`[Federal Register Volume 86, Number 127 (Wednesday, July 7, 2021)]
[Proposed Rules]
[Pages 36018-36060]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-13773]



[[Page 36017]]

Vol. 86

Wednesday,

No. 127

July 7, 2021

Part III





Department of Energy





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10 CFR Parts 429 and 431





Energy Conservation Program: Test Procedure for Dehumidifying Direct 
Expansion-Dedicated Outdoor Air Systems; Proposed Rule

  Federal Register / Vol. 86 , No. 127 / Wednesday, July 7, 2021 / 
Proposed Rules  

[[Page 36018]]


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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2017-BT-TP-0018]
RIN 1904-AD93


Energy Conservation Program: Test Procedure for Dehumidifying 
Direct Expansion-Dedicated Outdoor Air Systems

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

ACTION: Notice of proposed rulemaking and request for comment.

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SUMMARY: The U.S. Department of Energy (DOE) is proposing to establish 
definitions for ``direct expansion-dedicated outdoor air systems'' (DX-
DOAS or DX-DOASes) and ``dehumidifying direct expansion-dedicated 
outdoor air systems'' (DDX-DOAS or DDX-DOASes). DX-DOASes are a 
category of small, large, and very large commercial package air 
conditioning and heating equipment under the Energy Policy and 
Conservation Act (EPCA), as amended. In addition, DOE is proposing to 
establish a test procedure to measure the energy efficiency of DDX-
DOASes, which aligns with the most recent version of the relevant 
industry consensus test standards for DDX-DOASes, with certain minor 
modifications. Lastly, DOE is proposing to add supporting definitions, 
energy efficiency metrics for dehumidification and heating modes, and 
provisions governing public representations as part of this rulemaking. 
DOE welcomes written comment from the public on any subject within the 
scope of this document (including topics not specifically raised in 
this proposal), as well as the submission of data and other relevant 
information.

DATES: Comments: DOE will accept written comments, data, and 
information regarding this notice of proposed rulemaking (NOPR) on or 
before September 7, 2021. See section V, ``Public Participation,'' for 
details.
    Meeting: DOE will hold a webinar on Monday, August 2, 2021 from 
10:00 a.m. to 4:00 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. Follow the 
instructions for submitting comments.
    Alternatively, interested persons may submit comments, identified 
by docket number EERE-2017-BT-TP-0018, by any of the following methods:
    1. Federal eRulemaking Portal: www.regulations.gov.
    2. Email: to [email protected]. Include 
docket number EERE-2017-BT-TP-0018 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 (Public Participation).
    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 Covid-19 pandemic. DOE is currently accepting only 
electronic submissions at this time. 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/webinar attendee lists and transcripts, 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/#docketDetail;D=EERE-2017-BT-TP-0018. The docket web page contains 
instructions on how to access all documents, including public comments, 
in the docket. See section V (Public Participation) for information on 
how to submit comments through www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: Ms. Catherine Rivest, U.S. Department 
of Energy, Office of Energy Efficiency and Renewable Energy, Building 
Technologies Office, EE-5B, 1000 Independence Avenue SW, Washington, 
DC, 20585-0121. Telephone: (202) 586-7335. Email: 
[email protected].
    Mr. Eric Stas, U.S. Department of Energy, Office of the General 
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585. 
Telephone: (202) 586-5827. Email: [email protected]v.
    For further information on how to submit a comment, review other 
public comments and the docket, or participate in the webinar, contact 
the Appliance and Equipment Standards Program staff at (202) 287-1445 
or by email: [email protected].

SUPPLEMENTARY INFORMATION: DOE proposes to incorporate by reference the 
following industry standards into title 10 of the Code of Federal 
Regulations (CFR) part 431:

Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 
920-2020 (I-P), ``2020 Standard for Performance Rating of Direct 
Expansion-Dedicated Outdoor Air System Units,'' approved February 4, 
2020.
American National Standards Institute (ANSI)/AHRI Standard 1060-2018, 
``2018 Standard for Performance Rating of Air-to-Air Exchangers for 
Energy Recovery Ventilation Equipment,'' approved 2018.

    Copies of AHRI Standard 920-2020 (I-P), and ANSI/AHRI Standard 
1060-2018 can be obtained from the Air-conditioning, Heating, and 
Refrigeration Institute, 2311 Wilson Blvd., Suite 400, Arlington, VA 
22201, (703) 524-8800, or online at: www.ahrinet.org.

ANSI/American Society of Heating, Refrigerating and Air-Conditioning 
Engineers (ASHRAE) Standard 37-2009, ``Methods of Testing for Rating 
Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment,'' 
ASHRAE approved June 24, 2009.
ANSI/ASHRAE Standard 41.1-2013, ``Standard Method for Temperature 
Measurement,'' ANSI approved January 30, 2013.
ANSI/ASHRAE Standard 41.6-2014, ``Standard Method for Humidity 
Measurement,'' ANSI approved July 3, 2014.
ANSI/ASHRAE Standard 198-2013, ``Method of Test for Rating DX-Dedicated 
Outdoor Air Systems for Moisture Removal Capacity and Moisture Removal 
Efficiency,'' ANSI approved January 30, 2013.

    Copies of ANSI/ASHRAE Standard 37-2009, ANSI/ASHRAE Standard 41.1-
2013, ANSI/ASHRAE Standard 41.6-2014, and ANSI/ASHRAE Standard 198-2013 
can be obtained from the American Society of Heating,

[[Page 36019]]

Refrigerating and Air-Conditioning Engineers, 180 Technology Parkway, 
Peachtree Corners, GA 30092, (404) 636-8400, or online at: 
www.ashrae.org.
    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 of Applicability
    1. Equipment Coverage
    2. Scope of Test Procedure
    3. Capacity Limit
    4. Industry Terminology
    B. Test Procedure for Dehumidifying Dedicated Outdoor Air 
Systems
    1. Industry Consensus Test Standards
    2. Efficiency Metrics
    a. Dehumidification Metric
    b. Heating Metric
    c. ISMRE2 and ISCOP2 Weighting Factors
    3. Test Method
    a. Definitions
    b. Break-In Period
    c. Airflow-Measuring Apparatus
    d. Test Operating Conditions
    i. Target Supply and Return Airflow Rates
    ii. Units With Cycle Reheat Functions
    iii. Target Supply Air Dry-Bulb Temperature
    iv. Target Supply Air Dew-Point Temperature
    v. Units With Staged Capacity Control
    e. Water-Cooled and Water-Source Heat Pump DX-DOAS Equipment
    i. Test Conditions for Multiple-Inlet Water Sources
    ii. Condenser Liquid Flow Rate
    iii. Water Pump Effect
    iv. Energy Consumption of Heat Rejection Fans and Chillers
    v. Chilled Water Coil Exclusion
    f. Defrost Energy Use for Air-Source Heat Pump
    g. General Control Setting Requirements
    h. Ventilation Energy Recovery Systems
    i. Exhaust Air Transfer and Leakage
    ii. Purge Angle Setting
    iii. Return Air External Static Pressure Requirements
    iv. Target Return Airflow Rate
    i. Demand-Controlled Ventilation
    j. Tolerances for Supply and Return Airflow and External Static 
Pressure
    k. Secondary Dehumidification and Heating Capacity Tests
    l. Corrections
    i. Calculation of the Degradation Coefficient
    ii. Non-Standard Low-Static Motor
    iii. Calculation of Supplementary Heat Penalty
    4. Determination of Represented Values
    a. Basic Model
    b. Sampling Plan Requirements
    c. Multiple Refrigerants
    d. Alternative Energy-Efficiency Determination Methods
    e. Rounding
    5. Configuration of Unit Under Test
    C. Other Comments
    D. Test Procedure Costs, Harmonization, and Other Topics
    1. Test Procedure Costs and Impact
    2. Harmonization With Industry Standards
    3. Other Test Procedure Topics
    E. Compliance Date
    IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Order 12866
    B. Review Under the Regulatory Flexibility Act
    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

    Small, large, and very large commercial package air conditioning 
and heating equipment 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)(B)-(D)) As defined by 
the Energy Policy and Conservation Act, as amended (EPCA), ``commercial 
package air conditioning and heating equipment'' means air-cooled, 
water-cooled, evaporatively-cooled, or water-source (not including 
ground-water-source) electrically operated, unitary central air 
conditioners and central air conditioning heat pumps for commercial 
application. (42 U.S.C. 6311(8)(A)) Industry standards generally 
describe unitary central air conditioning equipment as one or more 
factory-made assemblies that normally include an evaporator or cooling 
coil and a compressor and condenser combination. Units equipped to also 
perform a heating function are included as well.\1\ Direct expansion-
dedicated outdoor air systems (DX-DOASes) provide conditioning of 
outdoor ventilation air using a refrigeration cycle consisting of a 
compressor, condenser, expansion valve, and evaporator,\2\ and 
therefore, DOE has initially concluded that DX-DOASes are a category of 
commercial package air conditioning and heating equipment subject to 
EPCA. An industry consensus test standard has been established for a 
subset of DX-DOASes (i.e., dehumidifying DX-DOASes (DDX-DOASes)), which 
are the subject of this test procedure proposal. The following sections 
discuss DOE's authority to establish test procedures for DDX-DOASes, as 
well as relevant background information regarding DOE's proposed 
adoption of the industry consensus test standard, and proposed 
clarifications to the industry test procedure for this equipment.
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    \1\ See American Society of Heating, Refrigerating and Air-
Conditioning Engineers (ASHRAE) Standard 90.1, ``Energy Standard for 
Buildings Except Low-Rise Residential Buildings.''
    \2\ Other types of dedicated outdoor air systems are available 
that do not utilize direct expansion (e.g., units that use chilled 
water, rather than refrigerant, as the heat transfer medium); these 
are discussed in section III.B.3.e.v. of this document.
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A. Authority

    EPCA,\3\ as amended, among other things, authorizes DOE to regulate 
the energy efficiency of a number of consumer products and certain 
industrial equipment. Title III, Part C \4\ of EPCA, Public Law 94-163 
(42 U.S.C. 6311-6317, as codified), added by Public Law 95-619, Title 
IV, Sec.  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 
small, large, and very large commercial package air conditioning and 
heating equipment. (42 U.S.C. 6311(1)(B)-(D)) DOE has initially 
determined that commercial package air conditioning and heating 
equipment includes DX-DOASes. As discussed in section I.B of this 
document, DX-DOASes had not previously been addressed in DOE 
rulemakings and are not currently subject to Federal test procedures or 
energy conservation standards.
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    \3\ 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).
    \4\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
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    Under EPCA, DOE's energy conservation program consists essentially 
of four parts: (1) Testing, (2) labeling, (3) Federal energy 
conservation standards, and (4) certification and enforcement 
procedures. Relevant provisions of EPCA specifically include 
definitions (42 U.S.C. 6311), energy conservation standards (42 U.S.C. 
6313), test procedures (42 U.S.C. 6314),

[[Page 36020]]

labeling provisions (42 U.S.C. 6315), 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(b); 42 U.S.C. 6296), and (2) making representations about the 
efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE uses 
these test procedures to determine whether the equipment complies with 
relevant standards promulgated under EPCA.
    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 (b); 42 U.S.C. 6297) DOE may, however, grant waivers 
of Federal preemption in limited circumstances for particular State 
laws or regulations, in accordance with the procedures and other 
provisions of EPCA. (42 U.S.C. 6316(b)(2)(D))
    Under 42 U.S.C. 6314, the statute also sets forth the criteria and 
procedures DOE is required to follow when prescribing or amending test 
procedures for covered equipment. Specifically, EPCA requires that any 
test procedure prescribed or amended shall be reasonably designed to 
produce test results which measure energy efficiency, energy use, or 
estimated annual operating cost 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 requires that the test procedures for commercial package air 
conditioning and heating equipment be those generally accepted industry 
testing procedures or rating procedures developed or recognized by the 
Air-Conditioning, Heating, and Refrigeration Institute (AHRI) or by the 
American Society of Heating, Refrigerating and Air-Conditioning 
Engineers (ASHRAE), as referenced in ASHRAE Standard 90.1, ``Energy 
Standard for Buildings Except Low-Rise Residential Buildings'' (ASHRAE 
Standard 90.1). (42 U.S.C. 6314(a)(4)(A)) Further, if such an industry 
test procedure is amended, DOE must update its test procedure to be 
consistent with the amended industry test procedure, unless DOE 
determines, by rule published in the Federal Register and supported by 
clear and convincing evidence, that such amended test procedure would 
not meet the requirements in 42 U.S.C. 6314(a)(2) and (3), related to 
representative use and test burden. (42 U.S.C. 6314(a)(4)(B))
    EPCA also requires that, at least once every seven years, DOE 
evaluate test procedures for each type of covered equipment, including 
commercial package air conditioning and heating equipment to determine 
whether amended test procedures would more accurately or fully comply 
with the requirements for the test procedures not to 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. 
6314(a)(1)-(3)) In addition, if DOE determines that a test procedure 
amendment is warranted, it 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 in the Federal Register its determination not to amend the 
test procedures. (42 U.S.C. 6314(a)(1)(A)(ii))
    As discussed in section I.B of this document, a test procedure for 
a subset of DX-DOASes (i.e., DDX-DOASes), was first specified by ASHRAE 
Standard 90.1 in the 2016 edition (ASHRAE Standard 90.1-2016). Pursuant 
to 42 U.S.C. 6314(a)(4)(B), and following updates to the relevant test 
procedures which were referenced in ASHRAE Standard 90.1, DOE is 
publishing this NOPR proposing to establish a test procedure for DDX-
DOASes in satisfaction of its aforementioned obligations under EPCA.

B. Background

    From a functional perspective, DX-DOASes operate similarly to other 
categories of commercial package air conditioning and heat pump 
equipment, in that they provide conditioning using a refrigeration 
cycle consisting of a compressor, condenser, expansion valve, and 
evaporator. DX-DOASes provide ventilation and conditioning of 100-
percent outdoor air to the conditioned space, whereas for typical 
commercial package air conditioners that are central air conditioners, 
outdoor air makes up only a small portion of the total airflow (usually 
less than 50 percent). DX-DOASes are typically installed in addition to 
a local, primary cooling or heating system (e.g., commercial unitary 
air conditioner, variable refrigerant flow system, chilled water 
system, water-source heat pumps)--the DX-DOAS conditions the outdoor 
ventilation air, while the primary system provides cooling or heating 
to balance building shell and interior loads and solar heat gain. 
According to ASHRAE, a well-designed system using a DX-DOAS can 
ventilate a building at lower installed cost, reduce overall annual 
building energy use, and improve indoor environmental quality.\5\
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    \5\ From the June 2018 ASHRAE eSociety Newsletter (Available at: 
www.ashrae.org/news/esociety/what-s-new-in-doas-and-refrigerant-research) (Last accessed May 24, 2021).
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    On October 26, 2016, ASHRAE published ASHRAE Standard 90.1-2016, 
which for the first time specified a test standard and efficiency 
standards for DX-DOASes. ASHRAE Standard 90.1-2016 (and the subsequent 
2019 edition) defines DX-DOAS as a type of air-cooled, water-cooled, or 
water-source factory assembled product that dehumidifies 100% outdoor 
air to a low dew point and includes reheat that is capable of 
controlling the supply dry-bulb temperature of the dehumidified air to 
the designed supply air temperature. This conditioned outdoor air is 
then delivered directly or indirectly to the conditioned spaces. It may 
precondition outdoor air by containing an enthalpy wheel, sensible 
wheel, desiccant wheel, plate heat exchanger, heat pipes, or other heat 
or mass transfer apparatus.
    Although ASHRAE Standard 90.1-2016 uses the term ``DX-DOAS,'' the 
definition of this term provided therein describes a subset of DX-
DOASes, specifically DDX-DOASes. The ASHRAE definition of ``DX-DOAS'' 
is generally equivalent to the equipment DOE is proposing to define as 
DDX-DOAS and for which DOE is proposing to adopt the industry consensus 
standard. DDX-DOASes dehumidify air to a low dew point. When operating 
in humid conditions, the dehumidification load from the outdoor 
ventilation air is a much larger percentage of the total cooling load 
for a DDX-DOAS than for a typical commercial air conditioner. 
Additionally, compared to a typical commercial air conditioner, the 
amount of total cooling (both sensible and latent) is much greater per 
pound of air for a DDX-DOAS at design conditions (i.e., the warmest/
most humid expected summer conditions), and a DDX-DOAS is designed to 
accommodate greater variation in entering air temperature and humidity 
(i.e., a typical commercial air conditioner would not be able to 
dehumidify 100-percent outdoor ventilation air to the levels achieved 
by

[[Page 36021]]

a DDX-DOAS). Not all DX-DOASes have this dehumidification capability, 
which is why DOE is proposing a separate definition. (See section 
III.B.2.a of this NOPR for further details.)
    The amendment to ASHRAE Standard 90.1 to specify an industry test 
standard for equipment that DOE calls DDX-DOAS triggered DOE's 
obligations vis-[agrave]-vis test procedures under 42 U.S.C. 
6314(a)(4)(B), as outlined previously. On July 25, 2017, DOE published 
a request for information (RFI) (the July 2017 ASHRAE TP RFI) in the 
Federal Register to collect information and data to consider new and 
amended DOE test procedures for commercial package air conditioning and 
heating equipment, given the test procedure updates included in ASHRAE 
Standard 90.1-2016. 82 FR 34427. As part of the July 2017 ASHRAE TP 
RFI, DOE requested comment on several aspects regarding test procedures 
for DDX-DOASes in consideration of adopting a new DOE test procedure 
for this equipment, including: Incorporation by reference of the 
relevant industry test standard(s); efficiency metrics and 
calculations, and additional topics that may inform DOE's decisions in 
a future test procedure rulemaking.\6\ 82 FR 34427, 34435-34439 (July 
25, 2017). On October 25, 2019, ASHRAE published an updated version of 
ASHRAE Standard 90.1 (i.e., ASHRAE Standards 90.1-2019), which 
maintained the DDX-DOAS provisions as first introduced in ASHRAE 
Standard 90.1-2016 without revisions.
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    \6\ In the July 2017 ASHRAE TP RFI, DOE referred to DDX-DOASes 
simply as ``DOASes.''
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    DOE received a number of comments from interested parties in 
response to the July 2017 ASHRAE TP RFI, which covered multiple 
categories of equipment. Table I-1 lists the commenters relevant to 
DDX-DOASes, along with each commenter's abbreviated name used 
throughout this NOPR. DOE considered these comments in the preparation 
of this NOPR. Discussion of the relevant comments, and DOE's responses, 
are provided in the appropriate sections of this document.

 Table I-1--Interested Parties Providing DX-DOAS-Related Comments on the
                   July 2017 ASHRAE Test Procedure RFI
------------------------------------------------------------------------
                 Name                       Abbreviation       Type \1\
------------------------------------------------------------------------
Air-Conditioning, Heating, and         AHRI.................  IR
 Refrigeration Institute.
Appliance Standards Awareness Project  Joint Advocates......  EA
 (ASAP), Alliance to Save Energy
 (ASE), American Council for an
 Energy-Efficient Economy (ACEEE),
 Northwest Energy Efficiency Alliance
 (NEEA), and Northwest Power and
 Conservation Council (NPCC).
Carrier Corporation, part of United    Carrier..............  M
 Technologies Climate, Controls &
 Security (CCS) business.
Goodman Global, Inc..................  Goodman..............  M
The Greenheck Group..................  Greenheck............  M
Ingersoll Rand.......................  Ingersoll Rand.......  M
Lennox International, Inc............  Lennox...............  M
Mitsubishi Electric Cooling & Heating  Mitsubishi...........  M
 \2\.
National Comfort Institute...........  NCI..................  IR
Pacific Gas and Electric Company       CA IOUs..............  U
 (PG&E), Southern California Gas
 Company (SoCalGas), San Diego Gas
 and Electric (SDG&E), and Southern
 California Edison (SCE),
 collectively referred to as
 California Investor-Owned Utilities
 (CA IOUs).
------------------------------------------------------------------------
\1\ EA: Efficiency/Environmental Advocate; IR: Industry Representative;
  M: Manufacturer; U: Utility.
\2\ Mitsubishi commented that it fully supports all of the comments
  submitted by AHRI on DX-DOAS issues.

    On February 14, 2020, DOE published a final rule updating its 
procedures for consideration of new and amended energy conservation 
standards at 10 CFR part 430, subpart C, appendix A, ``Procedures, 
Interpretations, and Policies for Consideration of New or Revised 
Energy Conservation Standards and Test Procedures for Consumer Products 
and Certain Commercial/Industrial Equipment'' (the Process Rule). 85 FR 
8626. As part of the update, the Process Rule now applies explicitly to 
commercial and industrial equipment. 10 CFR 431.4. The updated Process 
Rule also includes provisions specific to the consideration of new and 
amended energy conservation standards and test procedures for covered 
equipment subject to the ASHRAE provisions of EPCA. See Process Rule, 
10 CFR part 430, subpart C, appendix A, sections 2 and 9.
    With respect to DOE's consideration of changes to the relevant 
industry consensus test procedure(s) for covered ASHRAE equipment, the 
Process Rule now provides that DOE will do so only if it can meet a 
very high bar to demonstrate the ``clear and convincing evidence'' 
threshold. 10 CFR part 430, subpart C, appendix A, section 9(b). Clear 
and convincing evidence would exist only where the specific facts and 
data made available to DOE regarding a particular ASHRAE amendment 
demonstrates that there is no substantial doubt that that the industry 
test procedure does not meet the EPCA requirements. Id. DOE will make 
this determination only after seeking data and information from 
interested parties and the public to help inform DOE's views. DOE will 
seek from interested stakeholders and the public data and information 
to assist in making this determination, prior to publishing a proposed 
rule to adopt a different test procedure. Id.

II. Synopsis of the Notice of Proposed Rulemaking

    In this NOPR, DOE is proposing to establish a definition for DX-
DOAS as a category of commercial package air conditioning and heating 
equipment and adopt a new test procedure for a subset of DX-DOASes 
(i.e., DDX-DOASes), consistent with the industry consensus test 
standard as specified in ASHRAE Standard 90.1-2019. The proposed test 
procedure applies to all DDX-DOASes for which ASHRAE 90.1-2019 
specifies standards, with the exception of ground-water-source DDX-
DOASes, as discussed in section III.A.1 of this NOPR. More 
specifically, DOE proposes to update 10 CFR 431.96, ``Uniform test 
method for the measurement of energy efficiency of commercial air 
conditioners and heat pumps,'' to adopt a new test procedure for DDX-
DOASes as follows: (1) Incorporate by reference AHRI Standard 920-2020 
(I-P), ``Performance Rating of

[[Page 36022]]

Direct Expansion-Dedicated Outdoor Air System Units'' (AHRI 920-2020), 
the most recent version of the test procedure recognized by ASHRAE 
Standard 90.1 for DDX-DOASes, and the relevant industry standards 
referenced therein; (2) establish the scope of coverage for the DDX-
DOAS test procedure; (3) add definitions for DX-DOASes and DDX-DOASes, 
as well as additional terminology required by the test procedure; (4) 
adopt the integrated seasonal moisture removal efficiency, as measured 
according to the most recent applicable industry standard (ISMRE2), and 
integrated seasonal coefficient of performance (ISCOP2), as measured 
according to the most recent applicable industry standard, as energy 
efficiency descriptors for dehumidification and heating mode, 
respectively; and (5) establish representation requirements. DOE 
proposes to add a new Appendix B to Subpart F of Part 431, titled 
``Uniform test method for measuring the energy consumption of 
dehumidifying direct expansion-dedicated outdoor air systems,'' 
(Appendix B) that would include the new test procedure requirements for 
DDX-DOASes. In conjunction, DOE proposes to amend Table 1 in 10 CFR 
431.96 to identify the newly added Appendix B as the applicable test 
procedure for testing DDX-DOASes. DOE has tentatively determined that 
the proposed test procedure would not be unduly burdensome to conduct.
    DOE's proposed actions are summarized in Table II.1 and addressed 
in detail in section III of this document.

      Table II.1--Summary of Proposed Test Procedure for DDX-DOASes
------------------------------------------------------------------------
          Proposed test procedure                    Attribution
------------------------------------------------------------------------
Incorporates by reference AHRI 920-2020 and  Adopt industry test
 other relevant industry test standards       procedure.
 referenced by that standard. AHRI 920-2020
 includes:
    --test methods for DDX-DOAS with and
     without ventilation energy recovery
     systems (VERS);
    --test operating conditions, including
     Standard Rating Conditions, simulated
     ventilation air conditions for
     optional test methods for DDX-DOASes
     with VERS, supply air target
     conditions, supply and return airflow
     rates, and external static pressure;
    --testing instrumentation and apparatus
     instructions;
    --test operating and condition
     tolerances \7\;
    --a list of components that must be
     present for testing; and
    --provisions for testing units with
     certain optional features.
Defines DX-DOASes as covered equipment       Establish equipment
 which meet the EPCA definition for small,    coverage.
 large, or very-large commercial package
 air conditioning and heating equipment.
Defines the scope of coverage of the test    Clarify scope of test
 procedure, including defining DDX-DOASes     procedure.
 to distinguish them from other kinds of
 equipment and a capacity limit based on
 moisture removal capacity (MRC).
Adopts ISMRE2 and ISCOP2 as the seasonal     Adopt industry test
 efficiency descriptors for                   procedure.
 dehumidification and heating mode,
 respectively, as specified in AHRI 920-
 2020.
Provides minor corrections and additional    Clarify instructions in the
 instruction consistent with AHRI 920-2020    industry test procedure.
 by:
--specifying the external head pressure
 requirements for DDX-DOASes with integral
 water pumps;
    --specifying general control setting
     requirements;
    --correcting a typographical error in
     the calculation of the degradation
     coefficient; and
    --providing a missing definition
     necessary for the interpretation of
     the airflow setting instructions.
Specifies representation requirements,       Provide for representations
 including a basic model definition,          of energy efficiency
 sampling plan requirements, and use of       consistent with other
 alternative energy-efficiency                commercial air conditioner/
 determination methods (AEDMs).               heat pump equipment.
------------------------------------------------------------------------

III. Discussion
---------------------------------------------------------------------------

    \7\ ``Test operating tolerance'' refers to the maximum 
permissible range that a measurement may vary over a specified test 
interval. ``Test condition tolerance'' refers to the maximum 
permissible difference between the average value of the measured 
test parameter and the specified test condition.
---------------------------------------------------------------------------

    The following sections discuss DOE's proposal to define DX-DOASes 
as a category of small, large and extra-large commercial package air 
conditioning and heating equipment and to adopt a new test procedure 
for DDX-DOASes, a subset of DX-DOASes, and address relevant comments 
received in response to specific issues DOE raised in the July 2017 
ASHRAE TP RFI. Commenters' references to ``DX-DOASes'' or ``DOASes'' 
have been changed to ``DDX-DOASes'' where DOE understands the 
commenters to be specifically discussing DX-DOASes that would meet the 
dehumidification performance criterion as proposed.

A. Scope of Applicability

1. Equipment Coverage
    As discussed, DOE has initially determined that DX-DOASes are a 
category of small, large, and very large commercial package air 
conditioning and heating equipment and, therefore, are covered 
equipment under EPCA. (42 U.S.C. 6311(1)(B)-(D)) DX-DOASes operate 
similarly to more typical commercial package air conditioning equipment 
in that they provide conditioning of outdoor ventilation air using a 
refrigeration cycle consisting of a compressor, condenser, expansion 
valve, and evaporator. However, DX-DOASes are designed to provide 
ventilation and conditioning of 100-percent outdoor air, while outdoor 
air makes up only a small portion of the total airflow for typical 
commercial package air conditioning and heating equipment (e.g., 
usually less than 50 percent).
    As discussed further in section III.A.4 of this document, industry 
provides several definitions for DX-DOASes, but DOE notes that the 
industry definitions for ``DX-DOAS'' specifically refer to the DDX-
DOASes that are covered by the scope of those industry test standards, 
which does not include non-dehumidifying (i.e., sensible-only) DX-
DOASes that exist on the market.
    In this NOPR, DOE is proposing to define ``direct expansion-
dedicated outdoor air system, or DX-DOAS,'' as a category of small, 
large, or very large commercial package air conditioning and heating 
equipment which is capable of providing ventilation and conditioning of 
100-percent outdoor air or marketed in materials (including but not 
limited to, specification sheets, insert sheets, and online materials) 
as having such capability. This proposed definition is based, in part, 
on the definition in section 3.6 of AHRI 920-

[[Page 36023]]

2020, as discussed in section III.A.4 of this document.
    The proposed definition of DX-DOAS would include all air-cooled, 
air-source heat pump, and water-cooled equipment subcategories 
specified in ASHRAE Standard 90.1. For water-source heat pump 
equipment, ASHRAE Standard 90.1 includes three configurations--ground-
source, closed loop; ground-water-source; and water-source. The EPCA 
definition for ``commercial package air conditioning and heating 
equipment'' specifically excludes ground-water-source equipment (42 
U.S.C. 6311(8)(A)), so in proposing to define (at 10 CFR 431.92) DX-
DOAS as a category of small, large, or very large commercial package 
air conditioning and heating equipment, ground-water-source DX-DOASes 
would be excluded from coverage under EPCA.
    Issue-1: DOE requests comment on the proposed definition for 
``direct expansion-dedicated outdoor air system.'' DOE also requests 
comment on any additional characteristics not yet considered that could 
help to distinguish DX-DOASes from other commercial package air 
conditioning and heating equipment.
2. Scope of Test Procedure
    DOE is proposing to establish a test procedure for a subset of DX-
DOASes (i.e., DDX-DOASes). When operating in humid conditions, the 
dehumidification load is a much larger percentage of the total cooling 
load for a DDX-DOAS than for a typical commercial package air 
conditioning system. DDX-DOASes in particular handle a significantly 
higher amount of total cooling (both sensible and latent) per pound of 
air at design conditions (i.e., the warmest or most humid expected 
summer conditions), and a DDX-DOAS is designed to accommodate greater 
variation in entering air temperature and humidity, because outdoor 
conditions can vary much more than typical indoor conditions. As 
discussed, not all DX-DOASes are designed to dehumidify outdoor air at 
the most humid expected summer conditions to a level consistent with 
comfortable indoor conditions, such as a dew point temperature less 
than 55 [deg]F (e.g., sensible-only cooling \8\ DX-DOASes). AHRI stated 
that sensible-only 100-percent outdoor air units should not be covered 
by ANSI/AHRI 920-2015 because they are not intended to dehumidify the 
ventilation air. (AHRI, No. 11 at pp. 10-11) \9\
---------------------------------------------------------------------------

    \8\ ``Sensible cooling'' refers to the process of cooling air by 
reducing its dry bulb temperature without changing its moisture 
content.
    \9\ A notation in the form ``AHRI, No. 11 at pp. 10-11'' 
identifies a written comment: (1) Made by AHRI; (2) recorded in 
document number 11 that is filed in the docket of this test 
procedure rulemaking (Docket No. EERE-2017-BT-TP-0018) and available 
for review at www.regulations.gov; and (3) which appears on pages 10 
through 11 of document number 11.
---------------------------------------------------------------------------

    Because DOE is aware of sensible-only DX-DOASes, DOE aims to 
further delineate those DX-DOASes that would be subject to the proposed 
test procedure (i.e., DDX-DOASes). Section 2.2 of AHRI 920-2020 
explicitly excludes ``Sensible-only 100% Outdoor Air Units'' from the 
scope of its test standard. Accordingly, DOE proposes to define DDX-
DOASes (the subject of this proposed test procedure) in 10 CFR 431.92 
as those DX-DOASes specifically having the capability to dehumidify air 
to a dew point of 55 [deg]F when operating under Standard Rating 
Condition A as specified in Table 4 or Table 5 of AHRI 920-2020 with a 
barometric pressure of 29.92 in Hg. The 55 [deg]F dew point is 
specified in ANSI/AHRI 920-2015 and AHRI 920-2020 as the maximum dew 
point temperature for the supply air for the dehumidification mode 
tests.\10\ This maximum dew point temperature requirement for DDX-
DOASes provides a key differentiator from other DX-DOASes, which 
typically cannot dehumidify 100-percent outdoor air to a dew point this 
low. This element is consistent with the definition in AHRI 920-2020.
---------------------------------------------------------------------------

    \10\ AHRI 920-2020 acknowledges the influence of barometric 
pressure on humidity ratio for the inlet air conditions specified in 
terms of dry bulb and wet bulb temperature, allowing an upward 
adjustment of the maximum supply air dew point temperature that must 
be achieved, such that the moisture removal rate matches that which 
would occur at standard barometric pressure when supplying 55 [deg]F 
dew-point supply air--this maximum supply air dew point increases 
linearly as barometric pressure decreases, up to 57.3 [deg]F at the 
minimum-allowed 13.7 psia test pressure.
---------------------------------------------------------------------------

    AHRI 920-2020 does not specify at what airflow the dehumidification 
element is to be evaluated. DOE proposes to include within the proposed 
definition of DDX-DOAS that the DDX-DOAS be capable of providing the 
specified dehumidification capability for any portion of the range of 
air flow rates advertised in manufacturer materials. This provision 
would provide additional specificity to the definition found in AHRI 
920-2020 to account for manufacturers that may specify a range of 
airflows for a given model.
    As proposed, the test procedure would apply to DDX-DOASes within 
the capacity limits as discussed in the following section.
    Issue-1: DOE requests comment on the proposed definition for 
``dehumidifying direct expansion-dedicated outdoor air system.'' 
Specifically, DOE requests comment on the proposed criteria for 
distinguishing a ``dehumidifying direct expansion-dedicated outdoor air 
system'' from a ``direct expansion-dedicated outdoor air system'' more 
generally. DOE also requests comment on any additional characteristics 
not yet considered that could help to distinguish DDX-DOASes from DX-
DOASes more generally.
3. Capacity Limit
    As stated, EPCA defines as covered equipment small, large, and very 
large commercial package air conditioning and heating equipment. (42 
U.S.C. 6311(1)(B)-(D)) EPCA defines ``small commercial package air 
conditioning and heating equipment'' as commercial package air 
conditioning and heating equipment that is rated below 135,000 Btu per 
hour (cooling capacity). (42 U.S.C. 6311(8)(B)) The term ``large 
commercial package air conditioning and heating equipment'' means 
commercial package air conditioning and heating equipment that is 
rated--(i) at or above 135,000 Btu per hour; and (ii) below 240,000 Btu 
per hour (cooling capacity). (42 U.S.C. 6311(8)(C)) The term ``very 
large commercial package air conditioning and heating equipment'' means 
commercial package air conditioning and heating equipment that is 
rated--(i) at or above 240,000 Btu per hour; and (ii) below 760,000 Btu 
per hour (cooling capacity). (42 U.S.C. 6311(8)(D))
    In response to the July 2017 ASHRAE TP RFI, AHRI commented that 
DOE's regulations for DDX-DOASes should be capped at a reasonable 
capacity, similar to the 760,000 Btu/h limit for commercial packaged 
air conditioning equipment. AHRI stated that laboratory limitations may 
limit testing using ANSI/AHRI 920-2015 to 300 lbs. of moisture per hour 
at Standard Rating Condition A and to units not physically larger than 
more typical commercial package air conditioning and heating equipment 
with a capacity of 760,000 Btu/h. The commenter also stated that the 
market for these larger, typical commercial package air conditioning 
equipment and DDX-DOAS units (with a capacity greater than 760,000 Btu/
h, or equivalent) is very small and customized. AHRI stated that the 
customization helps customers minimize energy consumption for their 
application. (AHRI, No. 11 at p. 20)
    As discussed, DOE has tentatively concluded that DX-DOASes meet the 
EPCA definition for ``commercial package air conditioning and heating 
equipment,'' and, thus, are to be considered as a category of that 
covered equipment. (42 U.S.C. 6311(8)(A)) The upper capacity limit of 
commercial

[[Page 36024]]

package air conditioning subject to the DOE test procedures is 760,000 
Btu per hour, based on the definition of ``very large commercial 
package air conditioning and heating equipment.'' (42 U.S.C. 
6311(8)(D))
    For DDX-DOASes specifically, AHRI 920-2020 does not provide a 
method for determining capacity in terms of Btu per hour, but instead, 
it specifies a determination of capacity in terms of moisture removal 
capacity (MRC). DOE proposes to translate the upper capacity for 
coverage of commercial package air conditioning and heating units 
established in EPCA (i.e., 760,000 Btu per hour) from Btu per hour to 
MRC for DDX-DOASes. Specifically, DOE is proposing, consistent with 
section 6 of AHRI 920-2020, to translate the upper limit from Btu per 
hour to MRC of the DDX-DOAS when delivering dehumidified supply air at 
a 55 [deg]F dew point. Manufacturers would use their tested value of 
MRC to determine if a DDX-DOAS is subject to the test procedure.
    To translate Btu per hour to MRC, DOE calculated the maximum 
airflow that could be supplied at a 55 [deg]F dewpoint for Standard 
Rating Condition A as specified in Table 4 and Table 5 of AHRI 920-2020 
by cooling and dehumidifying it with an evaporator with a refrigeration 
capacity of 760,000 Btu per hour. DOE calculated this based on air 
entering the evaporator at Standard Rating Condition A (95 [deg]F dry-
bulb temperature and 78 [deg]F wet-bulb temperature) and air exiting 
the evaporator at 55 [deg]F dew point and 95-percent relative humidity 
at a standard barometric pressure of 29.92 in Hg. DOE then calculated 
the MRC that corresponds to those conditions. Based on these 
calculations, DOE is proposing to limit the scope of this proposed test 
procedure to DDX-DOAS units with a MRC less than 324 lbs. per hour 
based on Standard Rating Condition A as specified in Table 4 or Table 5 
of AHRI 920-2020.
    Issue-2: DOE seeks comment on its translation of Btu per hour to 
MRC and specifically its proposal to translate the upper capacity limit 
for DDX-DOASes such that a model would be considered in scope if it has 
an MRC less than 324 lbs. per hour.
4. Industry Terminology
    As stated, DOE is proposing definitions for DX-DOAS and DDX-DOAS 
following a review of industry standards and consistent with the 
applicability of the relevant industry testing standard. Both ANSI/AHRI 
920-2015 and ANSI/ASHRAE 198-2013 include definitions for ``DX-
Dedicated Outdoor Air System Units.'' Section 3.3 of ANSI/AHRI 920-2015 
defines ``DX-Dedicated Outdoor Air System Units'' as a type of air-
cooled, water-cooled, or water-source factory assembled product which 
dehumidifies 100-percent outdoor air to a low dew point, and includes 
reheat that is capable of controlling the supply dry-bulb temperature 
of the dehumidified air to the designed supply air \11\ temperature. 
This conditioned outdoor air is then delivered directly or indirectly 
to the conditioned space(s). It may pre-condition outdoor air by 
containing an enthalpy wheel, sensible wheel, desiccant wheel, plate 
heat exchanger, heat pipes, or other heat or mass transfer apparatus. 
This is the same definition used in ASHRAE Standard 90.1-2019.
---------------------------------------------------------------------------

    \11\ ``Supply air'' for a DDX-DOAS refers to conditioned air 
that is supplied to the conditioned space.
---------------------------------------------------------------------------

    Section 3 of ANSI/ASHRAE 198-2013 defines a ``DX Dedicated Outdoor 
Air Systems Unit (DX-DOAS)'' as a type of air-cooled, water-cooled, or 
water-source factory-assembled product that is capable of dehumidifying 
100-percent outdoor air to a low dew point and may be capable of 
controlling the dry-bulb temperature of the dehumidified air to the 
designed supply air temperature. This conditioned outdoor air may be 
delivered directly or indirectly to the conditioned space(s). It may 
pre-condition outdoor air prior to direct expansion cooling by 
incorporating an enthalpy wheel, sensible wheel, desiccant wheel, plate 
heat exchanger, heat pipes, or other heat or mass transfer apparatus. 
The product may also include a supplementary heating system for use 
when outdoor air requires heating beyond the capability of the 
refrigeration system and/or other heat transfer apparatus.
    As part of the July 2017 ASHRAE TP RFI, DOE requested comment on 
certain aspects of these two industry definitions of dedicated outdoor 
air systems. 82 FR 34427, 34435-34436 (July 25, 2017). On February 4, 
2020, AHRI published AHRI 920-2020, which made changes to the 
definition of ``Dedicated Outdoor Air System Unit'' as compared to the 
definition in ANSI/AHRI 920-2015 (and ASHRAE Standard 90.1-2019). 
Section 3.6 of AHRI 920-2020 defines ``Dedicated Outdoor Air System 
Unit'' as a type of air-cooled, evaporatively-cooled, or water-cooled 
air-conditioner, or an air-source or water source heat pump, that is a 
factory assembled product designed and marketed and sold to provide 
ventilation and dehumidification of 100% outdoor air, is capable of 
dehumidifying air to a 55 [deg]F dew point when operating under 
Standard Rating Condition A as specified in Table 4 or Table 5 of this 
test standard with a barometric pressure of 29.92 in Hg, and may 
include reheat. It may include pre-conditioning of outdoor air using an 
enthalpy wheel, sensible wheel, desiccant wheel, plate heat exchanger, 
heat pipes, or other heat or mass transfer apparatus. Heating 
components are optional and may include electrical resistance, steam, 
hot water, or gas heat. In addition, it may provide for air cleaning or 
may include mixing box or economizer dampers to allow return air to be 
intermittently used as allowed by the controls.
    Both ANSI/AHRI 920-2015 and ANSI/ASHRAE 198-2013 address equipment 
that dehumidifies (or is capable of dehumidifying) 100-percent outdoor 
air to a low dew point. As discussed, in its review of available 
equipment, DOE found units marketed as ``dedicated outdoor air 
systems,'' and other units marketed for ``100-percent outdoor air'' 
applications, both of which can also operate with less than 100-percent 
outdoor air. Such units have a return air damper that allows modulating 
the amount of return air that is recirculated from the conditioned 
space and mixed with the incoming outdoor air before the mixed air is 
conditioned. More typical commercial package air conditioning equipment 
also often incorporates a similar damper to mix return air and outdoor 
air. Additionally, like the industry definitions for dedicated outdoor 
air systems, which DOE notes would be DDX-DOASes as that term is 
proposed to be defined, some categories of commercial package air 
conditioning equipment can dehumidify 100-percent outdoor air, although 
typically not to a dew point as low as the industry specification for 
DDX-DOASes.
    As part of the July 2017 ASHRAE TP RFI, DOE requested information 
on the range of the maximum percentage of return air intake relative to 
total airflow of models of equipment that DOE generally referred to as 
``DOASes'' in order to determine whether the maximum return air 
percentage is an important distinguishing feature of DDX-DOASes. DOE 
also requested information on the difference in dehumidification 
capabilities of more typical commercial package air conditioning 
equipment and equipment that DOE referred to as DOASes when operating 
with 100-percent outdoor air. 82 FR 34427, 34435 (July 25, 2017).
    Ingersoll Rand and Carrier commented that there are not one or two 
features or criteria that definitively distinguish DDX-DOASes from more

[[Page 36025]]

typical commercial package air conditioning equipment. (Ingersoll Rand, 
No. 12 at p. 2; Carrier, No. 6 at p. 2) AHRI and Carrier commented that 
there may be several potential applications for DDX-DOASes, some of 
which may not be 100-percent outdoor air. (AHRI, No. 11 at p. 9; 
Carrier, No. 6 at p. 2) AHRI and Ingersoll Rand stated, for example, 
that DDX-DOASes may be supplied with recirculation dampers that allow 
them to efficiently dehumidify recirculated air when the building is 
unoccupied. AHRI stated that, as a result, it is not possible to select 
a specific crossover percentage of return air intake relative to total 
airflow that would differentiate DDX-DOASes from more typical 
commercial package air conditioning equipment. (AHRI, No. 11 at p. 9; 
Ingersoll Rand, No. 12 at p. 2) Goodman supported AHRI's position, 
adding that when the return air intake relative to the total airflow is 
less than 10-30 percent, ANSI/AHRI 920-2015 is more appropriate than 
ANSI/AHRI 340/360 \12\ in non-western climates. (Goodman, No. 14 at p. 
2)
---------------------------------------------------------------------------

    \12\ ANSI/AHRI Standard 340/360, ``Performance Rating of 
Commercial and Industrial Unitary Air-conditioning and Heat Pump 
Equipment'' (Available at: www.ahrinet.org/) (Last accessed April 
19, 2021).
---------------------------------------------------------------------------

    As discussed, not all DX-DOASes are designed to provide 
dehumidification (to a low dew point) over larger variation in entering 
air temperature and humidity. As such, DOE is proposing to define DDX-
DOAS to distinguish such equipment from DX-DOAS more generally, as 
provided in the previous sections. The DDX-DOAS definition is 
consistent with the definition in section 3.6 of AHRI 920-2020 for the 
equipment subject to the scope of that industry test standard.
    DOE noted in the July 2017 ASHRAE TP RFI that one difference 
between the definitions in ANSI/ASHRAE 198-2013 and ANSI/AHRI 920-2015 
(and now AHRI 920-2020) is related to reheat. ANSI/AHRI 920-2015 
specifies that a Direct Expansion-Dedicated Outdoor Air System Unit 
includes reheat, which is used to raise the temperature of cooled and 
dehumidified air to a design supply air temperature. The ANSI/ASHRAE 
198-2013 definition provides that a DX Dedicated Outdoor Air Systems 
Unit, as defined by that industry standard, may have reheat but does 
not require reheat. DOE requested comment on whether and how reheating 
functionality should be included in the DDX-DOAS definition. 82 FR 
34427, 34435-34436 (July 25, 2017).
    In response to the July 2017 ASHRAE TP RFI, AHRI and Greenheck 
commented that while capturing reheat performance in the test procedure 
for DDX-DOAS equipment is an important aspect to many installations, 
some building HVAC designs incorporating DDX-DOAS equipment operate 
without any reheat capabilities. AHRI and Greenheck suggested that the 
definition of DDX-DOAS should not require reheat, as it is important 
for owners and designers to be able to select 100-percent outdoor air 
units with varying amounts of reheat or no reheat. (AHRI, No. 11 at pp. 
10-11, 20-21; Greenheck, No. 13 at p. 2) AHRI further commented that 
DDX-DOAS design and optimum efficiency varies with climate and 
application, and that the design is often customized to accommodate the 
different needs of different applications. AHRI asserted that 
regulations must allow for these differences to avoid increasing energy 
consumption for a given project. (AHRI, No. 11 at p. 20-21) Greenheck 
commented that the supplementary heat penalty included in ANSI/AHRI 
920-2015 unfairly penalizes units without reheat, and Greenheck 
suggested two options for rating units without reheat. (Greenheck, No. 
13 at pp. 2-3). Carrier also commented that reheat functionality is an 
application issue and is not applicable to the definition in a test 
standard. (Carrier, No. 6 at p. 3)
    DOE recognizes that the optimum-efficiency DDX-DOAS design varies 
with climate and application. DOE also understands that the 
supplementary heat penalty in ANSI/AHRI 920-2015 is not representative 
of the way that units without reheat are used in the field. As is 
discussed in section III.B.2.a of this document, as part of AHRI 920-
2020, AHRI modified the ISMRE metric to remove the supplementary heat 
penalty in recognition that some installation conditions may not 
require reheating. As is discussed in section III.B.1 of this document, 
this metric was re-designated in AHRI 920-2020 as ISMRE2. AHRI 920-2020 
also includes a separate application rating metric, ISMRE270, to 
account for installations where reheating is required. Moreover, the 
updated definition in AHRI 920-2020 recognizes that there are units 
without reheat. As such, DOE is not proposing to include a reheat 
requirement in the DX-DOAS or DDX-DOAS definition, consistent with AHRI 
920-2020.
    Because of the difference in terminology between the proposed DOE 
test procedure and the relevant industry standards, DOE proposes to 
include a section 2.3(a) in its proposed Appendix B indicating that the 
different synonymous terms all refer to dehumidifying direct expansion-
dedicated outdoor air system as defined in 10 CFR 431.92.
    Issue-3: DOE requests comment on its proposal to clarify what terms 
are synonymous with DDX-DOAS.

B. Test Procedure for Dehumidifying Dedicated Outdoor Air Systems

    Pursuant to EPCA, in response to the DDX-DOAS-related updates to 
ASHRAE 90.1-2016 (maintained in ASHRAE 90.1-2019) and updates to the 
industry test standard referenced in ASHRAE 90.1, DOE proposes to adopt 
a test procedure for DDX-DOASes that incorporates by reference the 
latest applicable industry consensus test standards.
    In the following sections, DOE presents analysis and discussion of 
several test procedure issues and proposes a test procedure for DDX-
DOASes. As discussed in more detail in the following sections, DOE has 
initially determined that the proposed test procedure for DDX-DOASes 
would be representative of an average use cycle and not be unduly 
burdensome to conduct.
    DOE is adopting the generally accepted industry testing procedures 
for DDX-DOASes developed by AHRI (i.e., AHRI 920-2020) and referenced 
by ASHRAE Standard 90.1, with the following modifications as discussed 
in this NOPR:
    [ssquf] Using the nomenclature DDX-DOAS, rather than DX-DOAS, to 
define the equipment subject to the test procedure;
    [ssquf] Defining an upper limit of capacity consistent with EPCA's 
definition of very large commercial package air conditioning and 
heating equipment;
    [ssquf] Defining ``non-standard low-static fan motor,'' in order to 
determine the appropriate airflow setting procedure;
    [ssquf] Specifying the external head pressure requirements for 
testing DDX-DOASes with integral water pumps;
    [ssquf] Requiring that control settings remain unchanged for all 
Standard Rating Conditions once system set-up has been completed prior 
to testing;
    [ssquf] Specifying requirements for testing equipment available 
with multiple refrigerant options; and
    [ssquf] Correcting a typographical error within one of the 
equations.
1. Industry Consensus Test Standards
    As first established in ASHRAE 90.1-2016, ASHRAE Standard 90.1-2019 
specifies separate equipment classes for DDX-DOASes \13\ and sets 
minimum

[[Page 36026]]

efficiency levels using the integrated seasonal moisture removal 
efficiency (ISMRE) metric for all DDX-DOAS classes and also the 
integrated seasonal coefficient of performance (ISCOP) metric for air-
source heat pump and water-source heat pump DDX-DOAS classes. ASHRAE 
Standard 90.1-2019 specifies that both metrics are to be measured in 
accordance with ANSI/AHRI Standard 920-2015, ``Performance Rating of 
DX-Dedicated Outdoor Air System Units'' (ANSI/AHRI 920-2015). ANSI/AHRI 
920-2015 specifies the method for testing DDX-DOASes, in part, through 
a reference to ANSI/ASHRAE Standard 198-2013, ``Method of Test for 
Rating DX-Dedicated Outdoor Air Systems for Moisture Removal Capacity 
and Moisture Removal Efficiency'' (ANSI/ASHRAE 198-2013).
---------------------------------------------------------------------------

    \13\ As discussed, the term DX-DOAS as defined by ASHRAE 90.1-
2019 is equivalent to the term DDX-DOAS as defined by DOE in this 
NOPR.
---------------------------------------------------------------------------

    ANSI/AHRI 920-2015 specifies Standard Rating Conditions (i.e., 
instructions on setting air and liquid flow rates, and equations for 
calculating ISMRE and ISCOP). Table 2 and Table 3 of ANSI/AHRI 920-2015 
provide outdoor and return air conditions for four Standard Rating 
Conditions for the dehumidification test and two Standard Rating 
Conditions for the heating test for heat pump DDX-DOASes. These tables 
also provide condenser cooling water temperatures (for both cooling 
tower and chilled water condensers) for water-cooled (cooling-only) 
DDX-DOASes and water temperatures for water-source, ground-source 
closed-loop, and ground-water source \14\ heat pump DDX-DOASes.
---------------------------------------------------------------------------

    \14\ As discussed in section III.A.1 of this NOPR, the EPCA 
definition for ``commercial package air conditioning and heating 
equipment'' specifically excludes ground-water-source equipment (42 
U.S.C. 6311(8)(A)). Accordingly, DOE is proposing to exclude this 
equipment from the scope of applicability of the test procedure.
---------------------------------------------------------------------------

    ANSI/ASHRAE 198-2013 includes requirements on instrumentation, test 
set-up, tolerances, method of test, and calculations for moisture 
removal capacity (MRC), moisture removal efficiency (MRE), heating 
capacity (qhp) and heating coefficient of performance (COP). The MRE 
for the dehumidification test is calculated for Standard Rating 
Conditions \15\ A, B, C, and D of Table 2 or Table 3 of ANSI/AHRI 920-
2015 for air-cooled, water-cooled, and water-source heat pump DDX-
DOASes. Similarly, COP is calculated for the heating mode test for 
Standard Rating Conditions E and F of Table 2 or Table 3 of ANSI/AHRI 
920-2015 for heat pump DDX-DOASes. The MRE and COP values are 
subsequently used to calculate ISMRE and ISCOP using weights that 
correspond to temperature bin data for representative cities in the 
United States.
---------------------------------------------------------------------------

    \15\ Standard Rating Conditions in the AHRI 920 test procedure 
represent full-load and part-load operating conditions for testing 
DX-DOASes. Standard Rating Condition A represents full-load 
operation in dehumidification mode, whereas Standard Rating 
Conditions B-D represent part-load operation in dehumidification 
mode. Standard Rating Condition F represents full-load operation in 
heat pump mode at low temperatures, and Standard Rating Condition E 
represents full-load operation in heat pump mode at high 
temperatures.
---------------------------------------------------------------------------

    DOE notes that AHRI recently revised AHRI 920 and published an 
updated version on February 4, 2020, AHRI Standard 920-2020 (I-P), 
``Performance Rating of Direct Expansion Dedicated Outdoor Air System 
Units'' (AHRI 920-2020). AHRI 920-2020, which continues to reference 
ANSI/ASHRAE 198-2013, includes revisions that DOE has initially 
determined improve the representativeness, repeatability, and 
reproducibility of the test methods while also reducing test burden. 
These revisions include, among other things, the following: (1) 
Expanded scope of coverage of the test procedure by no longer imposing 
an upper limit of 97 lbs/hr on DDX-DOAS MRC, thereby making the test 
procedure applicable to all DDX-DOASes subject to standards under 
ASHRAE Standard 90.1; (2) revised outdoor air dry-bulb temperature 
conditions, external static pressures, humidity conditions, and 
weighting factors for ISMRE and ISCOP, which were redesignated as 
ISMRE2 and ISCOP2, respectively; (3) revised calculations for achieving 
the target supply air conditions for units with staged capacity 
control; (4) added a supplementary cooling penalty when the supply air 
dry-bulb temperature is greater than 75 [deg]F in dehumidification 
mode; (5) removed a supplementary heat penalty for the efficiency 
metric ISMRE2 when the supply air dry-bulb temperature is less than 70 
[deg]F in dehumidification mode; \16\ (6) revised condenser water 
conditions for water-cooled and water-source heat pump DDX-DOASes; (7) 
added requirements for supply air dew point temperature; \17\ (8) added 
requirements for outdoor coil liquid flow rate; (9) provided additional 
test unit, test facility, instrumentation, and apparatus set-up 
provisions; (10) revised test methods for DDX-DOASes equipped with 
VERS; (11) added requirements for relief-air-cooled DDX-DOASes and DDX-
DOASes equipped with desiccant wheels; and (12) included requirements 
for secondary capacity tests.
---------------------------------------------------------------------------

    \16\ As discussed in section III.B.3.a of this NOPR, AHRI 920-
2020 additionally provides a method for calculating 
ISMRE270, an application metric for the dehumidification 
efficiency with the inclusion of the supplementary heat penalty. The 
subscript ``70'' indicates the inclusion of energy use from any 
supplementary heat that is required to raise the supply air dry bulb 
temperature to 70 [deg]F.
    \17\ Dew point is the temperature below which water begins to 
condense from the water vapor state in humid air into liquid water 
droplets. Dew point varies with humidity (e.g., a low dew point 
indicates low humidity and vice versa) and is, therefore, used to 
specify the humidity of the supply air.
---------------------------------------------------------------------------

    DOE carefully reviewed both ANSI/AHRI 920-2015 and ANSI/ASHRAE 198-
2013, as well as the latest changes in AHRI 920-2020, in consideration 
of this NOPR. In the following sections, DOE discusses the proposed 
definition for DDX-DOASes, scope of the test procedure, efficiency 
metrics, test methods (including the updates to AHRI 920 in the 2020 
version listed in the prior paragraph), and sampling requirements. 
Generally, DOE incorporates industry standards into the regulations by 
reference to the standard. In this NOPR, DOE has proposed to 
incorporate by reference AHRI 920-2020.
    DOE is also proposing to incorporate by reference several industry 
standards that are referenced by AHRI 920-2020, as shown in Table III-
1.

 Table III-1--Additional Industry Standards Proposed To Be Incorporated
                              by Reference
------------------------------------------------------------------------
                                             Section(s) in AHRI 920-2020
             Industry standard              that reference this industry
                                                      standard
------------------------------------------------------------------------
ANSI/ASHRAE 198-2013......................  Section 5; Section 6;
                                             Appendix C.
ANSI/ASHRAE 37-2009.......................  Section 5; Section 6;
                                             Appendix C.
ANSI/ASHRAE 1060-2018.....................  Section C4.
ANSI/ASHRAE 41.1-2013.....................  Section C3.3.1.
ANSI/ASHRAE 41.6-2014.....................  Section C3.1.3.2.
------------------------------------------------------------------------

    In response to the July 2017 ASHRAE TP RFI, AHRI commented that the 
ISMRE and ISCOP levels specified for DDX-DOASes in ASHRAE 90.1-2016 
will need adjustment if changes to the test procedure negatively impact 
these values (AHRI, No. 11 at p. 20).
    This NOPR proposes to incorporate by reference the latest version 
of the industry test procedure for DDX-DOASes which is recognized by 
ASHRAE Standard 90.1: AHRI 920 (the latest version being AHRI 920-
2020). When the test procedures referenced in ASHRAE Standard 90.1 are 
updated, EPCA requires DOE to amend the Federal test procedures for 
such covered ASHRAE equipment (which manufacturers are required to use 
in order to certify compliance with energy

[[Page 36027]]

conservation standards mandated under EPCA) to be consistent with the 
amended industry consensus test procedure. (42 U.S.C. 6314(a)(4)(B))
    The energy efficiency standards specified in ASHRAE Standard 90.1 
are based on ANSI/AHRI 920-2015 and ANSI/ASHRAE 198-2013. However, the 
amendments adopted in AHRI 920-2020 result in changes to the measured 
efficiency metrics as compared to the results under ANSI/AHRI 920-2015. 
As discussed, DOE has not established in its regulations energy 
conservation standards specifically for DDX-DOASes. DOE will address 
any potential differences in the measured energy efficiency under the 
most recent industry test procedure as compared to the industry test 
procedure on which the ASHRAE Standard 90.1 levels are based at such 
time as DOE evaluates the ASHRAE Standard 90.1 levels for DDX-DOASes 
(i.e., by developing an appropriate crosswalk, as necessary). 
Specifically, DOE intends to request that DDX-DOAS manufacturers 
provide any data and/or analysis that indicates whether and how much 
the measured rating of DDX-DOASes would be expected to change under the 
most recent version of the industry consensus test standard.
    Issue-4: DOE requests comment and data on the development of a 
crosswalk from the efficiency levels in ASHRAE Standard 90.1 based on 
ANSI/AHRI 920-2015 to efficiency levels based on AHRI 920-2020. DOE is 
specifically seeking data on how dehumidification and heating 
efficiency ratings for a given DDX-DOAS model are impacted when 
measured using AHRI 920-2020 as compared to ANSI/AHRI 920-2015.
2. Efficiency Metrics
a. Dehumidification Metric
    ASHRAE 90.1-2016 adopted a dehumidification efficiency metric for 
DDX-DOASes. Specifically, ASHRAE 90.1-2016 uses ISMRE, as presented in 
section 3.10 of ANSI/AHRI 920-2015, as a seasonal efficiency metric 
calculated as a weighted average of MRE for four different 
dehumidification rating conditions. MRE for each test condition is the 
MRC for that condition divided by electric power input, including 
consideration of electric resistance reheat if needed to raise supply 
air temperature to 70 [deg]F (i.e., ``supplementary heat''). MRC 
represents the rate at which the DDX-DOAS removes humidity from the air 
in pounds of moisture per hour. As discussed further in section 
III.B.2.c of this document, AHRI indicated that the seasonal weighting 
factors for determining ISMRE, as specified in ANSI/AHRI 920-2015, were 
developed based on climate data from a sample of twelve cities chosen 
to be representative of a wide range of climatic data in the United 
States.
    The primary function of DDX-DOASes is to provide conditioned 
(cooled and dehumidified, or heated) outdoor air. In the cooling/
dehumidifying season, these units provide sensible cooling that reduces 
the temperature of the outdoor air in addition to dehumidifying. DOE 
noted in the July 2017 ASHRAE TP RFI that the ISMRE metric specified in 
ANSI/AHRI 920-2015 does not include any provisions to measure the 
sensible cooling contribution provided by the DDX-DOAS. 82 FR 34427, 
34436 (July 25, 2017). For Standard Rating Conditions A and B in Table 
2 and Table 3 of ANSI/AHRI 920-2015, conditioning the air to a space 
temperature (70 [deg]F) requires sensible cooling as well as latent 
cooling. In the July 2017 ASHRAE TP RFI, DOE requested comment on 
whether the DDX-DOAS efficiency metric should account for this sensible 
cooling. 82 FR 34427, 34436 (July 25, 2017).
    In response to the July 2017 ASHRAE TP RFI, AHRI commented that 
DDX-DOASes operate with a separate, sensible-cooling-only interior 
cooling system, and that adding sensible cooling to the metric for DDX-
DOAS would skew efficiency values toward the non-primary function of 
the DDX-DOAS. AHRI also stated that the capacity for sensible cooling 
varies between DDX-DOAS designs, so the use of space-neutral air \18\ 
gives a worst-case efficiency to be used as comparison. (AHRI, No. 11 
at p. 12) Carrier expressed concern that the current metric focuses on 
latent capacity and that a shortcoming of the test procedure is that it 
does not consider sensible capacity. Carrier also stated that 
considering only latent capacity would be acceptable if the unit 
delivers space-neutral air, but some DDX-DOASes can provide sensible 
cooling. (Carrier, No. 6 at p. 3)
---------------------------------------------------------------------------

    \18\ Space-neutral air, or neutral air, refers to air leaving an 
air conditioner being at the target conditions for the occupied 
space in the building (without the need for subsequent sensible or 
latent cooling).
---------------------------------------------------------------------------

    As discussed in section III.B.2.c of this NOPR, DOE proposes to 
incorporate by reference the dehumidification metrics contained in the 
updated version of the industry consensus standard, AHRI 920-2020. DOE 
notes that the revised dehumidification metric in AHRI 920-2020, 
ISMRE2, does not include provisions to determine the sensible cooling 
contribution in the metric. However, as discussed in section III.B.1 of 
this document, the ISMRE2 metric, which is specified in AHRI 920-2020 
as the required rating metric for dehumidification efficiency, removes 
the supplementary heat penalty to avoid penalizing DDX-DOAS units that 
provide sensible cooling below 70 [deg]F.
    DOE recognizes that the sensible cooling provided by a DDX-DOAS 
unit may be valuable in many applications because it reduces the 
cooling that must be provided by interior cooling systems, especially 
at high outdoor temperatures. However, for certain applications it may 
be important to reheat the supply air to balance the building's 
sensible cooling load.\19\ DOE may consider in a future rulemaking 
whether the efficiency metric should be revised to include sensible 
cooling, if information is made available to support such a change.
---------------------------------------------------------------------------

    \19\ As discussed in section III.B.1 of this document, AHRI 920-
2020 include separate application metrics (i.e., ISMRE270) to be 
used for additional representations and that are calculated with a 
supplementary heat penalty based on raising the supply air dry-bulb 
temperature up to 70 [deg]F.
---------------------------------------------------------------------------

    ASHRAE Standard 90.1-2016 uses ISMRE (using ANSI/AHRI 920-2015) as 
the metric for the specified minimum efficiencies for DDX-DOAS. As 
discussed in section III.B.1 of this NOPR, DOE is aware that updates to 
the industry test procedure in AHRI 920-2020 using ISMRE2 could impact 
the measured efficiencies of DDX-DOASes as compared to ISMRE measured 
in accordance with ANSI/AHRI 920-2015, thereby necessitating use of an 
appropriate crosswalk analysis. Therefore, DOE will address these 
potential impacts on the measured efficiencies in a separate standards 
rulemaking.
b. Heating Metric
    ASHRAE 90.1-2016 adopted ISCOP, as presented in ANSI/AHRI 920-2015, 
as the heating efficiency metric, and it also set minimum ISCOP 
efficiency levels for both air-source and water-source heat pump DDX-
DOASes. ISCOP is a seasonal energy efficiency metric and is calculated 
as the seasonal weighted average of heating COPs determined for two 
heating Standard Rating Conditions specified in Table 2 and Table 3 of 
ANSI/AHRI 920-2015.
    In the July 2017 ASHRAE TP RFI, DOE noted that although the 
Department has identified air-source heat pump DDX-DOASes available on 
the market, section 3.9 of ANSI/AHRI 920-2015 defines ISCOP as an 
energy efficiency metric only for water-source heat pump DDX-DOASes. 82 
FR 34427, 34436 (July 25, 2017). DOE also noted

[[Page 36028]]

in the July 2017 ASHRAE TP RFI that equations in section 10.9 of ANSI/
ASHRAE 198-2013 for calculating the COP are labeled for application to 
water-source heat pump DDX-DOASes, although DOE once again noted that 
they could be applied to air-source heat pump DDX-DOASes. Id. As part 
of the July 2017 ASHRAE TP RFI, DOE requested comment on the 
calculation procedure for COP for air-source heat pumps, including 
whether the equations in ANSI/ASHRAE 198-2013 are applicable to air-
source heat pumps. Id. DOE did not receive any comments on this topic. 
Because ASHRAE Standard 90.1-2016 specifies minimum efficiency levels 
for both air-source and water-source heat pump DDX-DOASes using ANSI/
AHRI 920-2015, DOE considers the ISCOP and COP calculations to be 
applicable to the minimum efficiency levels in ASHRAE Standard 90.1-
2016 for both equipment classes.
    In further clarification, AHRI 920-2020 revised the definition of 
``Direct Expansion-Dedicated Outdoor Air System Units'' and the heating 
efficiency metric (designated as ISCOP2) to include both air-source and 
water-source heat pump DDX-DOASes. The ISCOP2 metric specified in 
section 3.13 of AHRI 920-2020 also includes revisions to the outdoor 
air conditions, weighting factors, and treatment of heating capacity 
calculations. DOE is proposing to adopt ISCOP2 as the heating 
efficiency metric for DDX-DOASes under the DOE test procedure, 
expressed in Watts (W) of heating capacity per W of power input. As 
discussed in section III.B.1 of this NOPR, updates to the industry 
consensus test procedure in AHRI 920-2020 using ISCOP2 could impact the 
measured heating efficiencies of DDX-DOASes as compared to ISCOP 
measured in accordance with ANSI/AHRI 920-2015, thereby necessitating 
use of an appropriate crosswalk analysis. Therefore, DOE will address 
these potential impacts on the measured heating efficiencies in a 
separate standards rulemaking.
    ISCOP2 is calculated using COPISCOP values for Standard Rating 
Conditions E and F that apply a supplementary heat penalty to the total 
power input if the supply air dry-bulb temperature is less 70 [deg]F. 
Section 6.11 of AHRI 920-2020 includes additional application rating 
heating metrics, COPfull and COPDX-DOAS, for 
additional representations. COPDX-DOAS is calculated without 
a supplementary heat penalty, while COPfull is used for 
manufacturer-specified outdoor conditions. DOE is proposing in section 
2.2.2 of Appendix B to allow COPfull and 
COPDX-DOAS to be used by manufacturers for voluntary 
representations.
c. ISMRE2 and ISCOP2 Weighting Factors
    As part of the July 2017 ASHRAE TP RFI, DOE requested information 
about analysis of climate data relevant to the development of the ISMRE 
and ISCOP test conditions and weighting factors. 82 FR 34427, 34436 
(July 25, 2017). AHRI commented that the values and weightings for both 
the dehumidification and heating points in ANSI/AHRI 920-2015 were 
developed based on climatic data for a sample of twelve cities \20\ 
chosen to be representative of a wide range of climatic conditions in 
the United States. According to AHRI, the climatic bin data were based 
on 24-hour operation per day due to the variety of applications where 
DDX-DOASes are installed and provide a reasonable standard for 
assessing the part-load situations that will be encountered. (AHRI, No. 
11 at p. 12) DOE notes that these test conditions in ANSI/AHRI 920-2015 
were established to represent specific regions of the psychrometric 
chart, as shown in the following Table III-2 and Table III-3.
---------------------------------------------------------------------------

    \20\ The sample of 12 cities analyzed were: New York City, 
Atlanta, Chicago, El Paso, Houston, Kansas City, Miami, Minneapolis, 
Nashville, New Orleans, Norfolk, and Tucson.
---------------------------------------------------------------------------

    In the development of AHRI 920-2020, DOE provided input on weather 
data, and AHRI also reviewed Typical Meteorological Year (TMY) 2 \21\ 
weather data from the National Renewable Energy Laboratory. Based, in 
part, on this input and data, AHRI 920-2020 specifies the ISMRE2 and 
ISCOP2 test conditions and weighting factors, which represent the 
number of hours per year for each test condition. Accordingly, Table 
III-2 and Table III-3 also show the Standard Rating Conditions and 
weighting factors included in sections 6.1, 6.12, and 6.13 of AHRI 920-
2020. DOE is proposing to adopt the weighting factors for the ISMRE2 
(including the test conditions specific for ISMRE270) and 
ISCOP2 metrics, as specified in AHRI 920-2020.
---------------------------------------------------------------------------

    \21\ TMY stands for ``typical meteorological year'' and is a 
widely used type of data available through the National Solar 
Radiation Database. TMYs contain one year of hourly data that best 
represents median weather conditions over a multiyear period. The 
datasets have been updated occasionally, thus TMY, TMY2, and TMY3 
data are available. See nsrdb.nrel.gov/about/tmy.html (last accessed 
4/28/21).

  Table III-2--ANSI/AHRI 920-2015 and AHRI 920-2020 Dehumidification Mode Standard Rating Conditions and ISMRE/
                                        ISMRE2/ISMRE270 Weighting Factors
----------------------------------------------------------------------------------------------------------------
                                                    ANSI/AHRI 920-2015                   AHRI 920-2020
                                            --------------------------------------------------------------------
 Standard rating      Psychrometric chart       Representative                    Representative     ISMRE2 and
    condition         region represented     condition (dry-bulb     ISMRE     condition (dry-bulb    ISMRE270
                                              temperature/ wet-    weighting    temperature/ wet-     weighting
                                              bulb temperature)      factor     bulb temperature)      factor
----------------------------------------------------------------------------------------------------------------
A................  Above 55 [deg]F dew       95 [deg]F/78 [deg]F           12  95 [deg]F/78 [deg]F            14
                    point, Above 75 [deg]F
                    wet-bulb.
B................  Above 55 [deg]F dew       80 [deg]F/73 [deg]F           28  80 [deg]F/73 [deg]F            34
                    point, >69 [deg]F and
                    <=75 [deg]F wet-bulb.
C................  Above 55 [deg]F dew       68 [deg]F/66 [deg]F           36  70 [deg]F/66 [deg]F            39
                    point, >62 [deg]F and
                    <=69 [deg]F wet-bulb.
D................  Above 55 [deg]F dew       60 [deg]F/58 [deg]F           24  63 [deg]F/59 [deg]F            13
                    point, >56 [deg]F and
                    <=62 [deg]F wet-bulb.
----------------------------------------------------------------------------------------------------------------


[[Page 36029]]


   Table III-3--ANSI/AHRI 920-2015 and AHRI 920-2020 Heating Mode Standard Rating Conditions and ISCOP/ISCOP2
                                                Weighting Factors
----------------------------------------------------------------------------------------------------------------
                                                     ANSI/AHRI 920-2015                   AHRI 920-2020
                                             -------------------------------------------------------------------
  Standard rating      Psychrometric chart       Representative                    Representative
     condition         region represented     condition (dry-bulb     ISCOP     condition (dry-bulb     ISCOP2
                                               temperature/ wet-    weighting    temperature/ wet-    weighting
                                               bulb temperature)      factor     bulb temperature)      factor
----------------------------------------------------------------------------------------------------------------
E.................  Below 55 [deg]F dew       35 [deg]F/29 [deg]F           77  47 [deg]F/43 [deg]F           91
                     point, >23 [deg]F and
                     <=64 [deg]F dry-bulb.
F.................  Below 55 [deg]F dew       16 [deg]F/12 [deg]F           23  17 [deg]F/15 [deg]F            9
                     point, <=23 [deg]F dry-
                     bulb.
----------------------------------------------------------------------------------------------------------------

3. Test Method
    This section discusses the various issues that DOE identified in 
the industry consensus test standards applicable to DDX-DOASes, 
including those raised in the July 2017 ASHRAE TP RFI and considered as 
part of DOE's review of AHRI 920-2020. These issues include: (1) 
Definitions for certain terms used in the DDX-DOAS test procedure; (2) 
optional break-in period for DDX-DOASes; (3) test facility, 
instrumentation, and apparatus set-up issues; (4) DDX-DOAS unit set-up; 
(5) test operating conditions; (6) requirements for water-cooled and 
water-source heat pump DDX-DOASes; (7) defrost energy use; (8) test 
methods for DDX-DOASes equipped with VERS; (9) tolerances; and (10) 
secondary verification tests for dehumidification and heating tests.
    Table 1 to 10 CFR 431.96 specifies the applicable industry test 
procedure for each category of commercial package air conditioning and 
heating equipment and specifies any additional testing requirements 
that may also apply. In this NOPR, DOE is proposing to add test 
procedure requirements for DDX-DOASes in a separate appendix in subpart 
F to 10 CFR part 431 (i.e., proposed Appendix B). Accordingly, DOE 
proposes to include DDX-DOASes in Table 1 to 10 CFR 431.96 and to 
reference Appendix B for the DDX-DOASes test procedure.
a. Definitions
    Section 3 of AHRI 920-2020 and section 3 of ANSI/ASHRAE 198-2013 
define terms used in the industry consensus test standards for DDX-
DOASes. DOE reviewed these sections and is proposing generally to adopt 
the definitions in section 3 of AHRI 920-2020 (as enumerated in section 
2.2.1(a) of proposed Appendix B). As discussed, DOE is proposing 
definitions in the test procedure provisions for ``direct expansion-
dedicated outdoor air system, or DX-DOAS'' as a category of commercial 
package air conditioning and heating equipment, and ``dehumidifying 
direct expansion-dedicated outdoor air system, or DDX-DOAS,'' as a 
subset of DX-DOAS.
    As discussed in the following paragraphs DOE is also proposing to 
define ``integrated seasonal coefficient of performance 2, or ISCOP2,'' 
``integrated seasonal moisture removal efficiency 2, or ISMRE2,'' and 
``ventilation energy recovery system, or VERS.'' In section 1.1 of 
Appendix B, DOE proposes to provide that where any definitions conflict 
between AHRI 920-2020 (or any of the industry standards referenced) and 
the CFR, the CFR provisions control.
    DOE notes that 10 CFR 431.92 includes definitions for the 
efficiency metrics used for commercial package air conditioners and 
heat pumps. Consistent with this approach, DOE is proposing definitions 
at 10 CFR 431.92 for ``integrated seasonal coefficient of performance 
2, or ISCOP2'' and ``integrated seasonal moisture removal efficiency 2, 
or ISMRE2'' that are consistent with the definitions for these metrics 
defined in sections 3.12 and 3.13 of AHRI 920-2020 and that 
specifically reference the DDX-DOAS test procedure in proposed Appendix 
B.
    A ``ventilation energy recovery system'' (VERS) pre-conditions the 
outdoor air before it enters the conditioning coil, thereby reducing 
the cooling, dehumidification, or heating load on the refrigeration 
system of the DDX-DOAS. ASHRAE Standard 90.1-2019 specifies separate 
equipment classes and minimum efficiency levels for DDX-DOASes with 
VERS equipment. DOE notes that neither a definition for a VERS nor a 
different term for this system is included in the previous test 
standards ANSI/AHRI 920-2015 and ANSI/ASHRAE 198-2013. However, AHRI 
920-2020 does include a definition for VERS. DOE proposes, consistent 
with AHRI 920-2020, to define a VERS as a system that preconditions 
outdoor ventilation air entering the equipment through direct or 
indirect thermal and/or moisture exchange with the exhaust air, which 
is defined as the building air being exhausted to the outside from the 
equipment.
    A VERS may also be used by commercial air-conditioning equipment 
other than DDX-DOASes. However, for commercial air-conditioning 
equipment other than DDX-DOASes, neither ASHRAE Standard 90.1-2019 nor 
the DOE energy conservation standards establish equipment classes based 
on the presence of VERS. Under the DOE test procedures for commercial 
package air conditioners and heat pump equipment other than DDX-DOASes, 
VERS is a feature that is not installed for testing. Because an 
understanding of VERS may be relevant to commercial package air 
conditioners and heat pumps other than the proposed DDX-DOAS category 
of equipment, DOE is proposing to establish a definition of VERS, 
consistent with AHRI 920-2020, in 10 CFR 431.92 so that it is broadly 
applicable when used in reference to both DDX-DOASes as well as other 
commercial package air conditioning and heat pump equipment.
    Additionally, DOE is proposing to amend the definition of 
``commercial HVAC & WH product'' at 10 CFR 431.2 to explicitly include 
DDX-DOAS.
    Issue-5: DOE requests comment on the terminology DOE proposes to 
use for DDX-DOASes, including ``integrated seasonal coefficient of 
performance 2, or ISCOP2;'' ``integrated seasonal moisture removal 
efficiency 2, or ISMRE2;'' and ``ventilation energy recovery system, or 
VERS.''
    In the July 2017 ASHRAE TP RFI, DOE sought clarification on the 
difference between a reheat system and supplementary heat in ANSI/AHRI 
920-2015 and ANSI/ASHRAE 198-2013. 82 FR 34427, 34436 (July 25, 2017). 
The definition for supplementary heat provided in section 3.21 of ANSI/
AHRI 920-2015 does not state whether it includes heat provided by 
reheat systems such as wrap-around heat pipes and wrap-around vapor 
compression systems.
    In response to the July 2017 ASHRAE TP RFI, AHRI suggested a 
revised definition for ``supplementary heat'' that

[[Page 36030]]

excludes heat provided by the vapor compression cycle or a sub-system 
that transfers heat from one part of the unit to another (e.g., wrap-
around heat pipe, wrap-around vapor compression system). (AHRI, No. 11 
at p. 11)
    DOE notes that section 3.25 of AHRI 920-2020 has clarified this 
issue by defining ``supplementary heat'' to exclude a system that 
transfers heat from the outdoor air to the supply air. The AHRI 920-
2020 definition distinguishes reheat provided by a vapor compression 
cycle that is driving the dehumidification process from common 
supplementary heat options such as fuel-fired heating, steam or hot 
water heating coils, and electric resistance. Further, section 3.25 of 
AHRI 920-2020 also states that reheat provided by secondary heat pumps, 
wrap around heat pumps, or wrap around heat pipes are not considered as 
supplementary heat. As discussed, DOE proposes to adopt the definition 
for ``supplementary heat'' provided in section 3.25 of AHRI 920-2020, 
as enumerated in section 2.2.1(a) of the proposed Appendix B, which 
references section 3 of AHRI 920-2020.
b. Break-In Period
    As part of the DOE test procedures for other commercial package air 
conditioners and heat pumps, DOE provides the option for a ``break-in'' 
period, not to exceed 20 hours, with no ambient temperature 
requirements, prior to performing a test. See 10 CFR 431.96(c). This is 
intended to allow the unit to achieve optimal performance prior to the 
test. Neither ANSI/AHRI 920-2015 nor ANSI/ASHRAE 198-2013 specify a 
break-in period for testing DDX-DOASes. In response to the July 2017 
ASHRAE TP RFI, AHRI commented that proper compressor break-in must be 
allowed to provide a fair and accurate test. AHRI also stated that it 
had previously submitted comments that 16 hours is not sufficient. 
(AHRI, No. 11 at p. 20)
    DOE addressed comments previously submitted by AHRI that DOE should 
require a minimum 16-hour break-in period for all commercial air 
conditioning equipment as part of the rulemaking finalized in a May 16, 
2012 final rule for energy conservation standards and test procedures 
for commercial heating, air-conditioning, and water-heating equipment. 
77 FR 28928, 28943. As part of that final rule, DOE determined that 
adopting a minimum break-in period of 16 hours would unnecessarily 
increase testing costs for manufacturers of equipment that can achieve 
stability in less than 16 hours. In recognition that different 
equipment will require different amounts of break-in time to achieve 
optimal performance and that break-in periods of longer than 16 hours 
may be required for some equipment, DOE adopted an optional break-in 
period up to a maximum period of 20 hours to allow the unit to achieve 
optimal performance before testing for commercial air conditioning and 
heating equipment. 77 FR 28928, 28943-28944 (May 16, 2012). Section 5.6 
of AHRI 920-2020 incorporates the same break-in period provision, not 
to exceed 20 hours. Therefore, DOE proposes to adopt the optional 
break-in period up to a maximum of 20 hours for DDX-DOASes specified in 
AHRI 920-2020 (section 5.6 Break-in), as enumerated in section 2.2.1(b) 
of the proposed Appendix B, which references section 5 of AHRI 920-
2020.
c. Airflow-Measuring Apparatus
    Figures 1 and 2 of ANSI/ASHRAE 198-2013 present the typical test 
set-up for DDX-DOASes with and without energy recovery. The figures 
show airflow and condition measuring apparatus at both the inlet and 
the outlet ends of each airflow path (i.e., the outdoor/supply and 
return/exhaust paths). DOE stated in the July 2017 ASHRAE TP RFI that 
it is not clear whether airflow-measuring apparatus are required for 
both entering and leaving air of each airflow path. 82 FR 34427, 34439 
(July 25, 2017). DOE requested comment on whether it is beneficial or 
necessary to use two airflow-measuring apparatus per airstream when 
testing DDX-DOAS equipment. Id.
    AHRI and Carrier both commented that using two airflow devices per 
airstream would be difficult and costly due to challenges with space 
constraints, additional physical barriers that can increase temperature 
stratification in the test chamber, and issues associated with meeting 
the specified design conditions due to fan reheat energy in the airflow 
measuring stations. (AHRI, No. 11 at p. 19; Carrier, No. 6 at p. 7) 
AHRI further commented that while additional airflow measuring stations 
have the benefit of monitoring cross-leakage or general leakage in the 
cabinet, it makes testing difficult, if not impossible, to perform. 
(AHRI, No. 11 at p. 19) None of the commenters indicated that use of 
two airflow-measuring apparatus per airflow path is necessary to obtain 
accurate measurements.
    Based on comments from AHRI and Carrier, DOE tentatively concludes 
that requiring two airflow-measuring apparatus per airflow path may be 
unduly burdensome for certain manufacturers. However, DOE also 
recognizes that the additional measurements may provide an indication 
of crossflow and/or leakage. DOE has tentatively concluded that AHRI 
920-2020 offers a more suitable approach to airflow measurement, for 
the reasons that follow. Section C2.2 of AHRI 920-2020 requires just 
one airflow-measuring apparatus per airflow path. To provide a check 
for general cabinet leakage, section C5.1 of AHRI 920-2020 specifies a 
methodology for performing a secondary capacity measurement that does 
not require a second airflow-measuring apparatus (rather, the 
methodology for verifying dehumidification capacity is based on a 
measurement of the weight of collected condensate). The requirement for 
just one airflow-measuring apparatus per airflow path is consistent 
with the DOE test procedures for all other commercial and residential 
air-conditioning and heating systems and limits the testing costs and 
burden on manufacturers.
    Regarding the commenters' concern that the fan heat of the airflow-
measuring apparatus might affect the controlled air conditions, DOE 
recognizes that this could affect the temperature of the return air 
entering the DDX-DOAS under test. A similar issue could occur when 
duct-inlet booster fans are used for moving outdoor air either to the 
outdoor ventilation air inlet from a separate room, or when moving 
desiccant regeneration air from another room. On this topic, section 
C3.2.2 of AHRI 920-2020 specifies that in such circumstances, the air 
conditions are to be measured downstream of the fan and that the 
sampled air used for the air condition measurement be returned: (a) To 
a location between the flow nozzles and the fan of a return airflow-
measuring apparatus, or (b) to the separate room from which air is 
drawn when a boost fan is used in the inlet duct. Accordingly, in this 
NOPR, DOE is proposing to adopt the provisions for the airflow-
measuring apparatus specified in AHRI 920-2020 section C2.2, ``Use of a 
Single Airflow Rate Measuring Apparatus per Airflow Path'' in Appendix 
C of AHRI 920-2020 (rather than the dual measurement apparatus 
specifications in Figures 1 and 2 of ANSI/ASHRAE 198-2013), as 
enumerated in section 2.2.1(f) of the proposed Appendix B, which 
references Appendix C of AHRI 920-2020.
d. Test Operating Conditions
    Through incorporation by reference of AHRI 920-2020, DOE is 
proposing to adopt the test operating conditions

[[Page 36031]]

specified in AHRI 920-2020 for DDX-DOAS units. These include: (1) 
Standard Rating Conditions (Tables 4 and 5 of section 6 of AHRI 920-
2020, as enumerated in section 2.2.1(c) of the proposed Appendix B, 
which references section 6 of AHRI 920-2020 omitting sections 6.1.2 and 
6.6.1); (2) simulated ventilation air conditions for testing under 
Option 2 for DDX-DOASes with VERS (section 5 of AHRI 920-2020 (which 
includes section 5.4.1.2 Option 2), as enumerated in section 2.2.1(b) 
of the proposed Appendix B, which references section 5 of AHRI 920-
2020); (3) atmospheric pressure (section 5 of AHRI 920-2020 (which 
includes section 5.10 Atmospheric Pressure), as enumerated in section 
2.2.1(b) of the proposed Appendix B); (4) target supply air conditions 
(section 6 of AHRI 920-2020 (which includes section 6.1.3 Supply Air 
Dewpoint Temperature and section 6.1.4 Supply Air Dry Bulb 
Temperature), as enumerated in section 2.2.1(c) of the proposed 
Appendix B); (5) external static pressure (section 6 of AHRI 920-2020 
(which includes section 6.1.5.6 External Static Pressure), as 
enumerated in section 2.2.1(c) of the proposed Appendix B); and (6) 
target supply and return airflow rates (section 6 of AHRI 920-2020 
(which includes section 6.1.5 Supply and Return Airflow Rates), as 
enumerated in section 2.2.1(c) of the proposed Appendix B).
    DOE received comments from interested parties regarding target 
supply and return airflow rates and target supply air conditions in 
response to the July 2017 ASHRAE TP RFI, and the following section 
discusses these specific issues.
i. Target Supply and Return Airflow Rates
    Section 5.2.2 of ANSI/AHRI 920-2015 and section 8.1 of ANSI/ASHRAE 
198-2013 require the supply airflow rate to be set in accordance with 
manufacturer specifications. In the July 2017 ASHRAE TP RFI, DOE 
observed that many DDX-DOAS models are capable of operating over a 
range of airflow rates. 82 FR 34427, 34437 (July 25, 2017). DOE expects 
these models to have supply air fans that can be configured with a 
range of speeds to accommodate the airflow range and the variation in 
duct length in field installations. Id. The performance of these models 
may also vary significantly from the low end to the high end of the 
specified airflow range. As part of the July 2017 ASHRAE TP RFI, DOE 
sought comments on how manufacturers select the airflow rate for 
testing, given the large range of airflows that are typical of DDX-DOAS 
units. Id.
    In response to this issue, AHRI commented that the optimum-
efficiency airflow varies with each application and that the 
manufacturer should specify the design airflow rate as long as it 
achieves the 55 [deg]F dew point temperature. (AHRI, No. 11 at pp. 13-
14) The approach described by AHRI is consistent with the approach of 
AHRI 920-2020, which stipulates the use of the manufacturer-specified 
airflow in section 6.1.5 of that document. This section of AHRI 920-
2020 also addresses how to set the airflow when it is not specified by 
the manufacturer and the case where the dehumidification provided is 
not consistent with DDX-DOAS performance (i.e., provision of supply air 
at 55 [deg]F or lower dew point, when using the manufacturer-specified 
airflow).\22\
---------------------------------------------------------------------------

    \22\ Section 6.1.3 of AHRI 920-2020 includes an adjustment for 
maximum supply air dew point temperature to increase linearly as 
barometric pressure decreases, up to 57.3 [deg]F at the minimum-
allowed 13.7 psia test pressure.
---------------------------------------------------------------------------

    As discussed, DOE is proposing to adopt the provisions in section 
6.1.3 and 6.1.5 of AHRI 920-2020, which specify that the target supply 
airflow rate be the manufacturer-specified airflow rate and that, for 
Standard Rating Condition A, achieves dehumidification consistent with 
providing a 55 [deg]F dew point temperature in standard atmospheric 
pressure conditions. In cases where supply airflow is not specified by 
the manufacturer, or supply air dew point exceeds the maximum when 
using the manufacturer-specified airflow, AHRI 920-2020 requires 
setting airflow for Standard Rating Condition A such that the supply 
air dew point does not exceed the maximum.
ii. Units With Cycle Reheat Functions
    As part of the July 2017 RFI, DOE noted that provisions regarding 
reheat and the supplementary heat penalty specified in ANSI/AHRI 920-
2015 and ANSI/ASHRAE 198-2013 were unclear. 82 FR 34427, 34436 (July 
25, 2017). Most of the DDX-DOAS models that are equipped with the 
capability to reheat dehumidified air to space-neutral conditions use 
hot refrigerant gas discharged by the compressor to reheat the 
dehumidified air leaving the evaporator coil. Other approaches can also 
be used to transfer heat from one part of the DDX-DOAS to another. 
(Section 3.21.1 of AHRI 920-2020 defines all of these methods as 
``cycle reheat.'') Reheat may also be provided by supplementary heat 
sources, such as a gas furnace or an electric resistance heater, but 
these are not considered cycle reheat. A discussion of cycle reheat 
capability with respect to the scope of this test procedure is provided 
in section III.A.4 of this document, and a discussion of the 
supplementary heat penalty is provided in section III.B.3.a of this 
document.
    ANSI/AHRI 920-2015 requires that supply air dew point temperature 
be 55 [deg]F or lower, which generally means (i.e., for a DDX-DOAS that 
removes moisture by latent cooling without the use of desiccants) that 
the air must be cooled to a temperature that is, at most, a few degrees 
above 55 [deg]F. Section 6 of ANSI/AHRI 920-2015 does not explicitly 
require testing with reheat turned on, but note 3 to Table 2 and note 3 
to Table 3 of that industry standard require the DDX-DOAS to condition 
supply air to a minimum dry-bulb temperature of 70 [deg]F for all 
dehumidification and heating tests--and this would have to be 
accomplished with active reheat (as discussed in the following 
paragraphs). Further, for units unable to meet this minimum threshold, 
section 6.1.3.1 of ANSI/AHRI 920-2015 specifies the application of a 
supplementary heat penalty to represent the power input that would be 
required to heat the supply air to the 70 [deg]F target using electric 
resistance heating.
    DOE noted in the July 2017 RFI that ANSI/ASHRAE 198-2013 includes 
two dehumidification tests, one with cycle reheat functions turned on 
and the other with cycle reheat functions turned off (sections 8.3.1.1 
and 8.3.1.2, respectively). DOE further noted that ANSI/AHRI 920-2015 
does not, however, specify which of these values is used in the 
calculation of ISMRE. 82 FR 34427, 34436 (July 25, 2017).
    As part of the July 2017 ASHRAE TP RFI, DOE requested comment on 
whether the dehumidification test with cycle reheat on or off should be 
used to calculate ISMRE, and how and when the supplementary heat 
penalty is applied. 82 FR 34427, 34436 (July 25, 2017). AHRI commented 
that the dehumidification efficiency metrics specified in ANSI/AHRI 
920-2015 are based on supply air at a dry-bulb temperature of 70 
[deg]F, and if the unit requires reheat to be on (as described in ANSI/
ASHRAE 198-2013) for supply air temperature control, then this reheat-
on test is needed to determine dehumidification capacity and 
efficiency. (AHRI, No. 11 at p. 11) DOE understands AHRI's comment to 
mean that ANSI/AHRI 920-2015 effectively requires cycle reheat to be 
activated during dehumidification tests in order to meet both the 
supply air dew point and dry-bulb temperature requirements.
    In contrast to ANSI/AHRI 920-2015, AHRI 920-2020 more explicitly

[[Page 36032]]

addresses the use of cycle reheat for dehumidification tests and 
provides more information on when the supplementary heat penalty should 
be used. As discussed in section III.B.2.a of this NOPR, DOE is 
proposing to adopt the revised MRE and ISMRE2 metrics specified in AHRI 
920-2020, which do not include a supplementary heat penalty. Section 
6.1.4.2 of AHRI 920-2020 specifies that when determining MRE and 
ISMRE2, the manufacturer shall specify whether cycle reheat is to be 
activated for the test. As discussed in section III.B.2.a of this 
document, AHRI 920-2020 provides separate application metrics (i.e., 
MRE70 and ISMRE270) which may be used for 
representations and which require a supply air dry-bulb temperature 
above 70 [deg]F (and below 75 [deg]F). For these separate application 
metrics, if cycle reheat cannot achieve 70 [deg]F, a supplementary heat 
penalty is applied based on raising the supply air dry-bulb temperature 
up to 70 [deg]F (see section 6.1.4.1 of AHRI 920-2020). DOE has 
tentatively determined that these provisions in AHRI 920-2020 clarify 
the requirements for cycle reheat and the supplementary heat penalty, 
so the Department is proposing to adopt these provisions in this NOPR 
(section 6 of AHRI 920-2020, as enumerated in section 2.2.1(c) of the 
proposed Appendix B).
iii. Target Supply Air Dry-Bulb Temperature
    As discussed, in the July 2017 ASHRAE TP RFI, DOE noted that ANSI/
AHRI 920-2015 includes a requirement of minimum supply air temperature 
of 70.0 [deg]F for all Standard Rating Conditions and a maximum dew-
point temperature of 55.0 [deg]F for Standard Rating Conditions for 
dehumidification. In that document, DOE further noted that ANSI/ASHRAE 
198-2013 requires a supply air temperature of 75.2 [deg]F or as close 
to this value as the controls will allow during testing. As part of the 
July 2017 ASHRAE TP RFI, DOE requested comment on the difference in 
target supply air temperature requirements between ANSI/AHRI 920-2015 
and ANSI/ASHRAE 198-2013, and the appropriate supply air temperature 
for use in the DOE test procedure for DDX-DOASes. 82 FR 34427, 34438 
(July 25, 2017).
    AHRI and Goodman commented that the minimum supply air temperature 
should be 70 [deg]F. AHRI added that ANSI/ASHRAE 198-2013, which was 
developed based on previous versions of AHRI 920 that required a supply 
air temperature of 75 [deg]F, is being updated to reflect the new value 
of 70 [deg]F. (AHRI, No. 11 at p. 17; Goodman, No. 14 at p. 2)
    As discussed in the previous subsection, DOE proposes to 
incorporate by reference the provisions in section 6.1.4 of AHRI 920-
2020, which specifies setting the supply air dry-bulb temperature to 
within a range of 70-75 [deg]F for tests to determine dehumidification 
metrics. For all dehumidification tests, 75 [deg]F represents the 
maximum supply air dry-bulb temperature above which a supplementary 
cooling penalty must be applied. As noted in section III.B.3.d.ii of 
this NOPR, a supplementary heat penalty must be applied for ISCOP2 
calculations when the minimum supply air dry-bulb temperature of 70 
[deg]F cannot be met in heating mode.
iv. Target Supply Air Dew-Point Temperature
    Note 5 to Table 2 and note 6 to Table 3 in ANSI/AHRI 920-2015 state 
that the maximum dew point for Standard Rating Conditions A through D 
shall be 55.0 [deg]F. The industry consensus standard does not specify 
whether these conditions apply to the outdoor air, supply air, or 
return air. DOE interprets these requirements to apply to the supply 
air because the humidity levels for outdoor air and return air are 
already specified in the same tables.
    Furthermore, although ANSI/AHRI 920-2015 specifies a maximum dew 
point temperature, the industry test standard does not include 
requirements to ensure that the dew-point temperature is maintained at 
the same level while testing at the different Standard Rating 
Conditions specified in ANSI/AHRI 920-2015. Many DDX-DOASes are 
equipped with modulating/variable capacity compressors, thereby 
allowing control for a given supply air dew point temperature. Allowing 
a lower dew point temperature for Standard Rating Conditions B, C, and 
D specified in ANSI/AHRI 920-2015 could give a better MRE rating for 
those test points, but the unit would use more energy to the extent it 
provides unnecessary excess dehumidification if operated in that 
manner. DOE also recognizes that the conditioned space latent cooling 
requirements for Standard Rating Condition A specified in ANSI/AHRI 
920-2015 represent the worst-case scenario, so there would be no need 
to deliver a lower dew point (i.e., excess dehumidification) for 
Standard Rating Conditions B, C, and D. AHRI 920-2020 revises the 
supply air dew point requirements. Section 6.1.3 of AHRI 920-2020 
requires that the average supply air dew point for Standard Rating 
Condition B, C, and D must be within 0.3 [deg]F of the Standard Rating 
Condition A dew point value.
    Accordingly, in this NOPR, DOE proposes to adopt the relevant 
provisions found in section 6.1.3 in AHRI 920-2020, which explicitly 
state that the supply air dew point temperature shall be 55.0 [deg]F or 
below for all Standard Rating Conditions A through D when operated at a 
barometric pressure of 29.92 in Hg, and that the supply air dew point 
temperature for Standard Rating Conditions B, C, and D must be within 
0.3 [deg]F of the measured supply air dew point temperature for 
Standard Rating Condition A, as noted above.
v. Units With Staged Capacity Control
    During testing, DDX-DOAS units with modulating compressors may be 
able to achieve supply air conditions within the proposed tolerances of 
the target conditions for Standard Rating Conditions B, C, and D. 
However, units with staged capacity will not likely be able to do this 
because they control capacity in larger increments. DDX-DOAS units with 
staged capacity or reheat control unable to maintain stable operation 
at the proposed dry-bulb and dew-point temperature targets within 
proposed tolerances would have to cycle between two stages (or cycle 
between the compressor(s) being on and off) to deliver average 
conditioning consistent with the target.
    Neither ANSI/AHRI 920-2015 nor ANSI/ASHRAE 198-2013 have provisions 
to address units that cycle. In response to the July 2017 ASHRAE TP 
RFI, AHRI commented that the time average testing method suggested by 
DOE in its initial review section 6.6 of ANSI/AHRI 920-2015 would 
prevent credit for over-dehumidifying at Standard Rating Conditions B, 
C, and D, but is excessively complex. Instead, AHRI recommended a 
calculated adjustment that does not credit moisture removal in excess 
of the Standard Rating Condition A design dew-point temperature. (AHRI, 
No. 11 at p. 20)
    This issue has now largely been addressed in AHRI 920-2020. 
Specifically, section 6 of AHRI 920-2020 prescribes a method to address 
DDX-DOASes with staged capacity control that is consistent with the 
aforementioned method of DOE's initial review. It differs from DOE's 
suggested method in that it applies the weighted averaging on the basis 
of the supply air humidity ratio rather than the dew point, and that it 
applies any applicable supplementary cooling or heat penalty to 
operation at each particular stage rather than after determination of a 
weighted average supply air dry-bulb

[[Page 36033]]

temperature. Given the development of defined test requirements and 
equations addressing over-dehumidification, DOE initially concludes 
that the method in AHRI 920-2020 is not excessively complex. AHRI 920-
2020 requires that when testing DDX-DOASes with staged capacity control 
in a dehumidification test condition having a supply condition dew 
point target (e.g., Conditions B, C, or D), if the dew point 
temperature cannot be controlled within the specified test tolerances 
for a given part-load condition, a weighted average of the results of 
two tests that bracket the target dew point temperature will be used. 
In this NOPR, DOE is proposing to adopt the provisions in section 6 of 
AHRI 920-2020 for achieving the target supply air conditions for units 
with staged capacity control.
    Staging of compressor capacity may also affect operation in heating 
mode. Section 6 of AHRI 920-2020 prescribes methods for determining COP 
to account for cycling between compressor stages, or for operation when 
the lowest-capacity compressor stage provides more capacity than 
required to heat the supply air to 75 [deg]F. These methods are similar 
to the AHRI 920-2020 method for addressing staged compressor capacity 
for dehumidification. Accordingly, DOE proposes to adopt the provisions 
in AHRI 920-2020 for staged capacity heat pump DDX-DOASes in heating 
mode.
e. Water-Cooled and Water-Source Heat Pump DX-DOAS Equipment
i. Test Conditions for Multiple-Inlet Water Sources
    As discussed in the July 2017 ASHRAE TP RFI, the inlet water 
temperatures in ANSI/AHRI 920-2015 Table 2 for testing water-cooled 
DDX-DOASes differ from the water-source heat pump inlet temperature 
conditions specified in Table 3 for water-source heat pump DDX-DOASes 
tested using the ``water source'' test conditions. DOE requested 
comment on the need for different dehumidification test conditions for 
a water-cooled DDX-DOAS as compared to a water-source heat pump DDX-
DOAS using the closed water loop test conditions. 82 FR 34427, 34438 
(July 25, 2017). In the July 2017 ASHRAE TP RFI, DOE also pointed out 
that Tables 2 and 3 in ANSI/AHRI 920-2015 include two application 
configurations \23\ for water-cooled DDX-DOASes and three application 
configurations for water-source heat pump DDX-DOASes. Id. DOE notes 
that ASHRAE 90.1-2016 established different standards for each of these 
five application configurations.
---------------------------------------------------------------------------

    \23\ In the context of ANSI/AHRI 920-2015, an application 
configuration specifies test conditions based on the expected 
application of the DDX-DOAS.
---------------------------------------------------------------------------

    In response to the July 2017 ASHRAE TP RFI on this issue, AHRI 
commented that the two sets of water temperatures for water-cooled DDX-
DOASes and water-source heat pump DDX-DOASes should be identical and 
that the differences would be resolved in an update to ANSI/AHRI 920-
2015. (AHRI, No. 11 at p. 17) AHRI also commented that in almost all 
cases, a single design is used for water-cooled equipment used with 
cooling tower water and chilled water, and, similarly, a single design 
is used for all of the water-source applications, adding that for each 
of these cases, a single set of water conditions can be used for 
testing. AHRI recommended that the various entering water and inlet 
fluid conditions remain as presented in the ANSI/AHRI 920-2015 
standard, but any regulated products are to be tested to the ``Chilled 
Water Entering Condenser Temperature'' column values in Table 2 and the 
``Water Source Heat Pumps'' column values in Table 3. (AHRI, No. 11 at 
p. 17)
    In response, DOE notes that AHRI 920-2020 still provides separate 
inlet fluid rating conditions for the different water-cooled and water-
source heat pump DDX-DOAS applications but now identifies some as 
optional application rating conditions. In light of the retention of 
these separate inlet fluid rating conditions in AHRI 920-2020, DOE 
surmises that AHRI's and industry's original position on these 
conditions, as set forth in the comments in response to the July 2017 
ASHRAE TP RFI, changed during the course of developing that industry 
consensus standard. Table 4 of AHRI 920-2020 continues to include 
separate inlet fluid rating conditions for water-cooled cooling tower 
and water-cooled chilled water DDX-DOASes, but Note 3 to Table 4 of 
AHRI 920-2020 indicates that the water-cooled chilled water condition 
is the optional application rating condition, contrary to AHRI's 
recommendation in response to the July 2017 ASHRAE TP RFI. Table 5 of 
AHRI 920-2020 includes separate inlet fluid rating conditions for 
water-source and ground-source closed-loop heat pump DDX-DOASes but 
identifies the ground-source closed-loop conditions as the optional 
application rating condition. Tables 4 and 5 of AHRI 920-2020 also 
revise the inlet temperatures of the rating conditions for water-cooled 
cooling tower, water-source heat pump, and water-source ground-source 
closed-loop heat pump DDX-DOASes. In this NOPR, DOE is proposing to 
adopt the water/fluid rating conditions provided in AHRI 920-2020 
(section 6 of AHRI 920-2020, which includes Table 4 and Table 5, as 
enumerated in section 2.2.1(c) and 2.2.2 of the proposed Appendix B), 
including the chilled water and ground-source closed-loop conditions 
specified as optional in AHRI 920-2020 so as to allow for voluntary 
representations for those applications. In any future energy 
conservation standards rulemaking for DDX-DOASes, DOE would consider 
establishing standards and the corresponding certification requirements 
in the context of the inlet fluid temperature conditions specific for 
water-cooled cooling towers and for water-source heat pumps provided in 
Table 4 and Table 5 of AHRI 920-2020, respectively.
ii. Condenser Liquid Flow Rate
    In the July 2017 ASHRAE TP RFI, DOE noted that ANSI/AHRI 920-2015 
provides instructions for setting the condenser liquid flow rate in 
section 6.1.4 and condenser liquid entering temperature in Tables 2 and 
3 when conducting the dehumidification test for water-cooled and water-
source heat pump DDX-DOASes. 82 FR 34427, 34437 (July 25, 2017). 
Section 6.1.4 of ANSI/AHRI 920-2015 indicates to use the liquid flow 
rates ``specified by the manufacturer.'' The manufacturer must specify 
a single liquid flow rate for tests at all Standard Rating Conditions 
as defined in ANSI/AHRI 920-2015, unless the unit is equipped with 
automatic control of the liquid flow rate.
    In the July 2017 ASHRAE TP RFI, DOE noted that ANSI/AHRI 340/360-
2007 and ANSI/AHRI 210/240-2008, which are incorporated by reference as 
DOE's test procedures for rating water-cooled commercial air-
conditioning equipment, specify inlet and outlet water temperature 
requirements rather than relying on manufacturers to determine water 
flow rate. Further, both of these industry consensus standards specify 
that the full-load water flow rate determined for the Standard Rating 
Conditions should also be used for part-load rating conditions. DOE 
further stated in the July 2017 ASHRAE TP RFI that these test methods 
reflect the typical design temperature differential for cooling towers 
serving water-cooled equipment, and they are very common for control of 
condenser water pumps; hence, it is not clear to DOE why the same test 
method would not be adopted for water-cooled DDX-DOAS. 82 FR 34427, 
34437 (July 25 2017). As part of the July 2017 ASHRAE TP RFI, DOE 
requested information on how

[[Page 36034]]

condenser water flow rates are set in the field, how they are 
controlled at part-load, and whether the relevant provisions in ANSI/
AHRI 920-2015 provide sufficient guidance regarding how to set up water 
flow for DDX-DOASes with automatic water flow control systems. Id.
    AHRI and Carrier commented that the condenser water flow rates 
should be set by the manufacturer or the installation instructions, 
consistent with ANSI/AHRI 920-2015. (AHRI, No. 11 at p. 15; Carrier, 
No. 6 at p. 5) Carrier added that for part-load conditions, setting the 
condenser water flow rate will depend on what is needed for head 
pressure control, and that this should be defined in the installation 
instructions and followed for the test. Carrier stated that some 
equipment may require no control and that others may use head pressure 
flow regulating valves. (Carrier, No. 6 at p. 5) AHRI argued that any 
variation in flow rate that occurs automatically based on the operation 
and the equipment design will be measured during testing, with the 
pressure drop at that flow rate also being measured. AHRI indicated 
that the pumping penalty accounts for different manufacturer 
specifications of flow rates and pressure drop at each of the test 
conditions. (AHRI, No. 11 at p. 15)
    As part of its update to the industry consensus test standard for 
DDX-DOASes, AHRI added additional requirements for liquid flow rate. 
More specifically, while section 6.1.6.1 of AHRI 920-2020 continues to 
provide that the water flow rate be specified by the manufacturer, the 
test method now adds that it must deliver a liquid temperature rise no 
less than 8 [deg]F when testing under Standard Rating Condition A. 
Section 6.1.6.2 of AHRI 920-2020 requires that the flow rate set under 
Standard Rating Condition A be used for testing at the remaining 
Standard Rating Conditions (B through F), unless automatic adjustment 
of the liquid flow rate is provided by the equipment. Section 6.1.6.2 
of AHRI 920-2020 also requires that if condenser water flow rate is 
modulated under part-load conditions, the flow rate must not exceed the 
flow rate set for Condition A.
    DOE has tentatively concluded that the addition of a minimum 
temperature differential in AHRI 920-2020 better reflects control 
strategies for cooling towers serving water-cooled equipment and for 
condenser water pumps while still leaving flexibility for manufacturers 
to specify full-load flow rate and to implement options for modulating 
flow rate at part-load conditions. The Department notes that the 
provision allowing for automatic adjustment of the liquid flow rate for 
part-load tests accounts for manufacturer control strategies, such as 
condenser head pressure control, and is also accounted for in the water 
pump effect (discussed in the following section). DOE has tentatively 
concluded that these provisions would be representative of flow rates 
during an average use cycle and would not be unduly burdensome to 
conduct. Therefore, DOE is proposing to adopt the liquid flow 
requirements in AHRI 920-2020 for water-cooled and water-source heat 
pump DDX-DOASes (section 6 of AHRI 920-2020, which includes section 
6.1.6 Liquid Flow Rates for Water-Cooled, Water-Source Heat Pump, and 
Ground-Source Heat Pump), as enumerated in section 2.2.1(c) of the 
proposed Appendix B.
iii. Water Pump Effect
    As part of the July 2017 ASHRAE TP RFI, DOE noted that ANSI/AHRI 
920-2015 includes an equation for calculating the ``water pump 
effect,'' which is an estimate of the energy consumption of non-
integral water pumps (i.e., pumps that are not part of the DDX-DOAS 
unit and whose power consumption would, therefore, not already be part 
of the measured power). 82 FR 34427, 34438 (July 25 2017). DOE noted 
that section 6.1.3 of ANSI/AHRI 920-2015 implies that this calculation 
applies solely to water pumps serving refrigerant-to-liquid heat 
recovery devices--no indication is given whether the equation also 
applies for pumps serving water-source or water-cooled condensers--
although it is possible that the term ``refrigerant-to-liquid heat 
recovery device'' refers to the condenser of a water-source heat pump 
DDX-DOAS. Id.
    In the July 2017 ASHRAE TP RFI, DOE requested confirmation that the 
``refrigerant-to-liquid heat recovery device'' cited in section 6.1.3 
of ANSI/AHRI 920-2015 is intended to include heat exchangers used for 
heat rejection during the dehumidification cycle, and comment on 
whether Equation 1 of this section for estimating the energy use of 
water pumps is appropriate for DDX-DOASes with water-cooled condensers. 
Id. In its comments, AHRI confirmed that the term ``refrigerant-to-
liquid heat recovery device'' is intended to include liquid-to-
refrigerant heat exchangers used in the dehumidification cycle and 
heating cycle. (AHRI, No. 11 at p. 16)
    The revisions to the industry consensus testing standard in AHRI 
920-2020 clarify this matter and are consistent with the public 
comments received. Section 6.1.6.4 of AHRI 920-2020 provides the water 
pump effect equation, and section 11.1 of AHRI 920-2020 states within 
the definition of symbol PE,x that the water pump effect 
applies to all water-cooled and water-source units without integral 
water pumps. Thus, DOE is proposing to adopt the water pump effect 
provisions in sections 6.1.6.4 and 11.1 of AHRI 920-2020 to account for 
the energy use of water pumps for water-cooled condensers, as 
enumerated in section 2.2.1(c) and section 2.2.1(d) of the proposed 
Appendix B, which reference sections 6 and 11 of AHRI 920-2020, 
respectively.
    In further clarification, the total pump effect does not need to be 
calculated for pumps that are integral to the DDX-DOAS, because the 
power for these pumps would be measured as part of the main DDX-DOAS 
power measurement. Currently, the number of DDX-DOAS models on the 
market with integral pumps is very limited. However, AHRI 920-2020 does 
not explicitly state the amount of external head pressure \24\ to use 
when testing DDX-DOASes with integral pumps, a necessary parameter. DOE 
notes that the calculation of the water pump effect for DDX-DOASes 
without integral pumps specified AHRI 920-2020 includes a fixed adder 
of 25 Watts per gallon per minute based on 20 feet of water column of 
external head pressure, a value which the Department reasons could be 
suitably applied to DDX-DOASes with integral pumps. Accordingly, DOE is 
proposing to include additional specifications in section 2.2.1(c)(ii) 
of proposed Appendix B that DDX-DOASes with integral pumps be 
configured with an external head pressure equal to 20 feet of water 
column (i.e., the same level of external head pressure used in the 
calculation of the pump effect for DDX-DOASes without integral pumps).
---------------------------------------------------------------------------

    \24\ ``External head pressure'' reflects the pump power output, 
in that it represents the height to which the pump can raise the 
water if the water were being moved opposite the force of gravity.
---------------------------------------------------------------------------

    DOE has initially determined that the proposal to specify the same 
external head pressure for integral pumps as the external head pressure 
used in the calculation of the pump effect for DDX-DOASes without 
integral pumps is consistent with the industry consensus test 
procedure. The proposed requirement would provide additional direction 
for treatment of integral pumps consistent with the treatment of non-
integral pumps and would provide for the representative comparability 
of results between DDX-DOASes with and without integral pumps. To the 
extent the industry test procedure does not specify an external head 
pressure for DDX-DOASes with an integral pump,

[[Page 36035]]

the industry test procedure would not ensure that measured results are 
comparative, and due to the potential variation resulting from the 
absence of the specification, the industry test procedure would not 
ensure that the results reflect the equipment's representative average 
energy efficiency or energy use. As such, DOE has initially determined, 
supported by clear and convincing evidence, that in the absence of a 
specification for the external head pressure for an integrated pump, 
the industry test procedure would not meet the statutory requirements 
of 42 U.S.C. 6314(a)(2)-(3) and is, therefore, proposing the 
supplemental specification.
    In addition, DOE is proposing a condition tolerance of up to 1 foot 
of water column greater than the 20-foot requirement (which equates to 
5 percent), which is equivalent to the condition tolerance on air side 
external static pressure in Table 9 of AHRI 920-2020 (Test Operating 
and Test Condition Tolerances); namely, the provision in that table 
provides for up to 0.05 inch of water column greater than the target 
external static pressure, which is around 1 inch of water column. 
Similarly, DOE is proposing an operating tolerance of up to 1 foot of 
water column, which is equivalent to the operating tolerance on air 
side external static pressure in Table 9 of AHRI 920-2020; namely, the 
provision in that table provides for 0.05 inch of water column. To the 
extent the industry test procedure does not specify a condition 
tolerance and operating tolerance for the water column, the industry 
test procedure would not ensure consistent and comparable results and 
would not ensure that the results reflect the equipment's 
representative average energy efficiency or energy use. As such, DOE 
has initially determined, supported by clear and convincing evidence, 
in the that absence of such tolerances for the water column, the 
industry test procedure would not meet the statutory requirements of 42 
U.S.C. 6314(a)(2)-(3) and is, therefore, proposing the supplemental 
specification.
    Issue-6: DOE requests comment on the proposal to require that 
water-cooled and water-source DDX-DOASes with integral pumps be set up 
with an external pressure rise equal to 20 feet of water column with a 
condition tolerance of -0/+1 foot and an operating tolerance of 1 foot.
iv. Energy Consumption of Heat Rejection Fans and Chillers
    Neither ANSI/AHRI 920-2015 nor ANSI/ASHRAE 198-2013 address 
accounting for the energy consumption of heat rejection fans (e.g., 
cooling tower fans) for water loops serving the condensers of water-
cooled DDX-DOASes. 82 FR 34427, 34438 (July 25, 2017). DOE noted that 
section 6.1 of AHRI 340/360-2007, which is used for rating certain 
water-cooled commercial package air conditioning and heat pump 
equipment, provides a power consumption adjustment for both the cooling 
tower fan and the circulating water pump (it is assumed that the pump 
is external to the air conditioning equipment). Id. In addition, 
neither ANSI/AHRI 920-2015 nor ANSI/ASHRAE 198-2013 address accounting 
for the energy consumption of chiller systems used to provide chilled 
water to DDX-DOASes with chilled-water-cooled condensers. In the July 
2017 ASHRAE TP RFI, DOE requested comment on accounting for the energy 
consumption for heat-rejection fans and chiller systems employed in 
water-cooled or water-loop DDX-DOASes. Id.
    AHRI commented that the AHRI test standard for certain commercial 
package air conditioning and heat pump equipment includes the cooling 
tower fan and pump energy as part of a flat rate adjustment, but that 
the International Organization for Standardization (ISO) test standard 
for water-source heat pumps does not account for cooling tower fan 
energy use at this time. AHRI stated that the minimum efficiency values 
for DDX-DOASes specified in ASHRAE 90.1-2016 were based on the current 
ANSI/AHRI 920-2015 standard that does not account for the energy 
consumption of heat-rejection fans or the chiller system, although it 
does account for the additional water pumping energy (see the 
discussion of the water pump effect in section III.B.3.e.iii of this 
document). AHRI stated that, as a result, DOE should not account for 
this energy in the efficiency metric for DDX-DOASes because doing so 
introduces unknown impacts on the design and costs associated with 
meeting the minimum efficiency requirements. (AHRI, No. 11 at pp. 16-
17) Carrier also commented that heat-rejection fans are not part of a 
water-cooled unit but are part of the cooling tower rating and are 
covered by Table 6.8.1.7 in ASHRAE 90.1-2016. (Carrier, No. 6 at p. 5) 
Carrier commented that chiller system energy use should not be included 
in the efficiency metric because this is not a system rating and is 
only a component rating method for the DDX-DOAS itself. (Carrier, No. 6 
at p. 6)
    The revised AHRI 920-2020 also does not include energy use of the 
heat-rejection fans and chiller systems employed in water-cooled or 
water-loop DDX-DOASes. DOE observes that accounting for this energy use 
is not a consistent industry practice, as evidenced by the differences 
between the AHRI 340/360-2007 approach for more typical commercial 
package air conditioning equipment and the ISO approach for water-
source heat pumps. The heat rejection fan addition for more typical 
water-cooled commercial package air conditioning equipment is a modest 
energy adder (around 10 percent of unit power).\25\ Furthermore, 
including the energy of the heat rejection fan and chiller systems 
would not help to distinguish between models of different efficiency, 
since the adder would be identical for two same-capacity models with 
different efficiencies. For these reasons, and consistent with AHRI 
920-2020, DOE is not proposing in this NOPR to include any energy 
consumption associated with heat rejection fans, cooling towers, or 
chiller systems used to cool the water loops of water-cooled or water-
source DDX-DOASes.
---------------------------------------------------------------------------

    \25\ For example, for a minimally-compliant 120,000 Btu/h water-
cooled unit with gas heat having a 12.5 EER (see 10 CFR 431.97 Table 
1), the total electricity use is 120,000 Btu/h / 11.9 Btu/Wh = 
10,084 W, and the heat rejection fan adder is 120,000 Btu/h x (10 W 
per 1,000 Btu/h) = 1,200 W.
---------------------------------------------------------------------------

v. Chilled Water Coil Exclusion
    In the July 2017 ASHRAE TP RFI, DOE noted that section 2 of ANSI/
ASHRAE 198-2013 specifically excludes equipment with water coils that 
are supplied by a chiller located outside of the unit. 82 FR 34427, 
34438 (July 25 2017). However, Table 2 in ANSI/AHRI 920-2015 includes 
operating conditions for which a water-cooled condenser is supplied 
with chilled water, and ASHRAE 90.1-2016 established standard levels 
for DDX-DOASes that operate with chilled water as the condenser cooling 
fluid. As part of the July 2017 ASHRAE TP RFI, DOE requested 
confirmation that the ANSI/ASHRAE 198-2013 chiller exclusion applies to 
cooling coils rather than condenser coils. Id.
    In response to the July 2017 ASHRAE TP RFI, AHRI commented that 
both ANSI/AHRI 920-2015 and ANSI/ASHRAE 198-2013 were designed for 
units that contain vapor compression cycle-based cooling and 
dehumidification with direct expansion coils. AHRI stated that direct 
application of chilled water coils to cool and dehumidify is outside 
the scope of the standard, as the energy for cooling is expended at an 
external source of chilled water. (AHRI, No. 11 at p. 18) Carrier 
commented that chillers should

[[Page 36036]]

only be used for cooling coils and not for condenser heat rejection 
unless there is heat reclaim, and that this should be addressed through 
a building efficiency standard such as ASHRAE 90.1. (Carrier, No. 6 at 
p. 7)
    AHRI 920-2020 did not make a change to the exclusion of DOASes with 
water coils that are supplied by a chiller located outside of the unit; 
AHRI's comment explains that the exclusion exists because chilled water 
coil units that use the chilled water for cooling are not DX units, and 
the industry test procedures are only for DOASes with DX cooling. 
ASHRAE Standard 90.1 does not include standards for non-DX DOASes such 
as those with chilled water coils used for cooling. Based on AHRI 920-
2020, and ANSI/ASHRAE 198-2013 as referenced, and the comments 
received, DOE did not consider DOAS units that use chilled water coils 
directly for cooling and dehumidifying. However, the comments provided 
in response to the July 2017 ASHRAE TP RFI, as discussed in section 
III.B.3.e.i of this document, indicate that DX-DOASes and DDX-DOASes 
may still use chilled water for condenser coils. (AHRI, No. 11 at p. 
17)
f. Defrost Energy Use for Air-Source Heat Pump
    In the July 2017 ASHRAE TP RFI, DOE noted that tests conducted at 
35 [deg]F dry-bulb temperature for consumer central air conditioning 
heat pumps (which are air-source) consider the impacts of defrosting of 
the outdoor coil in the energy use measurement (see section 3.9 of 10 
CFR part 430, subpart B, appendix M), while defrost is not addressed in 
ANSI/ASHRAE 198-2013. 82 FR 34427, 34436 (July 25 2017). DOE stated 
that defrost has a real impact on efficiency because of energy use 
associated with defrost and because a system cannot continue to provide 
heating during defrost operation, thereby reducing time-averaged 
capacity. Id. Hence, DOE noted that consideration of defrost could 
provide a more field-representative measurement of performance. DOE 
requested comment on whether testing for test condition E of ANSI/AHRI 
920-2015 Table 2 (i.e., 35 [deg]F dry-bulb/29 [deg]F wet-bulb) should 
consider energy use associated with defrost. Id.
    On this issue, AHRI commented that, due to the constant volume 
nature of the airflow in DDX-DOASes, the addition of defrost to DDX-
DOASes presents challenges, and it is not in a position to present a 
proper solution at this time. AHRI also stated that it is aware of 
manufacturers that disable the heat pump operation in cold temperatures 
to avoid this issue. (AHRI, No. 11 at p. 13) The Joint Advocates, 
Goodman, and Carrier commented that defrost should be accounted for in 
the test procedure to provide a more representative measurement of 
field energy use. (Joint Advocates, No. 9 at p. 4; Goodman, No. 14 at 
p. 2; Carrier, No. 6 at p. 4) Carrier added that DOE should use the T-
test \26\ defined in ANSI/AHRI 340/360 and ANSI/AHRI 210/240. (Carrier, 
No. 6 at p. 4) Goodman indicated that it will be very difficult to 
precisely capture defrost in the DDX-DOASes test procedure. (Goodman, 
No. 14 at p. 2)
---------------------------------------------------------------------------

    \26\ The T-test is a non-steady-state (transient) test that 
includes measurement of both the heating energy use as the outdoor 
coil accumulates frost and the defrost energy use as the unit 
undergoes multiple defrost cycles, as referenced in section 8.8.3 of 
ANSI/ASHRAE 37-2009.
---------------------------------------------------------------------------

    DOE understands that AHRI is referring to challenges in field 
operation defrosting for air-source heat pump DDX-DOASes. Preventing 
cold outdoor air from being brought into the supply air stream during a 
defrosting sequence (when the DDX-DOAS cannot operate as a heat pump) 
would require interruptions to the supply airflow, which is 
inconsistent with building code requirements to provide a continuous 
supply of ventilation air for most DDX-DOAS applications. DOE is aware 
of only a limited number of air-source heat pump DDX-DOAS units. DOE 
understands that these units may not continue heat pump operation 
during potential frosting conditions as a result of these challenges in 
field operation. Given these factors, DOE is not aware of test data 
(e.g., from T-tests) for such heat pumps during extended heating mode 
operation to understand better the level of frost accumulation and 
associated defrost energy expenditure. DOE also notes that AHRI 920-
2020 does not include any provisions for testing or calculating the 
defrost energy of DDX-DOAS air-source heat pumps. However, AHRI 920-
2020 arguably addresses this issue in another fashion, namely by 
providing in section 5.5 that defrost control settings specified by the 
manufacturer in installation instructions may be set prior to heating 
mode tests in order to achieve steady-state conditions during the 
heating mode tests. As discussed in section III.B.3.d of this document, 
DOE is proposing to adopt the provisions of AHRI 920-2020 section 5.5, 
Defrost Controls for Air-Source Heat Pump during Heating Mode, as 
enumerated in section 2.2.1(b) of the proposed Appendix B. If these 
settings fail to prevent frost accumulation during the heating mode 
tests (resulting in unsteady conditions), then the manufacturer would 
need to seek a waiver from the test procedure to obtain an alternate 
method of test from DOE pursuant to 10 CFR 431.401. However, section 
5.5 of AHRI 920-2020 also specifies that the Standard Rating Condition 
F heating mode test (which represents low temperature environmental 
conditions where frosting is likely) is optional to conduct, and if the 
Standard Rating Condition F test is not conducted, a default COP of 1.0 
(corresponding to electric resistance heating) is assigned at this 
rating point instead. Therefore, the manufacturer may choose to not 
conduct a test at Standard Rating Condition F instead of seeking a 
waiver. DOE has tentatively concluded that the test method set forth in 
section 5.5 of AHRI 920-2020 for defrost controls for air-source heat 
pump DDX-DOASes during heating mode offers a reasonable and workable 
approach, so the Department proposes to adopt such approach into the 
Federal test procedure.
    Due to the lack of sufficient information on how air-source heat 
pump DDX-DOAS units operate under frosting conditions, DOE is not 
proposing to include any provisions for including the defrost energy of 
DDX-DOAS air-source heat pumps.
g. General Control Setting Requirements
    Requirements for adjustment of unit controls during set-up for 
testing of a DDX-DOAS are addressed in specific sections of AHRI 920-
2020. Some examples include the following. Section 5.2, ``Equipment 
Installation,'' requires that units be installed per manufacturer's 
installation instructions (MII). Section 5.4.3, ``Deactivation of 
VERS,'' indicates that operation of the VERS may be deactivated for 
Standard Rating Conditions C or D if the VERS is capable of being 
deactivated. Section 5.5, ``Defrost Controls for Air-Source Heat Pump 
during Heating Mode,'' provides instructions for setting of defrost 
controls.
    However, DOE notes that the test standard provides no general 
requirements indicating whether control settings can be adjusted as the 
test transitions through the four Standard Rating Conditions used for 
testing. Manual readjustment of control settings would not generally 
occur in field operation of DDX-DOASes as outdoor air conditions change 
(i.e., in the field, controls are configured at the time of 
installation and would not be actively adjusted on an ongoing basis in 
response to changes in outdoor temperature or humidity). Hence, to 
further ensure the representativeness of the test procedure, DOE is 
proposing

[[Page 36037]]

inclusion of a general requirement that control settings remain fixed 
and that there be no further manual adjustment thereof, once set 
initially for the first of the Standard Rating Conditions (Standard 
Rating Condition A). Absent such instruction, the controls could be 
adjusted as the test transitions through the four Standard Rating 
Conditions used for testing, which as discussed, would not be 
representative of the operation of the unit in the field. As such, DOE 
has initially determined, supported by clear and convincing evidence, 
that absent instruction for the control settings to be fixed during 
testing, the industry test procedure would not meet the statutory 
requirements of 42 U.S.C. 6314(a)(2)-(3) and is, therefore, proposing 
such instruction.
    Notwithstanding this proposal, DOE recognizes that some manual 
intervention, as permitted by AHRI 920-2020, and as specified in 
supplemental test instructions (STI),\27\ may be necessary as the test 
transitions through Standard Rating Conditions. However, such manual 
interventions are only permitted in limited and specific instances as 
identified in the test standard or STI. An example of such an allowed 
intervention is the use of the manual setting of compressor capacity 
staging for tests using the ``Weighted average method,'' as described 
in section 6.9.1 of AHRI 920-2020. In field operation, a DDX-DOAS set 
per the manufacturer's installation instructions would attempt to 
achieve the target supply air dew point over the average of a time 
period with cycling (unsteady) operation between two compressor stages; 
to address this, the test standard calls for manual intervention, using 
two steady-state tests, one using each stage, and calculating a 
weighted average of the results. (This provision is discussed in depth 
in section III.B.3.d.v of this NOPR.)
---------------------------------------------------------------------------

    \27\ ``STI'' is defined in AHRI 920-2020 as additional 
instructions provide by the manufacturer and certified to the U.S. 
DOE. As explained in section III.C.1 of this document, this NOPR 
does not propose certification requirements for DDX-DOAS--such 
requirements will instead be proposed in a separate Energy 
Conservation Standard rulemaking. Consistent with certification 
provisions for other commercial packaged air-conditioning and 
heating equipment, manufacturers include STI as part of the 
certification (see 10 CFR 429.43(b)(4)). DOE is proposing that 
manufacturers must adhere to the provisions of this test procedure 
starting on the compliance date for the related energy conservation 
standard rulemaking. Hence, this approach does not require that STI 
exist earlier than the date it must be certified to DOE.
---------------------------------------------------------------------------

    Thus, DOE is proposing to require that all control settings are to 
remain unchanged for all Standard Rating Conditions once system set-up 
has been completed, and component operation shall be controlled by the 
unit under test once the provisions in section 6 of AHRI 920-2020 
(Rating Requirements) are met, except as specifically allowed by the 
test standard or STI (see section 2.2.1(b)(i) of the proposed Appendix 
B).
    Issue-7: DOE requests comment on the proposed general control 
setting requirement for DDX-DOASes.
h. Ventilation Energy Recovery Systems
    As discussed in section III.A.1 of this NOPR, the industry 
definition of ``DX-Dedicated Outdoor Air System Units'' is inclusive of 
units that provide pre-conditioning of outdoor air by direct or 
indirect transfer with return/exhaust air using an enthalpy wheel, 
sensible wheel, desiccant wheel, plate heat exchanger, heat pipes, or 
other heat or mass transfer apparatus. These pre-conditioning features 
are broadly referred to as ventilation energy recovery systems 
(``VERS'', or ``energy recovery''). ASHRAE Standard 90.1-2016 defines 
separate equipment classes and efficiency levels for DDX-DOASes with 
VERS.
    Section 5.4 of AHRI 920-2020 specifies testing requirements for 
DDX-DOASes equipped with VERS. Section 5.4.1 of AHRI 920-2020 specifies 
that units equipped with VERS can be tested using either one of two 
options: ``Option 1'' or ``Option 2''. Option 1 requires operating the 
DDX-DOAS unit with VERS as it would operate in the field, maintaining 
the appropriate return air and outdoor air conditions for airflows 
entering the unit, and operating the VERS to provide energy recovery 
during the test (see section 5.4.1.1 of AHRI 920-2020).\28\ In addition 
to specifying the outdoor air dry-bulb temperature and humidity 
conditions, Table 4 and Table 5 of AHRI 920-2020 specify return air 
inlet conditions that are applicable to DDX-DOASes with VERS. Section 
C2.4 in Appendix C of AHRI 920-2020 also specifies that the return air 
be ducted into the unit from a separate test room maintaining the 
required return air inlet conditions.
---------------------------------------------------------------------------

    \28\ The Option 1 test method includes additional specificity to 
the test room configuration for testing DDX-DOAS with energy 
recovery by allowing use of the three-chamber approach in addition 
to the example configuration provided in the current industry 
consensus test standard, in which the outdoor room is conditioned to 
both the required outdoor dry-bulb and humidity conditions.
---------------------------------------------------------------------------

    Option 2 involves setting the conditions of the air entering the 
unit so as to simulate the conditions that would be provided by the 
VERS in operation (see section 5.4.1.2 of AHRI 920-2020). Option 2 uses 
energy recovery device performance ratings based on ANSI/AHRI 1060-2018 
to calculate the air dry-bulb temperature and humidity conditions that 
would be provided by the energy recovery device. ANSI/AHRI 1060-2018 
references ANSI/ASHRAE 84-2013, ``Method of Testing Air-to-Air Heat/
Energy Exchangers,'' (ANSI/ASHRAE 84-2013) (approved by ASHRAE on 
January 26, 2013) for conducting the test. These industry test 
standards provide a method for rating the performance of VERS in terms 
of sensible and latent effectiveness. DOE also notes that the 
performance ratings for energy recovery devices certified using ANSI/
AHRI 1060-2018 are listed in AHRI's directory of certified product 
performance.\29\
---------------------------------------------------------------------------

    \29\ AHRI's directory of certified product performance for air-
to-air energy recovery ventilators can be found at 
www.ahridirectory.org/ahridirectory/pages/erv/defaultSearch.aspx.
---------------------------------------------------------------------------

    The operating conditions specified in ANSI/AHRI 1060-2018 may be 
different than the operating conditions specified for testing DDX-DOAS 
(i.e., airflow rate, which subsequently affects factors such as 
transfer/leakage airflow \30\). Hence, section C4 of AHRI 920-2020 
provides methods to adjust, for the DDX-DOAS operating conditions, the 
effectiveness values for sensible and latent transfer measured using 
ANSI/AHRI 1060-2018. Section C4 of AHRI 920-2020 also provides default 
values for sensible effectiveness and latent effectiveness. These can 
be used in cases where performance rating information based on ANSI/
AHRI 1060-2018 is not available for a VERS, or the rotational speed for 
an energy recovery wheel has been changed from the speed used to 
determine performance ratings using ANSI/AHRI 1060-2018.
---------------------------------------------------------------------------

    \30\ As discussed in section III.B.4.g.i of this NOPR, DDX-
DOASes with energy recovery wheel VERS may experience air transfer 
and leakage from the outdoor air path to the exhaust air (outdoor 
air transfer and leakage) and return air to the supply air (return 
air transfer and leakage).
---------------------------------------------------------------------------

    The Option 2 approach would reduce test burden for most test 
laboratories by reducing the number of test rooms required as compared 
to conducting tests using Option 1. Because the outdoor ventilation air 
and return air would be maintained at the same conditions, there would 
be no transfer of heat or moisture in the VERS, nor any change of VERS-
outlet supply air conditions associated with transfer or leakage of 
return air to the supply air plenum. In addition, testing using Option 
2 is conducted with all components operating (e.g., with an energy 
recovery wheel rotating, or with the pump of a glycol-water runaround 
loop activated), such that all measurements would be representative

[[Page 36038]]

of the pressure drops and power consumption associated with the VERS. 
This approach avoids separate testing to measure power input of 
auxiliary components or of the exhaust air fan.
    Option 2 is applicable for DDX-DOASes for which a VERS provides the 
initial outdoor ventilation air treatment. DDX-DOAS units with VERS 
that provide conditioning downstream of the conditioning coil could not 
be tested using Option 2, since this option addresses VERS pre-
conditioning only upstream of the conditioning coil. Such units would 
need to be tested using Option 1.
    In response to the July 2017 ASHRAE TP RFI, AHRI commented that 
testing of DDX-DOAS units with VERS would generally require a facility 
with three adjacent test chambers, which is not available in the known 
stock of existing laboratory spaces. (AHRI, No. 11 at p. 14) AHRI 
stated that the test facility arrangement for testing of DDX-DOASes 
with energy recovery presented in ANSI/ASHRAE 198-2013,\31\ as 
referenced by AHRI 920-2020, is not adequate because laboratories 
cannot maintain both the required dry-bulb temperature and high 
humidity conditions in the outdoor room, since removing the high 
condenser heat load using a conventional conditioning system also 
excessively dehumidifies the chamber. The commenter also argued that 
capacity and stratification are significant issues with the existing 
test arrangement. AHRI surmised that a separate, third test room to 
provide conditioned outdoor air for the entering air to the energy 
recovery device would be required to provide adequate stability for 
testing. AHRI further asserted that because it is not feasible to 
adequately test units with VERS, DOE should limit the scope of the 
Federal test procedure at this time to DDX-DOAS units without VERS. 
(AHRI, No. 11 at p. 15)
---------------------------------------------------------------------------

    \31\ See section 6.1.1.2 and Figure 2 of ANSI/ASHRAE 198-2013.
---------------------------------------------------------------------------

    Based on DOE's review of the test requirements and equipment 
available on the market, DOE is aware of test facilities capable of 
testing using Option 1 for smaller DDX-DOAS units. Test facilities with 
similar configurations used for testing variable refrigerant flow 
multi-split air-conditioning and heat pump equipment would be large 
enough and equipped with enough controlled test rooms to meet the DDX-
DOAS test procedure requirements. DDX-DOAS units with physical 
dimensions under 10 feet by 10 feet (typically less than 100 lbs. per 
hour MRC at Standard Rating Condition A), which represent more than 50 
percent of equipment models available on the market, could be tested in 
these existing test facilities.
    Option 2 allows existing test facilities to test all DDX-DOAS 
units, including units larger than those that can be tested using 
Option 1. As discussed, Option 2 requires neither a separate third test 
room to condition the outdoor ventilation air to the required 
temperature and humidity conditions, nor that the outdoor room in which 
the unit is located be conditioned to both the required dry-bulb and 
humidity conditions, because it does not require use of an air stream 
at outdoor air conditions. Aside from the chamber in which the test 
unit is installed, it requires only a second chamber at the simulated 
conditions. The inclusion of Option 2 in AHRI 920-2020 reduces testing 
burden compared to the ANSI/AHRI 920-2015, which only provides test 
set-up and provisions that are mostly equivalent to the Option 1 method 
in AHRI 920-2020 discussed previously. For these reasons, DOE 
tentatively concludes that existing test facilities would be capable of 
using the proposed test procedure for testing DDX-DOASes both with and 
without VERS.
    DOE is required under EPCA to adopt a Federal test procedure that 
is consistent with the applicable test procedure specified in the 
amended ASHRAE Standard 90.1 unless DOE determines, supported by clear 
and convincing evidence, that to do so would result in a test procedure 
that is not designed to produce test results which reflect the energy 
efficiency of DDX-DOASes in a representative average-use cycle or would 
be unduly burdensome to conduct. (42 U.S.C. 6314(a)(4)(B); 42 U.S.C. 
6314(a)(2) and (3)) In this NOPR, DOE is proposing to adopt the two 
options (i.e., Option 1 and Option 2) for testing DDX-DOASes with 
energy recovery, as provided in section 5.4.1 of AHRI 920-2020 (as 
enumerated in section 2.2.1(b) of the proposed Appendix B). As 
discussed further in section III.B.3.a of this NOPR, DOE is proposing 
to define a ``ventilation energy recovery system'' as a feature that 
provides pre-conditioning of outdoor ventilation air entering the 
equipment through direct or indirect thermal and/or moisture exchange 
with the exhaust air leaving the unit.
    In addition, DOE notes that the relevant industry test standards 
(AHRI 920-2020 and ASHRAE 198-2013) in some cases use synonymous but 
different terms to denote VERS. DOE proposes to include a section 
2.3(b) in its proposed Appendix B indicating that the different 
synonymous terms all refer to VERS as defined in 10 CFR 431.92.
    The following subsections address specific aspects of the proposed 
test procedure pertaining to DDX-DOASes with VERS.
i. Exhaust Air Transfer and Leakage
    DOE is aware that DDX-DOASes with energy recovery wheel VERS may 
experience air transfer and leakage from the outdoor air path to the 
exhaust air (outdoor air transfer and leakage) and return air to the 
supply air (return air transfer and leakage). Some of this air is 
leakage past the diametral seals that separate the outdoor and exhaust 
plenums on one side of the wheel and the return and supply plenums on 
the other side. Additional leakage from outdoor to exhaust or return to 
supply could be due to loose cabinet construction of the DDX-DOAS 
itself. Depending on the geometry of the energy recovery wheel media 
(e.g., whether the sheets of media making up the energy recovery wheel 
core are oriented parallel to this leakage flow direction), the air may 
pass through a portion of the media near the diametral seal. In 
addition, as a portion of the wheel passes from one side of the seal to 
the other, the air within that portion reverses direction--this 
represents either return air transferred to the supply side or outdoor 
air transferred to the exhaust side. The exhaust air transfer ratio 
(EATR) is defined in section 3.8 of AHRI 920-2020 as the fraction of 
airflow leaving the VERS that transfers or leaks from the return air 
inlet rather than passing through the VERS from the outdoor air inlet.
    The return air that transfers and leaks to the supply air side of 
an energy recovery wheel did not enter the DDX-DOAS as outdoor 
ventilation air. Therefore, the amount of fresh outdoor air delivered 
by the DDX-DOAS is less than the supply airflow and is equal to the 
supply airflow multiplied by the factor (1-EATR). In addition, the 
return air is already at neutral space conditions. Hence, the energy 
recovery wheel does not provide any meaningful conditioning for this 
air. When calculating MRC for a DDX-DOAS with an energy recovery wheel, 
section 10.5 of ANSI/ASHRAE 198-2013 indicates that the calculation is 
based on the full supply airflow. DOE notes that any transfer or 
leakage air would increase the apparent dehumidification provided by 
the DDX-DOAS unit, since this air is already at space-neutral 
conditions--thus, a high EATR would boost the efficiency rating without 
providing any real benefit (for VERS other than energy recovery wheels, 
the EATR is considered to be equal to 0, under the assumption that 
cabinet air leakage

[[Page 36039]]

through the VERS is negligible, so this issue would not affect these 
other VERS). ANSI/AHRI 920-2015 includes tracer gas tests for measuring 
EATR in its standard rating requirements (see section 5.1). As part of 
the July 2017 ASHRAE TP RFI, DOE raised this issue, while recognizing 
that such leakage may be low enough in most energy recovery wheels that 
the EATR measurement could represent an unnecessary addition to test 
burden. 82 FR 34427, 34437 (July 25 2017). DOE requested comment on 
whether EATR should be included in the test procedure for DDX-DOASes 
and, if so, how it should be used in determining DX-DOAS ratings. Id.
    In response to the RFI, on this issue, AHRI commented that the 
intent of the DOE test procedure for DDX-DOASes should not be to 
quantify energy recovery performance. AHRI pointed out that the AHRI 
certification directory publishes EATR values based on AHRI 1060. 
(AHRI, No. 11 at p. 15) In addition, AHRI argued that test laboratories 
of sufficient size for testing DDX-DOASes are not currently equipped 
with tracer gas test equipment, as specified in ANSI/ASHRAE 84-2013. 
(AHRI, No. 11 at p. 14) No other comments were received on this issue.
    Since the July 2017 ASHRAE TP RFI, further refinements were made to 
the industry consensus test standard which have bearing on this matter. 
Specifically, sections 6 and C4 of AHRI 920-2020 were revised to 
include methods to estimate EATR without requiring a tracer gas 
measurement, and to account for EATR's impact on DDX-DOAS performance, 
using calculations tailored for testing under either Option 1 or Option 
2. These include using an EATR value that is based on testing in 
accordance with ANSI/AHRI 1060-2018 with zero purge angle,\32\ zero 
return-to-supply pressure differential, and 100-percent of nominal 
energy recovery wheel supply airflow, and adjusting the EATR value for 
the DDX-DOAS supply airflow rate based on an assumption that the 
leakage/transfer flow is not affected by the supply and return air flow 
rates. The adjusted value of EATR is then used in the calculation of 
DDX-DOAS performance. Specifically, the MRC calculations in section 6.9 
of AHRI 920-2020 take into account the conditioning of the air that 
leaked or transferred from the return plenum to the supply plenum 
(equal to adjusted EATR multiplied by supply airflow) only from return 
conditions to supply conditions to reflect the fact that this air did 
not enter the DDX-DOAS unit at outdoor air conditions. In cases where 
EATR rating information based on ANSI/AHRI 1060-2018 is not available, 
or if, for an energy recovery wheel, the rotational speed has been 
changed from the speed used to determine performance ratings using 
ANSI/AHRI 1060-2018, sections 6.5 and C4 of AHRI 920-2020 provide a 
default value of EATR that would be used to rate the DDX-DOAS.
---------------------------------------------------------------------------

    \32\ A purge mechanism cleans the portion of the wheel that has 
had contact with return air before it is used to precondition 
outdoor air. The cleaning is provided by outdoor air that passes 
through this portion of the wheel and is diverted into the return 
plenum to be discharged through the exhaust blower. Most purge 
mechanisms allow adjustment of the angle of the wheel sector that is 
subject to this cleaning function. At zero purge angle, there is no 
purge cleaning provided.
---------------------------------------------------------------------------

    DOE has tentatively determined that the use of default or certified 
values for EATR in AHRI 920-2020 (instead of tracer gas tests) has 
addressed AHRI's comments on quantifying energy recovery performance. 
Accordingly, DOE is proposing to adopt these changes made by AHRI 920-
2020 (section 6.5 Determination of EATR), as enumerated in section 
2.2.1(c) of the proposed Appendix B; and Appendix C of AHRI 920-2020 
(which includes section C4 Simulated Ventilation Air Conditions for 
Testing Under Option 2), as enumerated in section 2.2.1(f) of the 
proposed Appendix B).
ii. Purge Angle Setting
    Section 6.6 of ANSI/ASHRAE 198-2013 requires that for any DDX-DOAS 
equipped with an energy recovery wheel, the purge angle of such feature 
must be set to zero when testing the DDX-DOAS unit. As part of the July 
2017 ASHRAE TP RFI, DOE requested comment on whether all purge devices 
are adjustable to zero purge and whether it is always clear how to set 
them to zero purge. 82 FR 34427, 34439 (July 25, 2017). DOE also 
requested comment on whether it is appropriate to set purge to zero or 
whether it would be more appropriate to set purge to its highest 
setting or to some other standard setting. Id.
    None of the comments on the RFI indicated that there are purge 
devices that are not adjustable to zero angle, nor that it is unclear 
how to adjust purge angle to zero. Carrier commented that for the short 
period of time required for a performance test, it should not be a 
problem to set the purge angle to zero. (Carrier, No. 6 at p. 8) As 
discussed previously, AHRI stated that there are no independent 
laboratories capable of testing DDX-DOAS units with VERS. As a result, 
AHRI argued that this issue does not need to be addressed at this time. 
However, AHRI stated, if in the future laboratories are able to test 
DDX-DOASes equipped with VERS, then manufacturers should be allowed to 
specify the purge setting for testing, as is done in AHRI 1060. (AHRI, 
No. 11 at p. 20)
    DOE has tentatively concluded that a zero purge angle aligns with 
the selection that manufacturers would generally make (i.e., a zero 
purge angle), because non-zero purge prevents the purge portion of the 
wheel from contributing to energy recovery effectiveness (since outdoor 
ventilation air passing through it is ejected out of the unit to the 
exhaust rather than becoming part of the supply airflow). Also, the 
purge section restricts the flow area for the remaining outdoor air 
that becomes supply air, thus increasing pressure drop and fan power. 
For these reasons, energy recovery wheel performance (and likewise DDX-
DOAS performance and efficiency) will be reduced when operating with a 
non-zero purge angle. Furthermore, basing DDX-DOAS performance ratings 
on a zero purge angle provides greater consistency in testing. DOE 
notes that section C4.1 of AHRI 920-2020--the industry consensus test 
standard--includes a requirement for testing DDX-DOAS units using zero 
purge angle, whether testing using Option 1 or Option 2 (through 
inclusion of EATR0, which is defined in section 11 of AHRI 
920-2020 as being determined using zero purge angle). For these 
reasons, DOE is proposing to adopt the requirement in AHRI 920-2020 to 
use a zero purge angle for testing DDX-DOAS with energy recovery wheels 
(section C4.1 of Appendix C of AHRI 920-2020), as enumerated in section 
2.2.1(f) of the proposed Appendix B.
iii. Return Air External Static Pressure Requirements
    ANSI/ASHRAE 198-2013 specifies testing DDX-DOASes with VERS with 
return air passing into the unit and exiting at the exhaust air 
connection. DOE noted in the July 2017 ASHRAE TP RFI that ANSI/AHRI 
920-2015 does not address setting the external static pressure (ESP) 
for the return airflow. 82 FR 34427, 34437 (July 25, 2017). DDX-DOAS 
units are typically installed and operated in the field with return air 
ducting. Therefore, when in operation, the return air fans consume 
additional energy to overcome the static pressure imposed by the return 
air ducts. As part of the July 2017 ASHRAE TP RFI, DOE requested 
comment on the ESP levels that should be used for return airflow. Id.
    In response, AHRI stated that Table 4 of ANSI/AHRI 920-2015 was 
intended to represent ESP of both supply and return airflow. AHRI also 
stated that

[[Page 36040]]

revisions to ANSI/AHRI 920-2015 will refer to the same table for return 
airflow ESP. (AHRI, No. 11 at p. 15) DOE received no other comments on 
this issue.
    Consistent with the AHRI comment, section 6.1.5.6 of AHRI 920-2020 
does include different ESP requirements for supply and return airflow, 
thereby resolving the identified issue. Accordingly, DOE is proposing 
to adopt the ESP requirements set forth in AHRI 920-2020 (section 6.1.5 
Supply and Return Airflow Rates), as enumerated in section 2.2.1(c) of 
the proposed Appendix B).
iv. Target Return Airflow Rate
    In the July 2017 ASHRAE TP RFI, DOE noted that for testing DDX-DOAS 
units equipped with VERS, Tables 2 and 3 in ANSI/AHRI 920-2015 provide 
return airflow temperature conditions and indicate that the temperature 
conditions apply to units with energy recovery at balanced airflow. 82 
FR 34427, 34437 (July 25, 2017). It is unclear from ANSI/AHRI 920-2015 
what airflow streams should be balanced, how to determine if they are 
balanced, and within what tolerances they should be balanced. In the 
July 2017 ASHRAE TP RFI, DOE requested comments on which airflow 
streams should be balanced and whether balanced airflow is 
representative of field use. Id.
    On this topic, AHRI raised a number of issues with testing DDX-DOAS 
equipped with VERS generally, as previously discussed. AHRI also stated 
that using balanced airflows is consistent with the test procedure for 
rating VERS described in ANSI/AHRI 1060-2018. AHRI further commented 
that in field operation, unbalanced flows may be needed to maintain 
positive building pressure; however, most equipment selection is done 
at or near balanced airflows. (AHRI, No. 11 at pp. 14-15)
    Subsequent updates to the industry consensus test standard at AHRI 
920-2020 shed further light on this issue. Specifically, section 6.1.5 
of AHRI 920-2020 specifies the return airflow rate must be within 3 
percent of the measured supply airflow rate. Based on DOE's review of 
DDX-DOAS product literature and consideration of the AHRI comment, it 
has become apparent that there is no clear optimal ratio of supply 
airflow to return airflow for DDX-DOAS testing to be representative of 
field use. Therefore, DOE has tentatively concluded that the provision 
in AHRI 920-2020 is appropriate.
i. Demand-Controlled Ventilation
    DDX-DOAS units are often used in demand-controlled ventilation 
(DCV) operation, which regulates the building ventilation requirement 
based on parameters such as building occupancy. Typically, a DCV system 
monitors the concentration of carbon dioxide (CO2) in the 
return air or in the building and regulates the supply airflow rate 
accordingly. During periods of non-occupancy, which could represent a 
significant portion of field-use, the DCV system controls the unit to 
operate at a low airflow rate, thereby reducing the unit's overall 
energy use. DDX-DOASes using DCV systems are typically equipped with 
variable-speed supply fans that can be adjusted to meet changing 
ventilation needs. In the July 2017 ASHRAE TP RFI, DOE sought comments 
on whether to include operation under DCV conditions (i.e., low supply 
airflow conditions) to be included as part of DOE's test procedure. 82 
FR 34427, 34437 (July 25, 2017).
    In response to this issue, the Joint Advocates encouraged DOE to 
adopt an efficiency metric that captures the benefits of DCV. The Joint 
Advocates stated that adopting such a metric could provide more field-
representative equipment ratings and better inform consumers when 
purchasing equipment. Further, the Joint Advocates argued that 
capturing the benefits of DCV would promote adoption of variable speed 
fans, provide more flexibility in building operation, and reduce energy 
use. (Joint Advocates, No. 9 at p. 2, 4) AHRI and Carrier commented 
that the performance of the DX-DOAS under DCV operation must be 
characterized prior to developing a test procedure and that adopting 
provisions to address DCV operation could significantly increase the 
cost and complexity of testing. AHRI further stated that DCV operation 
is primarily controlled by building operators. Carrier stated that 
performance would depend highly on the building type, occupancy, and 
site requirements for demand ventilation. (AHRI, No. 11 at p. 14; 
Carrier, No. 6 at p. 4)
    DOE reviewed the comments and considered whether to adopt testing 
conditions to account for the energy use profiles of models with low 
supply airflow rates that are typically experienced by units with DCV. 
Incorporation of the airflow modulation that would be enabled by DCV 
might provide more representative efficiency ratings, help in consumer 
decision making, and potentially promote the market penetration of 
variable speed fans. However, DOE is not aware of representative field 
data regarding the typical DDX-DOAS duty cycle when operating with DCV 
and, thus, agrees with the comments of AHRI and Carrier that 
characterization of DCV performance would be an important first step in 
integrating this control feature into the test procedure. DOE further 
agrees that adopting additional testing requirements to capture the 
effect of DCV could significantly increase testing cost and complexity, 
as noted in comments provided by AHRI and Carrier. Given the lack of 
data on in-field performance and the anticipated additional testing 
burden of such a test, DOE has tentatively decided not to include 
performance under DCV operation in its proposed test procedure for DDX-
DOASes at this time.
j. Tolerances for Supply and Return Airflow and External Static 
Pressure
    DOE noted in the July 2017 ASHRAE TP RFI that Table 1 of ANSI/
ASHRAE 198-2013 includes operating and condition tolerances of 5 
percent for airflow rate. 82 FR 34427, 34439 (July 25, 2017). It 
includes a test operating tolerance for ESP equal to 0.05 in 
H2O and a test condition tolerance for ESP of 0.02 in 
H2O. As provided in section 5.2.2 of ANSI/AHRI 920-2015, the 
airflow rate and ESPs are set at Standard Rating Condition C dry-bulb 
temperatures without the refrigeration systems and energy recovery (if 
applicable) in operation. ANSI/AHRI 920-2015 states in section 5.2.2.4 
that once the airflow rate is set, the fan speeds shall not be adjusted 
for the remaining tests. DDX-DOAS units that are for use with air 
ducting are required by the industry test standard to be set up with 
ESP requirements in Table 4 of ANSI/AHRI 920-2015, and units tested as 
if they would be installed without ducts are tested with 0 in 
H2O ESP.
    DOE notes that while operating in dehumidification mode, the 
airflow rates and ESPs may fluctuate more than for ``dry'' operation as 
condensate accumulates and then drains from the cooling coil. In 
addition, for dehumidification and heating tests, the density of supply 
air may be different, which may change fan performance, and, thus, the 
ESP. These factors could cause the supply air ESP to fluctuate more 
than the operating tolerances specified in Table 1 of ANSI/ASHRAE 198-
2013, and/or to deviate from the specified ESP by more than the test 
condition tolerance. Likewise, the airflow rates could fluctuate more 
than the specified operating tolerances, and the average airflows could 
deviate by more than the test condition tolerances

[[Page 36041]]

from their target values. If this occurs, it is not clear how 
manufacturers would correct the issue without being able to adjust the 
fan speed and ESP, since such action is precluded by section 5.2.2.4 of 
ANSI/AHRI 920-2015.
    In the July 2017 ASHRAE TP RFI, DOE noted that the 5-percent 
condition tolerance on airflow rate is less stringent than the 3-
percent condition tolerance adopted in DOE's test procedure for more 
typical commercial package air equipment. 82 FR 344271, 34439 (July 25, 
2017). On August 6, 2015, DOE published a test procedure NOPR that 
proposed to apply a 5-percent condition tolerance on 
cooling full-load indoor airflow rate for more typical commercial 
package air conditioning equipment. 80 FR 46870, 46873. In response to 
the proposed tolerance for more typical commercial package air 
conditioning equipment, DOE received several comments suggesting that a 
5-percent tolerance would result in too much variation in the 
measurement of energy efficiency ratio and cooling capacity. After 
considering stakeholder comments, DOE adopted a 3-percent tolerance in 
a final rule published on December 23, 2015. 80 FR 79655, 79659-79660. 
As part of the July 2017 ASHRAE TP RFI, DOE expressed concern that that 
the 5-percent condition tolerance on airflow in ANSI/ASHRAE 198-2013 
may result in too much test variability for DDX-DOASes and requested 
comment on whether this airflow tolerance is acceptable. 82 FR 34427, 
34439 (July 25, 2017).
    AHRI commented in response to the July 2017 ASHRAE TP RFI that 
manufacturers who have performed testing have stated that meeting the 
tolerances specified in ANSI/AHRI 920-2015 and ASHRAE 198-2013 is not 
feasible due to how the testing is performed. Once the refrigeration 
system is engaged for determining ISMRE and ISCOP ratings, changes in 
moisture present on the cooling coil and air density affect the 
standard airflow and associated ESP. AHRI recommended that the 0.05 in H2O ESP tolerance and a 3-percent airflow 
tolerance be observed during the airflow and fan speed setting at 
Standard Rating Condition C without the refrigeration system operating. 
AHRI also stated that during the Standard Rating Condition tests, the 
DDX-DOAS fan speeds and airflow-measuring apparatus fan speeds shall 
not be adjusted, consistent with airflow setting and operation in the 
field. Nevertheless, AHRI stated that the average measured airflows 
should be required to be within 5 percent of the manufacturer's rated 
standard airflow during all rating tests and that the average measured 
ESPs should be within 15 percent of the required ESP to indicate a 
valid test, but the commenter did not indicate whether the fans of the 
test unit or the airflow-measuring apparatus should be adjusted to 
maintain these tolerances. (AHRI, No. 11 at p. 18)
    DOE notes that AHRI 920-2020 revised the test condition and 
operating tolerances for airflow and ESP. Section 6.1.5 of AHRI 920-
2020 specifies airflow test condition tolerances of 3 
percent of the manufacturer-provided airflow rate for all DDX-DOASes 
when setting the airflow, provided that this airflow rate meets the 
supply air dew point temperature requirement, as discussed in section 
III.B.4.d.i of this NOPR. For setting the return airflow rate, section 
6.1.5 of AHRI 920-2020 specifies the same test condition tolerances as 
for supply airflow rate, except that for return airflow rate, the 
target is equal to the measured supply airflow rate. This specification 
ensures that supply and return airflows remain balanced, as discussed 
in section III.B.3.h.iv of this NOPR. These test condition tolerances 
for airflow and ESP are only required when setting the airflow. Once 
the airflow rate is set, the dehumidification and heating tests are 
then conducted without further adjustments to the supply fan, return 
fan, or airflow measuring apparatus. Section 6.1.5 and Table 9 of AHRI 
920-2020 indicate that the supply and return airflow and ESP condition 
tolerances are not required to be maintained during the 
dehumidification and heating tests. While these provisions are contrary 
to AHRI's recommendation in response to the July 2017 ASHRAE TP RFI to 
impose a 5-percent airflow condition tolerance and a 15-percent ESP 
condition tolerance during dehumidification and heating tests, DOE 
believes these changes in AHRI 920-2020 address AHRI's concerns about 
testing problems associated with the tolerances in ANSI/AHRI 920-2015 
and ASHRAE 198-2013.
    AHRI 920-2020 additionally includes a list of test operating 
tolerances, including those for external static pressure and airflow 
nozzle differential pressure. AHRI 920-2020 does not include changes to 
the test operating tolerance for ESP (0.05 in H2O total observed range, 
specified in Table 9 of AHRI 920-2020). Whereas ANSI/ASHRAE 198-2013 
provides a 5-percent operating tolerance directly on the airflow rate, 
Table 9 of AHRI 920-2020 provides a 5-percent operating tolerance for 
airflow rate in the form of airflow nozzle differential pressure. DOE 
has initially determined that the airflow operating tolerance approach 
in AHRI 920-2020 is preferable because the airflow nozzle differential 
pressure provides a more direct indication of the airflow variation, 
since airflow is calculated based on this value. Additionally, other 
industry test standards such as ANSI/ASHRAE 37-2009 include an 
operating tolerance on the nozzle pressure drop rather than directly on 
airflow. DOE believes that these operating tolerances, in addition to 
the condition tolerances for setting airflow, would maintain repeatable 
and reproducible results while ensuring that testing is representative 
of field use. Accordingly, DOE is proposing to adopt the test condition 
and operating tolerances for airflow and ESP specified in AHRI 920-2020 
(section 6.1.5 Supply and Return Airflow Rates and section 6.6.2 Test 
Measurement Tolerances, which contains Table 9), as enumerated in 
section 2.2.1(c) of the proposed Appendix B).
k. Secondary Dehumidification and Heating Capacity Tests
    Commercial package air-conditioners and heat pumps with cooling 
capacity less than 135,000 Btu/h are required to undergo a secondary 
test to verify the cooling or heating capacity and energy efficiency 
results (see, e.g., ANSI/ASHRAE 37-2009 section 7.2.1, which is 
referenced by appendix A to subpart F of 10 CFR part 431). Neither 
ANSI/AHRI 920-2015 nor ANSI/ASHRAE 198-2013 specify a secondary test 
method for verifying the dehumidification and heating capacity of DDX-
DOAS, but section 6.7 of AHRI 920-2020 does specify secondary tests. 
The measurement of dehumidification and heating performance of DDX-
DOASes is based on measurements of airflow rate, temperature, and 
humidity, which have uncertainties associated with them. Thus, a 
secondary test method may be essential to confirm the accuracy of the 
primary test method.
    As part of the July 2017 ASHRAE TP RFI, DOE requested comment on 
the need for a secondary test method requirement for DDX-DOAS testing. 
82 FR 34427, 34439 (July 25, 2017). AHRI commented that condensate 
measurement would be appropriate as a secondary method, if energy 
recovery units are excluded from the test procedure. (AHRI, No. 11 at 
p. 19)
    Section C5.1 of AHRI 920-2020 includes a condensate-based test 
method as a secondary measure of dehumidification capacity. The method 
measures the weight of the condensate (i.e., water vapor in the outdoor 
ventilation air that condenses on the conditioning coil and is removed 
from

[[Page 36042]]

the air) collected during the dehumidification test and uses it to 
calculate a secondary measure of MRC. This secondary measure of MRC is 
then compared to the primary MRC measurement, which is based on supply 
and outdoor ventilation airflow and air condition measurements.
    AHRI 920-2020 requires this secondary measure of MRC for all 
dehumidification tests, and comparison to the primary measure of MRC at 
Standard Rating Condition A. This requirement is for all DDX-DOAS units 
that: (a) Do not use condensate collected from the dehumidification 
coil to enhance condenser cooling or include a secondary 
dehumidification process for which the moisture removed from the supply 
air stream is not collectable in liquid form, and (b) either are not 
equipped with VERS or are equipped with VERS and tested using Option 2 
(see section C5.1 of AHRI 920-2020). AHRI 920-2020 does not require a 
secondary dehumidification capacity measurement for DDX-DOAS units 
equipped with VERS that are tested using Option 1. DOE understands that 
this is because: (a) No viable method has been developed and validated 
that appropriately accounts for the water vapor that transfers between 
air streams of an energy recovery wheel, and (b) the test burden of 
accounting for moisture in the exhaust air stream would be excessive. 
DOE is proposing to adopt the secondary capacity test measurements 
specified in AHRI 920-2020 (section C5.1 Dehumidification Capacity 
Verification), as enumerated in section 2.2.1(f) of the proposed 
Appendix B), including the cooling condensate secondary test 
measurement discussed previously.
    For DDX-DOAS units with energy recovery tested using Option 2, as 
discussed in section III.B.3.h of this NOPR, the test is conducted by 
setting the conditions of the air entering the unit (at both the 
outdoor air inlet and return air inlet) to simulate the conditions that 
would be provided by the energy recovery device in operation. As a 
result, the moisture removal (in dehumidification mode) or heating (in 
heating mode for heat pump DDX-DOAS) measured during the Option 2 
primary and secondary capacity tests reflects only the moisture removed 
or heating by the conditioning coil. The MRC or qhp for the DDX-DOAS is 
calculated by adjusting the measured moisture removal or heating for 
the primary test to account for the total moisture removal or heating 
by the energy recovery device and the conditioning coil. Because the 
moisture removal or heating capacity measured for the primary and 
secondary tests are based on the simulated test conditions, sections 
6.9 and 6.10 of AHRI 920-2020 use these measured values for the 
secondary capacity verification under Option 2. DOE is proposing to 
adopt these requirements specified in AHRI 920-2020 (section 6.9 
Moisture Removal Efficiency Ratings and section 6.10 Heating Capacity), 
as enumerated in section 2.2.1(c) of the proposed Appendix B).
a. Corrections
    In addition to substantive changes, AHRI 920-2020 also provides 
minor corrections to instructions in ANSI/AHRI 920-2015. However, in 
its review of AHRI 920-2020, DOE identified an error and an omission in 
the latest industry test procedure. Specifically, DOE notes that 
section 6.9.2 of AHRI 920-2020 provides erroneous instruction for the 
calculation of the degradation coefficient, and sections 6.1.5.2.3 and 
6.1.5.2.4 of AHRI 920-2020 refer to the term ``non-standard low-static 
motor'' without providing a definition or explanation of this term. DOE 
proposes to correct the calculation instruction and define the term 
``non-standard low-static motor,'' as discussed further in the 
following paragraphs. DOE also notes a correction made by AHRI 920-2020 
to address an error in the calculation of supplementary heat penalty in 
ANSI/AHRI 920-2015.
i. Calculation of the Degradation Coefficient
    As mentioned in section III.B.3.d.v of this NOPR, AHRI 920-2020 
includes provisions for cases where the unit provides excess 
dehumidification or heating capacity when operating at its lowest-
capacity compressor stage. A degradation coefficient is applied to the 
MRE and MRE70 when the supply air dew point temperature 
measured when operating the unit at its lowest-capacity compressor 
stage is lower than the target supply air dew point temperature in 
excess of the specified test condition tolerance. This degradation 
coefficient accounts for the re-evaporation of condensate which occurs 
during cycling operation (i.e., when the compressor cycles on and off 
to achieve the target supply air dew point temperature). DOE 
understands that the degradation is more pronounced for DDX-DOASes 
equipped with VERS for latent energy recovery (or total energy 
recovery), and, thus, the degradation coefficient should be greater for 
DDX-DOASes operating total energy recovery VERS. Equation 20 in section 
6.9.2 of AHRI 920-2020 appears to incorrectly attribute the lower 
degradation coefficient to DDX-DOASes operating with VERS. As such, DOE 
has initially determined, supported by clear and convincing evidence, 
that absent a correction, the degradation coefficient as applied in 
AHRI 920-2020 would not meet the statutory requirements of 42 U.S.C. 
6314(a)(2)-(3) because it would not produce representative results. DOE 
proposes to correct Equation 20 by specifying that it is to be used for 
DDX-DOASes ``without VERS, with deactivated VERS (see section 5.4.3 of 
AHRI 920-2020), or with sensible-only VERS tested under Standard Rating 
Conditions other than D'' (emphasis added) because DDX-DOASes with 
total energy recovery VERS or with sensible-only VERS tested under 
Standard Rating Condition D are considered separately in Equation 21, 
which calculates a greater degradation coefficient. This correction 
would be implemented in section 2.2.1(c)(iii) of proposed Appendix B.
ii. Non-Standard Low-Static Motor
    As mentioned in section III.B.3.d.i of this NOPR, section 6.1.5 of 
AHRI 920-2020 includes instructions for setting the supply airflow rate 
for testing. In particular, sections 6.1.5.2.1 through 6.1.5.2.5 of 
AHRI 920-2020 provide directions for adjusting the fans should an 
initial attempt at setting the airflow be unsuccessful.
    Section 6.1.5.2.3 of AHRI 920-2020 specifies that if a fan's 
maximum speed is too low to satisfy the airflow and external static 
pressure requirements within tolerance (i.e., the motor speed is at the 
highest setting, a larger compatible off-the-shelf sheave is not 
available, or increased speed would overload the motor or motor drive) 
and the motor is not a ``non-standard low-static motor,'' the tests are 
to be conducted at the fan's maximum speed with the external static 
pressure satisfying the requirements in Table 7. However, if the motor 
is a ``non-standard low-static motor,'' section 6.1.5.2.4 of AHRI 920-
2020 specifies that the maximum available speed should be used but the 
supply and return airflow rates should satisfy aforementioned tolerance 
requirements (implying that the external static pressure requirements 
in Table 7 need not be met). AHRI 920-2020 does not define ``non-
standard low-static motor'' in order to determine which of the two 
methods is appropriate. Without a definition of ``non-standard low-
static motor,'' manufacturers may not apply the ``maximum speed'' 
provisions consistently, and the potential for variation risks results 
that do not reflect the equipment's representative average energy 
efficiency or energy use. As

[[Page 36043]]

such, DOE has initially determined, supported by clear and convincing 
evidence, that in the absence of a definition of ``non-standard low-
static motor,'' the industry test procedure would not meet the 
statutory requirements of 42 U.S.C. 6314(a)(2)-(3).
    DOE understands that a non-standard low-static fan motor may be 
used for DDX-DOASes where the application requires less ductwork, which 
results in a lower external static pressure when operating at the same 
nominal supply or return airflow rate. This motor would be distributed 
in commerce as part of an individual model within the same basic model 
of DDX-DOAS that is also distributed in commerce with a motor that can 
meet the external static pressure required by AHRI 920-2020. A parallel 
situation occurs for Commercial and Industrial Unitary Air-conditioning 
and Heat Pump Equipment, for which section D3 in Appendix D of AHRI 
Test Standard 340/360-2019, ``Performance Rating of Commercial and 
Industrial Unitary Air-conditioning and Heat Pump Equipment'' (AHRI 
340/360-2019) defines ``non-standard motor'' as an indoor fan motor 
that is not the standard indoor fan motor and that is distributed in 
commerce as part of an individual model within the same Basic Model. 
The same section D3 defines ``standard indoor fan motor'' as the motor 
specified by the manufacturer for testing and shall be distributed in 
commerce as part of a particular model. In both cases, the non-standard 
motor has a horsepower level that is not compatible with the external 
static pressure rating condition--for DDX-DOAS, the issue arises when 
the non-standard motor does not have sufficient power to deliver the 
required external static pressure. Therefore, in the proposed Appendix 
B in section 2.2.1(a)(i), DOE is proposing to define ``non-standard 
low-static fan motor'' as a supply fan motor that cannot maintain 
external static pressure as high as specified in Table 7 of AHRI 920-
2020 when operating at a manufacturer-specified airflow rate and that 
is distributed in commerce as part of an individual model within the 
same basic model of a DDX-DOAS that is distributed in commerce with a 
different motor specified for testing that can maintain the required 
external static pressure.
    Issue-8: DOE is requesting comment on the proposed definition of 
``non-standard low-static fan motor'' and whether the proposed 
definition reflects stakeholder understanding of the term.
iii. Calculation of Supplementary Heat Penalty
    Section 6.1.3.1 of ANSI/AHRI 920-2015 includes a supplementary heat 
penalty for units that are unable to achieve the minimum supply air 
dry-bulb temperature of 70 [deg]F while testing at each Standard Rating 
Condition specified in Table 2 and Table 3 of ANSI/AHRI 920-2015. The 
supplementary heat penalty calculates the difference in enthalpy from 
the delivered supply air and air at the minimum supply air temperature 
(70 [deg]F). After reviewing the equations, DOE noted in the July 2017 
ASHRAE TP RFI that the term for supply airflow rate is missing from the 
supplementary heat penalty equations. 82 FR 34427, 34436 (July 25, 
2017).
    In response to the July 2017 ASHRAE TP RFI, AHRI confirmed that the 
supplementary heat formula in ANSI/AHRI 920-2015 is missing the airflow 
term, QSA, in section 6.1.3.1, and the organization committed to 
include such term in the next revision of the test standard. (AHRI, No. 
11 at p. 11) DOE notes that this change has been included in AHRI 920-
2020, thereby resolving the problem. Accordingly, DOE proposes to adopt 
the revised supplementary heat penalty equation contained in AHRI 920-
2020 that includes the supply airflow rate term (section 6.1.3.1 
Initial Standard Rating Condition A Dehumidification Test), as 
enumerated in section 2.2.1(c) of the proposed Appendix B).
    In the July 2017 ASHRAE TP RFI, DOE further noted that section 
6.1.3.1 of ANSI/AHRI 920-2015 calls for a supplementary heat penalty if 
the supply air temperature is less than 70 [deg]F, but the 
incorporation of this penalty into the MRE and COP equations is not 
clearly described. DOE also noted that it is not clear whether the 
ANSI/ASHRAE 198-2013 test method considers this penalty. 82 FR 34427, 
34436-34437 (July 25, 2017).
    AHRI commented that the supplementary heat penalty should be added 
if the minimum 70 [deg]F temperature is not met, and that this value is 
added to the measured power input, which is represented as PT in 
section 10.6 of ANSI/ASHRAE 198-2013. (AHRI, No. 11 at p. 11) DOE notes 
that this clarification is included in section 6.9 of AHRI 920-2020 in 
the calculation of MRE70, which incorporates the energy 
impact of heating the supply air to 70 [deg]F. As discussed in section 
III.B.2 of this NOPR, DOE is proposing to adopt the ISMRE2 metric 
specified in section 6.13 of AHRI 920-2020 that does not include the 
supplementary heat penalty as the regulated metric for DDX-DOAS, while 
the MRE70 (and ISMRE270) metric that incorporates 
the supplementary heat penalty may be used for representations. As a 
result, the supplementary heat penalty would only be added to the total 
power input for the calculation of the optional MRE70 
ratings.
    With regards to the COP calculation, AHRI commented that the intent 
was that the supplementary heat penalty would be added to the numerator 
as additional heat capacity and the denominator as additional power 
consumed to calculate a COP indicative of running an electric heater to 
meet a supply air temperature of 70 [deg]F. (AHRI, No. 11 at p. 13) DOE 
notes that this clarification was included in section 6.11.2 of AHRI 
920-2020 in the renamed COPISCOP metric, and accordingly, DOE is 
proposing to adopt the revised COPISCOP calculation (section 6.11.2 of 
AHRI 920-2020), as enumerated in section 2.2.1(c) of the proposed 
Appendix B).
2. Determination of Represented Values
a. Basic Model
    To determine the energy efficiency of a basic model, DOE's 
certification requirements generally require manufacturers to test a 
sample of units of that basic model to represent its performance. (10 
CFR 429.11) The basic model may include multiple individual models 
having similar performance features and characteristics. Typically, DOE 
provides a definition of a basic model for each type of covered 
equipment. In this NOPR, DOE proposes a definition for DDX-DOAS basic 
model derived from the basic model definition for other commercial 
packaged air conditioning and heating equipment set forth at 10 CFR 
431.92. Specifically, DOE replaced the criterion to have common nominal 
cooling capacity with common nominal MRC. DOE is also proposing to 
include the common nominal MRC in the definition of a basic model for 
small, large and very large air-cooled or water-cooled commercial 
package air conditioning and heating equipment, which includes DDX-
DOASes. The proposed definition of basic model of a DDX-DOAS also 
specifies that a basic model must include units with similar VERS 
equipment. DOE is proposing in this specification to reflect that 
ASHRAE Standard 90.1 delineates DDX-DOAS equipment classes, in part, 
based on VERS, and the proposed test procedure considers the 
conditioning contribution of the VERS equipment.

[[Page 36044]]

    DOE is proposing that a basic model for a DDX-DOAS means all units 
manufactured by one manufacturer within a single equipment class; with 
the same or comparably performing compressor(s), heat exchangers, 
ventilation energy recovery system(s) (if present), and air moving 
system(s), and with a common ``nominal'' moisture removal capacity. 
This proposed definition of a basic model of a DDX-DOAS would be 
included in the regulatory text in 10 CFR 431.92.
    Issue-9: DOE seeks comment on the proposed definition of basic 
model of a DDX-DOAS.
b. Sampling Plan Requirements
    DOE is proposing sampling requirements to determine the represented 
values for DDX-DOAS (i.e., dehumidification and heating efficiencies 
and MRC). More specifically, by proposing to define (at 10 CFR 431.92) 
DDX-DOAS as a subset of DX-DOAS, and to define DX-DOAS as a category of 
small, large, or very large commercial package air conditioning and 
heating equipment, the proposal would apply the same sampling 
requirements to DDX-DOASes as applicable to other commercial package 
air conditioning and heating equipment under 10 CFR 429.43, Commercial 
heating, ventilating, air conditioning (HVAC) equipment.
    In response to DOE's request for general comment on issues 
associated with adopting the industry test procedures for certain 
commercial package air conditioning and heat pump equipment in the July 
2017 ASHRAE TP RFI (82 FR 34427, 34445 (July 25, 2017)), Lennox 
recommended that DOE harmonize the certification criteria for 
commercial HVAC equipment in 10 CFR 429.43 with those for central air 
conditioners, a consumer product, in 10 CFR 429.16. In particular, 
Lennox stated that commercial equipment currently has a more stringent 
confidence limit of 95 percent, but the commenter argued that current 
testing technology does not support this level of precision. (Lennox, 
No. 8 at p. 6) As DOE is proposing to apply the sampling requirements 
of 10 CFR 431.43 to DDX-DOASes, Lennox's comment regarding the 
confidence limit for represented values of energy efficiency, energy 
consumption, and capacity is relevant to DDX-DOASes.
    Other manufacturers did not raise concerns regarding the confidence 
limit required for sampling more typical commercial package air 
conditioning and heat pump equipment, and Lennox has not provided data 
regarding variability of units in production and testing. Absent more 
specific information or data regarding the stringency of the confidence 
level, DOE is not proposing a change.\33\
---------------------------------------------------------------------------

    \33\ DOE notes that it has previously requested data regarding 
the variability of units of small, large, and very large air-cooled 
commercial package air conditioning and heating equipment in 
production and testing to enable DOE to review and make any 
necessary adjustments to the specified confidence levels. See 80 FR 
79655, 79659 (Dec. 23, 2015). However, DOE did not receive any 
relevant data in response to that request.
---------------------------------------------------------------------------

    Issue-10: DOE requests comment on the sampling plan proposed for 
DDX-DOASes. DOE specifically requests information and data regarding 
the proposed confidence level and whether variability of testing of 
DDX-DOASes would require a less stringent level, and if so, what that 
level should be.
c. Multiple Refrigerants
    DOE recognizes that some commercial package air conditioning and 
heating equipment may be sold with more than one refrigerant option 
(e.g., R-410A or R-407C). Typically, manufacturers specify a single 
refrigerant in their literature for each unique model, but in its 
review, DOE has identified at least one commercial package air 
conditioning and heating equipment manufacturer that provides two 
refrigerant options under the same model number. The refrigerant chosen 
by the customer in the field installation may impact the energy 
efficiency of a unit. For this reason, DOE is proposing representation 
requirements specific for models approved for use with multiple 
refrigerants.
    Use of a refrigerant that requires different hardware (such as R-
407C as compared to R-410A) would represent a different basic model, 
and according to the current CFR, separate representations of energy 
efficiency are required for each basic model. On the other hand, some 
refrigerants (such as R-422D and R-427A) would not require different 
hardware, and a manufacturer may consider them to be the same basic 
model. In the latter case of multiple refrigerant options, DOE proposes 
to add a new paragraph at 10 CFR 429.43(a)(3) specifying that a 
manufacturer must determine the represented values for that basic model 
based on the refrigerant(s)--among all refrigerants listed on the 
unit's nameplate--that result in the lowest ISMRE2 and ISCOP2 
efficiencies, respectively. For example, the dehumidification 
performance metric ISMRE2 must be based on the refrigerant yielding the 
lowest ISMRE2, and the heating performance metric ISCOP2 (if the unit 
is a heat pump DDX-DOAS) must be based on the refrigerant yielding the 
lowest ISCOP2. These represented values would apply to the basic model 
for all refrigerants specified by the manufacturer as appropriate for 
use, regardless of which one may actually be used in the field, where 
only one set of values is reported.
    DOE notes that this proposal reflects the proposed definition of 
basic model for DDX-DOASes as discussed in section III.B.4.a of this 
NOPR. Units within a basic model of DDX-DOAS must have the same or 
comparably performing compressor(s), heat exchangers, ventilation 
energy recovery system(s) (if present), and air moving system(s), and 
with a common ``nominal'' moisture removal capacity.
    Issue-11: DOE requests comment on its proposal regarding 
representations for models approved for use with multiple refrigerants.
d. Alternative Energy-Efficiency Determination Methods
    DOE proposes to allow DDX-DOAS manufacturers to use alternative 
energy-efficiency determination methods (AEDMs) for determining the 
ISMRE2 and ISCOP2 (if applicable) in accordance with 10 CFR 429.70. By 
proposing to define (at 10 CFR 431.92) DDX-DOAS as a subset of DX-DOAS, 
and to define DX-DOAS as a category of small, large, or very large 
commercial package air conditioning and heating equipment, the 
provisions of 10 CFR 429.43 authorizing use of an AEDM for commercial 
HVAC equipment would apply to DDX-DOAS. DOE notes that the proposed 
requirements for use of AEDMs to determine DDX-DOAS represented values 
are consistent with AEDM requirements for all other categories of 
commercial package air-conditioning and heating equipment.
    DOE proposes to create four validation classes of DDX-DOASes within 
the Validation classes table at 10 CFR 429.70(c)(2)(iv): Air-cooled/
air-source and water-cooled/water-source, each with and without VERS. 
The separation into air-cooled/air-source and water-cooled/water source 
validation classes is the same approach used for other categories of 
commercial package air-conditioning and heating equipment. For DDX-
DOASes, the additional class separation by presence of energy recovery 
reflects ASHRAE Standard 90.1 delineating equipment classes, in part, 
based on the presence of VERS and the significant differences in the 
test methods required with energy recovery. These differences in the 
test procedures include the potential need for a third test chamber for 
the Option 1 approach for testing DDX-DOASes with energy recovery, and 
the

[[Page 36045]]

requirement to account for the performance of the energy recovery 
device for the Option 2 approach (see section III.B.3.g of this NOPR).
    DOE proposes to require testing of two basic models to validate the 
AEDMs for each validation class--this is identical to the requirements 
for other categories of commercial package air-conditioning and heating 
equipment. Finally, DOE proposes to specify in the table at 10 CFR 
429.70(c)(5)(vi) a tolerance of 10 percent for DDX-DOAS verification 
tests for ISMRE2 and ISCOP2 when comparing test results with certified 
ratings. Again, this is identical to the tolerances for ``integrated'' 
ratings for other categories of commercial package air-conditioning and 
heating equipment.
    Issue-12: DOE requests comment on its proposals for AEDM 
requirements for DDX-DOAS equipment. DOE requests comment specifically 
on whether the proposed 10-percent tolerance for comparison of test 
results with rated values is appropriate. If the 10-percent tolerance 
is not appropriate, DOE requests comment on why it is not appropriate, 
as well as comment indicating an appropriate tolerance.
e. Rounding
    Sections 6.1.2.1 through 6.1.2.8 of AHRI 920-2020 specify rounding 
for DDX-DOAS performance metrics. DOE proposes to adopt these rounding 
requirements as part of the DOE test procedure, as enumerated in 
section 2.2.1(c)(iv) of the proposed Appendix B.
    Issue-13: DOE requests comment on its proposal to adopt the 
rounding requirements for key metrics as specified in sections 6.1.2.1 
through 6.1.2.8 of AHRI 920-2020.
3. Configuration of Unit Under Test
    DOE recognizes that DDX-DOASes are distributed in commerce in a 
variety of configurations consisting of different combinations of 
components. DOE proposes in section 2.2.1(g) of Appendix B to adopt the 
requirements of appendix F to AHRI 920-2020, which includes a list of 
components that must be present for testing DDX-DOASes and a list of 
components that are optional for testing. Appendix F in AHRI 920-2020 
also includes explicit instructions on how representations can be made 
for equipment that include these optional components. AHRI 920-2020 
specifies the following list of components that must be present for 
testing:
     Supply air filter(s);
     Compressor(s);
     Outdoor coil(s) or heat exchanger(s);
     Outdoor coil fan(s)/motor(s) (for air-cooled and air-
source systems only);
     Conditioning coil(s);
     Refrigerant expansion device(s);
     Supply/outdoor ventilation fan(s)/motor(s), and
     System controls.
    AHRI 920-2020 also specifies that for supply air filters, the 
filter shall have a ``minimum efficiency reporting value'' (MERV) 
specification no less than MERV 8. For individual models that use 
filters with efficiency higher than MERV 8 (which generally have higher 
pressure drop and could reduce relative tested efficiency), section 
F2.4 of AHRI 920-2020 allows manufacturers the option of testing these 
individual models as a separate basic model or combined into a basic 
model with other individual models that meet the basic model definition 
and are tested with a MERV 8 filter. Adopting Appendix F of AHRI 920-
2020 without changes would allow manufacturers to provide efficiency 
representations based on either testing option for individual models 
that use filters with efficiency higher than MERV 8.
    DOE notes that the list of components that are optional for testing 
specified in section F2.4 of AHRI 920-2020 includes features that may 
reduce tested efficiency but may also in certain applications: (a) 
Maintain or improve field efficiency or (b) be required for safety. 
Given the potential benefits, DOE does not want to penalize equipment 
with such components, because that might disincentivize their adoption. 
By proposing to adopt Appendix F of AHRI 920-2020 without changes, the 
following instructions from AHRI 920-2020 would specify how to make 
representations for individual models of equipment that include these 
optional features:
     Individual models with features designated as ``optional'' 
may be represented separately as a unique basic model or certified 
within the same basic model as otherwise identical individual models 
without the feature pursuant to the definition of ``basic model'' in 
Sec.  431.92.
     If an otherwise identical model (within the same basic 
model) without the feature is distributed in commerce, test the 
otherwise identical model.
     If an otherwise identical model (within the same basic 
model) without the feature is not distributed in commerce, conduct 
tests with the feature present but configured and de-activated so as to 
minimize (partially or totally) the impact on the results of the test. 
Alternatively, the manufacturer may indicate in the supplemental 
testing instructions that the test shall be conducted using a 
specially-built otherwise identical unit that is not distributed in 
commerce and does not have the feature.
    This approach ensures that equipment distributed in commerce with 
additional components outside the list of required components are still 
within the scope of the test procedure. The proposed approach also 
provides instruction on how to make representations for all component 
combinations (including those with optional components). In addition, 
this approach allows manufacturers the flexibility to make 
representations of equipment with components designated as ``optional'' 
based on testing otherwise identical individual models without the 
feature.

C. Other Comments

    In response to the July 2017 ASHRAE TP RFI, DOE received several 
general comments not specific to any one equipment category or test 
procedure. This section addresses those comments.
    NCI recommended that DOE follow the development of ASHRAE 221P, 
``Test Method to Measure and Score the Operating Performance of an 
Installed Constant Volume Unitary HVAC System,'' and consider where it 
may be appropriately applied within EPCA test procedures. (NCI, No. 4 
at pp. 1-2) NCI stated that it has collected data indicating that 
typical split systems and packaged units serving residential and small 
commercial buildings typically deliver 50 percent to 60 percent of the 
rated capacity to the occupied zone, thereby making laboratory tests 
unrepresentative of field performance. (Id.)
    As noted in section I.A of this document, EPCA prescribes that the 
test procedures for commercial package air conditioning and heating 
equipment must be those generally accepted industry testing procedures 
or rating procedures developed or recognized by industry as referenced 
in ASHRAE Standard 90.1. (42 U.S.C. 6314(a)(4)(A)) DOE notes that 
ASHRAE Standard 90.1 does not reference ANSI/ASHRAE Standard 221-2020, 
``Test Method to Field-Measure and Score the Cooling and Heating 
Performance of an Installed Unitary HVAC System'' \34\ (ASHRAE 221-
2020) as the applicable test procedure corresponding to industry 
standards. NCI also did not provide data on field performance or any 
correlations between field performance and laboratory test performance 
for DX-DOASes or DDX-DOASes for DOE to

[[Page 36046]]

consider. Furthermore, ASHRAE 221-2020 does not provide a method to 
determine the dehumidification efficiency and heating efficiency of 
DDX-DOASes, as AHRI 920-2020 does. As discussed in section II of this 
document, DOE is proposing to incorporate by reference AHRI 920-2020 
(i.e., the test procedure recognized by ASHRAE Standard 90.1 for DDX-
DOASes) and the relevant industry standards referenced therein, 
consistent with EPCA requirements.
---------------------------------------------------------------------------

    \34\ Available at: webstore.ansi.org/tandards/ASHRAE/ANSIASHRAEStandard2212020 (Last accessed April 19, 2021).
---------------------------------------------------------------------------

    The CA IOUs commented that while the July 2017 ASHRAE TP RFI 
expressed interest in reducing burden to manufacturers, DOE already 
took steps to reduce burden by allowing alternative energy efficiency 
or energy use determination methods (AEDMs). (CA IOUs, No. 7 at pp. 1-
2) The CA IOUs stated that there are no further opportunities to 
streamline test procedures to limit testing burden. (Id.) Additionally, 
the CA IOUs emphasized the importance of accurate efficiency ratings 
for its incentive programs and customer knowledge, pointing to the 
statutory provision that test procedures must produce results that are 
representative of the product's energy efficiency. (Id.)
    Lennox stated that it generally supports DOE meeting the statutory 
requirements to design test procedures to measure energy efficiency 
during an average use cycle but requested that DOE also consider 
overall impacts to consumers and manufacturers. (Lennox, No. 8 at pp. 
1-2) The commenter stated that in commercial applications, predicting 
actual energy use from a single metric is difficult and that a metric 
better serves as a point of comparison. (Id.) Lennox suggested that DOE 
strike a balance between evaluating equipment in a meaningful way 
without introducing regulatory burden from overly complex test 
procedures or calculations that provide little value to consumers. 
(Id.)
    In response to the CA IOUs and Lennox, DOE notes that its approach 
to test procedures is largely dictated by the requirements of EPCA. As 
discussed, EPCA prescribes that the test procedures for commercial 
package air conditioning and heating equipment must be those generally 
accepted industry testing procedures or rating procedures developed or 
recognized by industry as referenced in ASHRAE Standard 90.1. (42 
U.S.C. 6314(a)(4)(A)) If such relevant industry test procedure is 
amended, DOE must update its test procedure to be consistent with the 
amended industry consensus test procedure, unless DOE determines, by 
rule published in the Federal Register and supported by clear and 
convincing evidence, that the amended test procedure would not meet the 
requirements in 42 U.S.C. 6314(a)(2) and (3) related to representative 
use and test burden. (42 U.S.C. 6314(a)(4)(B) and (C)) In establishing 
or amending its test procedures, DOE must develop test procedures that 
are reasonably designed to produce test results which reflect energy 
efficiency, energy use, and estimated operating costs of a type of 
industrial equipment during a representative average use cycle and that 
are not unduly burdensome to conduct. (42 U.S.C. 6314(a)(2)) DOE's 
considerations of these requirements in relation to individual test 
method issues are discussed within the relevant sections of this NOPR.
    The Joint Advocates stated that there are a number of ambiguities 
in industry test procedures and that DOE should address these 
ambiguities in order to provide a level playing field for manufacturers 
and to ensure that any verification or enforcement testing is 
consistent with manufacturers' own testing. (Joint Advocates, No. 9 at 
p. 2) In the context of a test procedure for DDX-DOASes, DOE addresses 
the potential for ambiguity as applicable, in the previous sections of 
this document.

D. Test Procedure Costs, Harmonization, and Other Topics

1. Test Procedure Costs and Impact
    EPCA requires DOE to adopt test procedures for small, large and 
very large commercial package air conditioning and heating equipment 
consistent with the amended industry test procedures developed or 
recognized AHRI as referenced in ASHRAE Standard 90.1, unless the 
Secretary determines that, supported by clear and convincing evidence, 
to do so would not meet the requirements for test procedures to be 
reasonably designed to produce results that reflect energy efficiency, 
energy use, and estimated operating costs during a representative 
average use cycle and not be unduly burdensome to conduct. (42 U.S.C. 
6314(a)(4)(B)) In this NOPR, DOE proposes to establish a test procedure 
for DDX-DOASes, which belong to a category of small, large, and very 
large commercial package air conditioning and heating equipment. DOE is 
proposing to establish a test procedure that incorporates by reference 
the applicable industry consensus test methods (including the energy 
efficiency descriptors) and that establishes representation 
requirements. DOE has tentatively determined that these proposed new 
test procedures would be representative of an average use cycle and 
would not be unduly burdensome for manufacturers to conduct. To the 
extent that DOE is proposing modifications to the industry consensus 
test procedure, DOE has tentatively determined that the proposed 
modifications are consistent with the industry consensus standard, and 
as explained in the prior sections, they are supported by clear and 
convincing evidence, because absent such modifications, the industry 
test procedure would not meet the requirements in 42 U.S.C. 6314(a)(2) 
and (3) related to representative use and test burden. (42 U.S.C. 
6314(a)(4)(B) and (C)). Further, DOE has tentatively determined that 
the proposed modifications would be unlikely to significantly increase 
burden, given that DOE is referencing the prevailing industry test 
procedure. So, presuming widespread usage of that test standard, its 
adoption as part of the Federal test procedure would be expected to 
result in little additional cost, even with the minor modifications 
proposed here. DOE has tentatively determined that the test procedure, 
if finalized as proposed, would not require manufacturers to redesign 
any of the covered equipment, would not require changes to how the 
equipment is manufactured, and would not impact the utility of the 
equipment.
    When the industry test procedure or rating procedure for a category 
of small, large, and very large commercial package air conditioning and 
heating equipment recognized in ASHRAE Standard 90.1 is amended, DOE is 
required to amend the Federal test procedure for the relevant category 
of small, large, and very large commercial package air conditioning and 
heating equipment consistent with the industry update, unless DOE 
determines by clear and convincing evidence that to do so would result 
in a test procedure that does not meet the EPCA requirements regarding 
representativeness and testing burden. (42 U.S.C. 6314(a)(4)(B)) As 
discussed, ASHRAE Standard 90.1-2016 established energy efficiency 
levels for DDX-DOASes (but written as ``DX-DOASes'' in ASHRAE Standard 
90.1) as a category of commercial package air conditioning and heating 
equipment and recognized ANSI/AHRI 920-2015 as the industry test 
procedure for these equipment. Subsequent to the establishment of 
standards and a test procedure for DDX-DOASes in ASHRAE Standard 90.1-
2016, ANSI/AHRI 920-2015 was updated. The 2020 version of AHRI 920 
(i.e., AHRI 920-2020) is the most recent version of the industry test 
procedure for DDX-

[[Page 36047]]

DOASes (still referred to in AHRI 920-2020 as simply ``DX-DOASes'').
    DOE is proposing to incorporate by reference the revised industry 
test standard, AHRI 920-2020, with certain modifications that are 
consistent with the industry test standard. DOE has tentatively 
concluded that the proposed test procedure in this NOPR would not add 
undue industry test burden, and that the proposed test procedure for 
this equipment is consistent with the industry test procedure update. 
Further discussion of the cost impacts of the proposed test procedure 
are presented in the following paragraphs.
    As noted previously, currently DOE does not prescribe test 
procedures for DDX-DOASes, and AHRI 920-2020 is the most recent version 
of the industry test procedure applicable to DDX-DOASes. DOE has 
tentatively determined that the proposal to incorporate by reference 
AHRI 920-2020 is consistent with current industry practice, and, 
therefore, manufacturers would not be expected to incur any additional 
costs if the proposal were finalized. Importantly, the proposals in 
this NOPR, if finalized, would not require manufacturers to certify 
ratings to DOE. DOE would address certification as part of any 
rulemaking to address energy conservation standards for DDX-DOASes.
    With that said, DOE is proposing to define ``dehumidifying direct 
expansion-dedicated outdoor air system'' (DDX-DOAS) based on the 
definition provided in AHRI 920-2020. The differences in the proposed 
definition as compared to the definition in AHRI 920-2020 are to 
provide clarity and use terminology consistent with DOE's test 
procedures for other categories of commercial package air conditioning 
and heating equipment.
    DOE is proposing to limit the applicability of the proposed test 
procedure to DDX-DOASes with any MRC less than 324 lbs. of moisture per 
hour, whereas the scope of AHRI 920-2020 is not limited based on MRC. 
In a comment provided in response to the July 2017 ASHRAE TP RFI, AHRI 
stated that laboratory limitations may limit testing using ANSI/AHRI 
920-2015 to 300 lbs. of moisture per hour at Standard Rating Condition 
A and to units not physically larger than more typical commercial 
package air conditioning equipment with a capacity of 760,000 Btu per 
hour. (AHRI, No. 11 at p. 20) As discussed in section III.A.3 of this 
document, DOE's proposal to limit the coverage of DDX-DOASes to 324 
lbs. of moisture per hour in the DDX-DOAS definition is a direct 
conversion from the maximum cooling capacity limit of 760,000 Btu per 
hour (which AHRI notes would be the upper limit for laboratory 
capabilities), and it is similar to the suggestion made by AHRI. Hence 
the definitional modifications to the industry standard will not change 
the scope of coverage of the proposed test procedure as compared to the 
industry standard, and if made final, would not result in any increase 
in test burden as compared to AHRI 920-2020.
    AHRI 920-2020 does not explicitly state the amount of external head 
pressure to use when testing water-cooled and water-source DDX-DOASes 
with integral pumps. As noted, there are a very limited number of DDX-
DOAS models with integral pumps on the market. DOE is proposing to 
require such units be tested with an external head pressure equal to 20 
-0/+1 feet of water column, which is the same level of external head 
pressure used in the calculation of the pump effect for DDX-DOASes 
without integral pumps. As such, DOE considers this proposal to be 
consistent with industry test procedure because it ensures that 
integral pumps are treated in the same way as non-integral pumps, and 
as such would not increase testing burden as compared to current 
industry practice.
    AHRI 920-2020 also does not explicitly provide directions for 
setting up the unit's control settings at each Standard Rating 
Condition. As discussed in section III.B.3.g of this document, DOE is 
proposing a general requirement for all control settings to remain 
unchanged for all Standard Rating Conditions once system set up has 
been completed, and that component operation shall be controlled by the 
unit under test once the provisions for rating requirements are met. 
This is likely how DDX-DOASes would be tested as per the existing 
instructions in AHRI 920-2020, but DOE is providing the additional 
specificity in order to ensure that the results of the testing are 
representative, repeatable, and reproducible, and as such would not 
increase testing burden as compared to current industry practice.
    AHRI 920-2020 incorrectly indicates that Equation 20 should be used 
to calculate the degradation coefficient for DDX-DOASes with VERS 
(because Equation 21 is indicated to apply for DDX-DOASes with VERS). 
This is discussed in further detail in section III.B.3.l.ii of this 
document. DOE is proposing to correct this statement to instead use 
this equation for DDX-DOASes without VERS, with deactivated VERS, or 
with sensible-only VERS tested under Standard Rating Conditions other 
than D. DOE considers this proposal to be consistent with the intent of 
the industry test procedure and would not increase testing burden as 
compared to AHRI 920-2020.
    DOE's proposal to provide a definition for ``non-standard low-
static fan motor'' also serves to provide clarity to the instructions 
present in AHRI 920-2020 without affecting the scope of coverage or 
testing burden. Absent this definition, as discussed in section 
III.B.3.l.iii of this document, it is not possible to determine the 
appropriate airflow setting procedure in section 6.1.5.2 of AHRI 920-
2020.
    AHRI 920-2020 does not provide instruction for testing a DDX-DOAS 
for which a manufacturer recommends more than one refrigerant option. 
DOE is proposing to require testing of such a unit with each 
recommended refrigerant if the different refrigerants require different 
hardware. This proposal is consistent with the treatment of basic 
models of commercial packaged air conditioners and heating equipment 
under 10 CFR 430.92, and, as such, it would be reflective of industry 
practice for commercial packaged air conditioner and heating equipment 
generally. Therefore, this proposed addition to the procedure laid out 
by AHRI 920-2020 would not increase testing burden as compared current 
industry practice.
    DOE is also proposing sampling requirements for making 
representations of ISMRE2 and ISCOP2, as applicable. AHRI 920-2020 does 
not contain comparable provisions. The sampling requirements proposed 
are consistent with the DOE sampling requirements generally for 
commercial packaged air conditioners and heating equipment, and, if 
made final, would be reflective of industry practice. Therefore, the 
proposed sampling requirements, if made final, would not increase 
testing burden as compared to the current industry practice.
    Issue-14: DOE requests comment on its understanding of the impact 
of the test procedure proposals in this NOPR, specifically DOE's 
initial conclusion that manufacturers would not incur any additional 
costs due to this proposal, if finalized, compared to current industry 
practice, as indicated by AHRI 920-2020.
4. Harmonization With Industry Standards
    DOE proposes to incorporate by reference the provisions in AHRI 
920-2020, including definitions, test methods, and rating requirements, 
with certain modifications previously discussed. Throughout this NOPR, 
DOE discusses adopting this most recent

[[Page 36048]]

relevant industry consensus testing standard for DDX-DOAS equipment, as 
required in 42 U.S.C. 6314 and discussed in section III.B of this NOPR.
    Issue-15: DOE seeks comment on the degree to which the DOE test 
procedure should consider and be harmonized further with the most 
recent relevant industry consensus testing standards for DDX-DOASes and 
whether there could be modifications to the industry test method that 
would provide additional benefits to the public. DOE also requests 
comment on the benefits and burdens of adopting any industry/voluntary 
consensus-based or other appropriate test procedure, without 
modification.
5. Other Test Procedure Topics
    In addition to the issues identified earlier in this document, DOE 
welcomes comment on any other aspect of the proposed test procedures 
for DDX-DOASes not already addressed by the specific areas identified 
in this document. DOE particularly seeks information that would ensure 
that the test procedure measures energy efficiency during a 
representative average use cycle, as well as information that would 
help DOE create a procedure that is not unduly burdensome to conduct.

E. Compliance Date

    EPCA prescribes that, if DOE amends a test procedure, all 
representations of energy efficiency and energy use, including those 
made in the context of certification and on marketing materials and 
product labels, must be made in accordance with that amended test 
procedure, beginning 360 days after publication of such a test 
procedure final rule in the Federal Register. (42 U.S.C. 6314(d)(1))

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866

    The Office of Management and Budget (OMB) has determined that this 
test procedure rulemaking does not constitute a ``significant 
regulatory actions'' under section 3(f) of Executive Order 12866, 
``Regulatory Planning and Review,'' 58 FR 51735 (Oct. 4, 1993). 
Accordingly, this action was not subject to review under the Executive 
Order by the Office of Information and Regulatory Affairs (OIRA) in 
OMB.

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 (August 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 at: energy.gov/gc/office-general-counsel. DOE 
reviewed this proposed rule under the provisions of the Regulatory 
Flexibility Act and the policies and procedures published on February 
19, 2003.
    The following sections detail DOE's IRFA for this test procedure 
rulemaking.
1. Description of Reasons Why Action Is Being Considered
    DOE is undertaking this test procedure rulemaking to establish a 
DOE test procedure for DDX-DOASes in response to updates to the 
relevant industry consensus standard, American Society of Heating, 
Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1, 
Energy Standard for Buildings Except Low-Rise Residential Buildings, 
which, with its 2016 publication, both added efficiency standards and 
specified a test procedure for this equipment (i.e., AHRI 920-2015). 
Subsequently, the Air-Conditioning, Heating, and Refrigeration 
Institute (AHRI) updated its test procedure with the publication of 
AHRI 920-2020. The Energy Policy and Conservation Act (EPCA) \35\ 
requires that each time the test procedure referenced by ASHRAE 
Standard 90.1 is updated, DOE must update the Federal test procedure 
consistent with the industry update, unless there is clear and 
convincing evidence that the update would not be representative of an 
average use cycle or would be unduly burdensome to conduct.
---------------------------------------------------------------------------

    \35\ 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. Objectives of, and Legal Basis for, Rule
    EPCA, as amended, among other things, authorizes DOE to regulate 
the energy efficiency of a number of consumer products and certain 
industrial equipment. Title III, Part C \36\ of EPCA, Public Law 94-163 
(42 U.S.C. 6311-6317, as codified), added by Public Law 95-619, Title 
IV, Sec.  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 
small, large, and very large commercial package air conditioning and 
heating equipment. (42 U.S.C. 6311(1)(B)-(D)) DOE has initially 
determined that commercial package air conditioning and heating 
equipment includes DX-DOASes. As discussed in section I.B of the NOPR 
document, DX-DOASes had not previously been addressed in DOE 
rulemakings and are not currently subject to Federal test procedures or 
energy conservation standards.
---------------------------------------------------------------------------

    \36\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
---------------------------------------------------------------------------

    Under EPCA, DOE's energy conservation program consists essentially 
of four parts: (1) Testing, (2) labeling, (3) Federal energy 
conservation standards, and (4) certification and enforcement 
procedures. Relevant provisions of EPCA specifically include 
definitions (42 U.S.C. 6311), energy conservation standards (42 U.S.C. 
6313), test procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 
6315), 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(b); 42 U.S.C. 6296), and (2) making representations about the 
efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE uses 
these test procedures to determine whether the equipment complies with 
relevant standards promulgated under EPCA.
    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 (b); 42 U.S.C. 6297) DOE may, however, grant waivers 
of Federal preemption in limited circumstances for particular State 
laws or regulations, in accordance with the procedures and other 
provisions of EPCA. (42 U.S.C. 6316(b)(2)(D))
    Under 42 U.S.C. 6314, the statute also sets forth the criteria and 
procedures DOE is required to follow when prescribing or amending test 
procedures for covered equipment. Specifically, EPCA requires that any 
test procedure prescribed or amended shall be reasonably designed to 
produce test results which measure energy

[[Page 36049]]

efficiency, energy use, or estimated annual operating cost 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 requires that the test procedures for commercial package air 
conditioning and heating equipment be those generally accepted industry 
testing procedures or rating procedures developed or recognized by the 
Air-Conditioning, Heating, and Refrigeration Institute (AHRI) or by the 
American Society of Heating, Refrigerating and Air-Conditioning 
Engineers (ASHRAE), as referenced in ASHRAE Standard 90.1, ``Energy 
Standard for Buildings Except Low-Rise Residential Buildings'' (ASHRAE 
Standard 90.1). (42 U.S.C. 6314(a)(4)(A)) Further, if such an industry 
test procedure is amended, DOE must update its test procedure to be 
consistent with the amended industry test procedure, unless DOE 
determines, by rule published in the Federal Register and supported by 
clear and convincing evidence, that such amended test procedure would 
not meet the requirements in 42 U.S.C. 6314(a)(2) and (3), related to 
representative use and test burden. (42 U.S.C. 6314(a)(4)(B))
    EPCA also requires that, at least once every seven years, DOE 
evaluate test procedures for each type of covered equipment, including 
commercial package air conditioning and heating equipment to determine 
whether amended test procedures would more accurately or fully comply 
with the requirements for the test procedures not to 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. 
6314(a)(1)-(3)) In addition, if DOE determines that a test procedure 
amendment is warranted, it 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 in the Federal Register its determination not to amend the 
test procedures. (42 U.S.C. 6314(a)(1)(A)(ii))
    A test procedure for a subset of DX-DOASes (i.e., DDX-DOASes), was 
first specified by ASHRAE Standard 90.1 in the 2016 edition (ASHRAE 
Standard 90.1-2016). Pursuant to 42 U.S.C. 6314(a)(4)(B), and following 
updates to the relevant test procedures which were referenced in ASHRAE 
Standard 90.1, DOE is publishing this NOPR proposing to establish a 
test procedure for DDX-DOASes in satisfaction of its aforementioned 
obligations under EPCA.
3. Description and Estimate of Small Entities Regulated
    For manufacturers of small, large, and very large air-conditioning 
and heating equipment (including DDX-DOASes), commercial warm-air 
furnaces, and commercial water heaters, 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 this 
rule. See 13 CFR part 121. The equipment covered by this rule are 
classified under North American Industry Classification System 
(``NAICS'') code 333415,\37\ ``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.
---------------------------------------------------------------------------

    \37\ 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 April 20, 2021).
---------------------------------------------------------------------------

    In reviewing the DDX-DOAS market, DOE used company websites, 
marketing research tools, product catalogues, and other public 
information to identify companies that manufacture DDX-DOASes. DOE 
identified 16 manufacturers of DDX-DOASes affected by this rulemaking. 
Out of these 16 manufacturers, DOE determined that three are domestic 
small businesses. DOE used subscription-based business information 
tools to determine headcount and revenue of the small businesses.
    Issue-16: DOE invites comment on the number of domestic small 
businesses producing DDX-DOASes for the U.S. market.
4. Description and Estimate of Compliance Requirements
    EPCA requires DOE to adopt test procedures for small, large, and 
very large commercial package air conditioning and heating equipment 
consistent with the amended industry test procedures developed or 
recognized by AHRI as referenced in ASHRAE Standard 90.1, unless the 
Secretary determines that, supported by clear and convincing evidence, 
to do so would not meet the requirements for test procedures to be 
reasonably designed to produce results that reflect energy efficiency, 
energy use, and estimated operating costs during a representative 
average use cycle and not be unduly burdensome to conduct. (42 U.S.C. 
6314(a)(4)(B)) In this NOPR, DOE proposes to establish a test procedure 
for DDX-DOASes, which belong to a category of small, large, and very 
large commercial package air conditioning and heating equipment. DOE is 
proposing to establish a test procedure that incorporates by reference 
the applicable industry consensus test methods (including the energy 
efficiency descriptors) and that establishes representation 
requirements. Although AHRI 920-2020 is not yet referenced as the 
applicable test procedure in ASHRAE Standard 90.1, it provides revised 
test methods that update ANSI/AHRI 920-2015, which is the referenced 
industry test standard. For these reasons, DOE has tentatively 
concluded that the methods in AHRI 920-2020 reflect the intention for 
prevalent industry practice: It is likely that manufacturers will use 
AHRI 920-2020 in the future.
    In its review of AHRI 920-2020, DOE estimated the cost for third-
party lab testing of basic models to range from $10,000 to $23,500 
depending on validation class, equipment capacity, and equipment 
configuration. However, manufactures are not required to perform 
laboratory testing on all basic models. DOE proposes to allow DDX-DOAS 
manufacturers to use alternative energy-efficiency determination 
methods (AEDMs) for determining the ISMRE2 and ISCOP2 (if applicable) 
in accordance with 10 CFR 429.70. 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 relatively straight-forward and reasonably 
accurate 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.
    DOE researched manufacturer DDX-DOAS offerings and estimated the 
cost to rate basic models according to the proposed DOE test procedure 
(which is not expected to have any additional cost over AHRI 920-2020 
\38\). Using

[[Page 36050]]

information collected on small business equipment offerings and the 
upper threshold of third-party testing costs, DOE estimates an average 
expense of approximately $200,000 per small manufacturer. These testing 
expenses would be less than 1% of revenue for each small business. DOE 
tentatively concludes that the estimate costs would not present a 
significant burden to small manufacturers.
---------------------------------------------------------------------------

    \38\ DOE has tentatively determined that the proposed 
modifications to AHRI 920-2020 would be unlikely to significantly 
increase burden, given that DOE is referencing the prevailing 
industry test procedure. So, presuming widespread usage of AHRI 920-
2020, its adoption as part of the Federal test procedure would be 
expected to result in little additional cost, even with the minor 
modifications proposed by DOE.
---------------------------------------------------------------------------

    The testing of DDX-DOASes would not be required until such time as 
DOE establishes DDX-DOAS energy conservation standards and 
manufacturers are required to comply with those energy conservation 
standards. As such, small manufacturers will have a substantial 
timeframe to prepare for the testing detailed in this NOPR. 
Additionally, small manufacturers already testing to AHRI 920-2020 
would incur no additional costs as a result of this proposed test 
procedure.
    Issue-17: DOE invites comment on the testing costs and timing of 
testing costs described in this IRFA.
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 proposed rule being considered in this 
action.
6. Significant Alternatives to the Rule
    DOE proposes to reduce burden on manufacturers, including small 
businesses, by allowing alternative energy efficiency or energy use 
determination methods (AEDMs) in lieu of physical testing all basic 
models. An AEDM is a computer modeling or mathematical tool that 
predicts the performance of non-tested basic models. The use of 
computer modeling is more time-efficient than physical testing. Without 
AEDMs, the average cost to rate all basic models would exceed $29 
million per small manufacturer, as compared to the $200,000 per small 
manufacturer in the current proposal.
    Additionally, DOE considered alternative test methods and 
modifications to the test procedure for DDX-DOASes, and the Department 
has tentatively determined that there are no better alternatives than 
the modifications and test procedures proposed in this NOPR, in terms 
of both meeting the agency's objectives and reducing burden. DOE 
examined relevant industry test standards, and the Department 
incorporated these standards in the proposed test procedures whenever 
appropriate to reduce test burden to manufacturers. Specifically, this 
NOPR proposes that DOE establish a test procedure for DDX-DOASes 
through incorporation by reference of AHRI 920-2020 with modifications 
that are not expected to increase test burden.
    In addition, individual manufacturers may petition for a waiver of 
the applicable test procedure. (See 10 CFR 431.401.) Also, Section 504 
of the Department of Energy Organization Act, 42 U.S.C. 7194, provides 
authority for the Secretary to adjust a rule issued under EPCA in order 
to prevent ``special hardship, inequity, or unfair distribution of 
burdens'' that may be imposed on that manufacturer as a result of such 
rule. Manufacturers should refer to 10 CFR part 1003 for additional 
details.

C. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of certain commercial package air condition and 
heating equipment must certify to DOE that their products comply with 
any applicable energy conservation standards. To certify 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/industrial equipment, including commercial package air 
condition and heating equipment. (See generally 10 CFR part 429.) The 
collection-of-information requirement for the certification and 
recordkeeping is subject to review and approval by 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.
    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

    DOE is analyzing this proposed regulation in accordance with the 
National Environmental Policy Act of 1969 (NEPA) and DOE's NEPA 
implementing regulations (10 CFR part 1021). DOE anticipates that this 
rulemaking qualifies for categorical exclusion A6 because it is a 
procedural rulemaking and meets the requirements for application of a 
categorical exclusion. 10 CFR part 1021, subpart D, Appendix A, section 
A6; See 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 (August 4, 
1999), imposes certain requirements on Federal 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

[[Page 36051]]

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 
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). 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 adopt a test procedure for 
measuring the energy efficiency of DDX-DOASes 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 test procedure for DDX-DOASes incorporate the 
following applicable industry consensus standards: AHRI 920-2020, ANSI/
AHRI 1060-2018, ANSI/ASHRAE 37-2009, ANSI/ASHRAE 41.1-2013, ANSI/ASHRAE 
41.6-2014, and ANSI/ASHRAE 198-2013. 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

[[Page 36052]]

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 test standards:
    (1) The test standard published by AHRI, titled ``2020 Standard for 
Performance Rating of DX-Dedicated Outdoor Air System Units,'' AHRI 
Standard 920-2020 (I-P). AHRI Standard 920-2020 (I-P) is an industry-
accepted test procedure for measuring the performance of DX-dedicated 
outdoor air system units. AHRI Standard 920-2020 (I-P) is available on 
AHRI's website at: www.ahrinet.org/App_Content/ahri/files/STANDARDS/AHRI/AHRI_Standard_920_I-P_2020.pdf.
    (2) The test standard published by AHRI, titled ``2018 Standard for 
Performance Rating of Air-to-Air Exchangers for Energy Recovery 
Ventilation Equipment,'' ANSI/AHRI Standard 1060-2018. ANSI/AHRI 
Standard 1060-2018 is an industry-accepted test procedure for measuring 
the performance of air-to-air exchangers for energy recovery 
ventilation equipment. ANSI/AHRI Standard 1060-2018 is available on 
AHRI's website at: www.ahrinet.org/App_Content/ahri/files/STANDARDS/AHRI/AHRI_Standard_1060_I-P_2018.pdf.
    (3) The test standard test standard published by ASHRAE, titled 
``Methods of Testing for Rating Electrically Driven Unitary Air-
Conditioning and Heat Pump Equipment,'' ANSI/ASHRAE Standard 37-2009. 
ANSI/ASHRAE Standard 37-2009 is an industry-accepted test procedure for 
measuring the performance of electrically driven unitary air-
conditioning and heat pump equipment. ANSI/ASHRAE Standard 37-2009 is 
available on ASHRAE's website (in partnership with Techstreet) at: 
www.techstreet.com/ashrae/standards/ashrae-37-2009?product_id=1650947.
    (4) The test standard published by ASHRAE, titled ``Standard Method 
for Temperature Measurement,'' ANSI/ASHRAE Standard 41.1-2013. ANSI/
AHRAE Standard 41.1-2013 is an industry-accepted test procedure for 
measuring temperature. ANSI/ASHRAE Standard 41.1-2013 is available on 
ASHRAE's website (in partnership with Techstreet) at: 
www.techstreet.com/ashrae/standards/ashrae-41-1-2013?product_id=1853241.
    (5) The test standard published by ASHRAE, titled ``Standard Method 
for Humidity Measurement,'' ANSI/ASHRAE Standard 41.6-2014. ANSI/AHRAE 
Standard 41.6-2014 is an industry-accepted test procedure for measuring 
humidity. ANSI/ASHRAE Standard 41.6-2014 is available on ASHRAE's 
website (in partnership with Techstreet) at: www.techstreet.com/ashrae/standards/ashrae-41-6-2014?product_id=1881840.
    (6) The test standard published by ASHRAE, titled ``Method for Test 
for Rating DX-Dedicated Outdoor Air Systems for Moisture Removal 
Capacity and Moisture Removal Efficiency,'' ANSI/ASHRAE Standard 198-
2013. ANSI/ASHRAE Standard 198-2013 is an industry-accepted test 
procedure for measuring the performance of DX-dedicated outdoor air 
system units. ANSI/ASHRAE Standard 198-2013 is available on ASHRAE's 
website (in partnership with Techstreet) at: www.techstreet.com/ashrae/standards/ashrae-198-2013?product_id=1852612.

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. Additionally, you may request an in-person 
meeting to be held prior to the close of the request period provided in 
the DATES section of this document. Requests for an in-person meeting 
may be made by contacting Appliance and Equipment Standards Program 
staff at (202) 287-1445 or by email: 
[email protected].

B. Procedure for Submitting Prepared General Statements for 
Distribution

    Any person who has an interest in the topics addressed in this 
notice, 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/public meeting. Such persons may 
submit requests to speak via email to the Appliance and Equipment 
Standards Program at: [email protected]. 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 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/public meeting. 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 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 rulemaking.
    The webinar/public meeting will be conducted in an informal, 
conference style. DOE will present summaries of comments received 
before the webinar/public meeting, allow time for prepared general 
statements by participants, and encourage all interested parties to 
share their views on issues affecting this 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 and comment on 
statements made by others. Participants should be prepared to answer 
questions by DOE and by other participants concerning these issues.

[[Page 36053]]

DOE representatives may also ask questions of participants concerning 
other matters relevant to this 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 above 
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 NOPR. 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.\39\ Interested parties may submit 
comments using any of the methods described in the ADDRESSES section at 
the beginning of this document.
---------------------------------------------------------------------------

    \39\ 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. 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 in 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 telefacsimiles (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 the proposed definition for 
``direct expansion-dedicated outdoor air system.'' DOE also requests 
comment on any additional characteristics not yet considered that could 
help to distinguish DX-DOASes from other commercial package air 
conditioning and heating equipment.
    Issue-2: DOE requests comment on the proposed definition for 
``dehumidifying direct expansion-dedicated outdoor air system.'' 
Specifically, DOE requests comment on the proposed criteria for 
distinguishing a ``dehumidifying direct expansion-dedicated outdoor air 
system'' from a ``direct expansion-dedicated outdoor air system'' more 
generally. DOE also requests comment on any additional characteristics 
not yet considered that could help to distinguish DDX-DOASes from DX-
DOASes more generally.
    Issue-3: DOE seeks comment on its translation of Btu per hour to 
MRC and specifically its proposal to translate the upper capacity limit 
for DDX-DOASes such that a model would be considered

[[Page 36054]]

in scope if it has an MRC less than 324 lbs. per hour.
    Issue-4: DOE requests comment on its proposal to clarify what terms 
are synonymous with DDX-DOAS.
    Issue-5: DOE requests comment and data on the development of a 
crosswalk from the efficiency levels in ASHRAE Standard 90.1 based on 
ANSI/AHRI 920-2015 to efficiency levels based on AHRI 920-2020. DOE is 
specifically seeking data on how dehumidification and heating 
efficiency ratings for a given DDX-DOAS model are impacted when 
measured using AHRI 920-2020 as compared to ANSI/AHRI 920-2015.
    Issue-6: DOE requests comment on the terminology DOE proposes to 
use for DDX-DOASes, including ``integrated seasonal coefficient of 
performance 2, or ISCOP2;'' ``integrated seasonal moisture removal 
efficiency 2, or ISMRE2;'' and ``ventilation energy recovery system, or 
VERS.''
    Issue-7: DOE requests comment on the proposal to require that 
water-cooled and water-source DDX-DOASes with integral pumps be set up 
with an external pressure rise equal to 20 feet of water column with a 
condition tolerance of -0/+1 foot and an operating tolerance of 1 foot.
    Issue-8: DOE requests comment on the proposed general control 
setting requirement for DDX-DOASes.
    Issue-9: DOE is requesting comment on the proposed definition of 
``non-standard low-static fan motor'' and whether the proposed 
definition reflects stakeholder understanding of the term.
    Issue-10: DOE seeks comment on the proposed definition of basic 
model of a DDX-DOAS.
    Issue-11: DOE requests comment on the sampling plan proposed for 
DDX-DOASes. DOE specifically requests information and data regarding 
the proposed confidence level and whether variability of testing of 
DDX-DOASes would require a less stringent level, and if so, what that 
level should be.
    Issue-12: DOE requests comment on its proposal regarding 
representations for models approved for use with multiple refrigerants.
    Issue-13: DOE requests comment on its proposals for AEDM 
requirements for DDX-DOAS equipment. DOE requests comment specifically 
on whether the proposed 10-percent tolerance for comparison of test 
results with rated values is appropriate. If the 10-percent tolerance 
is not appropriate, DOE requests comment on why it is not appropriate, 
as well as comment indicating an appropriate tolerance.
    Issue-14: DOE requests comment on its proposal to adopt the 
rounding requirements for key metrics as specified in sections 6.1.2.1 
through 6.1.2.8 of AHRI 920-2020.
    Issue-15: DOE requests comment on its understanding of the impact 
of the test procedure proposals in this NOPR, specifically DOE's 
initial conclusion that manufacturers would not incur any additional 
costs due to this proposal, if finalized, compared to current industry 
practice, as indicated by AHRI 920-2020.
    Issue-16: DOE seeks comment on the degree to which the DOE test 
procedure should consider and be harmonized further with the most 
recent relevant industry consensus testing standards for DDX-DOASes and 
whether there could be modifications to the industry test method that 
would provide additional benefits to the public. DOE also requests 
comment on the benefits and burdens of adopting any industry/voluntary 
consensus-based or other appropriate test procedure, without 
modification.
    Issue-17: DOE invites comment on the number of domestic small 
businesses producing DDX-DOASes for the U.S. market.
    Issue-18: DOE invites comment on the testing costs and timing of 
testing costs described in this IRFA.

VI. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this proposed 
rule.

List of Subjects

10 CFR Part 429

    Administrative practice and procedure, Confidential business 
information, Energy conservation, Household appliances, Imports, 
Incorporation by reference, Intergovernmental relations, Reporting and 
recordkeeping requirements, Small businesses.

10 CFR Part 431

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

Signing Authority

    This document of the Department of Energy was signed on June 23, 
2021, by Kelly Speakes-Backman, Principal Deputy Assistant Secretary 
and Acting Assistant Secretary for Energy Efficiency and Renewable 
Energy, 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 June 23, 2021.
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.  429.43 by adding paragraph (a)(3) to read as follows:


Sec.  429.43  Commercial heating, ventilating, air conditioning (HVAC) 
equipment.

    (a) * * *
    (3) Refrigerants: For dehumidifying direct expansion-dedicated 
outdoor air systems (DDX-DOASes), if a basic model is distributed in 
commerce for which the manufacturer specifies the use of more than one 
refrigerant option, the ISMRE2 and ISCOP2, as applicable, are 
determined for that basic model using the refrigerant that results in 
the lowest ISMRE2 and the refrigerant that results in the lowest 
ISCOP2, as applicable. For example, the dehumidification performance 
metric ISMRE2 must be based on the refrigerant yielding the lowest 
ISMRE2, and the heating performance metric ISCOP2 (if the unit is a 
heat pump DDX-DOAS) must be based on the refrigerant yielding the 
lowest ISCOP2. A refrigerant is considered approved for use if it is 
listed on the nameplate of the single package unit or outdoor unit. 
Pursuant to the definition of ``basic model'' in Sec.  431.92 of this 
chapter, specification of an additional refrigerant option that 
requires use of different hardware (i.e., compressors, heat exchangers, 
or air moving systems that are not the same or comparably performing), 
results in a different basic model.
* * * * *

[[Page 36055]]

0
3. Amend Sec.  429.70 by revising the tables in paragraphs (c)(2)(iv) 
and (c)(5)(vi)(B) to read as follows:


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

* * * * *
    (c) * * *
    (2) * * *
    (iv) * * *

------------------------------------------------------------------------
                                       Minimum number of distinct models
          Validation class               that must be tested per AEDM
------------------------------------------------------------------------
Air-Cooled, Split and Packaged Air    2 Basic Models.
 Conditioners (ACs) and Heat Pumps
 (HPs) less than 65,000 Btu/h
 Cooling Capacity (3-Phase).
------------------------------------------------------------------------
                 (A) Commercial HVAC Validation Classes
------------------------------------------------------------------------
Air-Cooled, Split and Packaged ACs    2 Basic Models.
 and HPs greater than or equal to
 65,000 Btu/h Cooling Capacity and
 Less than 760,000 Btu/h Cooling
 Capacity.
Water-Cooled, Split and Packaged ACs  2 Basic Models.
 and HPs, All Cooling Capacities.
Evaporatively-Cooled, Split and       2 Basic Models.
 Packaged ACs and HPs, All
 Capacities.
Water-Source HPs, All Capacities....  2 Basic Models.
Single Package Vertical ACs and HPs.  2 Basic Models.
Packaged Terminal ACs and HPs.......  2 Basic Models.
Air-Cooled, Variable Refrigerant      2 Basic Models.
 Flow ACs and HPs.
Water-Cooled, Variable Refrigerant    2 Basic Models.
 Flow ACs and HPs.
Computer Room Air Conditioners, Air   2 Basic Models.
 Cooled.
Computer Room Air Conditioners,       2 Basic Models.
 Water-Cooled.
Dehumidifying Direct Expansion-       2 Basic Models.
 Dedicated Outdoor Air Systems, Air-
 cooled or Air-source Heat Pump,
 Without Ventilation Energy Recovery
 Systems.
Dehumidifying Direct Expansion-       2 Basic Models.
 Dedicated Outdoor Air Systems, Air-
 cooled or Air-source Heat Pump,
 With Ventilation Energy Recovery
 Systems.
Dehumidifying Direct Expansion-       2 Basic Models.
 Dedicated Outdoor Air Systems,
 Water-cooled, Water-source Heat
 Pump, or Ground Source Closed-loop
 Heat Pump, Without Ventilation
 Energy Recovery Systems.
Dehumidifying Direct Expansion-       2 Basic Models.
 Dedicated Outdoor Air Systems,
 Water-cooled, Water-source Heat
 Pump, or Ground Source Closed-loop
 Heat Pump, With Ventilation Energy
 Recovery Systems.
------------------------------------------------------------------------
             (B) Commercial Water Heater Validation Classes
------------------------------------------------------------------------
Gas-fired Water Heaters and Hot       2 Basic Models.
 Water Supply Boilers Less than 10
 Gallons.
Gas-fired Water Heaters and Hot       2 Basic Models.
 Water Supply Boilers Greater than
 or Equal to 10 Gallons.
Oil-fired Water Heaters and Hot       2 Basic Models.
 Water Supply Boilers Less than 10
 Gallons.
Oil-fired Water Heaters and Hot       2 Basic Models.
 Water Supply Boilers Greater than
 or Equal to 10 Gallons.
Electric Water Heaters..............  2 Basic Models.
Heat Pump Water Heaters.............  2 Basic Models.
Unfired Hot Water Storage Tanks.....  2 Basic Models.
------------------------------------------------------------------------
           (C) Commercial Packaged Boilers Validation Classes
------------------------------------------------------------------------
Gas-fired, Hot Water Only Commercial  2 Basic Models.
 Packaged Boilers.
Gas-fired, Steam Only Commercial      2 Basic Models.
 Packaged Boilers.
Gas-fired Hot Water/Steam Commercial  2 Basic Models.
 Packaged Boilers.
Oil-fired, Hot Water Only Commercial  2 Basic Models.
 Packaged Boilers.
Oil-fired, Steam Only Commercial      2 Basic Models.
 Packaged Boilers.
Oil-fired Hot Water/Steam Commercial  2 Basic Models.
 Packaged Boilers.
------------------------------------------------------------------------
                (D) Commercial Furnace Validation Classes
------------------------------------------------------------------------
Gas-fired Furnaces..................  2 Basic Models.
Oil-fired Furnaces..................  2 Basic Models.
------------------------------------------------------------------------
       (E) Commercial Refrigeration Equipment Validation Classes
------------------------------------------------------------------------
Self-Contained Open Refrigerators...  2 Basic Models.
Self-Contained Open Freezers........  2 Basic Models.
Remote Condensing Open Refrigerators  2 Basic Models.
Remote Condensing Open Freezers.....  2 Basic Models.
Self-Contained Closed Refrigerators.  2 Basic Models.
Self-Contained Closed Freezers......  2 Basic Models.
Remote Condensing Closed              2 Basic Models.
 Refrigerators.
Remote Condensing Closed Freezers...  2 Basic Models.
------------------------------------------------------------------------
\1\ The minimum number of tests indicated above must be comprised of a
  transparent model, a solid model, a vertical model, a semi-vertical
  model, a horizontal model, and a service-over-the counter model, as
  applicable based on the equipment offering. However, manufacturers do
  not need to include all types of these models if it will increase the
  minimum number of tests that need to be conducted.

* * * * *
    (5) * * *
    (vi) * * *

[[Page 36056]]

    (B) * * *

------------------------------------------------------------------------
                                                            Applicable
             Equipment                     Metric            tolerance
------------------------------------------------------------------------
Commercial Packaged Boilers.......  Combustion                 5% (0.05)
                                     Efficiency.               5% (0.05)
                                    Thermal Efficiency..
Commercial Water Heaters or Hot     Thermal Efficiency..       5% (0.05)
 Water Supply Boilers.
                                    Standby Loss........       10% (0.1)
Unfired Storage Tanks.............  R-Value.............       10% (0.1)
Air-Cooled, Split and Packaged ACs  Seasonal Energy-           5% (0.05)
 and HPs less than 65,000 Btu/h      Efficiency Ratio.
 Cooling Capacity (3-Phase).
                                    Heating Season             5% (0.05)
                                     Performance Factor.
                                    Energy Efficiency          10% (0.1)
                                     Ratio.
Air-Cooled, Split and Packaged ACs  Energy Efficiency          5% (0.05)
 and HPs greater than or equal to    Ratio.
 65,000 Btu/h Cooling Capacity and
 Less than 760,000 Btu/h Cooling
 Capacity.
                                    Coefficient of                    5%
                                     Performance.
                                    Integrated Energy          10% (0.1)
                                     Efficiency Ratio.
Water-Cooled, Split and Packaged    Energy Efficiency          5% (0.05)
 ACs and HPs, All Cooling            Ratio.
 Capacities.
                                    Coefficient of             5% (0.05)
                                     Performance.
                                    Integrated Energy          10% (0.1)
                                     Efficiency Ratio.
Evaporatively-Cooled, Split and     Energy Efficiency          5% (0.05)
 Packaged ACs and HPs, All           Ratio.
 Capacities.
                                    Coefficient of             5% (0.05)
                                     Performance.
                                    Integrated Energy          10% (0.1)
                                     Efficiency Ratio.
Water-Source HPs, All Capacities..  Energy Efficiency          5% (0.05)
                                     Ratio.
                                    Coefficient of             5% (0.05)
                                     Performance.
                                    Integrated Energy          10% (0.1)
                                     Efficiency Ratio.
Single Package Vertical ACs and     Energy Efficiency          5% (0.05)
 HPs.                                Ratio.
                                    Coefficient of             5% (0.05)
                                     Performance.
Packaged Terminal ACs and HPs.....  Energy Efficiency          5% (0.05)
                                     Ratio.
                                    Coefficient of             5% (0.05)
                                     Performance.
Variable Refrigerant Flow ACs and   Energy Efficiency          5% (0.05)
 HPs.                                Ratio.
                                    Coefficient of             5% (0.05)
                                     Performance.
                                    Integrated Energy          10% (0.1)
                                     Efficiency Ratio.
Computer Room Air Conditioners....  Net Sensible               5% (0.05)
                                     Coefficient of
                                     Performance.
Dehumidifying Direct Expansion-     Integrated Seasonal        10% (0.1)
 Dedicated Outdoor Air Systems.      Coefficient of
                                     Performance 2.
                                    Integrated Seasonal        10% (0.1)
                                     Moisture Removal
                                     Efficiency 2.
Commercial Warm-Air Furnaces......  Thermal Efficiency..       5% (0.05)
Commercial Refrigeration Equipment  Daily Energy               5% (0.05)
                                     Consumption.
------------------------------------------------------------------------

* * * * *

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

0
4. 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
5. Amend Sec.  431.2 by revising the definition of ``Commercial HVAC & 
WH product'' to read as follows:


Sec.  431.2  Definitions.

* * * * *
    Commercial HVAC & WH product means any small, large, or very large 
commercial package air-conditioning and heating equipment (as defined 
in Sec.  431.92), packaged terminal air conditioner (as defined in 
Sec.  431.92), packaged terminal heat pump (as defined in Sec.  
431.92), single package vertical air conditioner (as defined in Sec.  
431.92), single package vertical heat pump (as defined in Sec.  
431.92), computer room air conditioner (as defined in Sec.  431.92), 
variable refrigerant flow multi-split air conditioner (as defined in 
Sec.  431.92), variable refrigerant flow multi-split heat pump (as 
defined in Sec.  431.92), direct expansion-dedicated outdoor air system 
(as defined in Sec.  431.92), commercial packaged boiler (as defined in 
Sec.  431.82), hot water supply boiler (as defined in Sec.  431.102), 
commercial warm air furnace (as defined in Sec.  431.72), instantaneous 
water heater (as defined in Sec.  431.102), storage water heater (as 
defined in Sec.  431.102), or unfired hot water storage tank (as 
defined in Sec.  431.102).
* * * * *
0
6. Amend Sec.  431.92 by:
0
a. Revising the definition of ``Basic model''; and
0
b. Adding, in alphabetical order, the definitions for ``Dehumidifying 
direct expansion-dedicated outdoor air system, or DDX-DOAS,'' ``Direct 
expansion-dedicated outdoor air system, or DX-DOAS,'' ``Integrated 
seasonal coefficient of performance 2, or ISCOP2,'' ``Integrated 
seasonal moisture removal efficiency 2, or ISMRE2,'' and ``Ventilation 
energy recovery system, or VERS''.
    The revision and additions read as follows:


Sec.  431.92  Definitions concerning commercial air conditioners and 
heat pumps.

* * * * *
    Basic model includes:
    (1) Computer room air conditioners means all units manufactured by 
one manufacturer within a single equipment class, having the same 
primary energy source (e.g., electric or gas), and which have the same 
or comparably performing compressor(s), heat exchangers, and air moving 
system(s) that have a common ``nominal'' cooling capacity.
    (2) Dehumidifying direct expansion-dedicated outdoor air system 
means all units manufactured by one manufacturer, having the same 
primary energy source (e.g., electric or gas), within a single 
equipment class; with the same or comparably performing compressor(s), 
heat exchangers, ventilation energy recovery system(s) (if

[[Page 36057]]

present), and air moving system(s) that have a common ``nominal'' 
moisture removal capacity.
    (3) Packaged terminal air conditioner (PTAC) or packaged terminal 
heat pump (PTHP) means all units manufactured by one manufacturer 
within a single equipment class, having the same primary energy source 
(e.g., electric or gas), and which have the same or comparable 
compressors, same or comparable heat exchangers, and same or comparable 
air moving systems that have a cooling capacity within 300 Btu/h of one 
another.
    (4) Single package vertical units means all units manufactured by 
one manufacturer within a single equipment class, having the same 
primary energy source (e.g., electric or gas), and which have the same 
or comparably performing compressor(s), heat exchangers, and air moving 
system(s) that have a rated cooling capacity within 1500 Btu/h of one 
another.
    (5) Small, large, and very large air-cooled or water-cooled 
commercial package air conditioning and heating equipment means all 
units manufactured by one manufacturer within a single equipment class, 
having the same or comparably performing compressor(s), heat 
exchangers, and air moving system(s) that have a common ``nominal'' 
cooling capacity.
    (6) Small, large, and very large water source heat pump means all 
units manufactured by one manufacturer within a single equipment class, 
having the same primary energy source (e.g., electric or gas), and 
which have the same or comparable compressors, same or comparable heat 
exchangers, and same or comparable ``nominal'' capacity.
    (7) Variable refrigerant flow systems means all units manufactured 
by one manufacturer within a single equipment class, having the same 
primary energy source (e.g., electric or gas), and which have the same 
or comparably performing compressor(s) that have a common ``nominal'' 
cooling capacity and the same heat rejection medium (e.g., air or 
water) (includes VRF water source heat pumps).
* * * * *
    Dehumidifying direct expansion-dedicated outdoor air system, or 
DDX-DOAS, means a direct expansion-dedicated outdoor air system that is 
capable of dehumidifying air to a 55 [deg]F dew point--when operating 
under Standard Rating Condition A as specified in Table 4 or Table 5 of 
AHRI 920-2020 (incorporated by reference, see Sec.  431.95) with a 
barometric pressure of 29.92 in Hg--for any part of the range of 
airflow rates advertised in manufacturer materials, and has a moisture 
removal capacity of less than 324 lb/h.
    Direct expansion-dedicated outdoor air system, or DX-DOAS, means a 
category of small, large, or very large commercial package air-
conditioning and heating equipment which is capable of providing 
ventilation and conditioning of 100-percent outdoor air or marketed in 
materials (including but not limited to, specification sheets, insert 
sheets, and online materials) as having such capability.
* * * * *
    Integrated seasonal coefficient of performance 2, or ISCOP2, means 
a seasonal weighted-average heating efficiency for heat pump dedicated 
outdoor air systems, expressed in W/W, as measured according to 
appendix B of this subpart.
    Integrated seasonal moisture removal efficiency 2, or ISMRE2, means 
a seasonal weighted average dehumidification efficiency for dedicated 
outdoor air systems, expressed in lbs. of moisture/kWh, as measured 
according to appendix B of this subpart.
* * * * *
    Ventilation energy recovery system, or VERS, means a system that 
pre-conditions outdoor ventilation air entering the equipment through 
direct or indirect thermal and/or moisture exchange with the exhaust 
air, which is defined as the building air being exhausted to the 
outside from the equipment.
* * * * *
0
7. Section 431.95 is amended by:
0
a. Revising paragraph (a) and the introductory text to paragraph (b);
0
b. Redesignating paragraphs (b)(6) and (7) as (b)(8) and (9);
0
c. Adding new paragraphs (b)(6) and (7);
0
d. Revising the introductory text to paragraph (c) and paragraph 
(c)(2);
0
e. Redesignating paragraphs (c)(3) and (4) as (c)(5) and (6); and
0
f. Adding new paragraphs (c)(3) and (4), and paragraph (c)(7).
    The revisions and additions read as follows:


Sec.  431.95  Materials incorporated by reference.

    (a) Certain material is incorporated by reference into this subpart 
with the 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 the U.S. Department of 
Energy, Office of Energy Efficiency and Renewable Energy, Building 
Technologies Program, 6th Floor, 950 L'Enfant Plaza SW, Washington, DC 
20024, (202) 586-1445, or go to: www.energy.gov/eere/buildings/appliance-and-equipment-standards-program, and may be obtained from the 
other sources in this section. It is also available for inspection at 
the National Archives and Records Administration (NARA). For 
information on the availability of this material at NARA, email: 
[email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.
    (b) AHRI. Air-Conditioning, Heating, and Refrigeration Institute, 
2311 Wilson Blvd., Suite 400, Arlington, VA 22201, (703) 524-8800, or 
go to: www.ahrinet.org.
* * * * *
    (6) AHRI Standard 920-2020 (I-P), (``AHRI 920-2020''), ``2020 
Standard for Performance Rating of DX-Dedicated Outdoor Air System 
Units,'' approved February 4, 2020, IBR approved for appendix B to this 
subpart.
    (7) AHRI Standard 1060-2018, (``ANSI/AHRI 1060-2018''), ``2018 
Standard for Performance Rating of Air-to-Air Exchangers for Energy 
Recovery Ventilation Equipment,'' approved 2018, (ANSI/AHRI 1060-2018), 
IBR approved for appendix B to this subpart.
    (c) ASHRAE. American Society of Heating, Refrigerating and Air-
Conditioning Engineers, 180 Technology Parkway, Peachtree Corners, 
Georgia 30092, (404) 636-8400, or go to: www.ashrae.org.
* * * * *
    (2) ANSI/ASHRAE Standard 37-2009, (``ANSI/ASHRAE 37'' or ``ANSI/
ASHRAE 37-2009''), ``Methods of Testing for Rating Electrically Driven 
Unitary Air-Conditioning and Heat Pump Equipment,'' ASHRAE approved 
June 24, 2009, IBR approved for Sec.  431.96 and appendices A and B to 
this subpart.
    (3) ANSI/ASHRAE Standard 41.1-2013, (``ANSI/ASHRAE 41.1-2013''), 
``Standard Method for Temperature Measurement,'' ANSI approved January 
30, 2013, IBR approved for appendix B to this subpart.
    (4) ANSI/ASHRAE Standard 41.6-2014, (``ANSI/ASHRAE 41.6-2014''), 
``Standard Method for Humidity Measurement,'' ANSI approved July 3, 
2014, IBR approved for appendix B to this subpart.
* * * * *
    (7) ANSI/ASHRAE Standard 198-2013, (``ANSI/ASHRAE 198-2013''),

[[Page 36058]]

``Method of Test for Rating DX-Dedicated Outdoor Air Systems for 
Moisture Removal Capacity and Moisture Removal Efficiency,'' approved 
by ANSI on January 30, 2013, IBR approved for appendix B to this 
subpart.
* * * * *
0
8. Amend Sec.  431.96 by:
0
a. Revising paragraph (a) and Table 1 in paragraph (b)(2); and
0
b. Designating the table in paragraph (d) as Table 2 to paragraph (d).
    The revisions read as follows:


Sec.  431.96   Uniform test method for the measurement of energy 
efficiency of commercial air conditioners and heat pumps.

    (a) Scope. This section contains test procedures for measuring, 
pursuant to EPCA, the energy efficiency of any small, large, or very 
large commercial package air-conditioning and heating equipment, 
packaged terminal air conditioners and packaged terminal heat pumps, 
computer room air conditioners, variable refrigerant flow systems, 
single package vertical air conditioners and single package vertical 
heat pumps, and dehumidifying direct expansion-dedicated outdoor air 
systems.
    (b) * * *
    (2) * * *

                                Table 1 to Paragraph (b)--Test Procedures for Commercial Air Conditioners and Heat Pumps
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                      Additional test
                                                               Cooling capacity or                                Use tests,        procedure provisions
           Equipment type                   Category            moisture removal       Energy efficiency       conditions, and      as indicated in the
                                                                    capacity               descriptor         procedures \1\ in     listed paragraphs of
                                                                                                                                        this section
--------------------------------------------------------------------------------------------------------------------------------------------------------
Small Commercial Package Air-        Air-Cooled, 3-Phase,    <65,000 Btu/h.........  SEER and HSPF........  AHRI 210/240-2008      Paragraphs (c) and
 Conditioning and Heating Equipment.  AC and HP.                                                             (omit section 6.5).    (e).
                                     Air-Cooled AC and HP..  >=65,000 Btu/h and      EER, IEER, and COP...  Appendix A to this     None.
                                                              <135,000 Btu/h.                                subpart.
                                     Water-Cooled and        <65,000 Btu/h.........  EER..................  AHRI 210/240-2008      Paragraphs (c) and
                                      Evaporatively-Cooled                                                   (omit section 6.5).    (e).
                                      AC.
                                                             >=65,000 Btu/h and      EER..................  AHRI 340/360-2007      Paragraphs (c) and
                                                              <135,000 Btu/h.                                (omit section 6.3).    (e).
                                     Water-Source HP.......  <135,000 Btu/h........  EER and COP..........  ISO Standard 13256-1   Paragraph (e).
                                                                                                             (1998).
Large Commercial Package Air-        Air-Cooled AC and HP..  >=135,000 Btu/h and     EER, IEER and COP....  Appendix A to this     None.
 Conditioning and Heating Equipment.                          <240,000 Btu/h.                                subpart.
                                     Water-Cooled and        >=135,000 Btu/h and     EER..................  AHRI 340/360-2007      Paragraphs (c) and
                                      Evaporatively-Cooled    <240,000 Btu/h.                                (omit section 6.3).    (e).
                                      AC.
Very Large Commercial Package Air-   Air-Cooled AC and HP..  >=240,000 Btu/h and     EER, IEER and COP....  Appendix A to this     None.
 Conditioning and Heating Equipment.                          <760,000 Btu/h.                                subpart.
                                     Water-Cooled and        >=240,000 Btu/h and     EER..................  AHRI 340/360-2007      Paragraphs (c) and
                                      Evaporatively-Cooled    <760,000 Btu/h.                                (omit section 6.3).    (e).
                                      AC.
Packaged Terminal Air Conditioners   AC and HP.............  <760,000 Btu/h........  EER and COP..........  Paragraph (g) of this  Paragraphs (c), (e),
 and Heat Pumps.                                                                                             section.               and (g).
Computer Room Air Conditioners.....  AC....................  <65,000 Btu/h.........  SCOP.................  ASHRAE 127-2007 (omit  Paragraphs (c) and
                                                                                                             section 5.11).         (e).
                                                             >=65,000 Btu/h and      SCOP.................  ASHRAE 127-2007 (omit  Paragraphs (c) and
                                                              <760,000 Btu/h.                                section 5.11).         (e).
Variable Refrigerant Flow Multi-     AC....................  <65,000 Btu/h (3-       SEER.................  AHRI 1230-2010 (omit   Paragraphs (c), (d),
 split Systems.                                               phase).                                        sections 5.1.2 and     (e), and (f).
                                                                                                             6.6).
                                                             >=65,000 Btu/h and      EER..................  AHRI 1230-2010 (omit   Paragraphs (c), (d),
                                                              <760,000 Btu/h.                                sections 5.1.2 and     (e), and (f).
                                                                                                             6.6).
Variable Refrigerant Flow Multi-     HP....................  <65,000 Btu/h (3-       SEER and HSPF........  AHRI 1230-2010 (omit   Paragraphs (c), (d),
 split Systems, Air-cooled.                                   phase).                                        sections 5.1.2 and     (e), and (f).
                                                                                                             6.6).
                                                             >=65,000 Btu/h and      EER and COP..........  AHRI 1230-2010 (omit   Paragraphs (c), (d),
                                                              <760,000 Btu/h.                                sections 5.1.2 and     (e), and (f).
                                                                                                             6.6).
Variable Refrigerant Flow Multi-     HP....................  <760,000 Btu/h........  EER and COP..........  AHRI 1230-2010 (omit   Paragraphs (c), (d),
 split Systems, Water-source.                                                                                sections 5.1.2 and     (e), and (f).
                                                                                                             6.6).
Single Package Vertical Air          AC and HP.............  <760,000 Btu/h........  EER and COP..........  AHRI 390-2003 (omit    Paragraphs (c) and
 Conditioners and Single Package                                                                             section 6.4).          (e).
 Vertical Heat Pumps.

[[Page 36059]]

 
Dehumidifying Direct Expansion-      All...................  <324 lbs. of moisture   ISMRE2 and ISCOP2....  Appendix B of this     None.
 Dedicated Outdoor Air Systems.                               removal/hr.                                    subpart.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Incorporated by reference; see Sec.   431.95.
\2\ Moisture removal capacity is determined according to appendix B of this subpart.

* * * * *
0
9. Add Appendix B to subpart F of part 431 to read as follows:

Appendix B to Subpart F of Part 431--Uniform Test Method for Measuring 
the Energy Consumption of Dehumidifying Direct Expansion-Dedicated 
Outdoor Air Systems

    Note: Beginning [date 360 days after publication of a test 
procedure final rule], representations with respect to energy use or 
efficiency of dehumidifying direct expansion-dedicated outdoor air 
systems must be based on testing conducted in accordance with this 
appendix. Manufacturers may elect to use this appendix early.
    1. Referenced materials.
    1.1. Incorporation by reference.
    DOE incorporated by reference in Sec.  431.95, the entire 
standard for AHRI 920-2020, ANSI/AHRI 1060-2018; ANSI/ASHRAE 37-
2009, ANSI/ASHRAE 41.1-2013, ANSI/ASHRAE 41.6-2014, and ANSI/ASHRAE 
198-2013. However, only enumerated provisions of AHRI 920-2020, 
ANSI/ASHRAE 37-2009, ANSI/ASHRAE 41.6-2014, and ANSI/ASHRAE 198-
2013, as set forth in paragraphs (a) through (d) of this section are 
applicable. To the extent there is a conflict between the terms or 
provisions of a referenced industry standard and the CFR, the CFR 
provisions control.
    (a) AHRI 920-2020:
    (i) Section 3--Definitions, as specified in section 2.2.1(a) of 
this appendix;
    (ii) Section 5--Test Requirements, as specified in section 
2.2.1(b) of this appendix;
    (iii) Section 6--Rating Requirements, as specified in section 
2.2.1(c) of this appendix, omitting section 6.1.2 (but retaining 
sections 6.1.2.1-6.1.2.8) and 6.6.1;
    (iv) Section 11--Symbols and Subscripts, as specified in section 
2.2.1(d) of this appendix;
    (v) Appendix A--References--Normative, as specified in section 
2.2.1(e) of this appendix;
    (vi) Appendix C--ANSI/ASHRAE Standard 198 and ANSI/ASHRAE 
Standard 37 Additions, Clarifications and Exceptions--Normative, as 
specified in section 2.2.1(f) of this appendix, and
    (vii) Appendix F--Unit Configuration for Standard Efficiency 
Determination--Normative, as specified in section 2.2.1(g) of this 
appendix.
    (b) ANSI/ASHRAE 37-2009:
    (i) Section 5.1--Temperature Measuring Instruments (excluding 
sections 5.1.1 and 5.1.2), as specified in sections 2.2.1(b) and (f) 
of this appendix;
    (ii) Section 5.2--Refrigerant, Liquid, and Barometric Pressure 
Measuring Instruments, as specified in section 2.2.1(b) of this 
appendix;
    (iii) Sections 5.3--Air Differential Pressure and Airflow 
Measurements, as specified in section 2.2.1(b) of this appendix;
    (iv) Sections 5.5(b)--Volatile Refrigerant Measurement, as 
specified in section 2.2.1(b) of this appendix;
    (v) Section 6.1--Enthalpy Apparatus (excluding 6.1.1 and 6.1.3 
through 6.1.6), as specified in section 2.2.1(b) of this appendix;
    (vi) Section 6.2--Nozzle Airflow Measuring Apparatus, as 
specified in section 2.2.1(b) of this appendix;
    (vii) Section 6.3--Nozzles, as specified in section 2.2.1(b) of 
this appendix;
    (viii) Section 6.4--External Static Pressure Measurements, as 
specified in section 2.2.1(b) of this appendix;
    (ix) Section 6.5--Recommended Practices for Static Pressure 
Measurements, as specified in section 2.2.1(f) of this appendix;
    (x) Section 7.3--Indoor and Outdoor Air Enthalpy Methods, as 
specified in section 2.2.1(f) of this appendix;
    (xi) Section 7.4--Compressor Calibration Method, as specified in 
section 2.2.1(f) of this appendix;
    (xii) Section 7.5--Refrigerant Enthalpy Method, as specified in 
section 2.2.1(f) of this appendix;
    (xiii) Section 7.6--Outdoor Liquid Coil Method, as specified in 
section 2.2.1(f) of this appendix;
    (xiv) Section 7.7--Airflow Rate Measurement (excluding sections 
7.7.1.2, 7.7.3, and 7.7.4), as specified in section 2.2.1(b) of this 
appendix;
    (xv) Table 1--Applicable Test Methods, as specified in section 
2.2.1(f) of this appendix;
    (xvi) Section 8.6--Additional Requirements for the Outdoor Air 
Enthalpy Method, as specified in section 2.2.1(f) of this appendix;
    (xvii) Table 2b--Test Tolerances (I-P Units), as specified in 
sections 2.2.1(c) and 2.2(f) of this appendix; and
    (xviii) Errata sheet issued on October 3, 2016, as specified in 
section 2.2.1(f) of this appendix.
    (c) ANSI/ASHRAE 41.6-2014:
    (i) Section 4--Classifications, as specified in section 2.2.1(f) 
of this appendix;
    (ii) Section 5--Requirements, as specified in section 2.2.1(f) 
of this appendix;
    (iii) Section 6--Instruments and Calibration, as specified in 
section 2.2.1(f) of this appendix;
    (iv) Section 7.1--Standard Method Using the Cooled-Surface 
Condensation Hygrometer as specified in section 2.2.1(f) of this 
appendix; and
    (v) Section 7.4--Electronic and Other Humidity Instruments. as 
specified in section 2.2.1(f) of this appendix.
    (d) ANSI/ASHRAE 198-2013:
    (i) Section 4.4--Temperature Measuring Instrument, as specified 
in section 2.2.1(b) of this appendix;
    (ii) Section 4.5--Electrical Instruments, as specified in 
section 2.2.1(b) of this appendix;
    (iii) Section 4.6--Liquid Flow Measurement, as specified in 
section 2.2.1(b) of this appendix;
    (iv) Section 4.7--Time and Mass Measurements, as specified in 
section 2.2.1(b) of this appendix;
    (v) Section 6.1--Test Room Requirements, as specified in section 
2.2.1(b) of this appendix;
    (vi) Section 6.6--Unit Preparation, as specified in section 
2.2.1(b) of this appendix;
    (vii) Section 7.1--Preparation of the Test Room(s), as specified 
in section 2.2.1(b) of this appendix;
    (viii) Section 7.2--Equipment Installation, as specified in 
section 2.2.1(b) of this appendix;
    (ix) Section 8.2--Equilibrium, as specified in section 2.2.1(b) 
of this appendix, and
    (x) Section 8.4--Test Duration and Measurement Frequency, as 
specified in section 2.2.1(b) of this appendix.
    1.2. Informational materials.
    DOE refers to the following provision of AHRI 920-2020, for 
informational purposes only:
    (a) Appendix E--Typical Test Unit Installations--Informative, as 
specified in section 2.2.1(g) of this appendix.
    (b) Reserved.
    2. Test Method.
    2.1. Capacity.
    Moisture removal capacity (in pounds per hour) and supply 
airflow rate (in standard cubic feet per minute) are determined 
according to AHRI 920-2020 (incorporated by reference; see Sec.  
431.95) as specified in section 2.2 of this appendix.
    2.2. Efficiency.
    2.2.1. Determine the ISMRE2 for all DDX-DOASes and the ISCOP2 
for all heat pump

[[Page 36060]]

DDX-DOASes in accordance with the following sections of AHRI 920-
2020.
    (a) Section 3--Definitions, including the references to ANSI/
AHRI 1060-2018 (incorporated by reference; see Sec.  431.95);
    (i) Non-standard Low-static Fan Motor. A supply fan motor that 
cannot maintain external static pressure as high as specified in 
Table 7 of AHRI 920-2020 when operating at a manufacturer-specified 
airflow rate and that is distributed in commerce as part of an 
individual model within the same basic model of a DDX-DOAS that is 
distributed in commerce with a different motor specified for testing 
that can maintain the required external static pressure.
    (b) Section 5--Test Requirements, including the references to 
sections 5.1, 5.2, 5.3, 5.5, 6.1, 6.2, 6.3, 6.4, and 7.7 (not 
including sections 7.7.1.2, 7.7.3, and 7.7.4) of ANSI/ASHRAE 37-2009 
(incorporated by reference; see Sec.  431.95), and sections 4.4, 
4.5, 4.6, 4.7, 5.1, 6.1, 6.6, 7.1, 7.2, 8.2, and 8.4 of ANSI/ASHRAE 
198-2013 (incorporated by reference; see Sec.  431.95);
    (i) All control settings are to remain unchanged for all 
Standard Rating Conditions once system set up has been completed, 
except as explicitly allowed or required by AHRI 920-2020 or as 
indicated in the supplementary test instructions (STI). Component 
operation shall be controlled by the unit under test once the 
provisions in section 2.2.1(c) of this appendix are met.
    (c) Section 6--Rating Requirements (omitting sections 6.1.2 and 
6.6.1), including the references to Table 2b of ANSI/ASHRAE 37-2009, 
and ANSI/ASHRAE 198-2013.
    (i) For water-cooled DDX-DOASes, the ``Condenser Water Entering 
Temperature, Cooling Tower Water'' conditions specified in Table 4 
of AHRI 920-2020 shall be used. For water-source heat pump DDX-
DOASes, the ``Water-Source Heat Pumps'' conditions specified in 
Table 5 of AHRI 920-2020 shall be used.
    (ii) For water-cooled or water-source DDX-DOASes with integral 
pumps, set the external head pressure to 20 ft. of water column, 
with a -0/+1 ft. condition tolerance and a 1 ft. operating 
tolerance.
    (iii) When using the degradation coefficient method as specified 
in section 6.9.2 of AHRI 920-2020, Equation 20 applies to DDX-DOAS 
without VERS, with deactivated VERS (see section 5.4.3 of AHRI 920-
2020), or sensible-only VERS tested under Standard Rating Conditions 
other than D.
    (iv) Rounding requirements for representations are to be 
followed as stated in sections 6.1.2.1 through 6.1.2.8 of AHRI 920-
2020;
    (d) Section 11--Symbols and Subscripts, including references to 
ANSI/ASHRAE 1060-2018;
    (e) Appendix A--References--Normative;
    (f) Appendix C--ANSI/ASHRAE 198-2013 and ANSI/ASHRAE 37 
Additions, Clarifications and Exceptions--Normative, including 
references to sections 5.1, 6.5, 7.3, 7.4, 7.5, 7.6, 8.6, Table 1, 
Table 2b, and the errata sheet of ANSI/ASHRAE 37-2009, ANSI/ASHRAE 
41.1-2013 (incorporated by reference; see Sec.  431.95), sections 4, 
5, 6, 7.1, and 7.4 of ANSI/ASHRAE 41.6-2014 (incorporated by 
reference; see Sec.  431.95), and ANSI/ASHRAE 1060-2018;
    (g) Appendix E--Typical Test Unit Installations--Informative, 
for information only;
    (h) Appendix F--Unit Configuration for Standard Efficiency 
Determination--Normative.
    2.2.2. Optional Representations. Test provisions for the 
determination of the metrics indicated in paragraphs (a) through (d) 
of this section are optional and are determined according to the 
applicable provisions in section 2.2.1 of this appendix. For water-
cooled DDX-DOASes, these optional representations may be determined 
using either the ``Condenser Water Entering Temperature, Cooling 
Tower'' or the ``Condenser Water Entering Temperature, Chilled 
Water'' conditions specified in Table 4 of AHRI 920-2020. For water-
source heat pump DDX-DOASes, these optional representations may be 
determined using either the ``Water-Source Heat Pumps'' or ``Water-
Source Heat Pump, Ground-Source Closed Loop'' conditions specified 
in Table 5 of AHRI 920-2020. The following metrics in AHRI 920-2020 
are optional:
    (a) ISMRE70;
    (b) COPFull,x:
    (c) COPDOAS,x: and
    (d) ISMRE2 and ISCOP2 for water-cooled DDX-DOASes using the 
``Condenser Water Entering Temperature, Chilled Water'' conditions 
specified in Table 4 of AHRI 920-2020 and for water-source heat pump 
DDX-DOASes using the ``Water-Source Heat Pump, Ground-Source Closed 
Loop'' conditions specified in Table 5 of AHRI 920-2020.
    2.3. Synonymous terms.
    (a) Any references to Dedicated Outdoor Air System Unit (DOAS 
Unit), Dedicated Outdoor Air System (DOAS), and Direct Expansion 
Dedicated Outdoor Air System (DX-DOAS) in AHRI 920-2020 and ANSI/
ASHRAE 198-2013 shall be considered synonymous with Dehumidifying 
Direct Expansion-Dedicated Outdoor Air System (DDX-DOAS) as defined 
in Sec.  431.92.
    (b) Any references to energy recovery or energy recovery 
ventilator (ERV) in AHRI 920-2020 and ANSI/ASHRAE 198-2013 shall be 
considered synonymous with ventilation energy recovery system (VERS) 
as defined in Sec.  431.92.

[FR Doc. 2021-13773 Filed 7-6-21; 8:45 am]
 BILLING CODE 6450-01-P`