAPHIC] [TIFF OMITTED] TP21AP22.070

Where:

BBL, in Btu/h, is the non-equipment-related box load calculated as 
described in section 4.6.3 of this appendix;
EBFcomp,off, in W, is the unit cooler off-cycle power consumption, 
equal to 0.1 times the unit cooler on-cycle power consumption; and
qBss(tj), in Btu/h, is the net capacity for outdoor temperature 
t<INF>j</INF>, calculated as described in Section 7.4.2 of AHRI 
1250-2020.

    4.7.12.2 Calculate the AWEF as follows:

[[Page 24020]]

[GRAPHIC] [TIFF OMITTED] TP21AP22.071

Where:

EBss(tj), in W, is the system power input for temperature 
t<INF>j</INF>, calculated as described in Section 7.4.2 of AHRI 
1250-2020;
EBcu,off in W, is the condensing unit off-cycle power consumption, 
measured as described in Section C3.5 of AHRI 1250-2020; and
n<INF>j</INF> are the hours for temperature bin j.

    4.7.13 High-Temperature Unit Coolers Tested Alone.
    4.7.13.1 Calculate Refrigeration System Power Input as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.072
    
Where:

qBmix,evap, in W, is the net evaporator capacity, measured as 
described in AHRI 1250-2020;
EBFcomp,on, in W, is the unit cooler on-cycle power consumption; and 
EER, in W, equals
[GRAPHIC] [TIFF OMITTED] TP21AP22.073

    4.7.13.2 Calculate the load factor LF as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.074
    
Where:

BBL, in Btu/h, is the non-equipment-related box load calculated as 
described in section 4.6.3 of this appendix; and
EBFcomp,off, in W, is the unit cooler off-cycle power consumption, 
equal to 0.1 times the unit cooler on-cycle power consumption.

    4.7.13.3 Calculate AWEF as follows:
    [GRAPHIC] [TIFF OMITTED] TP21AP22.075
    
    4.7.14 CO<INF>2</INF> Unit Coolers Tested Alone.
    Calculate AWEF for CO<INF>2</INF> Unit Coolers Tested Alone 
using the calculations specified in in Section 7.8 of AHRI 1250-2020 
for calculation of AWEF for Unit Cooler Tested Alone.
    4.8. Test Method.
    Test the Refrigeration System in accordance with AHRI 1250-2020 
to determine refrigeration capacity and power input for the 
specified test conditions, with revisions and additions as described 
in this section.
    4.8.1 Chamber Conditioning Using the Unit Under Test.
    In Appendix C, Section C5.2.2 of AHRI 1250-2020, for applicable 
system configurations (matched pairs, single-packaged refrigeration 
systems, and standalone unit coolers), the unit under test may be 
used to aid in achieving the required test chamber conditions prior 
to beginning any steady state test. However, the unit under test 
must be inspected and confirmed to be free from frost before 
initiating steady state testing.
    4.8.2 General Modification: Methods of Testing.
    4.8.2.1 Refrigerant Temperature Measurements.
    When testing a condensing unit alone, measure refrigerant liquid 
temperature leaving the condensing unit as required in Section 
C7.5.1.1.2 of Appendix C of AHRI 1250-2020 using the same 
measurement approach specified for the unit cooler in Section C3.1.3 
of Appendix C of AHRI 1250-2020. In all cases in which thermometer 
wells or immersed sheathed sensors are prescribed, if the 
refrigerant tube outer diameter is less than \1/2\ inch, the 
refrigerant temperature may be measured using the average of two 
temperature measuring instruments with a minimum accuracy of <plus-
minus>0.5 [deg]F placed on opposite sides of the refrigerant tube 
surface--resulting in a total of up to 8 temperature measurement 
devices used for the DX Dual Instrumentation method. In this case, 
the refrigerant tube shall be insulated with 1-inch thick insulation 
from a point 6 inches upstream of the measurement location to a 
point 6 inches downstream of the measurement location. Also, to 
comply with this requirement, the unit cooler/evaporator entering 
measurement location may be moved to a location 6 inches upstream of 
the expansion device and, when testing a condensing unit alone, the 
entering and leaving measurement locations may be moved to locations 
6 inches from the respective service valves.
    4.8.2.2 Mass Flow Meter Location.

[[Page 24021]]

    When using the DX Dual Instrumentation test method of AHRI 1250-
2020, applicable for unit coolers, dedicated condensing units, and 
matched pairs, the second mass flow meter may be installed in the 
suction line as shown in Figure C1 of AHRI 1250-2020.
    4.8.2.3 Subcooling at Refrigerant Mass Flow Meter.
    In Section C3.4.5 of Appendix C of AHRI 1250-2020, when 
verifying sub-cooling at the mass flow meters, only the sight glass 
and a temperature sensor located on the tube surface under the 
insulation are required. Subcooling shall be verified to be within 
the 3 [deg]F requirement downstream of flow meters located in the 
same chamber as a condensing unit under test and upstream of flow 
meters located in the same chamber as a unit cooler under test, 
rather than always downstream as indicated in AHRI 1250-2009, 
Section C3.4.5. If the subcooling is less than 3 [deg]F when testing 
a unit cooler, dedicated condensing unit, or matched pair (not a 
single-packaged system), cool the line between the condensing unit 
outlet and this location to achieve the required subcooling. When 
providing such cooling while testing a matched pair, also measure 
the refrigerant temperature upstream of the location that the line 
is being cooled, and increase the temperature used to calculate unit 
cooler entering enthalpy by the difference between the upstream and 
downstream temperatures.
    4.8.2.4 Installation Instructions.
    Manufacturer installation instructions or installation 
instructions described in this section refer to the instructions 
that come packaged with or appear on the labels applied to the unit. 
This does not include online manuals.
    Installation Instruction Hierarchy: If a given installation 
instruction provided on the label(s) applied to the unit conflicts 
with the installation instructions that are shipped with the unit, 
the label takes precedence. For testing of matched pairs, the 
installation instructions for the dedicated condensing unit shall 
take precedence. Setup shall be in accordance with the field 
installation instructions (laboratory installation instructions 
shall not be used). Achieving test conditions shall always take 
precedence over installation instructions.
    4.8.2.5 Refrigerant Charging and Adjustment of Superheat and 
Subcooling.
    All test samples shall be charged, and superheat and/or 
subcooling shall be set, at Refrigeration A test conditions unless 
otherwise specified in the installation instructions. If the 
installation instructions give a specified range for superheat, sub-
cooling, or refrigerant pressure, the average of the range shall be 
used as the refrigerant charging parameter target and the test 
condition tolerance shall be <plus-minus>50 percent of the range. 
Perform charging of near-azeotropic and zeotropic refrigerants only 
with refrigerant in the liquid state. Once the correct refrigerant 
charge is determined, all tests shall run until completion without 
further modification.
    4.8.2.5.1. When charging or adjusting superheat/subcooling, use 
all pertinent instructions contained in the installation 
instructions to achieve charging parameters within the tolerances. 
However, in the event of conflicting charging information between 
installation instructions, follow the installation instruction 
hierarchy listed in section 4.8.2.4. Conflicting information is 
defined as multiple conditions given for charge adjustment where all 
conditions specified cannot be met. In the event of conflicting 
information within the same set of charging instructions (e.g., the 
installation instructions shipped with the dedicated condensing 
unit), follow the hierarchy in Table 19 of this appendix for 
priority. Unless the installation instructions specify a different 
charging tolerance, the tolerances identified in Table 19 shall be 
used.

Table 19--Test Condition Tolerances and Hierarchy for Refrigerant Charging and Setting of Refrigerant Conditions
----------------------------------------------------------------------------------------------------------------
                                     Fixed orifice                                 Expansion valve
                    --------------------------------------------------------------------------------------------
      Priority           Parameter with                                 Parameter with
                          installation             Tolerance             installation            Tolerance
                       instruction target                             instruction target
----------------------------------------------------------------------------------------------------------------
1..................  Super-heat............  <plus-minus>2.0        Sub-cooling..........  10% of the Target
                                              [deg]F.                                       Value; No less than
                                                                                            <plus-minus>0.5
                                                                                            [deg]F, No more than
                                                                                            <plus-minus>2.0
                                                                                            [deg]F.
2..................  High Side Pressure or   <plus-minus>4.0 psi    High Side Pressure or  <plus-minus>4.0 psi
                      Saturation              or <plus-minus>1.0     Saturation             or
                      Temperature.            [deg]F.                Temperature.          <plus-minus>1.0
                                                                                            [deg]F.
3..................  Low Side Pressure or    <plus-minus>2.0 psi    Super-heat...........  <plus-minus>2.0
                      Saturation              or <plus-minus>0.8                            [deg]F.
                      Temperature.            [deg]F.
4..................  Low Side Temperature..  <plus-minus>2.0        Low Side Pressure or   <plus-minus>2.0 psi
                                              [deg]F.                Saturation             or
                                                                     Temperature.          <plus-minus>0.8
                                                                                            [deg]F.
5..................  High Side Temperature.  <plus-minus>2.0        Approach Temperature.  <plus-minus>1.0
                                              [deg]F.                                       [deg]F.
6..................  Charge Weight.........  <plus-minus>2.0 oz...  Charge Weight........  0.5% or 1.0 oz,
                                                                                            whichever is
                                                                                            greater.
----------------------------------------------------------------------------------------------------------------

    4.8.2.5.2. Dedicated Condensing Unit.
    If the Dedicated Condensing Unit includes a receiver and the 
subcooling target leaving the condensing unit provided in 
installation instructions cannot be met without fully filling the 
receiver, the subcooling target shall be ignored. Likewise, if the 
Dedicated Condensing unit does not include a receiver and the 
subcooling target leaving the condensing unit cannot be met without 
the unit cycling off on high pressure, the subcooling target can be 
ignored. Also, if no instructions for charging or for setting 
subcooling leaving the condensing unit are provided in the 
installation instructions, the refrigeration system shall be set up 
with a charge quantity and/or exit subcooling such that the unit 
operates during testing without shutdown (e.g., on a high-pressure 
switch) and operation of the unit is otherwise consistent with the 
requirements of the test procedure of this appendix and the 
installation instructions.
    4.8.2.5.3. Unit Cooler. Use the shipped expansion device for 
testing. Otherwise, use the expansion device specified in the 
installation instructions. If the installation instructions specify 
multiple options for the expansion device, any specified expansion 
device may be used. The supplied expansion device shall be adjusted 
until either the superheat target is met, or the device reaches the 
end of its adjustable range. In the event the device reaches the end 
of its adjustable range and the super heat target is not met, test 
with the adjustment at the end of its range providing the closest 
match to the superheat target, and the test condition tolerance for 
super heat target shall be ignored. The measured superheat is not 
subject to a test operating tolerance. However, if the evaporator 
exit condition is used to determine capacity using the DX dual-
instrumentation method or the refrigerant enthalpy method, 
individual superheat value measurements may not be equal to or less 
than zero. If this occurs, or if the operating tolerances of 
measurements affected by expansion device fluctuation are exceeded, 
the expansion device shall be replaced, operated at an average 
superheat value higher than the target, or both, in order to avoid 
individual superheat value measurements less than zero and/or to 
meet the required operating tolerances.
    4.8.2.5.4. Single-Packaged Unit. Unless otherwise directed by 
the installation instructions, install one or more refrigerant line 
pressure gauges during the setup of the unit, located depending on 
the parameters used to verify or set charge, as described in this 
section:
    4.8.2.5.4.1. Install a pressure gauge in the liquid line if 
charging is on the basis of subcooling, or high side pressure or

[[Page 24022]]

corresponding saturation or dew point temperature.
    4.8.2.5.4.2. Install a pressure gauge in the suction line if 
charging is on the basis of superheat, or low side pressure or 
corresponding saturation or dew point temperature. Install this 
gauge as close to the evaporator as allowable by the installation 
instructions and the physical constraints of the unit. Use methods 
for installing pressure gauge(s) at the required location(s) as 
indicated in the installation instructions if specified.
    4.8.2.5.4.3. If the installation instructions indicate that 
refrigerant line pressure gauges should not be installed and the 
unit fails to operate due to high pressure or low pressure 
compressor cut off, then a charging port shall be installed, and the 
unit shall be evacuated of refrigerant and charged to the nameplate 
charge.
    4.8.2.6 Ducted Units.
    For systems with ducted evaporator air, or that can be installed 
with or without ducted evaporator air: Connect ductwork on both the 
inlet and outlet connections and determine external static pressure 
(ESP) as described in Sections 6.4 and 6.5 of ANSI/ASHRAE 37. Use 
pressure measurement instrumentation as described in Section 5.3.2 
of ANSI/ASHRAE 37. Test at the fan speed specified in the 
installation instructions--if there is more than one fan speed 
setting and the installation instructions do not specify which speed 
to use, test at the highest speed. Conduct tests with the ESP equal 
to 50% of the maximum ESP allowed in the installation instructions, 
within a tolerance of -0.00/+0.05 inches of water column. If the 
installation instructions do not provide the maximum ESP, the ESP 
shall be set for testing such that the air volume rate is \2/3\ of 
the air volume rate measured when the ESP is 0.00 inches of water 
column within a tolerance of -0.00/+0.05 inches of water column.
    If testing using either the indoor or outdoor air enthalpy 
method to measure the air volume rate, adjust the airflow 
measurement apparatus fan to set the external static pressure--
otherwise, set the external static pressure by symmetrically 
restricting the outlet of the test duct. In case of conflict, these 
requirements for setting airflow take precedence over airflow values 
specified in manufacturer installation instructions or product 
literature.
    4.8.2.7 Two-Speed or Multiple-Speed Evaporator Fans. Two-Speed 
or Multiple-Speed evaporator fans shall be considered to meet the 
qualifying control requirements of Section C4.2 of Appendix C of 
AHRI 1250-2020 for measuring off-cycle fan energy if they use a fan 
speed no less than 50% of the speed used in the maximum capacity 
tests.
    4.8.2.8 Defrost.
    Use Section C10.2.1 of Appendix C of AHRI 1250-2020 for defrost 
testing. The Test Room Conditioning Equipment requirement of Section 
C10.2.1.1 of Appendix C of AHRI 1250-2020 does not apply.
    4.8.2.8.1 Adaptive Defrost.
    When testing to certify compliance to the energy conservation 
standards, use N<INF>DF</INF> = 4, as instructed in Section 
C10.2.1.7 or C10.2.2.1 of AHRI 1250-2020. When determining the 
represented value of the calculated benefit for the inclusion of 
adaptive defrost, use N<INF>DF</INF> = 2.5, as instructed in Section 
C10.2.1.7 or C10.2.2.1 of AHRI 1250-2020.
    4.8.2.8.2 Hot Gas Defrost.
    When testing to certify compliance to the energy conservation 
standards, remove the hot gas defrost mechanical components and 
disconnect all such components from electrical power. Test the units 
as if they are electric defrost units, but do not conduct the 
defrost tests described in Section C10.2.1 of AHRI 1250-2020. Use 
the defrost heat and power consumption values as described in 
Section C10.2.2 of AHRI 1250-2020 for the AWEF calculations.
    When determining the represented value of the calculated benefit 
for the inclusion of hot gas defrost, test with hot gas mechanical 
components installed, but do not conduct the defrost tests. Use the 
defrost heat and power consumption values as described in Section 
C10.1.1 of AHRI 1250-2020 for the AWEF calculations.
    4.8.2.9 Dedicated condensing units that are not matched for 
testing and are not single-packaged dedicated systems.
    The temperature measurement requirements of sections C3.1.3 and 
C4.1.3.1 Appendix C of AHRI 1250-2020 shall apply only to the 
condensing unit exit rather than to the unit cooler inlet and 
outlet, and they shall be applied for two measurements when using 
the DX Dual Instrumentation test method.
    4.8.2.10 Single-packaged dedicated systems.
    Use the test method in section C9 of Appendix C of AHRI 1250-
2020 as the method of test for single-packaged dedicated systems, 
with modifications as described in this section. Use two test 
methods listed in Table 20 of this appendix to calculate the net 
capacity and power consumption. The test method listed with a lower 
``Hierarchy Number'' and that has ``Primary'' as an allowable use in 
Table 20 shall be considered the primary measurement and used as the 
net capacity.

                             Table 20--Single-Packaged Methods of Test and Hierarchy
----------------------------------------------------------------------------------------------------------------
             Hierarchy No.                      Method of test                        Allowable use
----------------------------------------------------------------------------------------------------------------
1.....................................  Balanced Ambient Indoor         Primary.
                                         Calorimeter.
2.....................................  Indoor Air Enthalpy...........  Primary or Secondary.
3.....................................  Indoor Room Calorimeter.......  Primary or Secondary.
4.....................................  Balanced Ambient Outdoor        Secondary.
                                         Calorimeter.
5.....................................  Outdoor Air Enthalpy..........  Secondary.
6.....................................  Outdoor Room Calorimeter......  Secondary.
7.....................................  Single-Packaged Refrigerant     Secondary.
                                         Enthalpy\1\.
8.....................................  Compressor Calibration........  Secondary.
----------------------------------------------------------------------------------------------------------------
Notes:
\1\ See description of the single-packaged refrigerant enthalpy method in section 4.8.2.10.1 of this appendix.

    4.8.2.10.1 Single-Packaged Refrigerant Enthalpy Method.
    The single-packaged refrigerant enthalpy method shall follow the 
test procedure of the DX Calibrated Box method in AHRI 1250-2020, 
Appendix C, section C8 for refrigerant-side measurements with the 
following modifications.
    4.8.2.10.1.1 Air-side measurements shall follow the requirements 
of the primary single-packaged method listed in Table 20 of this 
appendix. The air-side measurements and refrigerant-side 
measurements shall be collected over the same intervals.
    4.8.2.10.1.2 A preliminary test at Test Rating Condition A is 
required using the primary method prior to any modification 
necessary to install the refrigerant-side measuring instruments. 
Install surface mount temperature sensors on the evaporator and 
condenser coils at locations not affected by liquid subcooling or 
vapor superheat (i.e., near the midpoint of the coil at a return 
bend), entering and leaving the compressor, and entering the 
expansion device. These temperature sensors shall be included in the 
regularly recorded data.
    4.8.2.10.1.3 After the preliminary test is completed, the 
refrigerant shall be removed from the equipment and the refrigerant-
side measuring instruments shall be installed. The equipment shall 
then be evacuated and recharged with refrigerant. Once the equipment 
is operating at Test Condition A, the refrigerant charge shall be 
adjusted until, as compared to the average values from the 
preliminary test, the following conditions are achieved:
    (1) Each on-coil temperature sensor indicates a reading that is 
within <plus-minus>1.0 [deg]F of the measurement in the initial 
test,
    (2) The temperatures of the refrigerant entering and leaving the 
compressor are within <plus-minus>4 [deg]F, and
    (3) The refrigerant temperature entering the expansion device is 
within <plus-minus>1 [deg]F. Once these conditions have been 
achieved over an interval of at least ten minutes, refrigerant

[[Page 24023]]

charging equipment shall be removed and the official tests shall be 
conducted.
    4.8.2.10.1.4 The lengths of liquid line to be added shall be 5 
feet maximum, not including the requisite flow meter. This maximum 
length applies to each circuit separately.
    4.8.2.10.1.5 Use section C9.2 of Appendix C of AHRI 1250-2020 
for allowable refrigeration capacity heat balance. Calculate the 
single-packaged refrigerant enthalpy (secondary) method test net 
capacity QBnet,secondary as follows:

QBnet,secondary = QBref-3.412.EBFcomp,on-QBsploss

Where:

QBref is the gross capacity;
EBFcomp,on is the evaporator compartment on-cycle power, including 
evaporator fan power; and
QBsploss is a duct loss calculation applied to the evaporator 
compartment of the single-packaged systems, which is calculated as 
indicated below.

QBsploss = UAcond x (Tevapside-Tcondside) + UAamb x (Tevapside-Tamb)

Where:

UA<INF>cond</INF> and UA<INF>amb</INF> are, for the condenser/
evaporator partition and the evaporator compartment walls exposed to 
ambient air, respectively, the product of the overall heat transfer 
coefficient and surface area of the unit as manufactured, i.e., 
without external insulation that might have been added during the 
test. The areas shall be calculated based on measurements, and the 
thermal resistance values shall be based on insulation thickness and 
insulation material;
T<INF>evapside</INF> is the air temperature in the evaporator 
compartment--the measured evaporator air inlet temperature may be 
used;
T<INF>condside</INF> is the air temperature in the condenser 
compartment--the measured chamber ambient temperature may be used, 
or a measurement may be made using a temperature sensor placed 
inside the condenser box at least 6 inches distant from any part of 
the refrigeration system; and
T<INF>amb</INF> is the air temperature outside the single-packaged 
system.

    4.8.2.10.1.6 For multi-circuit single-packaged systems utilizing 
the single-packaged refrigerant enthalpy method, apply the test 
method separately for each circuit and sum the separately-calculated 
refrigerant-side gross refrigeration capacities.
    4.8.2.10.2 Detachable single-packaged systems shall be tested as 
single-packaged dedicated refrigeration systems.
    4.8.2.11 Variable-Capacity and Multiple-Capacity Dedicated 
Condensing Refrigeration Systems.
    4.8.2.11.1 Manufacturer-Provided Equipment Overrides.
    Where needed, the manufacturer must provide a means for 
overriding the controls of the test unit so that the compressor(s) 
operates at the specified speed or capacity and the indoor blower 
operates at the speed consistent with the compressor operating level 
as would occur without override.
    4.8.2.11.2 Compressor Operating Levels.
    For variable-capacity and multiple-capacity compressor systems, 
the minimum capacity for testing shall be the minimum capacity that 
the system control would operate the compressor in normal operation. 
Likewise, the maximum capacity for testing shall be the maximum 
capacity that the system control would operate the compressor in 
normal operation. For variable-speed compressor systems, the 
intermediate speed for testing shall be the average of the minimum 
and maximum speeds. For digital compressor systems, the intermediate 
duty cycle shall be the average of the minimum and maximum duty 
cycles. For multiple-capacity compressor systems with three capacity 
levels, the intermediate operating level for testing shall be the 
middle capacity level. For multiple-capacity compressor systems with 
more than three capacity levels, the intermediate operating level 
for testing shall be the level whose displacement ratio is closest 
to the average of the maximum and minimum displacement ratios.
    4.8.2.11.3 Refrigeration Systems with Digital Compressor(s).
    Use the test methods described in section 4.8.2.10.1 of this 
appendix as the secondary method of test for refrigeration systems 
with digital compressor(s) with modifications as described in this 
section. The Test Operating tolerance for refrigerant mass flow rate 
and suction pressure in Table 2 of AHRI 1250-2020 shall be ignored. 
Temperature and pressure measurements used to calculate QBref shall 
be recorded at a frequency of once per second or faster and based on 
average values measured over the 30-minute test period.
    4.8.2.11.3.1 For Matched pair (not including single-packaged 
systems) and Dedicated Condensing Unit refrigeration systems, the 
preliminary test in sections 4.8.2.10.1.2 and 4.8.2.10.1.3 of this 
appendix is not required. The liquid line and suction line shall be 
25 feet <plus-minus> 3 inches, not including the requisite flow 
meters. Also, the term QBsploss in the equation to calculate net 
capacity shall be set equal to zero.
    4.8.2.11.3.2 For Dedicated Condensing Unit refrigeration 
systems, the primary capacity measurement method shall be balanced 
ambient outdoor calorimeter, outdoor air enthalpy, or outdoor room 
calorimeter.

[FR Doc. 2022-06423 Filed 4-20-22; 8:45 am]
BILLING CODE 6450-01-P


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