32332 Federal Register / Vol. 86, No. 115 / Thursday, June 17, 2021 / Proposed Rules 

DEPARTMENT OF ENERGY 

10 CFR Part 431 

[EERE–2017–BT–TP–0010] 

RIN 1904–AD78 

Energy Conservation Program: Test 

Procedures for Certain Commercial 

and Industrial Equipment; Early 

Assessment Review: Walk-In Coolers 

and Freezers 

AGENCY: Office of Energy Efficiency and 

Renewable Energy, Department of 

Energy. 

ACTION: Request for information. 

SUMMARY: The U.S. Department of 

Energy (‘‘DOE’’) is undertaking an early 

assessment review to determine whether 

amendments are warranted for the test 

procedures for walk-in coolers and 

walk-in freezers (‘‘WICFs’’ or ‘‘walkins’’). DOE has identified certain issues 

associated with the currently applicable 

test procedures on which DOE is 

interested in receiving comment. The 

issues outlined in this document 

address definitions and equipment 

classes of walk-in components, test 

procedure waivers received, and other 

test procedure issues related to walk-in 

doors, panels, and refrigeration systems. 

DOE welcomes written comments from 

the public on any subject within the 

scope of this document, including 

topics not raised in this request for 

information (‘‘RFI’’). 

DATES: Written comments and 

information are requested and will be 

accepted on or before July 19, 2021. 

ADDRESSES: Interested persons are 

encouraged to submit comments using 

the Federal eRulemaking Portal at 

https://www.regulations.gov. Follow the 

instructions for submitting comments. 

Alternatively, interested persons may 

submit comments by email to the 

following address: WICF2017TP0010@

ee.doe.gov. Include docket number 

EERE–2017–BT–TP–0010 and/or RIN 

number 1904–AD78 in the subject line 

of the message. Submit electronic 

comments in WordPerfect, Microsoft 

Word, PDF, or ASCII file format, and 

avoid the use of special characters or 

any form of encryption. No 

telefacsimiles (faxes) will be accepted. 

For detailed instructions on submitting 

comments and additional information 

on the rulemaking process, see section 

III (Submission of Comments) of this 

document. 

Although DOE has routinely accepted 

public comment submissions through a 

variety of mechanisms, including postal 

mail and hand delivery/courier, the 

Department has found it necessary to 

make temporary modifications to the 

comment submission process in light of 

the ongoing 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 for this activity, 

which includes Federal Register 

notices, comments, and other 

supporting documents/materials, is 

available for review at https://

www.regulations.gov. All documents in 

the docket are listed in the https://

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: 

https://www.regulations.gov/#!docket

Detail;D=EERE-2017-BT-TP-0010. The 

docket web page contains instructions 

on how to access all documents, 

including public comments, in the 

docket. See section III of this document 

for information on how to submit 

comments through https://

www.regulations.gov. 

FOR FURTHER INFORMATION CONTACT: 

Dr. Stephanie Johnson, U.S. Department 

of Energy, Office of Energy Efficiency 

and Renewable Energy, Building 

Technologies Office, EE–5B, 1000 

Independence Avenue SW, 

Washington, DC 20585–0121. 

Telephone: (202) 287–1943. Email: 

ApplianceStandardsQuestions@

ee.doe.gov. 

Mr. Michael Kido, U.S. Department of 

Energy, Office of the General Counsel, 

GC–33, 1000 Independence Avenue 

SW, Washington, DC 20585–0121. 

Telephone: (202) 586–8145. Email: 

Michael.Kido@hq.doe.gov. 

For further information on how to 

submit a comment or review other 

public comments and the docket, 

contact the Appliance and Equipment 

Standards Program staff at (202) 287– 

1445 or by email: 

ApplianceStandardsQuestions@

ee.doe.gov. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. Introduction 

A. Authority 

B. Rulemaking History 

II. Request for Information 

A. Scope and Definitions 

1. Walk-In Refrigeration Systems 

2.Walk-In Doors 

B. Industry Test Standards 

1. NFRC 100 and NFRC 102 

2. ASTM C518 

3. AHRI 1250 

C. Test Procedure for Walk-In Doors 

1. Surface Area Used for Determining 

Compliance With Standards 

2. Thermal Transmittance Area 

3. Electrical Door Components 

4. EER Values To Convert Thermal Load to 

Energy Consumption 

5. Thermal Transmittance 

a. Calibration of Hot Box for Measuring 

U-Factor 

b. Tolerances of Surface Heat Transfer 

Coefficients 

6. Air Infiltration Reduction 

D. Test Procedure for Walk-In Panels 

1. Panel Thickness 

2. Parallelism and Flatness 

3. Specimen Conditioning 

4. Overall Thermal Transmittance 

5. Display Panels 

E. Test Procedure for Walk-In Refrigeration 

Systems 

1. Single-Package Systems 

a. Calorimeter Method 

2. Wine Cellar Refrigeration Systems 

3. CO2 Systems 

4. Defrost Test Method 

a. Moisture Addition 

b. Hot Gas Defrost 

c. Adaptive Defrost 

5. Off-Cycle Energy Use 

6. Multi-Capacity and Variable-Capacity 

Condensing Units 

7. Systems for High-Temperature Freezer 

Applications 

8. Consideration for Refrigerant Glide 

III. Submission of Comments 

IV. Issues on Which DOE Seeks Comment 

I. Introduction 

DOE established an early assessment 

review process to conduct a more 

focused analysis that would allow DOE 

to determine, based on statutory criteria, 

whether an amended test procedure is 

warranted. 10 CFR 431.4; 10 CFR part 

430 subpart C appendix A section 8(a). 

This RFI requests information and data 

regarding whether an amended test 

procedure would more accurately and 

fully comply with the requirement that 

the test procedure produce results that 

measure energy use during a 

representative average use cycle for the 

equipment, and not be unduly 

burdensome to conduct. To inform 

interested parties and to facilitate this 

process, DOE has identified several 

issues associated with the currently 

applicable test procedures on which 

DOE is interested in receiving comment. 

Based on the information received in 

response to the RFI and DOE’s own 

analysis, DOE will determine whether to 

proceed with a rulemaking for an 

amended test procedure. 

If DOE makes an initial determination 

that an amended test procedure would 


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Federal Register / Vol. 86, No. 115 / Thursday, June 17, 2021 / Proposed Rules 32333 

1All 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). 

2For editorial reasons, upon codification in the 

U.S. Code, Part C was redesignated Part A–1. 

3The R-value is the capacity of an insulated 

material to resist heat-flow. See 42 U.S.C. 

6313(f)(1)(C) for the EPCA R-value requirements for 

non-display panels and doors. 

4The K factor represents the thermal conductivity 

of a material, or its ability to conduct heat, in units 

of Btu-in/(h-ft2-°F). 

5Appliance Standards and Rulemaking Federal 

Advisory Committee Refrigeration Systems Walk-in 

Coolers and Freezers Term Sheet, available at 

https://www.regulations.gov/document?D=EERE2015-BT-STD-0016-0056. 

more accurately or fully comply with 

statutory requirements, or DOE’s 

analysis is inconclusive as to whether 

amendments are warranted, DOE would 

undertake a rulemaking to issue an 

amended test procedure. If DOE makes 

an initial determination based upon 

available evidence that an amended test 

procedure would not meet the 

applicable statutory criteria, DOE would 

engage in notice and comment 

rulemaking before issuing a final 

determination that an amended test 

procedure is not warranted. 

A. Authority 

The Energy Policy and Conservation 

Act, as amended (‘‘EPCA’’),1 authorizes 

DOE to regulate the energy efficiency of 

a number of consumer products and 

certain industrial equipment. (42 U.S.C. 

6291–6317) Title III, Part C 2 of EPCA, 

added by Public Law 95–619, Title IV, 

section 441(a) (42 U.S.C. 6311–6317 as 

codified), established the Energy 

Conservation Program for Certain 

Industrial Equipment, which sets forth a 

variety of provisions designed to 

improve energy efficiency. This 

equipment includes walk-in coolers and 

freezers (collectively, ‘‘walk-ins’’ or 

‘‘WICFs’’), the subject of this document. 

(42 U.S.C. 6311(1)(G)) 

Under EPCA, DOE’s energy 

conservation program consists 

essentially of four parts: (1) Testing, (2) 

labeling, (3) Federal energy conservation 

standards (‘‘ECS’’), and (4) certification 

and enforcement procedures. Relevant 

provisions of EPCA include definitions 

(42 U.S.C. 6311), test procedures (42 

U.S.C. 6314), labeling provisions (42 

U.S.C. 6315), energy conservation 

standards (42 U.S.C. 6313), and the 

authority to require information and 

reports from manufacturers (42 U.S.C. 

6316). 

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 instances for 

particular State laws or regulations, in 

accordance with the procedures and 

other provisions set forth under 42 

U.S.C. 6316(b)(2)(D). 

EPCA also requires that, at least once 

every 7 years, DOE evaluate test 

procedures for each type of covered 

equipment, including walk-in coolers 

and freezers, to determine whether 

amended test procedures would more 

accurately or fully comply with the 

requirements for the test procedures to 

not be unduly burdensome to conduct 

and be reasonably designed to produce 

test results that reflect energy efficiency, 

energy use, and estimated operating 

costs during a representative average 

use cycle. (42 U.S.C. 6314(a)(1)) DOE is 

publishing this RFI to collect data and 

information to inform its decision to 

satisfy the 7-year-lookback review 

requirement. 

B. Rulemaking History 

DOE has established test procedures 

to measure walk-in energy use, 

establishing separate test procedures for 

the principal components that make up 

a walk-in (i.e., doors, panels, and 

refrigeration systems) with separate test 

metrics for each component. 10 CFR 

431.304(b). For walk-in doors and 

display panels, the efficiency metric is 

daily energy consumption, measured in 

kilowatt-hours per day (‘‘kWh/day’’), 

which accounts for the thermal 

conduction through the door or display 

panel and the direct and indirect 

electricity use of any electrical 

components associated with the door. 

10 CFR 431.304(b)(1)–(2) and 10 CFR 

part 431, subpart R, appendix A, 

‘‘Uniform Test Method for the 

Measurement of Energy Consumption of 

the Components of Envelopes of WalkIn Coolers and Walk-In Freezers’’ 

(‘‘Appendix A’’). 

For walk-in non-display panels and 

non-display doors, DOE codified in the 

Code of Federal Regulations (‘‘CFR’’) 

prescriptive standards established in 

EPCA based on R-value, expressed in 

units of (h-ft2-°F/Btu),3 which is 

calculated as 1/K multiplied by the 

thickness of the panel.4 10 CFR 

431.304(b)(3) and 10 CFR part 431 

subpart R, appendix B, titled ‘‘Uniform 

Test Method for the Measurement of 

R-Value for Envelope Components of 

Walk-In Coolers and Walk-In Freezers’’ 

(‘‘Appendix B’’). (See also, 42 U.S.C. 

6314(a)(9)(A)) The K factor is calculated 

based on American Society for Testing 

and Materials (‘‘ASTM’’) C518, 

‘‘Standard Test Method for Steady-State 

Thermal Transmission Properties by 

Means of the Heat Flow Meter 

Apparatus’’ (‘‘ASTM C518’’), which is 

incorporated by reference. Id. 

For walk-in refrigeration systems, the 

efficiency metric is Annual Walk-in 

Energy Factor (‘‘AWEF’’), which is 

determined by conducting the test 

procedure set forth in American 

National Standards Institute (‘‘ANSI’’)/ 

Air-Conditioning, Heating, and 

Refrigeration Institute (‘‘AHRI’’) 

Standard 1250P (I–P), ‘‘2009 Standard 

for Performance Rating of Walk-In 

Coolers and Freezers,’’ (‘‘AHRI 1250– 

2009’’), with certain adjustments 

specified in the CFR. 10 CFR 

431.304(b)(4) and 10 CFR part 431 

subpart R, appendix C, ‘‘Uniform Test 

Method for the Measurement of Net 

Capacity and AWEF of Walk-In Cooler 

and Walk-In Freezer Refrigeration 

Systems’’ (‘‘Appendix C’’). A 

manufacturer may also determine 

AWEF using an alternative efficiency 

determination method (‘‘AEDM’’). 10 

CFR 429.53(a)(2)(iii). An AEDM enables 

a manufacturer to utilize computerbased or mathematical models for 

purposes of determining an equipment’s 

energy use or energy efficiency 

performance in lieu of testing, provided 

certain prerequisites have been met. 10 

CFR 429.70(f). 

On August 5, 2015, DOE published its 

intention to establish a Working Group 

under the Appliance Standards and 

Rulemaking Federal Advisory 

Committee (‘‘ASRAC’’) to negotiate 

energy conservation standards to 

replace the standards established in the 

final rule published on June 3, 2014 

(‘‘June 2014 ECS final rule’’). 80 FR 

46521 (August 5, 2015). The Working 

Group assembled its recommendations 

into a Term Sheet 5 (Docket EERE–2015– 

BT–STD–0016, No. 56) that was 

presented to, and approved by, ASRAC 

on December 18, 2015 (‘‘Term Sheet’’). 

The Term Sheet provided 

recommendations for energy 

conservation standards to replace 

standards that had been vacated by the 

United States Court of Appeals for the 

Fifth Circuit in a controlling order 

issued August 10, 2015. It also included 

recommendations regarding definitions 

for a number of terms related to the 

WICF regulations, as well as 

recommendations to amend the test 

procedure that the Working Group 

viewed as necessary to properly 

implement the energy conservation 

standards recommendations. 

Consequently, DOE initiated both an 

energy conservation standards 

rulemaking and a test procedure 

rulemaking in 2016 to implement these 


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32334 Federal Register / Vol. 86, No. 115 / Thursday, June 17, 2021 / Proposed Rules 

6 Details of Executing the Test Procedures for 

Refrigeration Systems use in Walk-in Coolers and 

Freezers, available at https://www.regulations.gov/ 

document?D=EERE-2011-BT-TP-0024-0109. 

recommendations. The Term Sheet also 

included recommendations for future 

amendments to the test procedure 

intended to make DOE’s test procedure 

more fully representative of walk-in 

energy use. 

On December 28, 2016, DOE 

published a final rule amending the test 

procedure (‘‘December 2016 TP final 

rule’’), consistent with the Term Sheet 

recommendations and provisions to 

facilitate implementation of energy 

conservation standards for walk-in 

components. 81 FR 95758. 

Subsequently, on July 10, 2017, DOE 

published a final rule amending the 

energy conservation standards for WICF 

refrigeration systems (‘‘July 2017 ECS 

final rule’’). 82 FR 31808. 

To address Term Sheet 

recommendations regarding hot gas 

defrost, DOE published a final rule for 

hot gas defrost unit coolers on March 

26, 2021 (‘‘March 2021 hot gas defrost 

TP final rule’’) that amended the test 

procedure to rate hot gas defrost unit 

coolers using modified default values 

for energy use and heat load 

contributions that would make their 

ratings more consistent with those of 

electric defrost unit coolers. 86 FR 

16027. 

II. Request for Information 

DOE is publishing this RFI to collect 

data and information during the early 

assessment review to inform its 

decision, consistent with its obligations 

under EPCA, as to whether the 

Department should proceed with an 

amended test procedure rulemaking and 

if so, to assist in the development of 

proposed amendments. Accordingly, in 

the following sections, DOE has 

identified specific issues on which it 

seeks input to aid in its analysis of 

whether an amended test procedure for 

walk-in coolers and freezers would 

more accurately or fully comply with 

the requirement that the test procedure 

produces results that measure energy 

use during a representative average use 

cycle for the equipment, and not be 

unduly burdensome to conduct. DOE 

also welcomes comments on other 

issues relevant to its early assessment 

that may not specifically be identified in 

this document. 

A. Scope and Definitions 

This RFI covers equipment meeting 

the ‘‘walk-in cooler and walk-in freezer’’ 

definition codified in 10 CFR 431.302: 

An enclosed storage space refrigerated 

to temperatures (1) above 32 °F for walkin coolers and (2) at or below 32 °F for 

walk-in freezers, that can be walked 

into, and has a total chilled storage area 

of less than 3,000 square feet, but 

excluding equipment designed and 

marketed exclusively for medical, 

scientific, or research purposes. 10 CFR 

431.302. (See also 42 U.S.C. 6311(20)) In 

addition to the prescriptive 

requirements for walk-ins established by 

EPCA (42 U.S.C. 6313(f)(3)(A)–(D)) and 

codified at 10 CFR 431.306(a)–(b), DOE 

established performance-based energy 

conservation standards for doors and 

refrigeration systems. 10 CFR 

431.306(c)–(e). 

1. Walk-In Refrigeration Systems 

DOE is aware of equipment that 

would appear to meet the walk-in 

definition and for which there is no 

current DOE test procedure or energy 

conservation standard. DOE indicated in 

a public meeting on October 22, 2014 

that the WICF test procedures and 

standards did not apply to water-cooled 

condensing units or systems. (Docket 

EERE–2011–BT–TP–0024, No. 109 6 at 

p. 11) DOE notes that the EPCA 

definition for walk-ins makes no 

distinction on how the condenser is 

cooled. (42 U.S.C. 6311(20)(A)) 

The current DOE test procedure for 

walk-in refrigeration systems, which 

incorporates by reference AHRI 1250– 

2009, does not address how to test 

liquid-cooled systems. Additionally, 

liquid-cooled condensing units are 

outside the scope of the most recent 

version of AHRI 1250, AHRI 1250–2020. 

Liquid-cooled condensing units for 

walk-ins are readily available for a wide 

range of capacities and refrigerants from 

major walk-in refrigeration system 

manufacturers. (See for example, 

Airdyne W-series indoor units (watercooled), and Russell (water-cooled, 

glycol-cooled) (see Docket No. EERE– 

2017–BT–TP–0010–0001, Docket No. 

EERE–2017–BT–TP0010–0002, and 

Docket No. EERE–2017–BT–TP–0010– 

0003). 

Issue 1: DOE seeks comment on how 

liquid-cooled refrigeration systems are 

(or could be) used with respect to walkin applications. DOE requests comment 

on whether it should consider 

establishing a test procedure for liquidcooled refrigeration systems. If test 

procedures were considered for liquidcooled refrigeration systems, DOE 

requests information on whether there is 

an industry standard or standards that 

should be considered. 

DOE is considering modifying the 

current equipment class definitions for 

refrigeration systems, which are based 

on walk-in application temperature. In 

the June 2014 ECS final rule, DOE 

established equipment classes for 

medium- and low- temperature walk-in 

refrigeration systems. 79 FR 32050, 

32069–32070. While the terms 

‘‘medium-temperature’’ and ‘‘lowtemperature’’ are not explicitly defined, 

the June 2014 ECS final rule, 2015 

ASRAC negotiations, December 2016 TP 

final rule, and July 2017 ECS final rule 

all consistently used the term ‘‘mediumtemperature’’ to refer to walk-in cooler 

refrigeration systems and the term ‘‘lowtemperature’’ to refer to walk-in freezer 

refrigeration systems. 

Rating conditions are 35 °F for cooler 

systems and ¥10 °F for freezer systems. 

DOE acknowledges that there are 

‘‘medium-temperature’’ systems 

designed to operate between these two 

rating conditions, specifically between 

10 °F and 32 °F. However, the EPCA 

definitions for walk-in freezers and 

walk-in coolers draws the line between 

them at 32 °F, thus classifying such 

refrigeration systems as freezer 

refrigeration systems. DOE is 

considering whether equipment 

definitions and requirements should be 

amended to address these systems, 

which are discussed in detail in Section 

II.E.7. 

Finally, DOE is considering defining 

walk-in wine cellar refrigeration 

systems. These systems are typically 

designed to provide a cold environment 

at a temperature range between 45–65 °F 

with 50–70 percent relative humidity 

(‘‘RH’’), and typically are kept at 55 °F 

and 55 percent RH rather than the 35 °F 

and less than 50 percent RH test 

condition prescribed by the DOE test 

procedure. Operating a wine cellar at 

the 35 °F condition would adversely 

mechanically alter the intended 

performance of the system, which 

would include icing of the evaporator 

coil that could potentially damage the 

compressor, and would not result in an 

accurate representation of the 

performance of the cooling unit. To 

distinguish walk-in wine-cellar 

refrigeration systems from other walk-in 

cooler systems, DOE is considering 

whether to specify 45 °F as the 

minimum temperature at which a walkin wine cellar refrigeration system can 

effectively operate. If DOE were to 

specify a minimum operating 

temperature, DOE would need to 

develop a definition specific for 

products that operate in this 

temperature region. Walk-in wine cellar 

refrigeration systems are discussed in 

more detail in Section II.E.2. 

Issue 2: DOE seeks comment on how 

wine cellar refrigeration systems should 

be defined to best represent the 

conditions under which these systems 


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7 Data from the DOE CCMS database was accessed 

on March 6, 2020. This database can be found at 

http://www.regulations.doe.gov/certification-data/. 

8Unique individual models exclude any 

duplicate entries using the same individual model 

number. 

9 DOE understands that some certified passage 

doors may represent multi-door configurations in 

which the individual component doors each have 

a surface area of less than 32 square feet. 

10National Fenestration Rating Council (‘‘NFRC’’) 

100–2010, ‘‘Procedure for Determining Fenestration 

U-factors’’ (‘‘NFRC 100’’). 

11American Society for Testing and Materials 

(‘‘ASTM’’) C518–04, ‘‘Standard Test Method for 

Steady-State Thermal Transmission Properties by 

Means of the Heat Flow Meter Apparatus’’ (‘‘ASTM 

C518–04’’). 

12American National Standards Institute 

(‘‘ANSI’’)/Air-Conditioning, Heating, and 

Refrigeration Institute (‘‘AHRI’’) Standard 1250P 

(I–P), ‘‘2009 Standard for Performance Rating of 

Walk-In Coolers and Freezers’’ (‘‘AHRI 1250– 

2009’’). 

13AHRI 420–2008, ‘‘Performance Rating of 

Forced-Circulation Free-Delivery Unit Coolers for 

Refrigeration’’ (‘‘AHRI 420–2008’’). 

14ANSI/ASHRAE 23.1–2010, ‘‘Methods of 

Testing for Rating the Performance of Positive 

Displacement Refrigerant Compressors and 

Condensing Units that Operate at Subcritical 

Temperatures of the Refrigerant’’ (‘‘ASHRAE 23.1– 

2010’’). 

are designed to operate and to fully 

distinguish these systems from systems 

designed to meet safe food storage 

requirements. Additionally, DOE 

requests comment on applications other 

than wine cellar storage for refrigeration 

systems that are designed to operate at 

temperatures warmer than typical for 

coolers and for which testing at 35 °F 

would be representative of use. If there 

are such additional applications, DOE 

seeks information regarding the specific 

operating requirements (i.e., 

temperature and humidity) for these 

systems. 

2. Walk-In Doors 

DOE is also reviewing the definitions 

applicable to WICF doors. DOE defines 

a ‘‘door’’ as an assembly installed in an 

opening on an interior or exterior wall 

that is used to allow access or close off 

the opening and that is movable in a 

sliding, pivoting, hinged, or revolving 

manner of movement. For walk-in 

coolers and walk-in freezers, a door 

includes the door panel, glass, framing 

materials, door plug, mullion, and any 

other elements that form the door or 

part of its connection to the wall. 10 

CFR 431.302. DOE is interested in using 

language that is consistent across the 

walk-in door industry to define a door. 

Issue 3: DOE requests comment on the 

current definition of ‘‘door’’ in 10 CFR 

431.302. DOE seeks feedback on the 

terminology of door components used 

and whether these are consistently 

interpreted. DOE seeks specific feedback 

from manufacturers on how they use the 

term ‘‘door plug’’ and whether it is 

essential to the definition of a WICF 

‘‘door’’. 

DOE differentiates WICF doors by 

whether such doors are ‘‘display doors’’ 

or not display doors. A ‘‘display door’’ 

is defined as a door that: (1) Is designed 

for product display; or (2) has 75 

percent or more of its surface area 

composed of glass or another 

transparent material. 10 CFR 431.302. 

WICF doors that are not display doors 

are differentiated according to whether 

they are ‘‘freight doors’’ or ‘‘passage 

doors.’’ A ‘‘freight door’’ is a door that 

is not a display door and is equal to or 

larger than 4 feet wide and 8 feet tall. 

Id. A ‘‘passage door’’ is a door that is not 

a freight or display door. Id. 

The use of dimensions in the 

definition of freight door conveys that 

these doors are intended for large 

machines (e.g., forklifts) to pass through 

carrying freight. However, the definition 

does not explicitly provide whether 

classification as a freight door occurs 

when one of the dimensions exceeds the 

dimension provided in the definition, 

but the other dimension is smaller than 

the dimension provided in the 

definition. For such doors, in some 

cases the surface area could be larger 

than 32 square feet, the area of a 4-foot 

by 8-foot door provided in the definition 

(e.g., a door 5 feet wide and 7 feet tall, 

with a surface area of 35 square feet); in 

other cases, the surface area could be 

smaller than 32 square feet (e.g., a door 

5 feet wide and 6 feet tall, with a surface 

area of 30 square feet). DOE reviewed 

the surface area of certified freight and 

passage doors in DOE’s Compliance 

Certification Management System 

(‘‘CCMS’’) Database.7 Among 1,114 

unique individual models 8 of freight 

doors, 44 unique individual models 

have a surface area less than 32 square 

feet. These models appear to have been 

classified on the understanding that a 

door is a freight door if just one 

dimension is larger than the dimensions 

specified in the freight door definition. 

Among 1,540 unique individual models 

of passage doors, 789 unique individual 

models have a surface area greater than 

or equal to 32 square feet.9 These 

models either are multi-door 

configurations, or they have been 

classified assuming that to be a freight 

door, both dimensions must be equal to 

or exceed the dimensions in the freight 

door definition. DOE further notes that 

the standards for each class of WICF 

doors are a function of surface area, and 

that different standards apply for freight 

doors and passage doors. DOE seeks 

information that would inform any 

potential revision of the door 

definitions, particularly ‘‘freight door’’ 

and ‘‘passage door,’’ to improve their 

clarity and ensure that there is no 

overlap between these definitions. 

Issue 4: DOE requests comment on 

whether height and width or surface 

area are distinct attributes that 

effectively distinguish between passage 

and freight doors. DOE seeks 

information on any building codes, 

standards, or industry practices to 

support or refute maintaining the 

dimensions of a door as the defining 

characteristic which separates freight 

and passage doors. 

Issue 5: Regarding a door that meets 

the freight door definition but does so 

only because it has a multi-door 

configuration in which the individual 

component doors each would by 

themselves not meet the freight door 

definition, DOE seeks comment on how 

such doors should be classified, and 

whether such classification should 

depend on other factors, such as 

whether one or more frame members 

divides the door opening into smaller 

openings. 

Issue 6: DOE seeks comment on 

whether any attribute, or combination of 

attributes, other than size, would affect 

energy use and could be used to 

distinguish between freight doors and 

passage doors. If so, DOE requests data 

and comment on such attributes. 

B. Industry Test Standards 

The current DOE test procedure for 

walk-in coolers and freezers 

incorporates the following industry test 

standards: NFRC 100 10 into Appendix 

A; ASTM C518–04 11 into Appendix B; 

and AHRI 1250–2009 12, AHRI 420– 

2008 13 and ASHRAE 23.1–2010 14 into 

Appendix C. 

1. NFRC 100 and NFRC 102 

Appendix A requires manufacturers 

to determine door thermal transmittance 

according to NFRC 100. See Appendix 

A, Section 5.3. NFRC 100 includes a 

computational method to determine the 

thermal transmittance for a product line 

of doors if simulated results meet the 

validation requirements specified in 

NFRC 100. This approach may be less 

costly but generally may result in a 

higher, more conservative thermal 

transmittance value than the thermal 

transmittance value determined by 

testing each door. Section 4.3.2 of NFRC 

100 provides a method for physically 

testing the thermal transmittance of 

walk-in doors by referencing NFRC 102, 

‘‘Procedure for Measuring the SteadyState Thermal Transmittance of 

Fenestration Systems’’ (‘‘NFRC 102’’). 

DOE is considering explicitly 

incorporating by reference NFRC 102 as 


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15A split-system refrigeration system consists of 

two separate components: A unit cooler that is 

installed inside a walk-in enclosure, and a 

condensing unit, which is installed outside the 

enclosure, either inside a building in which the 

walk-in is constructed, or outdoors. 

the test method for determining the 

thermal transmittance of walk-in doors 

in place of NFRC 100 and adopting 

AEDM provisions for walk-in display 

and non-display doors to replace the 

computational methodology in NFRC 

100. 

Issue 7: DOE requests comment on the 

accuracy of the computational method 

in NFRC 100 to predict 

U-factor for display and non-display 

doors. DOE seeks feedback regarding the 

differences in results (if any) between 

those obtained using the NFRC 100 

computational method and those 

obtained when conducting physical 

testing using NFRC 102 for display and 

non-display doors. DOE is also 

interested in the magnitude of these 

differences and whether the 

computational method can be modified 

to yield results that more closely match 

the results obtained from actual 

physical testing. If manufacturers are 

aware of other methods to predict 

U-factor for either display doors or nondisplay doors besides NFRC 100, DOE 

requests how the results from these 

methods compare to physical testing. 

Issue 8: DOE seeks information from 

manufacturers and other interested 

parties regarding how the industry 

currently rates individual door models, 

including the prevalence within the 

industry of using the computational 

method from NFRC 100. DOE also 

requests information on the costs 

associated with the computational 

method of NFRC 100 or an alternative 

computational method compared to 

physically testing the thermal 

transmittance of walk-in doors using 

NFRC 102. 

2. ASTM C518 

Currently, section 4.2 of Appendix B 

references ASTM C518 to determine the 

thermal conductivity of panel insulation 

(the ‘‘K factor’’). EPCA requires that the 

measurement of the K factor used to 

calculate the R-value ‘‘be based on 

ASTM test procedure C518–2004.’’ (42 

U.S.C. 6314(a)(9)(A)(ii)) In December 

2015, ASTM published a revision of this 

standard (‘‘ASTM C518–15’’). ASTM 

C518–15 removed references to ASTM 

Standard C1363, ‘‘Test Method for 

Thermal Performance of Building 

Materials and Envelope Assemblies by 

Means of a Hot Box Apparatus’’ 

(‘‘ASTM C1363’’), and added references 

to ASTM Standard E456, ‘‘Terminology 

Relating to Quality and Statistics’’. 

Additionally, ASTM C518–15 relies 

solely on the International System of 

Units (‘‘SI units’’), with paragraph 1.13 

clarifying that these SI unit values are 

to be regarded as standard. 

In July 2017, ASTM published 

another revision of ASTM C518 

(‘‘ASTM C518–17’’). ASTM C518–17 

added a summary of precision statistics 

from an interlaboratory study from 

2002–2004 in section 10 ‘‘Precision and 

Bias’’. DOE has initially determined that 

the changes made in 2015 and 2017 to 

ASTM C518 do not substantively 

change the test method and, therefore, 

DOE is considering specifying ASTM 

C518–17 as the referenced test 

procedure in Appendix B. If DOE makes 

this change as part of a test procedure 

rulemaking, it would also consider any 

changes necessary to ensure rounding 

consistency when converting the output 

of ASTM C518–17 from SI units to 

English units. 

Issue 9: DOE requests comment on 

what issues, if any, would be present if 

ASTM C518–17 were to be referenced in 

the Appendix B test procedure for 

measuring panel K-factor, or average 

thermal conductivity. While not 

exhaustive, primary areas of interest to 

DOE include any differences between 

the currently referenced version of the 

industry standard (ASTM C518–04) and 

ASTM C518–17 that would result in a 

difference in the determined R-value 

and/or test burden (whether an increase 

or decrease), and if there are such 

differences, the magnitude of impact to 

the determined R-value and/or test 

burden. 

3. AHRI 1250 

The current DOE test procedures for 

walk-in refrigeration systems 

incorporate by reference AHRI 1250– 

2009. 10 CFR 431.303(b)(2). AHRI 1250– 

2009 provides test methods for 

determination of performance for 

matched pair refrigeration systems 

consisting of a unit cooler and a 

condensing unit, or for the individual 

unit cooler or condensing unit alone.15

In 2014, AHRI published a revision to 

this standard (‘‘AHRI 1250–2014’’). 

AHRI 1250–2014 primarily aligned the 

test standard for consistency with the 

DOE test procedure, e.g. specifying that 

unit coolers be tested using 25 °F 

saturated suction temperature for 

refrigerator unit coolers and ¥20 °F for 

freezer unit coolers. 

AHRI again published a revision to 

the standard in April 2020 (‘‘AHRI 

1250–2020’’). AHRI 1250–2020 includes 

many updates, including (a) providing 

complete instructions for testing of unit 

coolers alone instead of incorporating 

by reference AHRI 420, (b) providing 

complete instructions for testing of 

condensing units alone instead of 

incorporating by reference ASHRAE 

23.1–2010, (c) revision of instrument 

accuracy and test tolerances, (d) adding 

test methods for testing of singlepackage systems, (e) modified 

correlations for default evaporator fan 

power, defrost thermal load, and defrost 

energy use for use when testing 

condensing units alone, (f) correlations 

for defrost thermal load and energy use 

for use when testing hot gas defrost 

systems, (g) measurement of all relevant 

off-cycle energy use, including 

compressor crankcase heater energy use, 

and (h) methods to verify whether a 

refrigeration system has hot gas defrost 

and/or adaptive defrost capabilities. 

DOE may consider incorporating by 

reference AHRI 1250–2020 as the test 

method for walk-in refrigeration 

systems. 

Issue 10: DOE requests comment on 

what issues, if any, would be present if 

AHRI 1250–2020 were to be referenced 

in the Appendix C test procedure for 

measuring walk-in refrigeration system 

AWEF. While not exhaustive, primary 

areas of interest to DOE include any 

differences between the currently 

referenced version of the industry 

standard (AHRI 1250–2009) and AHRI 

1250–2020 that would result in a 

difference in the determined AWEF 

and/or test burden (whether an increase 

or decrease), and if there are such 

differences, the magnitude of impact to 

the determined AWEF and/or test 

burden. 

C. Test Procedure for Walk-In Doors 

In the following subsections, DOE 

discusses several topics specific to 

walk-in doors that may affect the test 

procedure’s ability to provide results 

that are more fully representative of 

walk-in door energy use during an 

average use cycle. In particular, the 

discussion focuses on: (a) The 

distinction between the surface area 

used for determining maximum energy 

consumption and the surface area used 

to calculate thermal transmittance; (b) 

walk-in door electrical components, 

such as motors, that may require 

specific consideration in the test 

procedure; (c) assumptions of 

refrigeration system energy efficiency 

ratio (‘‘EER’’) for calculating energy use 

associated with the thermal loads of 

walk-in doors; (d) calibrations of the hot 

box used for determining thermal 

transmittance (also referred to as ‘‘Ufactor’’); (e) maintaining tolerances on 

heat transfer coefficients for U-factor 

tests; and (f) measuring and accounting 

for air infiltration. 


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16As mentioned previously, NFRC 100 references 

NFRC 102 for determining U-factor through 

physical testing. NFRC 102 is based on American 

Society for Testing and Materials (‘‘ASTM’’) C1199– 

09, ‘‘Standard Test Method for Measuring the 

Steady-State Thermal Transmittance of Fenestration 

Systems Using Hot Box Methods’’ (‘‘ASTM C1199– 

09’’) with some modifications. 

1. Surface Area Used for Determining 

Compliance With Standards 

The surface area of display doors and 

non-display doors (designated as Add

and And, respectively) are used to 

determine maximum energy 

consumption in kWh/day of a walk-in 

door. 10 CFR 431.306(c)–(d). Surface 

area is defined in Appendix A as ‘‘the 

area of the surface of the walk-in 

component that would be external to the 

walk-in cooler or walk-in freezer as 

appropriate.’’ Appendix A, Section 3.4. 

DOE recognizes that this definition may 

benefit from additional detail. As 

currently written, the definition does 

not provide detail on how to determine 

the boundaries of the walk-in door from 

which height and width are determined 

to calculate surface area. Additionally, 

the definition does not specify if these 

measurements are to be strictly in-plane 

with the surface of the wall or panel that 

the walk-in door would be affixed to, or 

if troughs and other design features on 

the exterior surface of the walk-in door 

should be included in the surface area. 

Inconsistent determination of surface 

area, specifically with respect to the 

measurement boundaries, may result in 

unrepresentative maximum energy 

consumption. Display doors are 

fundamentally different from nondisplay doors in terms of their overall 

construction. For example, display door 

assemblies contain a larger frame 

encompassing multiple door openings; 

the entire assembly fits into an opening 

within a walk-in wall. Non-display 

doors differ in that they often are affixed 

to a panel-like structure that more 

closely resembles a walk-in wall rather 

than a traditional door frame. For the 

purposes of determining compliance 

with the standards, DOE interprets the 

surface area as the product of the height 

and width measurements of the door 

made external to the walk-in, where the 

height and width measurements are the 

maximum edge-to-edge dimensions of 

the door measured perpendicular to 

each other and parallel to the wall or 

panel of the walk-in to which the door 

is affixed. In applying this approach, 

DOE views the height and width 

measurements of display doors to 

include the frame and frame flange that 

overlaps the external edge of the WICF 

panel. For non-display doors, DOE 

views the height and width 

measurements to include only the 

swinging or sliding portion of the door 

and not the door frame or any localized 

appendages such as hinges or hanging 

rails and brackets. DOE seeks feedback 

on its interpretation of surface area for 

both display and non-display doors. 

DOE is also interested in feedback on 

whether additional detail is needed 

regarding the surface area for both nondisplay doors and display doors, and if 

so, what further detail should be 

provided. 

Issue 11: DOE requests comment on 

how manufacturers determine surface 

area for the purpose of evaluating 

compliance with the standards for both 

display doors and non-display doors. 

DOE seeks input on any distinction 

between display doors and non-display 

doors, especially the door frames, which 

may warrant surface area for each to be 

determined differently. 

Additionally, walk-in doors with 

antisweat heaters are subject to 

prescriptive standards for power use of 

antisweat heaters per square foot of door 

opening. 10 CFR 431.306(b)(3)–(4). 

Although ‘‘door opening’’ is not 

defined, DOE considers the relevant 

area for determining ‘‘power use per 

square foot of door opening’’ to be 

consistent with the surface area used to 

determine maximum energy 

consumption. 

Issue 12: DOE seeks feedback on how 

manufacturers interpret and measure 

door opening as it relates to prescriptive 

standards for antisweat heaters, 

including whether or not manufacturers 

agree that the door opening considered 

for antisweat heat should be consistent 

with the surface area used to determine 

maximum energy consumption. 

2. Thermal Transmittance Area 

Currently, equations 4–19 and 4–28 of 

Appendix A specify that surface area, as 

defined in section 3.4 of Appendix A, of 

display doors and non-display doors, 

respectively, are used to convert a 

door’s U-factor into a conduction load. 

This conduction load represents the 

amount of heat that transfers from the 

exterior to the interior of the walk-in. 

Based on recent review of the test 

procedure, DOE has identified that this 

defined surface area is inconsistent with 

the referenced industry test procedures 

for determining U-factor. 

As stated previously, Appendix A 

references NFRC 100 for the 

determination of U-factor. When 

conducting physical testing,16 U-factor 

(Us) is calculated using projected surface 

area (As). ASTM C1199–09, Section 

8.1.3. As is defined as ‘‘the projected 

area of test specimen (same as test 

specimen aperture in surround panel)’’. 

ASTM C1199–09, Section 3.3. This area 

differs from the currently defined areas 

(Add and And) in Appendix A. See 

Appendix A, Section 3.4. DOE is 

considering whether the surface area 

used in calculating the conduction load 

in Equations 4–19 and 4–28 of 

Appendix A should be the same surface 

area used to determine Us to provide 

greater consistency with the NFRC 100 

definition of U-factor: ‘‘The U-factor 

multiplied by the interior-exterior 

temperature difference and by the 

projected fenestration product area 

yields the total heat transfer through the 

fenestration product.’’ 

Issue 13: DOE requests feedback on 

specifying the surface area used to 

determine thermal conduction through a 

walk-in door from the surface area used 

to determine the maximum energy 

consumption of a walk-in door. 

3. Electrical Door Components 

Sections 4.4.2 and 4.5.2 of Appendix 

A include provisions for calculating the 

direct energy consumption of electrical 

components of display doors and nondisplay doors, respectively. For 

example, electrical components 

associated with doors could include, but 

are not limited to: Heater wire (for antisweat or anti-freeze application); lights 

(including display door lighting 

systems); control system units; and 

sensors. See Appendix A, Sections 4.4.2 

and 4.5.2. For each electricityconsuming component, the calculation 

of energy consumption is based on the 

component’s ‘‘rated power’’ rather than 

an actual measurement of its power 

draw. Section 3.5 of Appendix A 

defines ‘‘rated power’’ as the electricity 

consuming device’s power as specified 

on the device’s nameplate, or from the 

device’s product data sheet if the device 

does not have a nameplate or such 

nameplate does not list the device’s 

power. 

DOE has observed that walk-in doors 

often provide a single nameplate for the 

door, rather than providing individual 

nameplates for each electricityconsuming device. In many cases, the 

nameplate does not provide separate 

power information for the different 

electrical components. Also, the 

nameplate often specifies voltage and 

amperage (a measure of current) ratings 

without providing wattage (a measure of 

power) ratings, as is referenced by the 

definition of ‘‘rated power’’. While the 

wattage is equal to voltage multiplied by 

the current for many components, this 

may not be true of all components that 

may be part of a walk-in door assembly. 

Furthermore, nameplate labels typically 

do not specify whether any listed values 

of rated power or amperage represent 


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17PTO values are applied in order to reflect the 

hours in a day that an electricity-consuming device 

operates at its full rated or certified power (i.e., 

daily component energy use is calculated assuming 

that the component operates at it rated power for 

a number of hours equal to 24 multiplied by (1– 

PTO)). PTO should not be incorporated into the 

rated or certified power of an electricity-consuming 

device. 

18By letters dated July 26, 2017, December 21, 

2017, March 13, 2020, and June 5, 2020, Jamison 

Door Company, HH Technologies, Senneca 

Holdings, and Hercules, respectively, submitted 

petitions for waivers and interim waivers for basic 

models of motorized walk-in doors, requesting the 

use of alternate PTO values. (Jamison, EERE–2017– 

BT–WAV–0040, No. 2 at p. 2; HH Technologies, 

EERE–2018–BT–WAV–0001, No. 1 at p. 2; Senneca 

Holdings, EERE–2020–BT–WAV–0009, No. 3 at p. 

3; Hercules, EERE–2020–BT–WAV–0027, No. 2 at p. 

3). 

the maximum operation conditions or 

continuous steady-state operating 

conditions, which could differ for 

components such as motors that 

experience an initial surge in power 

before leveling off at a lower power 

level. These issues make calculating a 

door’s total energy consumption 

challenging when a test facility does not 

have in-depth knowledge of the 

electrical characteristics of the door 

components. 

DOE is considering whether there 

may be value in adding an option for 

direct measurement of door component 

electrical power, either as part of the 

test procedure for manufacturers 

wishing to make direct measurements, 

or for DOE testing, as an alternative to 

using the nameplate value. DOE seeks 

comment on issues that should be 

considered were DOE to develop 

requirements for such measurements, 

such as any additional instrumentation 

or test conditions that would be 

required. 

Issue 14: DOE seeks comment on 

whether, and if so how, an option for 

direct component power measurement 

could be included in the test procedure 

or compliance, certification, and 

enforcement (‘‘CCE’’) provisions to 

allow more accurate accounting for the 

direct electrical energy consumption of 

WICF doors. DOE also seeks input on 

whether specific provisions should be 

provided for determining power input 

from the information that is typically 

provided on nameplates, noting the 

limitations that were described above. 

As stated previously, Appendix A 

accounts for the energy consumption of 

various electrical components, 

including lights, sensors, anti-sweat 

heater wire, and other miscellaneous 

electrical devices. The test procedure 

assigns percent time off (‘‘PTO’’) values 

to various walk-in door components.17

Table II.1 lists the PTO values in the 

DOE test procedure for walk-in doors. 

This method provides a means to 

compare walk-in door performance 

while limiting the test burden on 

manufacturers. 

TABLE II.1—ASSIGNED PTO VALUES FOR WALK-IN DOOR COMPONENTS

Component type 

Percent time 

off 

(PTO) % 

Lights without timers, control system or other demand-based control ............................................................................................... 25 

Lights with timers, control system or other demand-based control .................................................................................................... 50 

Anti-sweat heaters without timers, control system or other demand-based control ........................................................................... 0 

Anti-sweat heaters on walk-in cooler doors with timers, control system or other demand-based control ......................................... 75 

Anti-sweat heaters on walk-in freezer doors with timers, control system or other demand-based control ........................................ 50 

All other electricity consuming devices without timers, control systems, or other auto-shut-off systems .......................................... 0 

All other electricity consuming devices for which it can be demonstrated that the device is controlled by a preinstalled timer,

control system or other auto- shut-off system ................................................................................................................................. 25 

DOE has received several petitions for 

waivers and interim waivers with regard 

to the PTO used for doors with 

motorized door openers.18 These 

manufacturers stated that the test 

procedure for walk-in doors overstates 

the energy consumption of motorized 

doors because the applicable PTO value 

prescribed in the test procedure is not 

representative of the actual energy use 

of the motorized doors used in these 

applications. Under the current test 

procedure, motorized door openers 

would be considered ‘‘other electricityconsuming devices,’’ with PTO values 

of either 0 percent or 25 percent. See 

Appendix A, Sections 4.4.2(a)(3) and 

4.5.2(a)(3). Based on the characteristics 

of its doors, each manufacturer 

requested a different PTO value (shown 

in Table II.2) to be applied to its basic 

models. After reviewing the 

performance data, equipment 

characteristics, and door-opening 

frequency assumptions presented by 

door manufacturers, and after soliciting 

and reviewing feedback from the public, 

DOE granted waivers to the 

manufacturers shown in Table II.2. 

TABLE II.2—PTO VALUES GRANTED IN DECISION AND ORDERS FOR MANUFACTURERS OF DOORS WITH MOTORIZED

DOOR OPENERS

Manufacturer 

Percent time 

off 

(PTO) % 

Decision and order Federal 

Register citation 

HH Technologies ............................................................................................................................ 96 83 FR 53457. (Oct. 23, 2018). 

Jamison Door Company ................................................................................................................. 93.5 83 FR 53460. (Oct. 23, 2018). 

Senneca Holdings .......................................................................................................................... 97 86 FR 75. (Jan. 4, 2021). 

Hercules ......................................................................................................................................... 92 86 FR 17801. (Apr. 6, 2021). 

DOE is reviewing the test procedure’s 

current PTO values and is interested in 

establishing standard PTO values for 

motorized door openers as well as any 

other electricity-consuming devices that 

would warrant PTOs different from 

those currently in Appendix A, also 

listed in Table II.1 of this document. 

DOE seeks information regarding how 

closely these values represent actual 

PTO values experienced in the field. In 

addition to motorized door openers, 


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19This data from the DOE CCMS database was 

accessed on March 17, 2021. This database can be 

found at http://www.regulations.doe.gov/ 

certification-data/. 

20The difference in EER values between coolers 

and freezers reflects the relative efficiency of the 

refrigeration equipment for the associated 

application. 75 FR 186, 197. As the temperature of 

the air surrounding the evaporator coil drops (that 

is, when considering a freezer relative to a cooler), 

thermodynamics dictates that the system 

effectiveness at removing heat per unit of electrical 

input energy decreases. Id. 

21The dewpoint temperature to be used for 

testing unit coolers alone is defined in section 3.3.1 

of Appendix C to be the Suction A saturation 

condition provided in Tables 15 or 16 of Appendix 

C (for refrigerator unit coolers and freezer unit 

coolers, respectively). Table 15 for refrigerator unit 

coolers defines the Suction A saturation condition 

(i.e., dewpoint temperature) as 25 °F. Table 16 for 

freezer unit coolers defines the Suction A dewpoint 

temperature as ¥20 °F. Furthermore, section 7.9.1 

of AHRI 1250–2009 specifies that for unit coolers 

rated at a suction dewpoint other than 19 °F for a 

refrigerator and ¥26 °F for a freezer, the Adjusted 

Dewpoint Value shall be 2 °F less than the unit 

cooler rating suction dewpoint—resulting in 

adjusted dewpoint values of 23 °F and ¥22 °F for 

refrigerator unit coolers and freezer unit coolers, 

respectively. 

DOE is also investigating whether any 

additional walk-in door electrical 

components, such as heated air vents 

and heated thresholds, would warrant 

the use of specific PTO values when 

calculating door energy use. 

Issue 15: DOE requests comment on 

the current PTO values and whether 

DOE should consider amending any of 

the current values or adding specific 

values for additional electrical 

components, specifically motorized 

door openers. DOE requests data from 

field studies or similar sources to 

support any proposed amendments (or 

additions) to these PTO values. 

DOE is aware that some 

manufacturers design and market walkin cooler display doors for high 

humidity applications. Ratings from the 

CCMS database 19 show these doors 

have more anti-sweat heater power per 

door opening area than standard cooler 

display doors. The average power use 

per door opening area for high humidity 

cooler doors is 1.66 W/ft2, while the 

average power use for cooler doors not 

marketed for high humidity applications 

made by the same manufacturers who 

produce the high humidity doors is 1.01 

W/ft2. Section 4.4.2(a)(2) of Appendix A 

requires a PTO value of 50 percent be 

used when determining the direct 

energy consumption for anti-sweat 

heaters with timers, control systems, or 

other demand-based controls situated 

within a walk-in cooler door (which 

would include walk-in cooler doors 

marketed for high humidity 

applications). This approach assumes 

that the anti-sweat heaters are not 

operating for 50 percent of the time. 

DOE recognizes that anti-sweat heaters 

may be in operation for a different 

amount of time in high humidity 

installations than in standard 

installations. 

Issue 16: DOE seeks feedback on 

whether the current PTO of 50 percent 

is appropriate for evaluating direct 

energy consumption of anti-sweat 

heaters with controls for walk-in cooler 

doors marketed for high humidity 

applications. DOE seeks feedback on the 

average amount of time per day or per 

year that anti-sweat heaters with 

controls are off for these high humidity 

doors and how this compares to 

standard (i.e., non-high humidity) walkin cooler display doors. 

4. EER Values To Convert Thermal Load 

to Energy Consumption 

To calculate the daily energy 

consumption associated with heat loss 

through a walk-in door, Appendix A 

requires dividing the calculated heat 

loss rate by specified EER values of 12.4 

Btu per Watt-hour (‘‘Btu/(W-h)’’) for 

coolers and 6.3 Btu/(W-h) for freezers. 

Appendix A, Sections 4.4.4(a) and 

4.5.4(a). DOE adopted these EER values 

in a final rule published April 15, 2011. 

76 FR 21580, 21586, 21594 (‘‘April 2011 

TP final rule’’). As explained in a notice 

of proposed rulemaking (‘‘NOPR’’) 

leading to this final rule, DOE defined 

nominal EER values because an 

envelope component manufacturer 

cannot control what refrigeration 

equipment is installed, and the defined 

EER value is intended to provide a 

nominal means of comparison rather 

than reflect an actual walk-in 

installation. 75 FR 186, 197 (January 4, 

2010) (‘‘January 2010 TP NOPR’’). DOE 

selected EER values of 12.4 Btu/(W-h) 

for coolers and 6.3 Btu/(W-h) for 

freezers because these are typical EER 

values of walk-in cooler and walk-in 

freezer refrigeration systems, 

respectively.20 75 FR 186, 209. 

The DOE test procedure also assigns 

nominal EER values when testing the 

refrigeration systems of walk-in unit 

coolers alone. When testing a unit 

cooler alone, the energy use attributed 

to the condensing unit is represented by 

a default value determined using the 

representative EER value specified for 

the appropriate ‘‘adjusted’’ dew point 

temperature in Table 17 of AHRI 1250– 

2009.21 The resulting EER values for 

unit coolers tested alone are 13.3 Btu/ 

(W-h) for coolers and 6.6 Btu/(W-h) for 

freezers, which are different than the 

EER values of 12.4 and 6.3, respectively, 

applied to walk-in doors, as described 

above. DOE notes that based on Table 17 

of AHRI 1250–2009, EER values of 12.4 

and 6.3 correspond to Adjusted 

Dewpoint Values of 19 °F for a 

refrigerator and ¥26 °F for a freezer (in 

contrast to Adjusted Dewpoint Values of 

23 °F and ¥22 °F for unit cooler 

refrigerators and freezers, respectively, 

tested alone as defined in Table 15 and 

Table 16 of AHRI 1250–2009 and 

subtracting 2 °F as specified in section 

7.9.1 of AHRI 1250–2009). 

DOE is considering whether to make 

the EER values used to calculate the 

energy consumption of walk-in doors 

consistent with the values used to 

calculate unit cooler energy 

consumption and whether such a 

change would provide a more accurate 

representation of the energy use of walkins. 

Issue 17: DOE seeks feedback on the 

current EER values specified in 

Appendix A used to calculate daily 

energy consumption for walk-in doors 

and the values used in testing of unit 

coolers alone, as specified in Appendix 

C. Specifically, DOE requests comment 

on which of these sets of EER values is 

more representative, whether DOE 

should make the values used for door 

testing and unit cooler testing consistent 

with each other, and if so, which of the 

sets of values should be used. 

5. Thermal Transmittance 

a. Calibration of Hot Box for Measuring 

U-factor 

As stated previously, NFRC 100 

references NFRC 102 as the physical test 

method for measuring U-factor, which 

in turn incorporates by reference ASTM 

C1199. ASTM C1199 references ASTM 

C1363–05, ‘‘Standard Test Method for 

Thermal Performance of Building 

Materials and Envelope Assemblies by 

Means of a Hot Box Apparatus’’ 

(‘‘ASTM C1363’’). Section 6.1 of ASTM 

C1199 and Annexes 5 and 6 of ASTM 

C1363 include calibration requirements 

to characterize metering box wall loss 

and surround panel flanking loss, but 

the frequency at which these 

calibrations should occur is not 

specified in these test standards. DOE 

notes that ASHRAE Standard 16–2016, 

‘‘Method of Testing for Rating Room Air 

Conditioners and Packaged Terminal 

Air Conditioners’’ (‘‘ASHRAE 16– 

2016’’), which is the test method 

incorporated by reference in the DOE 

test procedure for room air conditioners 

(10 CFR 430.3(g)(1)), uses in its 

determination of air conditioner 

capacity a value for heat loss through 

the partition wall based on prior 

calibration of the wall’s heat loss. 

Conceptually, this use of a calibrated 

heat loss value is similar to the use of 

calibrated thermal losses in ASTM 

C1199 and ASTM C1363. DOE notes 


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further that section 6.1.2.2 of ASHRAE 

16–2016 includes a requirement to 

calibrate the partition wall thermal loss 

at least every two years. DOE is 

interested in feedback on the frequency 

of calibration and how recalibrations are 

performed for test facilities using test 

standard ASTM C1199. 

Issue 18: DOE requests comment on 

how frequently test laboratories perform 

each of the calibration procedures 

referenced in ASTM C1199 and ASTM 

C1363, e.g., those used to determine 

calibration coefficients that are used to 

calculate metering box wall loss and 

surround panel flanking loss. DOE also 

requests comment on the magnitude of 

variation in the calibration coefficients 

measured during successive 

calibrations. 

b. Tolerances of Surface Heat Transfer 

Coefficients 

Section 6 of ASTM C1199 specifies 

the standardized heat transfer 

coefficients and their tolerances as part 

of the procedure to set the surface heat 

transfer conditions of the test facility 

using the Calibration Transfer Standard 

(‘‘CTS’’) test. The warm-side surface 

heat transfer coefficient must be within 

± 5 percent of the standardized warmside value, and the cold-side surface 

heat transfer coefficient must be within 

± 10 percent of the standardized coldside value (ASTM C1199–09, sections 

6.2.3 and 6.2.4). ASTM C1199 does not 

require that the measured surface heat 

transfer coefficients match or be within 

a certain tolerance of standardized 

values during sample testing—although 

test facility operational (e.g., cold side 

fan settings) condition would remain 

identical to those set during the CTS 

test. On the other hand, Appendix A 

states in section 5.3(a)(1) that the 

average surface heat transfer coefficient 

on the cold-side of the apparatus shall 

be 30 Watts per square-meter-Kelvin ± 5 

percent and that the average surface 

heat transfer coefficient on the warmside of the apparatus shall be 7.7 Watts 

per square-meter-Kelvin ± 5 percent. 

DOE originally proposed the heat 

transfer values and their associated 

tolerances in a supplemental notice of 

proposed rulemaking (‘‘SNOPR’’) 

published February 20, 2014 (‘‘February 

2014 AEDM TP SNOPR’’). 79 FR 9818, 

9837, 9847. DOE did not receive any 

comments from interested parties 

specific to the proposed tolerance of ±5 

percent for both the cold-side and 

warm-side heat transfer coefficients, and 

finalized these values in a final rule 

published on May 13, 2014 (‘‘May 2014 

AEDM TP final rule’’). 79 FR 27388, 

27415. 

DOE has found that meeting the 

standardized heat transfer values within 

specified tolerances in section 5.3(a)(1) 

of Appendix A on the warm-side and 

cold-side may not be achievable 

depending on the thermal transmittance 

through the door. Specifically, the 

warm-side heat transfer is dominated by 

natural convection and radiation and 

the heat transfer coefficient varies as a 

function of surface temperature. When 

testing doors with higher thermal 

resistance, less heat is transferred across 

the door from the warm-side to the coldside, so the warm-side surface 

temperature is closer to the warm-side 

air temperature. However, the CTS 

method in ASTM C1199 does not 

require measurement of the warm-side 

surface temperature of the door. Rather, 

this value is calculated based on the 

radiative and convective heat flows 

from the test specimen’s surface to the 

surroundings, which are driven by 

values determined from the calibration 

of the hot box (e.g., the convection 

coefficient). See ASTM C1199, Section 

9.2.1. When testing doors with 

extremely high- or low-thermal 

resistance, the resulting change in 

warm-side surface temperature can shift 

the warm-side heat transfer coefficient 

out of tolerance. The only way to adjust 

these coefficients to be within tolerance 

would be to recalibrate the hot box for 

a specific door, which would be 

burdensome and somewhat 

unpredictable. 

Issue 19: DOE requests feedback on 

whether the tolerances in section 

5.3(a)(1) of Appendix A applied to the 

surface heat transfer coefficients used to 

measure thermal transmittance are 

achievable for all walk-in doors and if 

not, whether the tolerances should be 

increased or omitted. Specifically, DOE 

seeks data to support any changes to the 

tolerances on the surface heat transfer 

coefficients. 

6. Air Infiltration Reduction 

EPCA includes prescriptive 

requirements for doors used in walk-in 

applications, which are intended to 

reduce air infiltration. Specifically, 

walk-ins must have (A) automatic door 

closers that firmly close all walk-in 

doors that have been closed to within 1 

inch of full closure (excluding doors 

wider than 3 feet 9 inches or taller than 

7 feet), and (B) strip doors, springhinged doors, or other method of 

minimizing infiltration when doors are 

open. 42 U.S.C. 6313(f)(1)(A)–(B). In the 

January 2010 TP NOPR and an SNOPR 

published on September 9, 2010 

(‘‘September 2010 TP SNOPR’’), DOE 

proposed methods for determining the 

thermal energy leakage due to steadystate infiltration through the seals of a 

closed door and door opening 

infiltration. 75 FR 186, 214–216 and 75 

FR 55068, 55107–55108. However, the 

April 2011 TP final rule did not include 

these methods because DOE concluded 

that steady-state infiltration was 

primarily influenced by on-site 

assembly practices rather than the 

performance of individual components. 

76 FR 21580, 21594–21595. Similarly, 

DOE stated that, based on its experience 

with the door manufacturing industry, 

door opening infiltration is primarily 

reduced by incorporating a separate 

infiltration reduction device at the 

assembly stage of the complete walk-in. 

Id. 

In this RFI, DOE is re-considering 

whether a method for measuring 

infiltration, specifically door opening 

infiltration, as well as a method to 

measure the impacts from technologies 

that reduce infiltration (e.g. fast-acting 

doors or air curtains), would improve on 

the current test procedure’s accuracy 

and ability to produce results reflecting 

a given walk-in door’s energy efficiency 

during a representative average use 

cycle, while not being unduly 

burdensome to conduct. Certain types of 

doors, like fast-acting doors, may have 

higher thermal transmittance, but may 

compensate for that factor by reducing 

infiltration from door openings— 

thereby, reducing a walk-in’s overall 

energy use. DOE is considering how it 

may account for these types of doors in 

the walk-in test procedure. 

In the January 2010 TP NOPR, DOE 

proposed to require that the thermal 

load from air infiltration associated with 

each door opening event be calculated 

using an analytical method based on 

equations published in the ASHRAE 

Refrigeration Handbook in combination 

with assumed values for door-opening 

frequency and duration. That proposed 

method would have accounted for the 

presence of infiltration reduction 

devices by discounting the thermal load 

from door opening air infiltration by the 

effectiveness of the air infiltration 

device. 75 FR 186, 196–197, 214–216. In 

order to determine the effectiveness of 

an infiltration reduction device, DOE 

proposed a two-part test that entailed 

measuring the concentration of tracer 

gas after a door opening event with and 

without the infiltration reduction device 

in place. Id. DOE proposed to use this 

effectiveness test for every unique doordevice combination offered by a 

manufacturer. Id. 

In the September 2010 TP SNOPR, 

DOE proposed a method for determining 

the thermal load associated with steadystate infiltration through walk-in doors. 

75 FR 55068, 55084–55085, and 55107– 


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22 DOE proposed a small size door as 48 inches 

±0.5 inch wide and 84 inches ±0.5 inch high, a 

medium size door as 96 inches ±0.5 inch wide and 

144 inches ±0.5 inch high, and a large size door as 

144 inches ±0.5 inch wide and 180 inches ±0.5 inch 

high. 75 FR 55068, 55107. 

23ASTM C518 uses ‘‘specimen’’ to refer to the 

piece of insulation that is cut to size for testing, 

while the CFR uses ‘‘sample’’. The discussion in 

this document is using ‘‘specimen’’ for consistency 

with the industry test standard. 

24Maintaining a flatness tolerance means that no 

part of a given surface is more distant than the 

tolerance from the ‘‘best-fit perfectly flat plane’’ 

representing the surface. Maintaining parallelism 

tolerance means that the range of distances between 

the best-fit perfectly flat planes representing the two 

surfaces is no more than twice the tolerance (e.g., 

for square surfaces, the distance between the most 

distant corners of the perfectly flat planes minus the 

distance between the closest corners is no more 

than twice the tolerance). 

55108. For each door type with identical 

construction and only differences in 

dimensional size, DOE proposed to 

require calculating steady-state 

infiltration according to NFRC 400– 

2010–E0A1 (‘‘Procedure for Determining 

Fenestration Product Air Leakage’’) by 

testing three representative doors, one 

each of a ‘‘small,’’ ‘‘medium,’’ and 

‘‘large’’ size.22 Id. The steady-state 

infiltration from the representative 

doors would then be extrapolated or 

interpolated, as appropriate, to other 

doors that have the same construction. 

Id. 

As noted, DOE is considering how to 

credit doors with infiltration-reducing 

features that reduce overall walk-in 

energy use and that are in addition to 

the prescriptive requirements mandated 

by EPCA. In doing so, DOE may 

consider a revised version of one of its 

previous proposals related to door 

infiltration, or offer a new method for 

determining heat load associated with 

infiltration. 

DOE requests comment on whether it 

should account for steady-state and/or 

door opening infiltration in its test 

procedure—and if so, why; and if not, 

why not. With respect to suggestions for 

potential test methods, DOE is 

particularly interested in 

recommendations regarding test 

methods and calculation methods used 

by the industry to quantify heat load 

from infiltration. With respect to each of 

these methods, DOE seeks supporting 

information regarding the necessary 

costs in carrying them out. DOE seeks 

information and data on whether testing 

results obtained under any of the 

methods could be used to interpolate 

the load resulting from air infiltration of 

other door sizes in a product line. DOE 

also requests information on door usage 

patterns per door type (e.g., display 

doors, passage doors, motorized doors, 

and fast-acting doors), including any 

supporting data from research or field 

studies. 

D. Test Procedure for Walk-In Panels 

In the following subsections, DOE 

presents several topics specific to walkin panels that, if adopted, may improve 

the current test procedure’s ability to 

provide results that more accurately 

depict walk-in panel energy use during 

a representative average use cycle 

without causing the test procedure to 

become unduly burdensome to conduct. 

That test procedure, found in 10 CFR 

part 431, subpart R, appendix B, 

provides a detailed method by which to 

measure the energy efficiency of a given 

panel used in the construction of a 

walk-in. Since publication of the 

December 2016 TP final rule, DOE has 

identified the potential need to provide 

additional clarification to Appendix B 

regarding the measurement of the 

thickness of walk-in panels (see Section 

II.D.1 of this document) and the 

procedure for determining parallelism 

and flatness of test specimens (see 

Section II.D.2 of this document). DOE 

also has identified differences between 

Appendix B and the industry test 

standards referenced, specifically for 

specimen 23 conditioning prior to testing 

(see Section II.D.3 of this document). In 

addition, DOE is examining the prospect 

of requiring a measurement for thermal 

transmittance for non-display panels 

(see Section II.D.4 of this document). 

While DOE previously adopted methods 

for measuring thermal transmittance in 

the April 2011 TP final rule, it later 

removed them. 79 FR 27387, 27405– 

27406. DOE remains interested in 

exploring the possibility of addressing 

this issue because of the potential 

variation in thermal transmittance of 

different panel designs with the same Rvalue, and seeks additional information 

regarding market-related and industry 

test method-related changes that would 

inform DOE’s potential reconsideration 

of adopting a test method for measuring 

thermal transmittance. Finally, DOE is 

seeking comment on the test procedure 

for display panels (Section II.D.5 of this 

document). 

1. Panel Thickness 

DOE’s test procedure for walk-in 

panels requires manufacturers to 

determine the panel’s R-value by 

measuring the thermal conductivity, 

referred to as the ‘‘K factor’’ of a 1 ± 0.1- 

inch specimen of insulation according 

to ASTM C518–04. The R-value of the 

walk-in panel is determined by dividing 

the panel thickness by the K factor. See 

10 CFR 431.304(b)(3) and Appendix B 

(detailing the test method used to 

measure the R-value for walk-in 

envelope components). DOE’s current 

test procedure for determining a panel’s 

R-value provides some direction for 

measuring panel thickness. However, 

because of the importance of this 

measurement in determining the panel’s 

R-value, DOE is considering whether to 

include additional details regarding the 

thickness measurement. 

Issue 20: DOE requests comment on 

how panel thickness is currently 

measured for determining the panel’s 

R-value per the DOE test procedure, 

including number of measurements, 

measurement location, and any steps 

that are routinely followed for the 

removal of the protective skins or facers 

to obtain the full panel thickness. DOE 

requests that commenters identify any 

specific guidelines, practices or 

standardized approaches that are 

followed, as well as their date of 

publication, if applicable. 

2. Parallelism and Flatness 

The test procedure for determining Rvalue also requires that the two surfaces 

of the tested specimen that contact the 

hot plate assemblies (as defined in 

ASTM C518) maintain ±0.03 inches 

flatness tolerance and also maintain 

parallelism with respect to one another 

within a tolerance of ±0.03 inches.24

Section 4.5 of Appendix B. The test 

procedure provides no direction on how 

flatness and parallelism should be 

measured or calculated. DOE is 

considering whether its test procedure 

should provide additional details 

indicating how to determine the flatness 

and parallelism of the tested specimen. 

Issue 21: DOE requests comment on 

how flatness and parallelism of the test 

specimen surfaces that contact the hot 

plate assemblies described in ASTM 

C518 are typically determined by test 

laboratories and whether the test 

procedure should be revised to clarify 

how to determine these parameters, e.g., 

what type of instruments are used to 

measure these values, how many 

measurements are made for a given 

specimen, and other details that could 

affect conclusions regarding compliance 

with the test procedure. 

3. Specimen Conditioning 

ASTM C518 directs that a test 

specimen cut from a panel be 

conditioned prior to testing. See ASTM 

C518–04, section 7.3 (referring to panel 

conditioning as ‘‘specimen 

conditioning’’). However, ASTM C518 

does not specify the conditions at which 

specimen conditioning would be 

conducted, nor the duration. ASTM 

C518 states that specimen conditioning 

details should be provided in the 


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25Thermal bridging occurs when a more 

conductive material allows an easy pathway for 

heat flow across a thermal barrier. 

material specifications, and if not 

provided, conditions should be selected 

so as not to change the specimen in an 

irreversible manner. Id. ASTM C518 

further states that material 

specifications typically call for 

specimen conditioning at 22 °C (72 °F) 

and 50 percent relative humidity until 

less than a 1 percent mass change is 

observed over a 24-hour period. Id. 

Calculations associated with 

conditioning are discussed in section 

8.1 of ASTM C518, including 

calculation of the ‘‘density of the dry 

specimen as tested,’’ which suggests 

that the purpose of conditioning is, at 

least in part, to dry the specimen, i.e., 

allow water to evaporate and/or diffuse 

out. 

DOE has not found specimen 

conditioning details to be provided by 

suppliers of insulation for any of the 

common insulation materials used in 

walk-ins. Given this lack of supplierprovided specimen conditioning details, 

it is DOE’s understanding that ‘‘material 

specifications’’ in section 7.3 refers to 

ASTM specifications, e.g. ASTM C578– 

2019, ‘‘Standard Specification for Rigid, 

Cellular Polystyrene Thermal 

Insulation’’ or ASTM C1029–2015, 

‘‘Standard Specification for SprayApplied Rigid Cellular Polyurethane 

Thermal Insulation’’. However, there is 

no uniform set of ASTM conditioning 

specifications, and the material 

specifications identified in ASTM C518 

as ‘‘typical’’ do not reflect what is 

provided in other ASTM standards. For 

example, ASTM C578–2019 calls for 

conditioning as specified in the 

applicable test procedure—this circular 

reference back to ASTM C518 means 

that ASTM C578–2019 effectively 

provides no explicit conditions. ASTM 

C1029–2015 calls for conditioning at 

73 ± 2 °F and 50 ± 5 percent relative 

humidity for 180 ± 5 days from time of 

manufacture. In the context of the DOE 

WICF test procedures, the ASTM 

C1029–2015 specifications may be 

insufficient or inappropriate because the 

date of manufacture of the insulation in 

a walk-in panel or door may not be 

known, and the 180-day condition 

would likely represent a significant test 

burden. 

In the absence of clear instructions in 

ASTM C518, test laboratories may be 

using conditioning times, temperature, 

and humidity consistent with the 

conditions identified in ASTM C518–04 

section 7.3 as ‘‘typical conditions.’’ 

Additionally, the provision in section 

4.5 of Appendix B requires that testing 

per ASTM C518–04 must be completed 

within 24 hours of specimens being cut 

for the purpose of testing, eliminating 

use of the 180-day conditioning 

provided in ASTM C1029–2015 or the 

example of typical specimen 

conditioning provided by ASTM C518. 

Issue 22: DOE requests comment on 

the extent to which manufacturers of 

insulation specify conditioning for 

insulation materials that differ from the 

typical conditioning approach described 

in ASTM C518. DOE also seeks feedback 

on whether more than one 24-hour 

conditioning period is ever needed to 

complete the conditioning (i.e., the 

change in specimen mass is less than 1 

percent after the first 24 hours of 

conditioning) for a specimen extracted 

from a WICF panel or door. Finally, 

DOE requests information or data on 

how specimen conditioning times less 

than or equal to 24 hours impacts the 

accuracy, repeatability, and 

representativeness of the test. 

4. Overall Thermal Transmittance 

In the April 2011 TP final rule, DOE 

adopted a test method for measuring the 

overall thermal transmittance of a walkin panel, including the impacts of 

thermal bridges 25 and edge effects (e.g., 

due to framing materials and fixtures 

used to mount cam locks). This method 

drew from an existing industry test 

method, incorporating by reference 

ASTM C1363–05. 76 FR 21580, 21605– 

21612. However, after receiving 

comments indicating that only two 

independent laboratories could conduct 

this test, DOE re-evaluated its earlier 

decision and removed this portion of 

the walk-in panel test procedure in the 

May 2014 AEDM TP final rule. 79 FR 

27388, 27405–27406. Despite this 

decision to remove its overall thermal 

transmittance measurement method 

from the walk-in test procedure, DOE 

remains concerned that elements like 

framing materials and fixtures used to 

mount cam locks can significantly affect 

walk-in panel energy efficiency 

performance. To address this issue, DOE 

is re-evaluating whether—and if so, 

how—to account for the overall thermal 

transmittance of walk-in panels in its 

test procedure. 

Issue 23: DOE requests information 

about panel construction factors that 

would affect thermal transmission and 

the magnitude of the energy efficiencyrelated impacts of thermal bridges in the 

panel assembly. Additionally, DOE 

requests comment on alternative test 

methods that measure the overall 

thermal transmittance of walk-in panels 

and the relative advantages and 

disadvantages of each. DOE also seeks 

feedback on the number and location of 

labs that have the facilities and are 

qualified to run ASTM C1363–05. 

5. Display Panels 

Display panels are defined in 10 CFR 

431.302 as panels entirely or partially 

comprised of glass, a transparent 

material, or both that are used for 

display purposes. Display panels are 

subject to the test procedure in 

Appendix A for determining U-factor, 

conduction load, and energy use. 10 

CFR 431.304(b)(1). Appendix A follows 

the procedure in NFRC 100 for 

determination of display panel U-factor. 

10 CFR 431.303. Although DOE 

established a test procedure for display 

panels, DOE has not established energy 

conservation standards for them. DOE 

received no comments in response to 

the proposed test procedure outlined for 

display panels in the September 2010 

TP SNOPR and DOE established 

Appendix A as the test procedure for 

display panels in the April 2011 TP 

Final Rule. 76 FR 21580, 21606. DOE is 

interested in any feedback on amending 

the current test procedure for display 

panels. 

Issue 24: DOE seeks feedback on the 

current test procedure for display panels 

in Appendix A and what amendments 

should be made, if any, to it. 

E. Test Procedure for Walk-In 

Refrigeration Systems 

DOE’s test procedure for walk-in 

refrigeration systems can be found in 

Appendix C to Subpart R of 10 CFR part 

431. The test procedure primarily 

incorporates by reference AHRI 1250– 

2009. 

DOE has also recently granted test 

procedure interim waivers and waivers 

to Appendix C specific to the testing of 

single-package systems, wine cellar 

refrigeration systems, and carbon 

dioxide (‘‘CO2’’) refrigerant based 

systems, summarized in Table II.3. Test 

procedure waivers provide alternate test 

provisions for units that DOE 

determines cannot be appropriately 

tested to its current test procedure. A 

waiver granted by DOE remains in effect 

until DOE amends its regulations so as 

to eliminate any need for it, pursuant to 

10 CFR 431.401(h) for commercial and 

industrial equipment. Sections II.E.1, 

II.E.2, and II.E.3, below discuss and 

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26 ‘‘Temperature glide’’ for a refrigerant refers to 

the increase in temperature at a fixed pressure as 

liquid refrigerant vaporizes during its conversion 

from saturated liquid to saturated vapor. 

refrigeration systems, and CO2 systems 

in the test procedure. 

TABLE II.3—INTERIM WAIVERS AND WAIVERS GRANTED TO MANUFACTURERS OF WALK-IN REFRIGERATION SYSTEMS

Manufacturer Subject Interim Waiver Federal Register 

citation 

Waiver decision and order 

Federal Register citation 

Air Innovations .............. Wine Cellar Refrigeration Systems ................... 86 FR 2403 (Jan. 12, 2021) ....... 86 FR 23702 (May 4, 2021). 

Vinotheque ................... Wine Cellar Refrigeration Systems ................... 86 FR 11961 (Mar. 1, 2021) ....... 86 FR 26504 (May 14, 2021). 

CellarPro ....................... Wine Cellar Refrigeration Systems ................... 86 FR 11972 (Mar. 1, 2021) ....... 86 FR 26496 (May 14, 2021). 

Vinotemp ...................... Wine Cellar Refrigeration Systems ................... 86 FR 23692 (May 4, 2021) ....... (*) 

HTPG ............................ CO2 Unit Coolers ............................................... 85 FR 83927 (Dec. 23, 2020) .... 86 FR 14887 (Mar. 19, 2021). 

Hussmann .................... CO2 Unit Coolers ............................................... 86 FR 10046 (Feb. 18, 2021) ..... 86 FR 24606 (May 7, 2021). 

Keeprite ........................ CO2 Unit Coolers ............................................... 86 FR 12433 (Mar. 3, 2021) ....... 86 FR 24603 (May 7, 2021). 

Store It Cold ................. Single-Package Systems ................................... 84 FR 11944 (Mar. 29, 2019) ..... 84 FR 39286 (Aug. 9, 2019). 

* A decision and order granting the manufacturer a waiver has not yet been issued. 

As noted earlier, during DOE’s 

previous rulemaking to develop 

standards for WICF refrigeration 

systems, the accompanying Term Sheet 

included a series of amendments to the 

test procedure that the Working Group 

viewed as necessary to properly 

implement its recommended energy 

conservation standards. Ultimately, 

DOE published final rules implementing 

the majority of both sets of 

recommendations. See 82 FR 31808, 

31808–31838 (July 10, 2017) (final rule 

amending the energy conservation 

standards for walk-ins) and 81 FR 95758 

(December 28, 2016) (final rule 

amending the walk-in test procedures). 

Three test procedure-related 

recommendations from the Term Sheet, 

however, were not part of DOE’s 

December 2016 TP final rule. (Term 

Sheet Recommendation #6). The 

Working Group believed these 

recommendations merited consideration 

by DOE as part of future amendments to 

help make the test procedure more fully 

representative of walk-in energy use. 

(Id.) Specifically, the Working Group 

recommended that DOE amend its 

procedure to (a) measure the energy use 

associated with the defrost function, 

taking into account the potential savings 

associated with hot gas and adaptive 

defrost, (b) incorporate the measurement 

of off-cycle power consumption, 

including crankcase heater power 

consumption, and (c) allow for separate 

ratings of stand-alone variable-capacity 

condensing units. (Id.). Sections II.E.4 

through II.E.6 of this document discuss 

these issues in more detail. 

Sections II.E.7 and II.E.8 discuss other 

issues that may also improve the test 

procedure’s ability to provide results 

that are more representative of walk-in 

energy use. Specifically, these include 

consideration of amended test 

procedures and new equipment classes 

for so-called high-temperature freezer 

refrigeration systems used for walk-ins 

at temperatures between 10 °F and 32 

°F, and discussion of the impact of 

refrigerant temperature glide 26 of 

zeotropic refrigerants such as R407A. 

1. Single-Package Systems 

As discussed in the December 2016 

TP final rule, single-package systems are 

considered a type of dedicated 

condensing refrigeration system. 81 FR 

95758, 95763–95764. The test methods 

in AHRI 1250–2009, which are 

incorporated by reference as DOE’s test 

procedure for walk-ins (10 CFR 

431.303(b)), do not fully address or 

account for the features of singlepackage systems. As discussed in the 

December 2016 TP final rule, 

commenters asserted that one practical 

challenge to testing single-package 

systems is the need to disassemble the 

unit under test in order to be able to 

install the refrigerant mass flow meters 

required for testing. Id. at 95763. Mass 

flow measurement is a key input in the 

calculation of capacity, as illustrated in 

equations C1 and C2 of AHRI 1250– 

2009. 

Regarding this class of equipment, 

DOE received a petition for waiver with 

regard to testing of single-package units. 

By letter dated May 9, 2020, Store It 

Cold submitted a petition for waiver and 

interim waiver from Appendix C for 

basic models of single-package systems. 

(EERE–2018–BT–WAV–0002, No. 2) 

Store It Cold stated that testing singlepackage systems with refrigerant mass 

flow meters installed produces results 

unrepresentative of their true energy 

consumption characteristics and would 

provide materially inaccurate 

comparative data. The petitioner 

requested that DOE permit the use of 

psychrometric ‘air-side’ measurements 

to determine the Gross Total 

Refrigeration Capacity of such systems. 

DOE granted a test procedure waiver 

and interim waiver to Store It Cold for 

specified basic models in 2019. 84 FR 

39286 (August 9, 2019) (‘‘Store It Cold 

Decision and Order’’). 

AHRI 1250–2020 addresses testing of 

single-package systems in section C9 

and incorporates by reference test 

standards developed for testing airconditioning units that include 

alternative test methods that have been 

adapted for testing single-package 

systems. The air enthalpy methods in 

section C9 of AHRI 1250–2020 

incorporate by reference ANSI/ASHRAE 

Standard 37–2009 (‘‘ASHRAE 37– 

2009’’), ‘‘Methods of Testing for Rating 

Electrically Driven Unitary AirConditioning and Heat Pump 

Equipment’’ and ANSI/ASHRAE 41.6– 

2014 (‘‘ASHRAE 41.6’’), ‘‘Standard 

Method for Humidity Measurement’’. 

The calorimeter methods in section C9 

of AHRI 1250–2020 incorporate by 

reference ANSI/ASHRAE Standard 16– 

2016 (‘‘ASHRAE 16–2016’’), ‘‘Method of 

Testing for Rating Room Air 

Conditioners, Packaged Terminal Air 

Conditioners, and Packaged Terminal 

Heat Pumps for Cooling and Heating 

Capacity’’. The compressor calibration 

methods in section C9 of AHRI 1250– 

2020 incorporate by reference ASHRAE 

37 and ANSI/ASHRAE 23.1–2010. 

AWEF calculations for matched pair 

and single-package systems are detailed 

in section 7.1.1 through 7.1.4 of AHRI 

1250–2020. 

AHRI 1250–2020 requires two 

simultaneous measurements of system 

capacity (i.e., a primary and secondary 

method), and section C9.2.1 of 

Appendix C provides a requirement that 

the measurements agree within 6 

percent. Table C4 to Appendix C to 

AHRI 1250–2020 details which of the 

test methods (calorimeter, air enthalpy, 

and compressor calibration) qualify as 

primary and/or secondary methods. 

Issue 25: DOE requests comment on 

whether the single-package system test 


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32344 Federal Register / Vol. 86, No. 115 / Thursday, June 17, 2021 / Proposed Rules 

27Air Innovations, Vinotheque Wine Cellars, 

Cellar Pro Cooling Systems, Vinotemp International 

Corp., and LRC Coil Company, respectively, 

submitted petitions for waivers and interim waivers 

for basic models of wine cellar walk-in refrigeration 

systems. (Air Innovations, EERE–2019–BT–WAV– 

0029, No. 6; Vinotheque, EERE–2019–BT–WAV– 

0038, No. 6; CellarPro, EERE–2019–BT–WAV–0028, 

No. 6; Vinotemp, EERE–2020–BT–WAV–0022, No. 

10; LRC Coil, EERE–2020–BT–WAV–0040, No. 1). 

and calculation methods described in 

AHRI 1250–2020 provide representative 

energy use. DOE also requests comment 

on whether DOE should incorporate by 

reference AHRI 1250–2020 as the test 

procedure for single-package systems. 

DOE also notes that, unlike split 

systems (i.e., matched-pair refrigeration 

systems), single-package systems may 

experience additional thermal losses 

because they circulate cold walk-in air 

through a cold section that has exterior 

surfaces exposed to warm air outside 

the walk-in enclosure. This exposure 

can contribute to additional infiltration 

losses, i.e., leakage of air between the 

interior and exterior of a walk-in. 

Accordingly, if these losses occur, they 

would reduce the net capacity of a 

single-package system without being 

fully captured by the refrigerant 

enthalpy methods established in AHRI 

1250–2009. 

Issue 26: DOE requests any data or 

calculations quantifying the additional 

thermal losses associated with testing 

single-package systems due to the 

exposure of their cold sides to the 

exterior air (i.e., surface and infiltration 

losses). DOE additionally requests 

comment on whether the AHRI 1250– 

2020 test methodology for singlepackage systems fully accounts for these 

additional losses. 

a. Calorimeter Method 

As previously mentioned, AHRI 

1250–2020 incorporates by reference 

ASHRAE 16–2016 as its indoor and 

outdoor room calorimeter method test 

procedure. ASHRAE 16–2016 includes a 

calorimeter test method with 

similarities to the calibrated box test 

method of AHRI 1250–2009, but with 

additional details and provisions. 

ASHRAE 16–2016 is used to measure 

the capacity and power input of singlepackage system products such as room 

air conditioners that have hot and cold 

sections, similar to single-package walkin systems. The ASHRAE 16–2016 

calorimeter test includes both outdoorand indoor-based calorimetric 

measurements of the capacity—the 

indoor side measurement is similar to 

that of the calibrated box test method, 

while the outdoor side provides a 

determination of system cooling 

capacity by measuring the cooling 

required to maintain the outdoor room 

temperature and humidity conditions. 

DOE’s work in evaluating singlepackage systems using the calorimeter 

methods referenced in AHRI 1250–2020 

has highlighted the need to make very 

precise determination of the calorimeter 

chamber cooling fluid heat capacity. 

This fluid cannot be pure water, since 

it must be below water freezing 

temperature for testing WICF 

refrigeration systems. This makes 

precise determination of heat capacity 

more challenging, since an accurate 

determination of glycol concentration is 

required. 

Issue 27: DOE requests comment and 

data on the use of water, glycol, or other 

heat transfer liquid in maintaining test 

compartment temperature using the 

calorimeter methods referenced in AHRI 

1250–2020 for the testing of singlepackage refrigeration systems. DOE 

requests comment on whether the 

description and requirements for 

calorimetric testing as provided in AHRI 

1250–2020 should be modified or 

enhanced in order to better ensure that 

measurements are accurate and 

repeatable. 

In addition, ASHRAE 16–2016 

requires that a pressure-equalizing 

device be installed between the indoor 

and outdoor test compartments to 

maintain a balanced pressure between 

the compartments and to measure the 

air flow required to maintain 

equalization. Assuming the test facility 

is otherwise airtight, the air flow 

transferred and measured by the 

pressure-equalizing device represents 

air transferred in the opposite direction 

through leaks inside the equipment as a 

result of pressure differences between 

the warm and cold side of the system set 

up by its fans. 

Given that the related calibrated box 

test method has no requirements for 

pressure equalization, DOE is 

considering the need for pressure 

equalization for single-package testing. 

Alternatives include (a) no requirement 

addressing transfer air or pressure 

equalization, or (b) a requirement that 

the test facility chambers be leak-free 

with no equalization requirement. DOE 

expects that the use of a pressure 

equalization apparatus would 

incrementally increase test facility cost 

and test burden, and would ensure 

operation with losses consistent with 

the measured air leakage, but such 

equalized pressure conditions may not 

be representative of WICF refrigeration 

system use. The alternative options may 

reduce facility cost and test burden. 

Option (a) may reduce accuracy and 

repeatability, while both options may 

mask potential performance degradation 

associated with air leakage. 

Issue 28: DOE requests comment on 

whether calorimeter test methods for 

single-package systems should 

implement a pressure-equalizing device, 

as included in ASHRAE 16–2016. DOE 

requests information on any additional 

cost and resource burdens, if any, 

manufacturers would face when 

employing these methods to evaluate 

single-package systems. 

Issue 29: DOE seeks comment 

regarding any alternative test methods 

not mentioned in this document that 

could be used to measure single-package 

system capacity. To the extent that any 

alternative test methods could be used 

for this purpose, DOE requests 

information on their advantages and 

disadvantages in measuring singlepackage system capacity. 

2. Wine Cellar Refrigeration Systems 

DOE is aware of certain equipment 

within the walk-in definition that may 

be incapable of being tested in a manner 

that would yield results measuring the 

energy efficiency or energy use of that 

equipment during a representative 

average use cycle under the current 

version of the walk-in test procedure. 

Specifically, wine cellars that are 

installed in a variety of commercial 

settings are set to operate at a 

temperature range of 45 °F to 65 °F. 

They also meet the criteria established 

by Congress in the definition for a walkin. See generally 42 U.S.C. 6311(20). 

Under the walk-in test procedure, walkin coolers must be tested while 

operating at 35 °F. Section 3.1.1 of 

Appendix C. Wines often suffer from 

damage when stored at temperatures 

below 45 °F. To the extent that a wine 

cellar is not operated at 35 °F, applying 

the required 35 °F testing temperature 

condition when evaluating the energy 

usage of this equipment would not 

produce results representative of an 

average use cycle. 

DOE has received requests for waiver 

and interim waiver from several 

manufacturers from the test procedure 

in Appendix C for basic models of wine 

cellar refrigeration systems.27( ). 

Manufacturers stated that wine cellars 

are intended to operate at a temperature 

range of 45 to 65 °F and 50–70 percent 

relative humidity, rather than the 35 °F 

and less than 50 percent relative 

humidity test condition prescribed in 

Appendix C. Manufacturers asserted 

that testing at 35 °F would be 

unrepresentative of the true energy 

consumption characteristics of the 

specified units and that operation at this 

temperature may damage wine cellar 

refrigeration units. Given the number of 

waivers that DOE received, DOE 


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Federal Register / Vol. 86, No. 115 / Thursday, June 17, 2021 / Proposed Rules 32345 

28Memorandum from AHRI, ‘‘Department of 

Energy (DOE) Wine Cellar Cooling Systems Test 

Procedure Waiver Industry Comments from AHRI 

Membership’’, August 18, 2020. (EERE–2019–BT– 

WAV–0028, No. 5 (CellarPro); EERE–2019–BT– 

WAV–0029, No. 5 (Air Innovations); EERE–2019– 

BT–WAV–0038, No. 5 (Vinotheque); EERE–2019– 

BT–WAV–022, No. 2 (Vinotemp)) 

29The duct material, length, diameter, shape, and 

configuration are used to calculate the ESP 

generated in the duct, along with the temperature 

and flow rate of the air passing through the duct. 

The conditions during normal operation that result 

in a maximum ESP are used to calculate the 

reported maximum ESP values, which are 

dependent on individual unit design and represent 

manufacturer-recommended installation and use. 

30A ‘‘matched refrigeration system’’ is also called 

a ‘‘matched pair’’ and is a refrigeration system 

where the condensing system is distributed into 

commerce with a specific unit cooler(s). See 10 CFR 

431.302. 

31LRC Coil Company submitted a petition for 

waiver and interim waiver for specific basic models 

of unit cooler only walk-in wine cellar refrigeration 

systems. (LRC Coil, EERE–2020–BT–WAV–0040, 

No. 1) In reviewing another petition for waiver and 

interim waiver from Vinotheque for single-package 

system and matched-pair system basic models 

(Vinotheque, EERE–2019–BT–WAV–0038, No. 6), 

DOE noted that the manufacturer also offered unit 

cooler only systems distributed without a paired 

condensing system. 

engaged with AHRI, the industry trade 

association, to discuss how to develop 

a consistent alternate test approach for 

wine cellars that would be applicable to 

all impacted manufacturers. Ultimately, 

AHRI submitted a memorandum on 

behalf of its wine cellar members 

supporting (1) a 45 °F minimum 

operating temperature for wine cellar 

refrigeration systems, and (2) testing at 

50 percent of maximum external static 

pressure, with manufacturers providing 

maximum external static pressure 

values to DOE.28 After reviewing 

manufacturer websites, product 

specification sheets, suggested alternate 

test approaches provided by each 

manufacturer and by AHRI, and after 

soliciting and reviewing feedback from 

the public, DOE has granted interim 

waivers or waivers as summarized in 

Table II.3. 

These waivers have addressed testing 

for single-package, matched-pair, and 

unit-cooler-only wine cellar 

refrigeration systems. The alternative 

test procedures prescribed in these 

waivers address a number of differences 

in operation between wine cellar 

refrigeration systems and other walk-in 

refrigeration systems, including the 

following: 

• Unit cooler air inlet condition of 55 

°F and 55 percent RH, compared to 35 

°F and less than 50 percent RH for 

medium-temperature refrigeration 

systems in the DOE test procedure; 

• For single-package wine cellar 

systems, capacity measurement is 

conducted using a primary and a 

secondary capacity measurement 

method as specified in AHRI 1250– 

2020, using two of the following: The 

indoor air enthalpy method; the outdoor 

air enthalpy method; the compressor 

calibration method; the indoor room 

calorimeter method; the outdoor room 

calorimeter method; or the balanced 

ambient room calorimeter method. 

• Options for ducting on the 

condenser side, evaporator side, or both 

with specifications for setting the 

external static pressure. 

• For calculating AWEF, the wine 

cellar box load level is set equal to half 

of the refrigeration system capacity at 

the 95 °F test condition (for outdoor 

refrigeration systems) or 90 °F (for 

indoor refrigeration systems), rather 

than using a two-tiered set of high- and 

low-load period box load levels, as 

prescribed in AHRI 1250–2009. For 

calculating AWEF, the evaporator fan is 

assumed to operate for one-tenth of the 

compressor off-cycle period at the same 

wattage as applies for the compressor 

on-cycle. This contrasts with varying 

assumptions used for other WICF 

refrigeration systems, depending on the 

type of evaporator fan controls they use. 

Issue 30: DOE requests comment on 

the alternative test procedure for wine 

cellar walk-in refrigeration systems that 

it has granted in the interim waivers and 

waivers listed in Table II.3. DOE 

additionally seeks comment on whether 

the alternative test procedure prescribed 

for the specified basic models identified 

in the waivers would be appropriate for 

similar refrigeration equipment. 

As noted previously, wine cellar 

refrigeration systems are designed for 

both ducted and non-ducted air 

delivery; the DOE test procedure does 

not address the testing of ducted 

systems. For systems that can be 

installed with (1) ducted evaporator air, 

(2) with or without ducted evaporator 

air, (3) ducted condenser air, or (4) with 

or without ducted condenser air, the 

alternate test approach requires testing 

to be conducted at 50 percent of the 

maximum external static pressure 

(‘‘ESP’’), subject to a tolerance of ¥0.00/ 

+0.05 in. DOE understands that 

maximum ESP is generally not 

published in available literature such as 

installation instructions, but 

manufacturers do generally specify the 

size and maximum length of ductwork 

that is acceptable for any given unit in 

such literature. The duct specifications 

determine what ESP would be imposed 

on the unit in field operation.29 The 

provision of allowable duct dimensions 

is more convenient for installers than 

maximum ESP, since it relieves the 

installer from having to perform duct 

pressure drop calculations to determine 

ESP. This approach differs from the 

approach used in related products/ 

equipment, e.g., air conditioners, where 

ESP is a function of capacity—ESP does 

not correlate well with capacity for wine 

cellar refrigeration systems. 

Issue 31: DOE requests feedback on its 

approach for testing ducted units in its 

alternate test procedure for wine cellar 

refrigeration systems. Specifically, DOE 

requests comment and supporting data 

on whether testing at 50 percent of 

maximum ESP provides representative 

performance values, or whether other 

fractions of maximum ESP may be more 

appropriate. Additionally, DOE seeks 

comment on other industry test methods 

that include the testing of ducted units. 

Finally, DOE is interested in other 

alternative approaches for testing 

ducted units that have been 

demonstrated to provide repeatable and 

representative results. 

The above discussion assumes that 

wine cellar refrigeration systems are 

either a single-package system or a 

matched-pair.30 However, DOE has also 

received a petition for waiver for unit 

coolers that are distributed into 

commerce without a paired condensing 

system.31 DOE recognizes that these unit 

cooler-only models will need to be 

tested according to the provisions in 

AHRI 1250–2020 for unit coolers tested 

alone, for which calculation of AWEF 

requires use of an appropriate EER 

based on the suction dew point 

temperature. Table 18 in AHRI 1250– 

2020 provides EER values for medium 

and low temperature unit coolers tested 

alone. However, these values may not be 

appropriate for calculating AWEF for 

wine cellar unit coolers because this 

equipment likely operates with different 

suction dew point temperature and the 

counterpart condensing units likely use 

different compressor designs than those 

considered when developing the current 

EER values. 

Issue 32: DOE requests data and 

information on appropriate EER values 

for use in calculating AWEF for wine 

cellar unit coolers tested alone, and how 

these EER values might depend on 

refrigerant and/or capacity. DOE 

requests that commenters provide 

background explanation regarding how 

any such EER recommendations have 

been developed. 

Issue 33: Since unit coolers for wine 

cellar systems are sold alone, DOE seeks 

information on the characteristics of 

condensing units that would typically 

be paired with these unit coolers (e.g., 

make/model, compressor style, capacity 

range, manufacturers). 


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32346 Federal Register / Vol. 86, No. 115 / Thursday, June 17, 2021 / Proposed Rules 

32Heat Transfer Products Group, Hussmann 

Corporation, and Keeprite Refrigeration, 

respectively, submitted petitions for waivers and 

interim waivers for basic models of CO2 unit coolers 

used in transcritical booster systems. (HTPG, EERE– 

2020–BT–WAV–0025, No. 1; Hussmann, EERE– 

2020–BT–WAV–0026, No. 1; Keeprite, EERE–2020– 

BT–WAV–0028, No. 1). 

33 In a ‘‘hot gas’’ defrost system, hightemperature, high-pressure hot refrigerant gas from 

the discharge side of the compressor is introduced 

into the evaporator, where it condenses, thereby 

releasing latent heat into the evaporator. This heat 

is used to melt the frost that has accumulated on 

the outside of the evaporator coil. 

Additionally, DOE notes that its 

definitions for ‘‘single-packaged 

system’’ and ‘‘unit cooler’’ may not 

appropriately define ducted units. DOE 

currently defines a ‘‘single-packaged 

dedicated system’’ as ‘‘a refrigeration 

system (as defined in this section) that 

is a single-package system assembly that 

includes one or more compressors, a 

condenser, a means for forced 

circulation of refrigerated air, and 

elements by which heat is transferred 

from air to refrigerant, without any 

element external to the system imposing 

resistance to flow of the refrigerated air. 

10 CFR 431.302. Similarly, DOE defines 

a ‘‘unit cooler’’ as ‘‘an assembly, 

including means for forced air 

circulation and elements by which heat 

is transferred from air to refrigerant, 

thus cooling the air, without any 

element external to the cooler imposing 

air resistance. Id. Both definitions 

describe a single-package or unit cooler 

system, respectively, that is not ducted 

(i.e., there is no element external to the 

unit that imposes air resistance). 

Issue 34: DOE seeks comment on 

whether, and if so how, it should 

modify its definitions for ‘‘singlepackaged dedicated system’’ and ‘‘unit 

cooler’’ to address units that are 

designed to be installed with ducts. 

Issue 35: DOE requests comment on 

any other issues regarding testing of 

wine cellar refrigeration systems that 

may not be fully addressed by the 

current DOE test procedure. 

3. CO2 Systems 

DOE has also become aware of WICF 

unit coolers that are being used in CO2

transcritical booster systems that cannot 

be tested using the current set of test 

conditions. DOE has received several 

test procedure waiver petitions 

regarding CO2 unit coolers used in 

transcritical booster systems. 

Heat Transfer Product Group 

(‘‘HTPG’’), Hussmann, and Keeprite 

submitted petitions for waivers and 

interim waivers from Appendix C for 

specific basic models of CO2 direct 

expansion unit coolers).32 The DOE test 

procedure for unit coolers requires 

testing with liquid inlet saturation 

temperature of 105 °F and liquid inlet 

subcooling temperature of 9 °F, as 

specified by Tables 15 and 16 of AHRI 

1250–2009. However, CO2 has a critical 

temperature of 87.8 °F; therefore, it does 

not coexist as saturated liquid and gas 

above this temperature. The liquid inlet 

saturation temperature of 105 °F and the 

liquid inlet subcooling temperature of 9 

°F specified in Appendix C are not 

achievable by CO2 unit coolers. The 

three petitioners requested that DOE 

modify the test condition values to 

reflect typical operating conditions for a 

transcritical CO2 booster system (i.e., a 

liquid inlet saturation temperature of 38 

°F and a liquid inlet subcooling 

temperature of 5 °F). After reviewing 

manufacturer websites, product 

specification sheets, and suggested 

alternate test approaches provided by 

each manufacturer, DOE has granted 

waivers or interim waivers to the 

manufacturers listed in Table II.3. 

DOE is seeking comment on how to 

address CO2 system testing in a way that 

is representative of the average use cycle 

for these units and is not unduly 

burdensome to conduct. 

Issue 36: DOE requests comment on 

test conditions that would be most 

appropriate for evaluating the energy 

use of CO2 unit coolers. Additionally, 

DOE requests feedback on any 

additional changes that would need to 

be made to the DOE test procedure to 

accurately evaluate energy use of these 

systems, while minimizing test burden. 

While all CO2 refrigerant waiver 

petitions DOE has thus far received 

address unit coolers for use in 

transcritical booster systems, it is 

possible that other CO2 refrigeration 

system configurations may be relevant 

in the future, e.g., dedicated condensing 

units (‘‘DCUs’’), matched pairs, or 

single-package systems. DOE reviewed 

product literature and other information 

for CO2 systems having some of these 

alternative configurations. Most of this 

information pertains to manufacturers 

operating in Europe. 

Issue 37: DOE requests comment on 

the present and future expected use of 

walk-in refrigeration systems using CO2. 

DOE requests specific information about 

these systems that would suggest a need 

to modify the DOE test procedure to 

address such equipment. Specifically, 

DOE requests information on whether 

such equipment is sold in the U.S., 

whether this equipment is sold as 

matched pairs or individual 

components, and to what extent 

dedicated condensing units are 

configured to supply subcritical liquid 

(rather than supercritical gas) to the unit 

coolers. 

4. Defrost Test Method 

The April 2011 TP final rule 

incorporated AHRI 1250–2009 as DOE’s 

WICF refrigeration system test 

procedure, including that standard’s 

requirement that both frosted and dry 

coil defrost tests be conducted. 

Appendix C, Section 3. DOE later noted 

in the February 2014 AEDM TP SNOPR 

that this requirement may be overly 

burdensome for manufacturers to 

conduct, due to the difficulty of 

maintaining the moist air infiltration 

conditions for the frosted coil test in a 

repeatable manner. 79 FR 9818, 9831. 

Accordingly, in DOE’s May 2014 AEDM 

TP final rule, DOE adopted a set of 

nominal values for calculating defrost 

energy use for a frosted coil, number of 

defrosts per day if the unit has an 

adaptive defrost system, and daily 

contribution of heat load.33 79 FR 

27388, 27401. To address testing lowtemperature condensing units alone, the 

May 2014 AEDM TP final rule 

established nominal values for the 

defrost energy use and thermal load. In 

addressing refrigeration systems with 

hot gas defrost, the May 2014 AEDM TP 

final rule established nominal values for 

calculating hot gas defrost energy use 

and heat load. Id. 

The December 2016 TP final rule 

removed the method for calculating the 

defrost energy and defrost heat load of 

systems with hot gas defrost and 

established a new method to evaluate 

hot gas defrost refrigeration systems. 

That new method treated these hot gas 

defrost refrigeration systems as if they 

used electric defrost rather than hot gas 

defrost. This method relied on the same 

nominal values for defrost energy use 

and thermal load that the test procedure 

prescribes for electric-defrost 

condensing units that are tested alone. 

81 FR 95758, 95774–95777. This 

approach was modified in the March 

2021 hot gas defrost TP final rule that 

amended the test procedure to rate hot 

gas defrost unit coolers using modified 

default values for energy use and heat 

load contributions that would make 

their ratings more consistent with those 

of electric defrost unit coolers. 86 FR 

16027. The scope of the March 2021 hot 

gas defrost TP final rule is limited to 

unit coolers only. 86 FR 16027, 16030. 

a. Moisture Addition 

DOE is considering whether using a 

test method—possibly similar to the one 

detailed in section C11.3 of AHRI 1250– 

2009—to measure the energy use 

associated with the defrosting of frosted 

coils would provide a reasonably 

accurate accounting of defrost energy 


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34Sherif, S.A., P.J. Mago, and R.S. Theen. A Study 

to Determine Heat Loads Due to Coil Defrosting. 

1997. University of Florida: Gainesville, FL. 

ASHRAE Project No. 622–RP. Report No. UFME/ 

SEECL–9701. 

35Sherif, S.A., P.J. Mago, and R.S. Theen. A Study 

to Determine Heat Loads Due to Coil DefrostingPhase II. 2003. University of Florida: Gainesville, 

FL. ASHRAE Project No. 1094–RP. Report No. 

UFME/SEECL–200201. 

36 As previously mentioned, the March 2021 hot 

gas defrost TP final rule updated the defrost energy 

use and thermal load equations for hot gas defrost 

unit coolers tested alone to provide a consistent 

performance evaluation between hot gas defrost and 

electric defrost unit coolers when tested alone. 86 

FR 16027, 16030. However, this approach does not 

measure or account for actual hot gas defrost 

thermal load and energy use. 

usage and savings associated with 

technologies such as adaptive defrost 

and hot gas defrost. DOE is also 

considering adopting a test method to 

assess and confirm defrost adequacy. 

Any test method used to measure 

defrost energy use and adequacy would 

have to provide consistent, repeatable 

methods for (1) delivering a frost load to 

the test coil and (2) measuring the 

thermal load released into the 

refrigerated space during the defrost 

cycle, regardless of the method of 

defrost (e.g., electric or hot gas defrost), 

all while ensuring that the procedure 

provides results reflecting energy usage 

during a representative average use 

cycle and not be unduly burdensome to 

conduct. 

In AHRI 1250–2009, the moisture to 

provide a frost load is introduced 

through the infiltration of air at 75.2 °F 

dry-bulb temperature and 64.4 °F wetbulb temperature into the walk-in 

freezer at a constant airflow rate that 

depends on the refrigeration capacity of 

the tested freezer unit (equations C11 

and C12 in section C11.1.1 of AHRI 

1250–2009). A key issue with this 

approach is the difficulty in ensuring 

repeatable frost development on the unit 

under test, despite specifying the 

infiltration air dry-bulb and wet-bulb 

temperatures. For example, in addition 

to frost accumulating on the evaporator 

of the unit under test, frost may also 

accumulate on the evaporator of other 

cooling equipment used to condition the 

room, which could subsequently affect 

the rate of frost accumulation on the 

unit under test (by affecting the amount 

of moisture remaining in the air). 

ASHRAE-supported research— 

including a series of projects exploring 

frost loads and defrosting dynamics— 

suggest the possibility of alternative 

methods of creating a frost load. This 

work includes ASHRAE Project No. 

622–RP ‘‘A Study to Determine Heat 

Loads Due to Coil Defrosting’’ 34 (‘‘622– 

RP’’) and Project No. 1094–RP ‘‘A Study 

to Determine Heat Loads Due to Coil 

Defrosting-Phase II’’ 35 (‘‘1094–RP’’). For 

the experiments discussed in these 

reports, the researchers created a frost 

load by introducing steam directly into 

the refrigerated space. However, as 

discussed in 1094–RP, this approach 

can result in the suspension of ice 

crystals in the saturated room air and 

the formation of snow-like frost on the 

test coils. The researchers found that 

this snow-like frost degrades 

refrigeration system performance more, 

and is more difficult to defrost, than the 

ice-like frost that forms in sub-saturated 

air conditions. 622–RP and 1094–RP 

also observed that during the defrost 

cycle, a significant portion (a majority 

for some trials) of the coil frost was 

sublimated (converted to water vapor) 

rather than melted. This finding 

suggests that measuring the quantity of 

frost melt water mass may be a poor 

indicator of the frost load, since a 

significant portion of the frost would 

not be captured as melt water. DOE is 

interested in any viable alternate frost 

load delivery methods that could be 

used to apply a known and repeatable 

amount and type of frost. 

Issue 38: DOE requests information 

regarding potential methods of 

providing a measurable frost load and 

frost type for defrost testing, including 

data and information demonstrating the 

repeatability of such a test. 

Additionally, DOE requests data and 

information indicating what a typical 

frost load and frost type would be—for 

example, whether the moist air flow of 

section C11.1.1 of AHRI 1250–2009 

provides the appropriate amount of 

moisture, and if so, whether any data 

are available to support the use of this 

quantity. If such data are available, DOE 

asks that interested parties share it with 

the agency for further consideration. If 

such data are currently unavailable, 

DOE is interested in what kind and 

amount of testing would be needed to 

sufficiently validate an appropriate 

method to evaluate frost loads and frost 

types during defrost testing. 

b. Hot Gas Defrost 

Among its various recommendations, 

the Working Group recommended that 

DOE modify its current test procedure to 

account for hot gas defrost system 

performance. (Term Sheet 

Recommendation #6). As a result of this 

recommendation, DOE is interested in 

obtaining feedback on the most 

practicable method for measuring or 

otherwise accounting for hot gas defrost 

performance.36 DOE recognizes that in 

order to assess the energy performance 

of a defrost cycle, the test procedure 

must address both the energy consumed 

and the heat released into the 

refrigerated space by the defrost system. 

In general, for electric resistance heating 

systems, all the electrical energy 

consumed by the heater is transformed 

into heat, such that the energy 

consumed by the heater and the heat 

released into the space are equivalent. 

The procedure outlined in AHRI 1250– 

2009 is based on this principle and 

estimates the amount of heat released 

into the space by measuring energy 

consumption and subtracting the energy 

associated with frost melt that drains 

out of the chamber (section C11.1 of 

AHRI 1250–2009). 

Alternatively, for hot gas defrost 

systems, the heat energy released into 

the evaporator (in the form of latent 

heat), and ultimately into the 

refrigerated space, is greater than the 

electrical energy used by the compressor 

to drive the hot gas defrost system. The 

exact ratio of heat released to electrical 

energy consumed depends on the 

efficiency of the specific system design. 

Therefore, the amount of heat released 

into the room cannot be estimated by 

measuring the electrical energy 

consumption of the heating system. 

Because the procedure outlined in AHRI 

1250–2009 relies on an assumption that 

the energy consumed by the heater 

equals the heat released into the space, 

it is not applicable to hot gas defrost 

systems. DOE is not aware of a test 

method that can reliably be used to 

directly measure the thermal impact of 

hot gas defrost without a substantial 

increase in test burden. 

Alternatively, DOE could consider the 

use of a calculation method. In such an 

approach, rather than measure the heat 

released into the refrigerated space for 

the unit-under-test, that heat load would 

be calculated as a function of the 

refrigeration system’s steady-state 

capacity. The heat load-to-capacity 

relationship could be defined based on 

test data from actual hot gas defrost 

systems. Under this approach, the 

energy consumed by the hot gas defrost 

system could be quantified either by 

direct testing and measurement, or by 

using a calculation method, as described 

for heat load addition. DOE is aware 

that AHRI has developed a calculation 

method to represent hot gas defrost heat 

load and energy use contributions. This 

method is provided in Section C10.1 of 

AHRI 1250–2020 and prescribes 

equations to represent energy use and 

heat addition associated with defrost for 

different system configurations 

(matched-pair, single-package, unit 

cooler, condensing unit) and with 

consideration of whether hot gas is used 

only to defrost the evaporator or 


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37Working Group Meeting Stakeholder 

Presentation: Walk-in Refrigeration ASRAC 

Meeting, available at https://www.regulations.gov/ 

document?D=EERE-2015-BT-STD-0016-0038. 

whether it also maintains warm 

temperatures in the drip pan. 

Finally, if DOE were to modify its 

walk-in test procedure to account for 

hot gas defrost energy consumption and 

heat load, DOE would need to 

determine the types of refrigeration 

system configurations (i.e., matchedpairs, stand-alone unit coolers, and 

stand-alone condensing units) to which 

a hot gas defrost-specific test procedure 

would apply. For each configuration, 

DOE would also need to consider which 

methods (i.e., testing, calculation, or 

both) would be most appropriate. 

Issue 39: DOE requests comment on 

the specific refrigeration system 

configurations (i.e., matched-pairs, 

stand-alone unit coolers, and standalone condensing units) to which a hot 

gas defrost-specific test procedure 

would apply. DOE requests comment on 

which methods for determining energy 

and heat load (i.e., testing, calculation, 

or both) would be most appropriate for 

each refrigeration system and why. DOE 

requests comment on the methods 

related to hot gas defrost systems in 

AHRI 1250–2020. Finally, DOE requests 

data to help quantify the relationship 

between hot gas defrost heat load 

addition and energy consumption 

versus capacity and/or to confirm the 

relationships provided in the AHRI 

1250–2020 test methods for hot gas 

defrost. 

c. Adaptive Defrost 

In the December 2016 TP final rule, 

DOE established a method to address 

systems with adaptive defrost. That 

approach requires that the feature be 

deactivated during compliance testing 

but allows a manufacturer to account for 

a unit’s improved performance with 

adaptive defrost activated in its market 

representations. 81 FR 95758, 95767, 

95777, 95790. At the November 4, 2015 

Working Group meeting, Southern 

California Edison expressed concern 

with the assumption that the overall 

energy use of traditional defrost systems 

significantly exceeds adaptive defrost 

system energy use. Southern California 

Edison presented data showing that, for 

a tested adaptive defrost system, the 

reduction in energy use resulting from 

reduced defrost frequency is largely 

offset by an increase in energy use 

during the refrigeration on-cycle, due to 

the thermal resistance of the increased 

frost accumulation (Docket EERE–2015– 

BT–STD–0016, No. 38 37). The data 

presented by Southern California Edison 

illustrates just one potential 

complication in properly addressing the 

energy use impact of adaptive defrost— 

specifically, that an adaptive system 

that waits too long (i.e., when too much 

frost builds up on the coils) to defrost 

may significantly affect the on-cycle 

performance of the refrigeration system. 

On the other hand, an adaptive system 

that defrosts too frequently could 

increase defrost energy use if the defrost 

frequency is higher than the four 

defrosts per day that is typical for a 

conventional timed defrost. The 

sensitivity of the adaptive defrost 

savings potential to the magnitude of 

the moisture load also suggests that a 

single adaptive defrost test using a 

constant moisture load may not 

properly represent this technology’s 

benefits. The test procedure may have to 

account for the differences in daily and 

seasonal frosting patterns experienced 

by installed systems (e.g., frequent air 

infiltration during business hours and 

none during non-business hours—or 

infiltration of warm, moist air in 

summer and cool, dry air in winter). 

Issue 40: DOE requests comment on 

how the performance of adaptive defrost 

systems should be accounted for in the 

walk-in test procedure and which 

refrigeration systems (i.e., matchedpairs, stand-alone unit coolers, and 

stand-alone condensing units) should be 

evaluated under a potential adaptive 

defrost test procedure. Specifically, DOE 

requests data showing the performance 

of adaptive defrost systems relative to 

non-controlled defrost systems, 

including impacts to on-cycle operation. 

DOE requests data demonstrating 

seasonal and daily frosting patterns for 

walk-in applications. 

5. Off-Cycle Energy Use 

As discussed previously, the Working 

Group recommended that DOE amend 

its test procedure to address issues 

related to off-cycle power consumption 

(Term Sheet Recommendation #6). For 

walk-in refrigeration systems, the term 

‘‘off-cycle’’ refers to the period when the 

compressor is not running and defrost 

(if applicable) is not active. During the 

off-cycle, unit cooler fans and other 

auxiliary equipment will typically run 

or cycle on and off, thereby consuming 

energy. 

While the current DOE test procedure 

accounts only for fan power 

consumption during the off-cycle 

period, AHRI 1250–2020 includes 

requirements specific to off-cycle fan 

power consumption in Section C3.5, 

which addresses power measurements 

for unit coolers (including total power 

to the fan motor(s), pan heaters, and 

controls) and DCUs, in addition to 

prescribing off-cycle measurement 

intervals, operating tolerances and data 

collection rates. Section C4.2 provides a 

method for determining off-cycle power 

consumption. DOE is considering the 

incorporation of this updated industry 

test method into its test procedures 

should a rulemaking be initiated. 

Issue 41: DOE requests information 

and data on whether the off-cycle 

methods included in AHRI 1250–2020 

provide a representative and repeatable 

measure of the off-cycle power use for 

matched pairs, single-package systems, 

and also for unit coolers and/or 

condensing units tested alone, and if 

not, what modifications are 

recommended. DOE also seeks 

information on other off-cycle mode 

energy-consuming components that are 

not currently addressed by AHRI 1250– 

2020. In addition to identifying all offcycle mode energy-consuming 

components, DOE seeks information on 

the patterns and magnitudes of energy 

use by each of these components during 

the off-cycle. 

6. Multi-Capacity and Variable-Capacity 

Condensing Units 

In the July 2017 ECS final rule, DOE 

noted that it expected the majority of 

refrigeration equipment within the 

dedicated condensing class to be 

certified as stand-alone condensing 

units, with a much smaller number of 

systems certified as matched-pairs. 82 

FR 31808, 31832. However, the current 

DOE test procedure does not include a 

method for assessing stand-alone multiand variable-capacity systems. To 

address this gap, the Working Group 

recommended that DOE amend its test 

procedure to allow for separate ratings 

of stand-alone variable-capacity 

condensing units. (Term Sheet 

Recommendation #6). 

Historically, refrigeration systems 

have been designed using a single-speed 

compressor, which operates at full 

cooling capacity while the compressor 

is on. To match the cooling load of the 

space, which in most cases is less than 

the full cooling capacity of the 

compressor, a single-speed compressor 

cycles on and off at a particular duty 

cycle. This cycling behavior introduces 

inefficiencies due to the surge in power 

draw experienced at the beginning of 

each ‘‘on’’ cycle, before the compressor 

reaches steady-state performance. In 

contrast, variable-capacity systems 

employ an inverter compressor that can 

reduce its speed to match the observed 

cooling load. Accordingly, a variablespeed compressor runs continuously, 

adjusting its speed up or down as 

required, thereby avoiding compressor 

cycling when the full cooling capacity 


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38Multi-capacity product information from one 

manufacturer can be found at http://

www.regulations.gov Docket No. EERE–2017–BT– 

TP–0010–0004. 

39Lennox commented that the industry was 

moving to low-GWP refrigerants in response to the 

Environmental Protection Agency final rule under 

the Significant New Alternatives Policy (‘‘SNAP’’) 

program that prohibited the use of R–404A in 

certain retail food refrigeration applications, 

including WICF refrigeration systems starting July 

20, 2016. (Docket EERE–2016–BT–TP–0030, 

Lennox, No. 13 at p. 2) For further discussion of the 

SNAP rule, see section II.E.8 of this document. 

40Available at https://www.regulations.gov/ 

document?D=EERE-2015-BT-STD-0016-0089. 

of the compressor is not necessary to 

provide sufficient cooling to the space. 

Similarly, a multi-capacity compressor 

can ‘‘unload’’ individual cylinders 

within the compressor, which allows 

the compressor to remain on, but at a 

reduced capacity, to more closely match 

the required cooling load. 

The current DOE test procedure 

measures the performance of a walk-in 

condensing unit while operating under 

a full cooling load at a fixed capacity; 

i.e., the compressor is operated 

continuously in its ‘‘on’’ state. See AHRI 

1250–2009, Tables 11 through 14 and 

Appendix C, section 3.0. While AHRI 

1250–2009 and AHRI 1250–2020 both 

include test methods for multi- and 

variable-capacity matched pair 

refrigeration systems, there is no test 

method for multi- and variable-capacity 

condensing units when tested alone. As 

a result, any inefficiencies due to 

compressor cycling, and any 

performance benefit associated with 

part-load operation, are not captured 

during the DOE test. Consequently, the 

current test procedure may 

underestimate the efficiency benefits of 

multi- and variable-capacity systems. 

DOE is aware of some multi- or variablecapacity condensing units that are 

currently available on the market.38

Issue 42: DOE requests input on the 

development of test methods that would 

more accurately measure the energy use 

performance—including accounting for 

the potential efficiency benefits of 

multi- and variable-capacity systems— 

both for matched-pair and stand-alone 

condensing unit testing. DOE seeks data 

and information showing the potential 

magnitude of energy savings by 

reducing cycling losses in these multi 

and variable-capacity systems. DOE 

requests market information on whether 

there are multi- and variable-capacity 

condensing units available on the 

market (in addition to those already 

identified) and the brand name(s) and 

model numbers of those additional 

units. 

7. Systems for High-Temperature 

Freezer Applications 

In the June 2014 ECS final rule, DOE 

established equipment classes for 

medium- and low-temperature walk-in 

refrigeration systems. 79 FR 32050, 

32069–32070. While the terms 

‘‘medium-temperature’’ and ‘‘lowtemperature’’ are not explicitly defined, 

the June 2014 ECS final rule, 2015 

ASRAC negotiations, December 2016 TP 

final rule, and July 2017 ECS final rule 

all consistently used the term ‘‘mediumtemperature’’ to refer to walk-in cooler/ 

refrigerator refrigeration systems and the 

term ‘‘low-temperature’’ to refer to walkin freezer refrigeration systems. 

The current test procedure for walkin refrigeration systems specifies rating 

conditions of 35 °F for refrigerator 

systems and ¥10 °F for freezer systems 

(see section 5 of AHRI 1250–2009, 

incorporated by reference at 10 CFR 

431.303(b)). The 35 °F and ¥10 °F 

rating conditions produce a metric, 

AWEF, which is generally 

representative of the medium- and lowtemperature refrigeration systems’ 

energy use when installed in walk-in 

coolers and freezers, respectively. The 

AWEF metric forms the basis for energy 

conservation standards for medium- and 

low-temperature refrigeration systems. 

However, field usage data indicate that 

walk-in refrigeration systems operate at 

a broad range of application 

temperatures both above and below the 

respective 35 °F and ¥10 °F rating 

points. 

As discussed in the December 2016 

TP final rule, stakeholders commented 

that so-called ‘‘high-temperature’’ 

freezer walk-ins, which have an 

enclosed storage (i.e. room) temperature 

range of 10 °F to 32 °F, are refrigerated 

with medium-temperature condensing 

units. 81 FR 95758, 95790. Under the 

statutory definitions of ‘‘walk-in cooler’’ 

and ‘‘walk-in freezer,’’ this equipment 

would be considered a walk-in freezer 

because its room temperature is less 

than or equal to 32 °F 42 U.S.C. 

6311(20). Accordingly, these 

refrigeration systems would be tested 

using a room temperature of¥10 °F, as 

specified in Appendix C. However, 

stakeholders commented as to the 

difficulty these medium-temperature 

refrigeration systems have in meeting 

this temperature condition when using 

lower GWP refrigerants.39 81 FR 95758, 

95790. Lennox offered data suggesting 

that medium-temperature units 

generally perform more efficiently at the 

10 °F operating condition (i.e., the low 

end of the cited ‘‘high-temperature 

freezer’’ temperature range) than lowtemperature systems. (Docket EERE– 

2015–BT–STD–0016, Lennox, No. 89 40

at pp. 2–5) Lennox suggested that this 

‘‘high-temperature freezer’’ application 

may justifiably represent a third class of 

walk-in refrigeration systems, but also 

noted the reporting and testing burden 

that establishing an additional set of 

classes would incur. In response, DOE 

noted that manufacturers of equipment 

that cannot be tested in a way that 

properly represents their performance 

characteristics may petition DOE for test 

procedure waivers, as detailed in 10 

CFR 431.401. DOE also indicated that it 

may consider amending its regulations 

by establishing new equipment classes 

and applicable test methods. 81 FR 

95758, 95790–95791. 

DOE is currently considering how, if 

at all, to address high-temperature 

freezer walk-ins, including whether to 

establish test procedure provisions to 

specifically address the refrigeration 

systems serving such equipment. 

Multiple approaches are under 

consideration. One approach would 

allow walk-in manufacturers and 

contractors to install a medium 

temperature refrigeration system that is 

tested and certified based on the 

standardized 35 °F walk-in cooler 

temperature (or corresponding 

refrigerant suction conditions) as a 

walk-in freezer, if the walk-in 

refrigeration system is marketed at or 

above 10 °F. By extension, the approach 

would also allow representations of 

performance (e.g. capacity, power input) 

of such medium-temperature 

refrigeration systems for walk-in 

temperatures at 10 °F and higher 

without requiring them to be tested and 

certified based on the¥10 °F lowtemperature walk-in test condition. This 

approach would alleviate the need for a 

new high-temperature freezer 

equipment class (thus avoiding the 

associated certification test burden), 

while still allowing the potentially more 

efficient medium temperature 

refrigeration systems to be used for high 

temperature freezer applications. 

(Docket EERE–2015–BT–STD–0016, 

Lennox, No. 89 at pp. 2–5 (offering data 

suggesting that medium temperature 

units generally perform more efficiently 

at the 10 °F operating condition than 

low-temperature systems)). 

DOE could establish new definitions 

for the terms ‘‘low-temperature 

refrigeration system’’ and ‘‘mediumtemperature refrigeration system,’’ that 

implement this potential structure. For 

example, ‘‘low-temperature refrigeration 

system’’ could be defined as ‘‘a 

refrigeration system used to cool the 

interior of walk-in freezers and maintain 

a refrigerated room temperature of 10 °F 

or less,’’ while ‘‘medium-temperature 

refrigeration system’’ could be defined 


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as ‘‘a refrigeration system used to cool 

the interior of a walk-in cooler or a 

walk-in freezer operating above 10 °F.’’ 

Alternatively, another approach 

would allow medium-temperature 

refrigeration systems used in hightemperature freezer walk-in applications 

to be tested and certified at their lowest 

application temperature conditions. 

This approach would be similar to that 

taken for commercial refrigerators, 

freezers, and refrigerator-freezers, for 

which manufacturers report the lowest 

application product temperature, i.e. the 

lowest average compartment 

temperature at which the equipment is 

capable of operating during testing 

(section 2.2 of appendix B to 10 CFR 

part 431 subpart C). For walk-ins, this 

concept could be based on the lowest 

evaporator return air temperature for 

matched-pair refrigeration systems and 

the lowest saturated suction 

temperature (and a suitable 

corresponding return gas temperature) 

for condensing units tested separately. 

This approach would result in ratings 

for the units in high-temperature freezer 

applications that are directly 

representative of field performance, as 

the refrigeration system would be tested 

at a representative box temperature for 

such an application. Further, this 

approach would not presuppose what 

the optimal high-temperature freezer 

operating condition would be, i.e., it 

avoids selecting a standardized 

condition that may be unachievable by 

some units. However, AWEF ratings 

obtained from the lowest application 

temperature for different units, which 

would be rated for different box 

temperatures, would not be directly 

comparable. The approach would also 

add testing and reporting burden 

associated with the additional test 

condition. 

DOE is also considering a third 

approach that would establish a single 

standardized test condition at which 

high-temperature freezer refrigeration 

equipment would be tested. This 

approach would result in AWEF ratings 

that are slightly less representative of 

field performance than the lowest 

application temperature approach, 

while still creating the potential need to 

establish a new equipment class (or 

classes) for low-temperature 

refrigeration systems. However, under a 

standardized test condition approach, 

all high-temperature freezer 

refrigeration systems would be rated at 

the same condition, providing directly 

comparable ratings for models that serve 

similar applications. 

DOE is investigating if and how the 

calculations used for determining the 

AWEF of WICF condensing units tested 

alone and with matched systems would 

need to be modified for products 

certified with the latter two approaches 

discussed previously—for example, 

whether any potential changes to the 

specified duty cycle at 95 °F ambient 

temperature for an outdoor system 

would be necessary. 

Issue 43: DOE requests feedback on 

the three approaches discussed in this 

section to address high-temperature 

freezer walk-ins, as well as any other 

potential approaches not raised in this 

RFI. 

Issue 44: DOE also requests 

information that would help inform the 

development of test procedures for hightemperature freezer refrigeration 

systems, should such an approach be 

necessary. Additionally, DOE requests 

whether there are specific 

characteristics that distinguish a hightemperature freezer refrigeration system 

from a medium-temperature 

refrigeration system, in order to better 

define this category of equipment. 

Issue 45: DOE also requests comment 

on whether 10 °F is the appropriate 

lowest end of the application range for 

equipment used in walk-in hightemperature freezers that cannot be 

tested using the ¥10 °F freezer test 

condition. Furthermore, DOE requests 

comment on whether all mediumtemperature systems (matched-pair, 

condensing unit, evaporator) can be 

operated and tested at 10 °F (or 

equivalent refrigerant suction 

conditions), or whether there is a wide 

range at the low-end of the operating 

range that depends on the design of the 

system. 

Issue 46: Regarding the testing of a 

medium-temperature refrigeration 

system in the high-temperature freezer 

range, DOE requests information on 

what specified test procedure 

parameters would need to be altered 

(and how) in order for the test to be 

representative of field operation. (In 

answering, DOE requests that 

commenters provide the supporting 

reasons for any suggested 

recommendations.) DOE requests 

information on whether a single 

standardized high-temperature freezer 

room condition could be appropriate for 

testing this group of walk-ins, and if so, 

what such an appropriate temperature 

would be. 

Issue 47: Finally, DOE requests 

comment on what, if any, changes 

would be needed in the calculation of 

AWEF for high-temperature freezer 

operation, and why. 

If DOE were to pursue the lowest 

application temperature approach or the 

standardized high-temperature freezer 

test condition approach, DOE would 

need to establish certain new default 

values to calculate the AWEF and net 

capacity of stand-alone hightemperature freezer dedicated 

condensing units. Currently, the test 

procedure provides equations for 

determining evaporator fan power, 

defrost energy, and defrost heat load, all 

of which are used in lieu of matched 

unit cooler test data (section 3.4.2 of 

Appendix C). 

The current test procedure offers two 

separate equations that relate the 

cooling capacity to the evaporator fan 

power for medium- and lowtemperature unit coolers (section 3.4.2.2 

of Appendix C). Based on the 

condensing unit capacity at the medium 

temperature test condition (35 °F box 

temperature), using the mediumtemperature equation seems to be the 

most appropriate approach since the 

condensing units in question would also 

be certified as medium-temperature 

condensing units. This approach also 

assumes that fan energy use at hightemperature freezer conditions will be 

the same as fan energy use at mediumtemperature conditions, since it makes 

no adjustment in the calculated fan 

power for the high-temperature freezer 

application. 

Issue 48: DOE requests comment on 

the appropriateness of using the current 

medium-temperature refrigeration 

system default fan input power equation 

(found at section 3.4.2.2 of Appendix C) 

to represent the fan input power of hightemperature freezer refrigeration 

systems. If the current mediumtemperature refrigeration system default 

fan input power equation is not 

representative of the fan input power for 

high-temperature freezer refrigeration 

systems, DOE requests suggestions for a 

more appropriate equation, or 

alternative relationships to consider, as 

well as any relevant data. 

In the current test procedure, defrost 

energy and defrost heat load for standalone dedicated condensing units are 

estimated based on the condenser 

capacity using an equation in section 

3.4.2 of Appendix C. The calculations 

apply only to freezer models, since they 

assume that refrigeration systems 

serving walk-in coolers are not 

equipped for defrost capability and thus 

have no defrost energy or heat load. 

However, medium-temperature 

refrigeration systems designed for hightemperature freezer applications require 

defrost capability because frost that 

collects on the evaporator during the 

compressor off-cycle will not melt in the 

sub-freezing walk-in temperature 

conditions. The energy and heat load of 

these high-temperature freezer defrost 

systems may differ significantly from 


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41 http://www.unep.org/ozonaction/Portals/105/ 

documents/7809-e-Factsheet_Kigali_Amendment_

to_MP.pdf (last viewed February 3, 2017). 

42 The vacatur and remand in Mexichem, Inc. v. 

EPA was of the July 2015 EPA SNAP Rule and did 

not directly address the December 2016 EPA SNAP 

Rule. At issue was EPA’s use of its SNAP authority 

as a means to remove HFCs from the agency’s list 

of acceptable substitutes. On April 27, 2018, EPA 

published a notice stating that in the near-term it 

will not apply the HFC listings in the July 2015 

final rule pending a rulemaking and that it plans 

to begin a notice-and-comment rulemaking process 

to address the remand. 83 FR 18431. 

43 Following the decision in the Mexichem case, 

the court vacated the December 2016 SNAP Rule to 

the extent it requires manufacturers to replace HFCs 

that were previously and lawfully installed as 

substitutes for ozone-depleting substances. Case No. 

17–1024 (D.C. Cir. April 5, 2019). 

those of ¥10 °F freezers. Therefore, 

proper accounting for defrost of hightemperature freezer refrigeration 

systems requires developing a modified 

calculation. The equation found in 

section 3.4.2.4 of Appendix C used to 

calculate freezer equipment daily 

defrost energy use (‘‘DF’’) uses as inputs 

the condenser capacity (‘‘qmix,cd’’) and 

the number of defrost cycles per day 

(‘‘NDF’’). The daily defrost heat load 

(‘‘QDF’’) is directly dependent on DF 

(see relevant equation in section 3.4.2.5 

of Appendix C). DOE anticipates that a 

calculation of defrost impacts for hightemperature freezers, if adopted, would 

use similar equations with different 

magnitudes. 

Issue 49: DOE requests information or 

data that would indicate whether and 

how the equations used to calculate 

daily defrost energy use and heat 

addition in the test procedure should be 

modified for high-temperature freezer 

refrigeration systems rated as standalone condensing units (e.g., defrost 

heater wattage and daily energy use as 

a function of capacity for a 10 °F walkin temperature). If testing at the lowest 

application temperature is adopted, 

DOE requests comment on how the 

defrost equations should be modified to 

account for each model being tested at 

different conditions, and why. DOE 

requests information on whether frost 

loads and/or defrost frequency are 

different for high- temperature freezers 

than for ¥10 °F freezers. (DOE requests 

that commenters include any available 

supporting information when 

responding.) 

8. Consideration for Refrigerant Glide 

The analysis for the June 2014 ECS 

final rule assumed that the refrigerant 

R–404A would be used in all new 

refrigeration equipment meeting the 

standard. 79 FR 32050, 32074. In its 

subsequent negotiated rulemaking effort 

in 2015, WICF Working Group members 

suggested that DOE revise this approach 

by accounting for the use of a different 

refrigerant, R–407A, which was 

expected to become more commonly 

used for WICF applications. Consistent 

with that suggestion, DOE conducted 

the analysis for the July 2017 ECS final 

rule using R–407A as the refrigerant. 82 

FR 31808, 31835–31836. 

On July 20, 2015, the U.S. 

Environmental Protection Agency 

(‘‘EPA’’) published a final rule under the 

Significant New Alternatives Policy 

(‘‘SNAP’’) program listing as 

unacceptable the use of certain 

hydrofluorocarbons (‘‘HFCs’’), including 

the use of R–404A in WICF refrigeration 

systems. 80 FR 42870 (‘‘July 2015 EPA 

SNAP Rule’’). In October 2016, the 28th 

Meeting of the Parties to the Montreal 

Protocol adopted the Kigali Amendment 

on HFCs, which, upon ratification, 

requires parties to the protocol to reduce 

consumption and production of HFCs.41

On December 1, 2016, EPA published a 

final rule (‘‘December 2016 EPA SNAP 

Rule’’) that listed a number of 

refrigerants for use in certain refrigerant 

applications as unacceptable, starting 

January 1, 2023 for cold storage 

warehouse application, and January 1, 

2021 for retail food refrigerant 

applications. 81 FR 86778. The list of 

unacceptable refrigerants included R– 

407A. The validity of the SNAP 

approach, however, has been the subject 

of a legal challenge regarding EPA’s use 

of its SNAP authority to require 

manufacturers to replace HFCs with a 

substitute substance. 

In August 2017, the U.S. Court of 

Appeals for the District of Columbia 

Circuit vacated and remanded the July 

2015 EPA SNAP Rule to the extent that 

it required manufacturers to replace 

HFCs with a substitute 

substance.42 Mexichem Fluor, Inc. v. 

EPA, 866 F.3d 451 (D.C. Cir. 2017). 

Subsequently, the December 2016 SNAP 

Rule was partially vacated by the 

court.43 While the United States has not 

ratified the Kigali Amendment, a 

significant portion of walk-in 

refrigeration systems currently use HFCbased refrigerants and may become 

affected by this Amendment to the 

Montreal Protocol. DOE plans to 

consider the potential impact (if any) of 

both the court’s decision and remand as 

well as the Amendment to the Montreal 

Protocol on the test procedure issues 

addressed in this RFI. 

Notwithstanding these legal 

developments, key differences between 

the refrigerants used in DOE’s separate 

analyses of walk-in refrigeration systems 

merit discussion. Both R–404A and 

R–407A are blends of refrigerants that 

have different boiling points. This 

means that, unlike pure substances such 

as water, the temperature of the 

refrigerant changes as it boils or 

condenses, because one of the 

refrigerants in the blend, having a lower 

boiling point, boils off sooner than the 

other(s). This phenomenon is called 

‘‘glide.’’ The refrigerants that make up 

R–404A have nearly identical boiling 

points, so this refrigerant has very little 

glide. In contrast, R–407A undergoes a 

much more significant temperature 

change when it boils—the temperature 

can rise as much as 8 degrees between 

the saturated liquid condition (the 

temperature at which a liquid begins to 

boil, also called the ‘‘bubble point’’) and 

the saturated vapor condition (the 

temperature at which a vapor begins to 

condense, also called the ‘‘dew point’’). 

The average of these two temperatures, 

bubble point and dew point, is called 

the mid-point temperature. 

The current DOE test procedure 

specifies that test conditions are based 

on dew point. DOE notes that if the 

refrigerant condition for a unit cooler is 

specified by dew point, the average 

refrigerant temperature would be 

significantly lower for a high-glide than 

for a low-glide refrigerant. As 

mentioned previously, DOE is 

considering changing its test procedure 

to be based on a refrigerant-neutral 

approach. One specific option would be 

to use the mid-point temperature. 

However, with walk-in refrigeration 

systems, the refrigerant entering the unit 

cooler is typically a two-phase 

refrigerant with a temperature higher 

than the bubble point. This scenario 

results in the average evaporator 

temperature being slightly greater than a 

mid-point equal to the average of bubble 

and dew point temperatures. To account 

for this difference, DOE could develop 

an approach to calculate and specify 

refrigerant temperatures in terms of a 

‘‘modified mid-point,’’ which would be 

a calculated value slightly higher than 

the mid-point of the selected refrigerant. 

Issue 50: DOE requests comment on 

the appropriateness of specifying 

refrigerant temperatures in terms of 

mid-point or a modified mid-point, 

rather than dew point, which is 

currently used. DOE seeks feedback on 

potential definitions to use for a 

modified mid-point temperature as 

applied to WICF refrigeration system 

testing. In addition, DOE requests 

comments on what other factors should 

be considered when modifying the 

refrigeration system test conditions from 

dew point to mid-point or modified 

mid-point specifications. 

III. Submission of Comments 

DOE invites all interested parties to 

submit in writing by the date specified 


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in the DATES heading, comments and 

information on matters addressed in this 

RFI and on other matters relevant to 

DOE’s early assessment of whether an 

amended test procedure for walk-in 

coolers and freezers is warranted and if 

so, what such amendments should be. 

Submitting comments via https://

www.regulations.gov. The https://

www.regulations.gov web page requires 

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 https://

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 https://

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 https://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 https://

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 https:// 

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. 

Submit these documents via email. 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). 

DOE considers public participation to 

be a very important part of the process 

for developing test procedures and 

energy conservation standards. DOE 

actively encourages the participation 

and interaction of the public during the 

comment period in each stage of this 

process. Interactions with and between 

members of the public provide a 

balanced discussion of the issues and 

assist DOE in the process. Anyone who 

wishes to be added to the DOE mailing 

list to receive future notices and 

information about this process should 

contact Appliance and Equipment 

Standards Program staff at (202) 287– 

1445 or via email at 

ApplianceStandardsQuestions@

ee.doe.gov. 

IV. 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 seeks comment on how 

liquid-cooled refrigeration systems are 

(or could be) used with respect to walkin applications. DOE requests comment 

on whether it should consider 

establishing a test procedure for liquidcooled refrigeration systems. If test 

procedures were considered for liquidcooled refrigeration systems, DOE 

requests information on whether there is 

an industry standard or standards that 

should be considered. 

Issue 2: DOE seeks comment on how 

wine cellar refrigeration systems should 

be defined to best represent the 

conditions under which these systems 

are designed to operate and to fully 

distinguish these systems from systems 

designed to meet safe food storage 

requirements. Additionally, DOE 

requests comment on applications other 

than wine cellar storage for refrigeration 

systems that are designed to operate at 

temperatures warmer than typical for 

coolers and for which testing at 35 °F 

would be representative of use. If there 

are such additional applications, DOE 

seeks information regarding the specific 

operating requirements (i.e., 

temperature and humidity) for these 

systems. 

Issue 3: DOE requests comment on the 

current definition of ‘‘door’’ in 10 CFR 

431.302. DOE seeks feedback on the 

terminology of door components used 

and whether these are consistently 

interpreted. DOE seeks specific feedback 

from manufacturers on how they use the 

term ‘‘door plug’’ and whether it is 

essential to the definition of a WICF 

‘‘door’’. 

Issue 4: DOE requests comment on 

whether height and width or surface 

area are distinct attributes that 

effectively distinguish between passage 

and freight doors. DOE seeks 

information on any building codes, 

standards, or industry practices to 

support or refute maintaining the 

dimensions of a door as the defining 


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characteristic which separates freight 

and passage doors. 

Issue 5: Regarding a door that meets 

the freight door definition but does so 

only because it has a multi-door 

configuration in which the individual 

component doors each would by 

themselves not meet the freight door 

definition, DOE seeks comment on how 

such doors should be classified, and 

whether such classification should 

depend on other factors, such as 

whether one or more frame members 

divides the door opening into smaller 

openings. 

Issue 6: DOE seeks comment on 

whether any attribute, or combination of 

attributes, other than size, would affect 

energy use and could be used to 

distinguish between freight doors and 

passage doors. If so, DOE requests data 

and comment on such attributes. 

Issue 7: DOE requests comment on the 

accuracy of the computational method 

in NFRC 100 to predict U-factor for 

display and non-display doors. DOE 

seeks feedback regarding the differences 

in results (if any) between those 

obtained using the NFRC 100 

computational method and those 

obtained when conducting physical 

testing using NFRC 102 for display and 

non-display doors. DOE is also 

interested in the magnitude of these 

differences and whether the 

computational method can be modified 

to yield results that more closely match 

the results obtained from actual 

physical testing. If manufacturers are 

aware of other methods to predict Ufactor for either display doors or nondisplay doors besides NFRC 100, DOE 

requests how the results from these 

methods compare to physical testing. 

Issue 8: DOE seeks information from 

manufacturers and other interested 

parties regarding how the industry 

currently rates individual door models, 

including the prevalence within the 

industry of using the computational 

method from NFRC 100. DOE also 

requests information on the costs 

associated with the computational 

method of NFRC 100 or an alternative 

computational method compared to 

physically testing the thermal 

transmittance of walk-in doors using 

NFRC 102. 

Issue 9: DOE requests comment on 

what issues, if any, would be present if 

ASTM C518–17 were to be referenced in 

the Appendix B test procedure for 

measuring panel K-factor, or average 

thermal conductivity. While not 

exhaustive, primary areas of interest to 

DOE include any differences between 

the currently referenced version of the 

industry standard (ASTM C518–04) and 

ASTM C518–17 that would result in a 

difference in the determined R-value 

and/or test burden (whether an increase 

or decrease), and if there are such 

differences, the magnitude of impact to 

the determined R-value and/or test 

burden. 

Issue 10: DOE requests comment on 

what issues, if any, would be present if 

AHRI 1250–2020 were to be referenced 

in the Appendix C test procedure for 

measuring walk-in refrigeration system 

AWEF. While not exhaustive, primary 

areas of interest to DOE include any 

differences between the currently 

referenced version of the industry 

standard (AHRI 1250–2009) and AHRI 

1250–2020 that would result in a 

difference in the determined AWEF 

and/or test burden (whether an increase 

or decrease), and if there are such 

differences, the magnitude of impact to 

the determined AWEF and/or test 

burden. 

Issue 11: DOE requests comment on 

how manufacturers determine surface 

area for the purpose of evaluating 

compliance with the standards for both 

display doors and nondisplay doors. 

DOE seeks input on any distinction 

between display doors and nondisplay 

doors, especially the door frames, which 

may warrant surface area for each to be 

determined differently. 

Issue 12: DOE seeks feedback on how 

manufacturers interpret and measure 

door opening as it relates to prescriptive 

standards for antisweat heaters, 

including whether or not manufacturers 

agree that the door opening considered 

for antisweat heat should be consistent 

with the surface area used to determine 

maximum energy consumption. 

Issue 13: DOE requests feedback on 

specifying the surface area used to 

determine thermal conduction through a 

walk-in door from the surface area used 

to determine the maximum energy 

consumption of a walk-in door. 

Issue 14: DOE seeks comment on 

whether, and if so how, an option for 

direct component power measurement 

could be included in the test procedure 

or compliance, certification, and 

enforcement (‘‘CCE’’) provisions to 

allow more accurate accounting for the 

direct electrical energy consumption of 

WICF doors. DOE also seeks input on 

whether specific provisions should be 

provided for determining power input 

from the information that is typically 

provided on nameplates, noting the 

limitations that were described above. 

Issue 15: DOE requests comment on 

the current PTO values and whether 

DOE should consider amending any of 

the current values or adding specific 

values for additional electrical 

components, specifically motorized 

door openers. DOE requests data from 

field studies or similar sources to 

support any proposed amendments (or 

additions) to these PTO values. 

Issue 16: DOE seeks feedback on 

whether the current PTO of 50 percent 

is appropriate for evaluating direct 

energy consumption of anti-sweat 

heaters with controls for walk- in cooler 

doors marketed for high humidity 

applications. DOE seeks feedback on the 

average amount of time per day or per 

year that anti-sweat heaters with 

controls are off for these high humidity 

doors and how this compares to 

standard (i.e., non-high humidity) walkin cooler display doors. 

Issue 17: DOE seeks feedback on the 

current EER values specified in 

Appendix A used to calculate daily 

energy consumption for walk-in doors 

and the values used in testing of unit 

coolers alone, as specified in Appendix 

C. Specifically, DOE requests comment 

on which of these sets of EER values is 

more representative, whether DOE 

should make the values used for door 

testing and unit cooler testing consistent 

with each other, and if so, which of the 

sets of values should be used. 

Issue 18: DOE requests comment on 

how frequently test laboratories perform 

each of the calibration procedures 

referenced in ASTM C1199 and ASTM 

C1363, e.g., those used to determine 

calibration coefficients that are used to 

calculate metering box wall loss and 

surround panel flanking loss. DOE also 

requests comment on the magnitude of 

variation in the calibration coefficients 

measured during successive 

calibrations. 

Issue 19: DOE requests feedback on 

whether the tolerances in section 

5.3(a)(1) of Appendix A applied to the 

surface heat transfer coefficients used to 

measure thermal transmittance are 

achievable for all walk-in doors and if 

not, whether the tolerances should be 

increased or omitted. Specifically, DOE 

seeks data to support any changes to the 

tolerances on the surface heat transfer 

coefficients. 

Issue 20: DOE requests comment on 

how panel thickness is currently 

measured for determining the panel’s 

R-value per the DOE test procedure, 

including number of measurements, 

measurement location, and any steps 

that are routinely followed for the 

removal of the protective skins or facers 

to obtain the full panel thickness. DOE 

requests that commenters identify any 

specific guidelines, practices or 

standardized approaches that are 

followed, as well as their date of 

publication, if applicable. 

Issue 21: DOE requests comment on 

how flatness and parallelism of the test 

specimen surfaces that contact the hot 


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plate assemblies described in ASTM 

C518 are typically determined by test 

laboratories and whether the test 

procedure should be revised to clarify 

how to determine these parameters, e.g., 

what type of instruments are used to 

measure these values, how many 

measurements are made for a given 

specimen, and other details that could 

affect conclusions regarding compliance 

with the test procedure. 

Issue 22: DOE requests comment on 

the extent to which manufacturers of 

insulation specify conditioning for 

insulation materials that differ from the 

typical conditioning approach described 

in ASTM C518. DOE also seeks feedback 

on whether more than one 24-hour 

conditioning period is ever needed to 

complete the conditioning (i.e., the 

change in specimen mass is less than 1 

percent after the first 24 hours of 

conditioning) for a specimen extracted 

from a WICF panel or door. Finally, 

DOE requests information or data on 

how specimen conditioning times less 

than or equal to 24 hours impacts the 

accuracy, repeatability, and 

representativeness of the test. 

Issue 23: DOE requests information 

about panel construction factors that 

would affect thermal transmission and 

the magnitude of the energy efficiencyrelated impacts of thermal bridges in the 

panel assembly. Additionally, DOE 

requests comment on alternative test 

methods that measure the overall 

thermal transmittance of walk-in panels 

and the relative advantages and 

disadvantages of each. DOE also seeks 

feedback on the number and location of 

labs that have the facilities and are 

qualified to run ASTM C1363–05. 

Issue 24: DOE seeks feedback on the 

current test procedure for display panels 

in Appendix A and what amendments 

should be made, if any, to it. 

Issue 25: DOE requests comment on 

whether the single-package system test 

and calculation methods described in 

AHRI 1250–2020 provide representative 

energy use. DOE also requests comment 

on whether DOE should incorporate by 

reference AHRI 1250–2020 as the test 

procedure for single-package systems. 

Issue 26: DOE requests any data or 

calculations quantifying the additional 

thermal losses associated with testing 

single-package systems due to the 

exposure of their cold sides to the 

exterior air (i.e., surface and infiltration 

losses). DOE additionally requests 

comment on whether the AHRI 1250– 

2020 test methodology for singlepackage systems fully accounts for these 

additional losses. 

Issue 27: DOE requests comment and 

data on the use of water, glycol, or other 

heat transfer liquid in maintaining test 

compartment temperature using the 

calorimeter methods referenced in AHRI 

1250–2020 for the testing of singlepackage refrigeration systems. DOE 

requests comment on whether the 

description and requirements for 

calorimetric testing as provided in AHRI 

1250–2020 should be modified or 

enhanced in order to better ensure that 

measurements are accurate and 

repeatable. 

Issue 28: DOE requests comment on 

whether calorimeter test methods for 

single-package systems should 

implement a pressure-equalizing device, 

as included in ASHRAE 16–2016. DOE 

requests information on any additional 

cost and resource burdens, if any, 

manufacturers would face when 

employing these methods to evaluate 

single-package systems. 

Issue 29: DOE seeks comment 

regarding any alternative test methods 

not mentioned in this document that 

could be used to measure single-package 

system capacity. To the extent that any 

alternative test methods could be used 

for this purpose, DOE requests 

information on their advantages and 

disadvantages in measuring singlepackage system capacity. 

Issue 30: DOE requests comment on 

the alternative test procedure for wine 

cellar walk-in refrigeration systems that 

it has granted in the interim waivers and 

waivers listed in Table II.3. DOE 

additionally seeks comment on whether 

the alternative test procedure prescribed 

for the specified basic models identified 

in the waivers would be appropriate for 

similar refrigeration equipment. 

Issue 31: DOE requests feedback on its 

approach for testing ducted units in its 

alternate test procedure for wine cellar 

refrigeration systems. Specifically, DOE 

requests comment and supporting data 

on whether testing at 50 percent of 

maximum ESP provides representative 

performance values, or whether other 

fractions of maximum ESP may be more 

appropriate. Additionally, DOE seeks 

comment on other industry test methods 

that include the testing of ducted units. 

Finally, DOE is interested in other 

alternative approaches for testing 

ducted units that have been 

demonstrated to provide repeatable and 

representative results. 

Issue 32: DOE requests data and 

information on appropriate EER values 

for use in calculating AWEF for wine 

cellar unit coolers tested alone, and how 

these EER values might depend on 

refrigerant and/or capacity. DOE 

requests that commenters provide 

background explanation regarding how 

any such EER recommendations have 

been developed. 

Issue 33: DOESince unit coolers for 

wine cellar systems are sold alone, DOE 

seeks information on the characteristics 

of condensing units that would typically 

be paired with these unit coolers (e.g., 

make/model, compressor style, capacity 

range, manufacturers). 

Issue 34: DOE seeks comment on 

whether, and if so how, it should 

modify its definitions for ‘‘singlepackaged dedicated system’’ and ‘‘unit 

cooler’’ to address units that are 

designed to be installed with ducts. 

Issue 35: DOE requests comment on 

any other issues regarding testing of 

wine cellar refrigeration systems that 

may not be fully addressed by the 

current DOE test procedure. 

Issue 36: DOE requests comment on 

test conditions that would be most 

appropriate for evaluating the energy 

use of CO2 unit coolers. Additionally, 

DOE requests feedback on any 

additional changes that would need to 

be made to the DOE test procedure to 

accurately evaluate energy use of these 

systems, while minimizing test burden. 

Issue 37: DOE requests comment on 

the present and future expected use of 

walk-in refrigeration systems using CO2. 

DOE requests specific information about 

these systems that would suggest a need 

to modify the DOE test procedure to 

address such equipment. Specifically, 

DOE requests information on whether 

such equipment is sold in the U.S., 

whether this equipment is sold as 

matched pairs or individual 

components, and to what extent 

dedicated condensing units are 

configured to supply subcritical liquid 

(rather than supercritical gas) to the unit 

coolers. 

Issue 38: DOE requests information 

regarding potential methods of 

providing a measurable frost load and 

frost type for defrost testing, including 

data and information demonstrating the 

repeatability of such a test. 

Additionally, DOE requests data and 

information indicating what a typical 

frost load and frost type would be—for 

example, whether the moist air flow of 

section C11.1.1 of AHRI 1250–2009 

provides the appropriate amount of 

moisture, and if so, whether any data 

are available to support the use of this 

quantity. If such data are available, DOE 

asks that interested parties share it with 

the agency for further consideration. If 

such data are currently unavailable, 

DOE is interested in what kind and 

amount of testing would be needed to 

sufficiently validate an appropriate 

method to evaluate frost loads and frost 

types during defrost testing. 

Issue 39: DOE requests comment on 

the specific refrigeration system 

configurations (i.e., matched-pairs, 


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stand-alone unit coolers, and standalone condensing units) to which a hot 

gas defrost-specific test procedure 

would apply. DOE requests comment on 

which methods for determining energy 

and heat load (i.e., testing, calculation, 

or both) would be most appropriate for 

each refrigeration system and why. DOE 

requests comment on the methods 

related to hot gas defrost systems in 

AHRI 1250- 2020. Finally, DOE requests 

data to help quantify the relationship 

between hot gas defrost heat load 

addition and energy consumption 

versus capacity and/or to confirm the 

relationships provided in the AHRI 

1250–2020 test methods for hot gas 

defrost. 

Issue 40: DOE requests comment on 

how the performance of adaptive defrost 

systems should be accounted for in the 

walk-in test procedure and which 

refrigeration systems (i.e., matchedpairs, stand-alone unit coolers, and 

stand-alone condensing units) should be 

evaluated under a potential adaptive 

defrost test procedure. Specifically, DOE 

requests data showing the performance 

of adaptive defrost systems relative to 

non-controlled defrost systems, 

including impacts to on-cycle operation. 

DOE requests data demonstrating 

seasonal and daily frosting patterns for 

walk-in applications. 

Issue 41: DOE requests information 

and data on whether the off-cycle 

methods included in AHRI 1250–2020 

provide a representative and repeatable 

measure of the off-cycle power use for 

matched pairs, single-package systems, 

and also for unit coolers and/or 

condensing units tested alone, and if 

not, what modifications are 

recommended. DOE also seeks 

information on other off-cycle mode 

energy-consuming components that are 

not currently addressed by AHRI 1250– 

2020. In addition to identifying all offcycle mode energy-consuming 

components, DOE seeks information on 

the patterns and magnitudes of energy 

use by each of these components during 

the off-cycle. 

Issue 42: DOE requests input on the 

development of test methods that would 

more accurately measure the energy use 

performance—including accounting for 

the potential efficiency benefits of 

multi- and variable-capacity systems— 

both for matched-pair and stand-alone 

condensing unit testing. DOE seeks data 

and information showing the potential 

magnitude of energy savings by 

reducing cycling losses in these multi 

and variable-capacity systems. DOE 

requests market information on whether 

there are multi- and variable-capacity 

condensing units available on the 

market (in addition to those already 

identified) and the brand name(s) and 

model numbers of those additional 

units. 

Issue 43: DOE requests feedback on 

the three approaches discussed in this 

section to address high-temperature 

freezer walk-ins, as well as any other 

potential approaches not raised in this 

RFI. 

Issue 44: DOE also requests 

information that would help inform the 

development of test procedures for hightemperature freezer refrigeration 

systems, should such an approach be 

necessary. Additionally, DOE requests 

whether there are specific 

characteristics that distinguish a hightemperature freezer refrigeration system 

from a medium-temperature 

refrigeration system, in order to better 

define this category of equipment. 

Issue 45: DOE also requests comment 

on whether 10 °F is the appropriate 

lowest end of the application range for 

equipment used in walk-in hightemperature freezers that cannot be 

tested using the ¥10 °F freezer test 

condition. Furthermore, DOE requests 

comment on whether all mediumtemperature systems (matched-pair, 

condensing unit, evaporator) can be 

operated and tested at 10 °F (or 

equivalent refrigerant suction 

conditions), or whether there is a wide 

range at the low-end of the operating 

range that depends on the design of the 

system. 

Issue 46: Regarding the testing of a 

medium-temperature refrigeration 

system in the high-temperature freezer 

range, DOE requests information on 

what specified test procedure 

parameters would need to be altered 

(and how) in order for the test to be 

representative of field operation. (In 

answering, DOE requests that 

commenters provide the supporting 

reasons for any suggested 

recommendations.) DOE requests 

information on whether a single 

standardized high-temperature freezer 

room condition could be appropriate for 

testing this group of walk-ins, and if so, 

what such an appropriate temperature 

would be. 

Issue 47: Finally, DOE requests 

comment on what, if any, changes 

would be needed in the calculation of 

AWEF for high-temperature freezer 

operation, and why. 

Issue 48: DOE requests comment on 

the appropriateness of using the current 

medium-temperature refrigeration 

system default fan input power equation 

(found at section 3.4.2.2 of Appendix C) 

to represent the fan input power of hightemperature freezer refrigeration 

systems. If the current mediumtemperature refrigeration system default 

fan input power equation is not 

representative of the fan input power for 

high-temperature freezer refrigeration 

systems, DOE requests suggestions for a 

more appropriate equation, or 

alternative relationships to consider, as 

well as any relevant data. 

Issue 49: DOE requests information or 

data that would indicate whether and 

how the equations used to calculate 

daily defrost energy use and heat 

addition in the test procedure should be 

modified for high-temperature freezer 

refrigeration systems rated as standalone condensing units (e.g., defrost 

heater wattage and daily energy use as 

a function of capacity for a 10 °F walkin temperature). If testing at the lowest 

application temperature is adopted, 

DOE requests comment on how the 

defrost equations should be modified to 

account for each model being tested at 

different conditions, and why. DOE 

requests information on whether frost 

loads and/or defrost frequency are 

different for high-temperature freezers 

than for ¥10 °F freezers. (DOE requests 

that commenters include any available 

supporting information when 

responding.) 

Issue 50: DOE requests comment on 

the appropriateness of specifying 

refrigerant temperatures in terms of 

mid-point or a modified mid-point, 

rather than dew point, which is 

currently used. DOE seeks feedback on 

potential definitions to use for a 

modified mid-point temperature as 

applied to WICF refrigeration system 

testing. In addition, DOE requests 

comments on what other factors should 

be considered when modifying the 

refrigeration system test conditions from 

dew point to mid-point or modified 

mid-point specifications. 


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Signing Authority 

This document of the Department of 

Energy was signed on June 3, 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 4, 

2021. 

Treena V. Garrett, 

Federal Register Liaison Officer, U.S. 

Department of Energy. 

[FR Doc. 2021–12081 Filed 6–16–21; 8:45 am] 

BILLING CODE 6450–01–P 


lotter on DSK11XQN23PROD with PROPOSALS2