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

Federal RegisterApr 21, 2022

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

[EERE-2017-BT-TP-0010]

RIN 1904-AD78

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

AGENCY:

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

ACTION:

Notice of proposed rulemaking and announcement of public webinar.

SUMMARY:

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

DATES:

DOE will accept comments, data, and information regarding this proposal no later than June 21, 2022.

See

section V, “Public Participation,” for details. DOE will hold a webinar on Monday, May 9, from 1:00 p.m. to 5:00 p.m.

See

section V, “Public Participation,” for webinar registration information, participant instructions, and information about the capabilities available to webinar participants.

ADDRESSES:

Interested persons are encouraged to submit comments using the Federal eRulemaking Portal at

www.regulations.gov,

under docket number EERE-2017-BT-TP-0010. Follow the instructions for submitting comments. Alternatively, interested persons may submit comments by email to

WICF2017TP0010@ee.doe.gov.

Include docket number EERE-2017-BT-TP-0010 in the subject line of the message.

No telefacsimiles (“faxes”) will be accepted. For detailed instructions on submitting comments and additional information on this process,

See

section V of this document.

Although DOE has routinely accepted public comment submissions through a variety of mechanisms, including postal mail and hand delivery/courier, the Department has found it necessary to make temporary modifications to the comment submission process in light of the ongoing coronavirus 2019 (“COVID-19 pandemic”). DOE is currently suspending receipt of public comments via postal mail and hand delivery/courier. If a commenter finds that this change poses an undue hardship, please contact Appliance Standards Program staff at (202) 586-1445 to discuss the need for alternative arrangements. Once the COVID-19 pandemic health emergency is resolved, DOE anticipates resuming all of its regular options for public comment submission, including postal mail and hand delivery/courier.

Docket:

The docket, which includes

Federal Register

notices, public meeting attendee lists and transcripts (if a public meeting is held), comments, and other supporting documents/materials, is available for review at

www.regulations.gov.

All documents in the docket are listed in the

www.regulations.gov

index. However, some documents listed in the index, such as those containing information that is exempt from public disclosure, may not be publicly available.

The docket web page can be found at

www.regulations.gov/docket/EERE-2017-BT-TP-0010.

The docket web page contains instructions on how to access all documents, including public comments, in the docket.

See

section V for information on how to submit comments through

www.regulations.gov.

FOR FURTHER INFORMATION CONTACT:

Dr. Stephanie Johnson, U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies Office, EE-2J, 1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: (202) 287-1943. Email

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, review other public comments and the docket, or participate in a public meeting (if one is held), contact the Appliance and Equipment Standards Program staff at (202) 287-1445 or by email:

ApplianceStandardsQuestions@ee.doe.gov.

SUPPLEMENTARY INFORMATION:

DOE proposes to maintain previously approved incorporations by reference and to incorporate by reference the following industry standards into part 431:

Copies of AHRI 420-2008, AHRI 1250-2009, and AHRI 1250-2020 can be obtained from the Air-Conditioning, Heating, and Refrigeration Institute, 2111 Wilson Boulevard, Suite 500, Arlington, VA 22201, or by going to

www.ahrinet.org.

ANSI/ASHRAE Standard 16-2016, “Method of Testing for Rating Room Air Conditioners, Packaged Terminal Air Conditioners, and Packaged Terminal Heat Pumps for Cooling and Heating Capacity,” approved October 31, 2016.

ANSI/ASHRAE Standard 23.1-2010, “Methods of Testing for Rating the Performance of Positive Displacement Refrigerant Compressors and Condensing Units that Operate at Subcritical Temperatures of the Refrigerant,” ANSI approved January 28, 2010.

ANSI/ASHRAE Standard 37-2009, “Methods of Testing for Rating Electrically Driven Unitary Air-Conditioning and Heat Pump Equipment,” approved June 24, 2009.

Copies of ANSI/ASHRAE 16, ASHRAE 23.1-2010, and ANSI/ASHRAE 37 can be obtained from the American Society of Heating, Refrigerating and Air-Conditioning Engineers, 180 Technology Parkway, Peachtree Corners, GA 30092, or by going to:

www.ashrae.org.

ASTM C518-17, “Standard Test Method for Steady state Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus,” ASTM approved May 1, 2017.

ASTM C1199-14, “Standard Test Method for Measuring the Steady state Thermal Transmittance of Fenestration Systems Using Hot Box Methods,” ASTM approved February 1, 2014.

Copies of ASTM C518-17 and ASTM C1199-14 can be obtained from the American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, or by going to

www.astm.org.

NFRC 102-2020 [E0A0], “Procedure for Measuring the Stready-State Thermal Transmittance of Fenestration Systems.”

Copies of NFRC 102-2020 can be obtained from the National Fenestration Rating Council, 6305 Ivy Lane, Ste. 140, Greenbelt, MD 20770, or by going to

www.nfrc.org/.

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

Table of Contents

I. Authority and Background

A. Authority

B. Background

II. Synopsis of the Notice of Proposed Rulemaking

III. Discussion

A. Scope and Definitions

1. Scope

a. Liquid-Cooled Refrigeration Systems

b. Carbon Dioxide Systems

c. Multi-Circuit Single-Packaged Refrigeration Systems

d. Ducted Units

2. Definitions

a. Walk-In Cooler and Walk-in Freezer

b. Doors

c. High-Temperature Refrigeration Systems

d. Ducted Fan Coil Units

e. Multi-Circuit Single-Packaged Refrigeration Systems

f. Attached Split Systems

g. Detachable Single-Packaged System

h. CO

Unit Coolers

i. Hot Gas Defrost

B. Industry Standards

1. Standards for Determining Thermal Transmittance (U-factor)

2. Standard for Determining R-Value

3. Standards for Determining AWEF

a. Changes Consistent With Subpart R, Appendix C

b. CFR Language Not Adopted in AHRI 1250-2020

c. Changes That May Impact the Determination of AWEF

d. Additional Amendments

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

1. Procedure for Determining Thermal Transmittance (U-Factor)

a. Reference to NFRC 102 in Place of NFRC 100

b. Exceptions to Industry Test Method for Determining U-Factor

c. Calibration of Hot Box for Measuring U-Factor

2. Additional Definitions

a. Surface Area for Determining Compliance With Standards

b. Surface Area for Determining U-Factor

3. Electrical Door Components

4. Percent Time Off Values

5. EER Values

6. Air Infiltration Reduction

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

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

1. Specimen Conditioning

2. Total Insulation and Test Specimen Thickness

3. Parallelism and Flatness

4. Insulation Aging

5. Determining Energy Consumption of Panels That Are Not Display Panels

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

1. Refrigeration Test Room Conditioning

2. Temperature Measurement Requirements

3. Hierarchy of Installation Instructions and Specified Refrigerant Conditions for Refrigerant Charging and Setting Refrigerant Conditions

a. Dedicated Condensing Unit Charging Instructions

b. Unit Cooler Charging Instructions

c. Single-Packaged Dedicated System Setup and Charging Instructions

d. Hierarchy of Setup Conditions if Manufacturer-Specified Setup Conditions Cannot Be Met

4. Subcooling Requirement for Mass Flow Meters

5. Instrument Accuracy and Test Tolerances

6. CO

Unit Coolers

7. High-Temperature Unit Coolers

G. Proposal To Establish Appendix C1

1. Off-Cycle Power Consumption

a. Off-Cycle Test Duration and Repetition

b. Off-Cycle Operating Tolerances and Data Collection Rates

c. Off-Cycle Load Points

d. Modification to AWEF Calculations

2. Single-Packaged Dedicated Systems

a. AHRI 1250-2020 Methods for Testing

b. Waivers

c. Suitability of the Single-Packaged Test Methods in AHRI 1250-2020

d. Single-Packaged Refrigerant Enthalpy Method

e. Multi-Circuit Single-Packaged Dedicated Systems

f. CO

Single-Packaged Dedicated Systems

3. Detachable Single-Packaged Dedicated Systems

4. Attached Split Systems

5. Systems for High-Temperature Freezer Applications

6. Systems for High-Temperature Applications

7. Variable-, Two-, and Multiple-Capacity Systems

a. Dedicated Condensing Units

b. Indoor Matched Pair and Single-Packaged Units

c. Revision to EER Calculation for Outdoor Variable-Capacity and Multiple-Capacity Refrigeration Systems

d. Digital Compressors

8. Defrost

a. Adaptive Defrost

b. Hot Gas Defrost

9. Refrigerant Glide

10. Refrigerant Temperature and Pressure Instrumentation Locations

11. Updates to Default Values for Unit Cooler Parameters

12. Calculations and Rounding

H. Alternative Efficiency Determination Methods

1. Doors

2. Refrigeration Systems

I. Sampling Plan for Enforcement Testing

J. Test Procedure Costs and Impact

1. Doors

2. Panels

3. Refrigeration Systems

K. Compliance Date and Waivers

L. Organizational Changes

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866 and 13563

B. Review Under the Regulatory Flexibility Act

1. Description of Why Action Is Being Considered

2. Objective of, and Legal Basis for, Rule

3. Description and Estimate of Small Entities Regulated

4. Description and Estimate of Compliance Requirements

a. Doors

b. Panels

c. Refrigeration Systems

5. Duplication, Overlap, and Conflict With Other Rules and Regulations

6. Significant Alternatives to the Rule

C. Review Under the Paperwork Reduction Act of 1995

D. Review Under the National Environmental Policy Act of 1969

E. Review Under Executive Order 13132

F. Review Under Executive Order 12988

G. Review Under the Unfunded Mandates Reform Act of 1995

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

I. Review Under Executive Order 12630

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

K. Review Under Executive Order 13211

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

M. Description of Materials Incorporated by Reference

V. Public Participation

A. Participation in the Webinar

B. Procedure for Submitting Prepared General Statements for Distribution

C. Conduct of the Webinar

D. Submission of Comments

E. Issues on Which DOE Seeks Comment

VI. Approval of the Office of the Secretary

I. Authority and Background

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

A. Authority

The Energy Policy and Conservation Act, as amended (“EPCA”),

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

of EPCA, added by Public Law 95-619, Title IV, section 441(a), established the Energy Conservation Program for Certain Industrial Equipment, which sets forth a variety of provisions designed to improve energy efficiency. This covered equipment includes walk-in coolers and walk-in freezers, the subject of this document. (42 U.S.C. 6311(1)(G))

All references to EPCA in this document refer to the statute as amended through the Energy Act of 2020, Public Law 116-260 (Dec. 27, 2020).

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

Under EPCA, the energy conservation program consists essentially of four parts: (1) Testing, (2) labeling, (3) Federal energy conservation standards (“ECS”), and (4) certification and enforcement procedures. Relevant provisions of EPCA include definitions (42 U.S.C. 6311), test procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315), energy conservation standards (42 U.S.C. 6313), and the authority to require information and reports from manufacturers (42 U.S.C. 6316).

The Federal testing requirements consist of test procedures that manufacturers of covered equipment must use as the basis for: (1) Certifying to DOE that their equipment complies with the applicable energy conservation standards adopted pursuant to EPCA (42 U.S.C. 6316(a); 42 U.S.C. 6295(s)), and (2) making representations about the efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE must use these test procedures to determine whether the equipment complies with relevant standards promulgated under EPCA. (42 U.S.C. 6316(a); 42 U.S.C. 6295(s))

Federal energy efficiency requirements for covered equipment established under EPCA generally supersede State laws and regulations concerning energy conservation testing, labeling, and standards. (42 U.S.C. 6316(a) and 42 U.S.C. 6316(b); 42 U.S.C. 6297) DOE may, however, grant waivers of Federal pre-emption for particular State laws or regulations, in accordance with the procedures and other provisions of EPCA. (42 U.S.C. 6316(a))

Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures DOE must follow when prescribing or amending test procedures for covered equipment. EPCA requires that any test procedures prescribed or amended under this section must be reasonably designed to produce test results that reflect the energy efficiency, energy use or estimated annual operating cost of a given type of covered equipment during a representative average use cycle and requires that test procedures not be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))

EPCA also requires that, at least once every 7 years, DOE evaluate test procedures for each type of covered equipment, including walk-ins, to determine whether amended test procedures would more accurately or fully comply with the requirements for the test procedures to not be unduly burdensome to conduct and be reasonably designed to produce test results that reflect the energy efficiency, energy use, and estimated operating costs during a representative average use cycle. (42 U.S.C. 6314(a)(1))

In addition, if the Secretary determines that a test procedure amendment is warranted, the Secretary must publish proposed test procedures in the

Federal Register

and afford interested persons an opportunity (of not less than 45 days' duration) to present oral and written data, views, and arguments on the proposed test procedures. (42 U.S.C. 6314(b)) If DOE determines that test procedure revisions are not appropriate, DOE must publish its determination not to amend the test procedures. (42 U.S.C. 6314(a)(1)(A)(ii)) DOE is publishing this notice of proposed rulemaking (“NOPR”) in satisfaction of the 7-year review requirement specified in EPCA.

B. Background

For measuring walk-in energy use, DOE has established separate test procedures for the principal components that make up a walk-in (

i.e.,

doors, panels, and refrigeration systems), with separate test metrics for each component. 10 CFR 431.304(b). For walk-in doors and display panels, the efficiency metric is daily energy consumption, measured in kilowatt-hours per day (“kWh/day”), which accounts for the thermal conduction through the door or display panel and the direct and indirect electricity use of any electrical components associated with the door. 10 CFR 431.304(b)(1)-(2) and 10 CFR part 431, subpart R, appendix A, “Uniform Test Method for the Measurement of Energy Consumption of the Components of Envelopes of Walk-In Coolers and Walk-In Freezers” (“appendix A”). The thermal transmittance through the door, which inputs into the calculation of thermal conduction, is determined using National Fenestration Rating Council (“NFRC”) 100-2010, “Procedure for Determining Fenestration U-factors” (“NFRC 100”).

For walk-in non-display panels and non-display doors, DOE codified in the CFR standards established in EPCA based on the R-value metric,

expressed in units of (h-ft

-°F/Btu),

which is calculated as the thickness of the panel in inches (“in.”) divided by the K-factor.

See

10 CFR 431.304(b)(3) and 10 CFR part 431, subpart R, appendix B, titled “Uniform Test Method for the Measurement of R-Value for Envelope Components of Walk-In Coolers and Walk-In Freezers” (“appendix B”). (

See also

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

1. Scope

The following sections discuss considerations and proposals regarding the scope of equipment covered by DOE's test procedures for walk-ins. As discussed, the DOE test procedures and standards apply to walk-in refrigeration systems, doors, and panels.

a. Liquid-Cooled Refrigeration Systems

A -liquid-cooled refrigeration system rejects heat during the condensing process to a liquid that transports the heat to a remote location. This is in contrast to an air-cooled system, which rejects heat to ambient air during the condensing process. DOE understands that liquid-cooled refrigeration systems are typically used in facilities where either cooling water or glycol is plumbed throughout the building prior to installation of the refrigeration unit, although it is possible that some such systems use potable water for condenser cooling and dispose the water in a drain after it passes through the condenser. As discussed in the June 2021 RFI, liquid-cooled dedicated condensing units for walk-ins are readily available for a wide range of capacities and refrigerants from major walk-in refrigeration system manufacturers (

see

for example, Airdyne W-series indoor units (water-cooled), and Russell (water-cooled, glycol-cooled)

86 FR 32332, 32334.

See

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

DOE notes that the EPCA definition for walk-ins makes no distinction on how the condenser is cooled. (42 U.S.C. 6311(20)(A)) However, the current DOE test procedure for walk-in refrigeration systems, which incorporates by reference AHRI 1250-2009, does not address how to test liquid-cooled systems. Additionally, liquid-cooled dedicated condensing units are outside the scope of AHRI 1250-2020, being specifically excluded in section 2.2.4.

In the June 2021 RFI, DOE requested comment on whether it should consider establishing a test procedure for liquid-cooled walk-in equipment. 86 FR 32332, 32334. Lennox, AHRI, Keeprite, National Refrigeration, and Hussmann recommended against establishing a separate test procedure for liquid-cooled refrigeration systems due to the small market size for such systems. (Lennox, No. 9 at p. 2; AHRI, No. 11 at p. 2; Keeprite, No. 12 at p. 1; National

Refrigeration, No 17 at p. 1; Hussmann, No. 18 at p. 2) Lennox, AHRI, Keeprite, and Hussmann also explained that the type of coolant used has the most impact on efficiency for liquid-cooled systems; however, coolants are not specified by the WICF system manufacturer. These stakeholders asserted that liquid-cooled systems do not have a large potential for energy savings since purchasers, rather than WICF manufacturers, specify the coolant system. (Lennox, No. 9 at p. 2; AHRI, No. 11 at p. 2; Keeprite, No. 12 at p. 1; Hussmann, No. 18 at p. 2) Keeprite also stated that liquid-cooled systems are generally more efficient than air cooled models. (Keeprite, No. 12 at p. 1)

ASAP recommended developing a test procedure for liquid-cooled systems since the systems are currently available in the market and there are no applicable test procedures. (ASAP, No. 13 at p. 1) ASAP stated that adopting test methods for liquid-cooled systems would provide purchasers with comparable ratings regardless of cooling type.

Id.

Daikin recommended considering EN 17432, “Packaged refrigerating units for walk-in cold rooms—Classification, performance and energy consumption testing” (“EN 17432”), which addresses water-cooled and liquid-cooled refrigeration systems. (Daikin, No. 17 at p. 1)

DOE reiterates that the scope of the walk-in definition includes liquid-cooled equipment. DOE recognizes the potential benefit of a test procedure for liquid-cooled walk-ins and the value that a reliable test procedure can provide to facilitate comparable representations of energy use for consumers. DOE has tentatively determined that liquid-cooled refrigeration systems may represent a small portion of the walk-in market and the potential for energy savings is likely limited. Therefore, although liquid-cooled refrigeration systems are considered to be covered equipment, DOE is not proposing to amend its procedures to include liquid-cooled refrigeration systems at this time.

b. Carbon Dioxide Systems

Currently, the DOE test procedure for walk-in refrigeration systems does not explicitly define scope based on refrigerant.

See

10 CFR 431.301, 10 CFR 431.304, and appendix A. DOE understands that the current test procedure, which is based on AHRI 1250-2009 (incorporated by reference, 10 CFR 431.303(b)), specifies test conditions that may not be consistent with the design and operation of carbon dioxide (“CO

'') refrigeration systems;

i.e.,

although AHRI 1250-2009 does not specifically exclude CO

systems, the test method is not designed to accommodate such systems.

The DOE test procedure for unit coolers requires testing with a liquid inlet saturation temperature of 105 °F and a liquid inlet subcooling temperature of 9 °F, as specified by Tables 15 and 16 of AHRI 1250-2009. However, CO

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 subpart R, appendix C, are not achievable by CO

unit coolers. DOE has granted waivers or interim waivers from subpart R, appendix C, for specific basic models of CO

unit coolers to the manufacturers listed in Table III.1 of this document. The alternate test procedure specified in these waivers modified the liquid inlet saturation temperature to 38 °F and the liquid inlet subcooling temperature to 5 °F. Pursuant to its waiver regulations, as soon as practicable after the granting of any waiver, DOE will publish in the

Federal Register

a notice of proposed rulemaking to amend its regulations so as to eliminate any need for the continuation of such waiver. 10 CFR 431.401(l). As soon thereafter as practicable, DOE will publish in the

Federal Register

a final rule to that effect.

Id.

Table III.1—Waivers Granted to Manufacturers of CO

Walk-In Refrigeration Systems

Manufacturer

Interim waiver

Federal Register

citation

Waiver decision and order

Federal Register

citation

Heat Transfer Products Group (“HTPG”)

85 FR 83927 (Dec. 23, 2020)

86 FR 14887 (Mar. 19, 2021).

Hussmann Corporation (“Hussmann”)

86 FR 10046 (Feb. 18, 2021)

86 FR 24606 (May 7, 2021).

Keeprite Refrigeration (“Keeprite”)

86 FR 12433 (Mar. 3, 2021)

86 FR 24603 (May 7, 2021).

RefPlus Inc. (“RefPlus”)

86 FR 43633 (Aug. 10, 2021)

The alternate test procedure granted in the CO

waivers and DOE's proposal with respect to refrigeration systems utilizing CO

as a refrigerant are further discussed in section III.F.6 of this document.

As discussed in the June 2021 RFI, all CO

refrigerant waiver petitions DOE has thus far received address unit coolers. 86 FR 32332, 32346. However, it is possible that other CO

refrigeration system configurations may be relevant in the future,

e.g.

dedicated condensing units, matched pairs, or single-packaged dedicated systems. DOE reviewed product literature and other information for CO

systems having some of these alternative configurations. Most of the information identified by DOE pertains to manufacturers operating in Europe.

In the June 2021 RFI, DOE requested comment on the future expected use of walk-in refrigeration systems using CO

. 86 FR 32332, 32346. Lennox, AHRI, National Refrigeration, and Hussmann stated that they are not aware of any transcritical

dedicated condensing units available in North America. (Lennox, No. 9 at p. 7; AHRI, No. 11 at p. 12; National Refrigeration, No 17 at p. 1; Hussmann, No. 18 at p. 14) National Refrigeration asserted that CO

tends to be used in large, complex multi-compressor systems and therefore, would not be used in smaller systems with just one dedicated condensing unit (National Refrigeration, No. 17 at p. 1) The CA IOUs stated that CO

unit coolers cannot be tested and rated at the temperatures and pressures used in the current test procedure for more traditional hydrofluorocarbon (“HFC”) refrigerants; however, single-packaged dedicated CO

refrigeration systems should be able to use the test methods established in AHRI 1250-2020 for single-packaged dedicated systems, because these test methods do not use refrigerant flow or refrigerant conditions for energy calculations. (CA IOUs, No. 14 at p. 4) Additionally, the CA IOUs urged DOE to ensure that the WICF test procedures and metrics continue to provide consumers with the information necessary to easily compare the

performance of products with the same utility.

Id.

refrigeration systems are transcritical because the high-temperature refrigerant that is cooled by ambient air is in a supercritical state, above the 87.8 °F critical point temperature, above which the refrigerant cannot exist as separate vapor and liquid phases.

DOE preliminarily finds that, in the North American market, CO

is primarily used in large rack systems, and that there do not appear to be any CO

dedicated condensing units available. Hence, DOE tentatively finds that adopting a test procedure for CO

dedicated condensing units is currently not warranted. However, DOE has also tentatively determined that the test methods in AHRI 1250-2020 for single-packaged dedicated systems do not need to be modified for CO

refrigerant as long as these units are tested using air enthalpy or calorimeter test methods, rather than a refrigerant enthalpy method. DOE further discusses its proposals for testing single-packaged dedicated systems in section III.G.2 of this document.

In this NOPR, DOE is proposing that walk-in refrigeration equipment utilizing CO

as a refrigerant meet the definition of a walk-in refrigeration system, but that the DOE test procedure, as proposed in this document, would apply only to (1) single-packaged dedicated systems and (2) unit cooler variants of CO

refrigeration systems. This proposal would exclude CO

dedicated condensing units from the proposed test procedure. The test procedures for CO

unit coolers and single-packaged refrigeration systems which use CO

as a refrigerant are outlined in more detail in sections III.F.6 and III.G.2.f of this document, respectively.

c. Multi-Circuit Single-Packaged Refrigeration Systems

DOE has received a request for waiver and interim waiver from Refrigerated Solutions Group (“RSG”) from the test procedure in subpart R, appendix C, for basic models of single-packaged dedicated systems having multiple refrigerant circuits within a single unit that share a single evaporator and a single condenser. (Docket EERE-2022-BT-WAV-0010, No. 1) In its petition, RSG stated that the current walk-in test procedure does not address multiple refrigeration circuits that are enclosed in a single unit.

Id.

Therefore, in this test procedure NOPR, DOE has initially determined that refrigeration systems with multiple refrigeration circuits that share a single evaporator and a single condenser and are used in walk-in applications meet the definition of “walk-in cooler and walk-in freezer.” Thus, DOE proposes to define “multi-circuit single-packaged dedicated system” in section III.A.2.e of this document. Additionally, DOE is proposing a test procedure for such systems.

d. Ducted Units

DOE is aware that some walk-in evaporators and/or dedicated condensing units are sold with provisions to be installed with duct(s) to circulate air between the walk-in and the refrigeration system. The current definition of “single-packaged dedicated system” specifies that such systems do not have “any element external to the system imposing resistance to flow of the refrigerated air;” and the definition of “unit cooler” specifies that such equipment does not have “any element external to the cooler imposing air resistance.” (10 CFR 431.302) As such, unit coolers and single-packaged dedicated systems sold for ducted installation are not addressed by either definition—also, the current test procedure does not include provisions for setup of ductwork. While the definition for condensing unit does not exclude systems intended for ducted installation, the current test procedure does not include provisions for setup of ductwork for these components either.

DOE has granted waivers from the test procedure in subpart R, appendix C, to Air Innovations, Vinotheque, Cellar Pro, and Vinotemp, and an interim waiver to LRC Coil, for walk-ins marketed for use as wine cellar refrigeration systems (

see

Table III.2). The waivers are discussed in more detail in sections III.A.2.c and III.G.6 of this document. Relevant to the present discussion of scope, the specific basic models for which waivers have been granted include equipment sold as ducted units. As a result of the test procedure waivers granted by DOE, DOE proposes to revise the single-packaged dedicated system definition to clarify that such systems may have provisions for ducted installation. DOE proposes to add a definition for “ducted fan coil unit,” the ducted equivalent of a unit cooler. In doing so, DOE preserves the standard industry definition of a unit cooler while expanding the scope of the test procedure to ducted units. DOE also proposes to add provisions in the test procedures to address setup of ductwork and the external static pressure that it imposes on refrigeration system fans—all in order to improve representativeness of the test procedure. These test procedure revisions are addressed in section III.G.6 of this document.

Table III.2—Interim Waivers and Waivers Granted to Manufacturers of Walk-ins Marketed as Wine Cellar Refrigeration Systems

Manufacturer

Interim waiver

Federal

citation

Waiver decision and order

Federal

citation

Air Innovations

86 FR 2403 (Jan. 12, 2021)

86 FR 23702 (May 4, 2021).

Vinotheque

86 FR 11961 (Mar. 1, 2021)

86 FR 26504 (May 14, 2021).

CellarPro

86 FR 11972 (Mar. 1, 2021)

86 FR 26496 (May 14, 2021).

Vinotemp

86 FR 23692 (May 4, 2021)

86 FR 36732 (July 13,2021).

LRC Coil

86 FR 47631 (Aug. 26, 2021)

2. Definitions

a. Walk-in Cooler and Walk-in Freezer

The term “walk-in cooler and walk-in freezer” means an enclosed storage space refrigerated to temperatures, respectively, above, and at or below 32 °F, that can be walked into, and has a total chilled storage area of less than 3,000 square feet; however, the term does not include products designed and marketed exclusively for medical, scientific, or research purposes. 10 CFR 431.302. (

See

also 42 U.S.C. 6311(20))

In this notice, DOE proposes to amend the definition of walk-in cooler and freezer to specify that a walk-in may be comprised of doors, panels, and refrigeration systems. As explained in section I.B of this document, DOE established separate test procedures and energy conservation standards for the principal components that make up a walk-in: panels, doors, and refrigeration systems. 76 FR 21580, 21582 and 79 FR 32050, 32051-32052. DOE noted in a final rule published March 7, 2011 (“March 2011 Compliance, Certification, and Enforcement (“CCE”) final rule”) that the legislative design standards set forth in EPCA provide the framework for a component-based approach since each design standard is based on the performance of a given component of the walk-in. 76 FR 12422, 12444. In order to align the definition with the regulatory scheme adopted by DOE, DOE proposes to revise the definition to mean an enclosed storage space, including but not limited to panels, doors, and refrigeration systems, refrigerated to temperatures, respectively, above, and at or below 32

degrees Fahrenheit that can be walked into, and has a total chilled storage area of less than 3,000 square feet; however, the terms do not include products designed and marketed exclusively for medical, scientific, or research purposes. DOE does not intend for this amended definition to expand the scope of the definition for walk-in coolers and freezers nor does it intend for this amended definition to expand the certification and compliance responsibilities of entities involved in manufacturing or assembling walk-ins or walk-in components. Instead, DOE's proposed revision to the definition of walk-in cooler and walk-in freezer clarifies that DOE has the authority to separately regulate walk-in components as well as a full walk-in system (including but not limited to panels, doors, and refrigeration systems). The March 2011 CCE final rule adopted a definition for a walk-in manufacturer to specify the entities responsible for certification and/or compliance of walk-ins or walk-in components. 76 FR 12422, 12442-12444. DOE emphasizes that both the component manufacturer and the assembler bear the responsibility of standards compliance, even though the component manufacturer is the entity responsible for certification. An assembler may rely on the certification from the component manufacturer regarding whether the component being used is certified as compliant with DOE standards.

Issue 1: DOE requests comment on its proposed changes to the definition for walk-in cooler and walk-in freezer.

b. Doors

With respect to walk-ins, DOE defines a “door” as an assembly installed in an opening on an interior or exterior wall that is used to allow access or close off the opening and that is movable in a sliding, pivoting, hinged, or revolving manner of movement. For walk-in coolers and walk-in freezers, a door includes the door panel, glass, framing materials, door plug, mullion, and any other elements that form the door or part of its connection to the wall. 10 CFR 431.302. In the June 2021 RFI, DOE requested feedback on the current definition of “door.” 86 FR 32332, 32335.

Hussmann stated that the current definition of door is sufficient. (Hussmann, No. 18 at p. 3) Anthony and AHRI stated that “door” is unclear and inadequately defined. (Anthony, No. 8 at p. 1; AHRI, No. 11 at p. 2) AHRI commented that the current definition seems to describe an individual “door” opening, but that the requirement for testing uses the opening space in the walk-in regardless of whether it contains more than one “door” opening. AHRI suggested that the definition of “door” should contain the door frame and all door components, and that DOE should differentiate between the number of openings for a specific door assembly inserted into the opening space, especially for display doors. (AHRI, No. 11 at pp. 2-3) Anthony asserted that any component that is part of the door assembly (

e.g.,

door, frame, wiring) is within the definition of a WICF door. (Anthony, No. 8 at pp. 1-2)

In the June 2021 RFI, DOE also requested comment specifically on the use of the term “door plug” within the definition of “door.” 86 FR 32332, 32335. Anthony and AHRI stated that they were unfamiliar with the term “door plug.” (Anthony, No. 8 at pp. 1-2; AHRI, No. 11 at pp. 2-3) Imperial Brown stated that the door plug is the moving part of the door that can swing or slide and comes attached to the frame. (Imperial Brown, No. 15 at p. 1) Hussmann stated that the term “door plug” is in reference to a regular door plug (

i.e.,

plugging heaters from a door to a frame system), and that Hussmann does not use the term “door plug” interchangeably with a “door.” (Hussmann, No. 18 at p. 3)

DOE recognizes that the current definition of “door” does not explicitly address that walk-in door assemblies may contain multiple door openings within one frame. DOE also notes that NFRC 100 includes several defined terms relating to door components (

e.g.,

door leaf), which differ from the terms used in DOE's definition of “door.” Additionally, certain stakeholders commented that they are unfamiliar with the term “door plug,” whereas others use it to describe different components of the door assembly.

DOE proposes to amend the definition of “door” to address doors with multiple openings within one frame; to include terminology that generally aligns with terminology used by the industry; and to remove use of the term “door plug,” which is being interpreted inconsistently by stakeholders. Specifically, DOE proposes to amend the definition of “door” to mean an assembly installed in an opening of an interior or exterior wall that is used to allow access or close off the opening and that is movable in a sliding, pivoting, hinged or revolving manner of movement. For walk-in coolers and walk-in freezers, a door includes the frame (including mullions), the door leaf or multiple door leaves (including glass) within the frame, and any other elements that form the assembly or part of its connection to the wall. DOE also proposes to define the term “door leaf” to mean the pivoting, rolling, sliding, or swinging portion of a door. DOE tentatively concludes that the proposed revision of “door” and proposed definition of “door leaf” better align with industry terminology and address doors with multiple openings within one frame. DOE does not intend for the proposed changes to the definition of “door” and the newly defined term for “door leaf” to change the scope of applicability of the DOE test procedures or the applicability of standards for walk-in doors.

As discussed in the June 2021 RFI, DOE differentiates WICF doors by whether such doors are “display doors” or not display doors (

i.e.,

“passage doors” or “freight doors”). 86 FR 32332, 32335. A “freight door” is a door that is not a display door and is equal to or larger than 4 feet wide and 8 feet tall. 10 CFR 431.302. A “passage door” is a door that is not a freight or display door.

Id.

The use of dimensions in the definition of freight door conveys that these doors typically allow large machines (

e.g.,

forklifts) to pass through carrying freight. However, the definition does not address instances where one dimension exceeds the height or width requirement per the definition, but the other dimension is smaller than the other dimension requirement per the definition. In some cases, the surface area for such doors could be larger than 32 square feet, the area of a 4-foot by 8-foot door provided in the definition (

e.g.,

a door 5 feet wide and 7 feet tall, with a surface area of 35 square feet); in other cases, the surface area could be smaller than 32 square feet (

e.g.,

a door 5 feet wide and 6 feet tall, with a surface area of 30 square feet). As part of the June 2021 RFI, DOE reviewed the certified surface areas of freight and passage doors in DOE's Compliance Certification Management System (“CCMS”) Database. DOE found that many models certified as passage doors had rated surface areas greater than or equal to 32 square feet while some models certified as freight doors had rated surface areas less than 32 square feet. 86 FR 32332, 32335.

In the June 2021 RFI, DOE requested comment on whether height and width or surface area effectively distinguish between passage and freight doors and whether there are any building codes, standards, or industry practices to support or refute maintaining dimensions of a door as the defining characteristics separating freight and passage doors. Additionally, DOE sought comment on any other attributes other than size which would

appropriately distinguish passage and freight doors. Lastly, DOE sought comment on how to classify non-display doors with multiple openings where the individual door openings do not meet the definition of freight door, but the overall door assembly would meet the definition of a freight door per the dimension requirements in the freight door definition.

Id.

The CA IOUs generally supported DOE updating its definitions related to walk-in doors to prevent mis-categorization. Specifically, the CA IOUs suggested that DOE align with industry definitions for freight doors, such as vertical or sectional overhead doors, and consider differentiating doors based on opening characteristics (

e.g.,

swing, horizontal slide, vertical slide, rollup) rather than size. (CA IOUs, No. 14 at p. 5)

Imperial Brown stated that the door width-in-clear

(or “WIC”) should be the determining factor for distinguishing passage and freight doors. Imperial Brown recommended that a freight door be identified as a door with a WIC of 48 inches or more and a height-in-clear

(“HIC”) of 78 inches or more, allowing for pallet and forklift traffic. (Imperial Brown, No. 15 at p. 1)

Imperial Brown defined WIC as the clear opening width, typically from left frame jamb to right frame jamb. (Imperial Brown, No. 15 at p. 1)

Imperial Brown defined HIC as the clear opening height, typically from door sill to frame header. (Imperial Brown, No. 15 at p. 1)

AHRI stated that the current area cut-off of 4 feet by 8 feet is sufficient for distinguishing between passage and freight doors. AHRI stated that there are no specific dimensions that distinguish freight from passage doors and that the dimensions tend to be application specific. AHRI also commented that generally the height of passage and freight doors are similar, but that the width varies. (AHRI, No. 11 at p. 3)

Regarding other characteristics that may distinguish passage and freight doors, both Anthony and Hussmann stated that they define passage doors and freight doors by whether the door is provided for personnel access to the WICF (

i.e.,

passage doors) or provided for stocking of product with the use of equipment (

i.e.,

freight doors). (Anthony, No. 8 at p. 2; Hussmann, No. 18 at pp. 3-4) Hussmann stated that passage doors must be large enough for individuals to pass through and meet requirements established by the Americans with Disabilities Act (“ADA”). (Hussmann, No. 18 at pp. 3-4)

Regarding non-display doors that contain multiple openings, AHRI and Hussmann commented that it is not necessary to change how non-display doors with multiple openings are classified. (AHRI, No. 11 at p. 3; Hussmann, No. 10 at p. 4) Imperial Brown stated that non-display doors with multiple openings should be considered freight doors only if they have an unobstructed WIC by HIC (

i.e.,

there are no mullions in the opening) that meets the freight door dimensional requirements. (Imperial Brown, No. 15 at p. 1)

Considering the comments received, DOE is not proposing to revise the definition of “freight door” at this time.

DOE is proposing to define the term “non-display door.” Although the test procedures outlined in 10 CFR 431.304 and appendices A and B use the term “non-display door,” it is not currently defined. The proposed definition would provide that a “non-display door” would mean a door that is not a display door.

Based on the input it has received, DOE has tentatively determined that differentiating walk-in doors based on opening characteristics would better align with industry terminology. Therefore, DOE is proposing to define three terms, which include some industry terminology identified in NFRC 100, to further differentiate among both display and non-display doors: “Hinged vertical door,” “roll-up door,” and “sliding door” (see proposed definitions set out in the regulatory text at the end of the document, proposed § 431.302).

Issue 2: DOE requests feedback on the proposed changes to the definition of “door” and the newly proposed definition for “door leaf.” DOE also seeks comment on the newly proposed definitions for certain door opening characteristics: “Hinged vertical door,” “roll-up door,” and “sliding door.”

c. High-Temperature Refrigeration Systems

As discussed previously, DOE has granted several manufacturers waivers and interim waivers from the test procedure in subpart R, appendix C, for basic models of refrigeration systems marketed as wine cellar refrigeration systems (

see

section III.A.1.d). These manufacturers stated that walk-ins used for wine storage are intended to operate at a temperature range of 45 to 65 °F and 50-70 percent relative humidity, rather than the 35 °F and less than 50 percent relative humidity test condition prescribed in subpart R, appendix C.

In the June 2021 RFI, DOE requested comment on how refrigeration systems marketed as wine cellar refrigeration systems should be defined to best represent the conditions under which these systems are designed to operate. 86 FR 32332, 32334-32335. AHRI, Lennox, and the CA IOUs recommended that DOE adequately define refrigeration systems marketed as wine cellar refrigeration systems and evaluate them as a separate efficiency class. (Lennox, No. 9 at p. 6; AHRI, No. 11 at p. 11; CA IOUs, No. 14 at pp. 3-4) AHRI and Hussmann suggested that refrigeration systems marketed as wine cellar refrigeration systems be defined as an enclosed storage space designed to be cooled to between 45 °F and 65 °F with a relative humidity range of 50 percent to 70 percent, and typically kept at 55 °F and 55% RH. (AHRI, No. 11 at p. 2; Hussmann, No. 18 at p. 3) Daikin stated that refrigeration systems marketed as wine cellar refrigeration systems operate between 37.4 °F and 68 °F, and between 70% and 85% relative humidity. (Daikin, No. 17 at p. 2)

In the June 2021 RFI, DOE also requested feedback on walk-in applications other than wine cellar cooling that may have a target room temperature of 35 °F and higher. 86 FR 32332, 32334-32335. Lennox, AHRI and Hussmann each stated that wine cellars are the only walk-in applications with a temperature range between 45 °F and 65 °F and with a relative humidity between 50 percent and 70 percent. (Lennox, No. 9 at p. 2; AHRI, No. 11 at p. 2; Hussmann, No. 18 at pp. 2-3) Daikin stated by way of example that florist coolers operate at 68 °F and between 90% to 95% humidity. (Daikin, No. 17 at p. 2)

DOE understands from these comments that there are walk-in applications other than wine cellars that require cooling to temperatures higher than 35 °F. To provide for testing of such walk-ins using test conditions that result in measurements of energy use in a representative average-use cycle DOE proposes to define walk-ins designed to operate at cooling temperatures above 45 °F as employing a “high-temperature refrigeration system”—which would mean a walk-in refrigeration system which is not designed to operate below 45 °F.” The proposed definition would provide for the testing of such units using specified conditions representative of their average use,

i.e.,

cooling the refrigerated space to a temperature above 45 °F. See the corresponding test procedure provisions proposed in section III.G.6 for further details.

d. Ducted Fan Coil Units

DOE has granted waivers to Air Innovations, Vinotheque, Cellar Pro, and Vinotemp, and an interim waiver to LRC Coil for walk-ins that are marketed

as wine cellar refrigeration systems that are designed and marketed as ducted units. (

See

Table III.2) The definitions for single-packaged units and unit coolers currently exclude ducted units, resulting in the lack of a test procedure for such units. 10 CFR 431.302. Specifically, the current single-packaged unit definition excludes units with “any element external to the system imposing resistance to flow of the refrigerated air.” Similarly, the current unit cooler definition specifically excludes units with “element[s] external to the cooler imposing air resistance.”

Id.

In the June 2021 RFI, DOE requested comment on changing the “single-packaged dedicated system” and “unit cooler” definitions to address units that are designed to be installed with ducts. 86 FR 32332, 32346. Lennox and AHRI both stated that the ASHRAE 210P committee

is working to define a “ducted unit cooler” and is currently considering defining it as “an assembly, including means for forced air circulation, capable of moving air against both internal and non-zero external flow resistance, and elements by which heat is transferred from air to refrigerant to cool the air, with provision for ducted installation.” (Lennox, No. 9 at p. 6; AHRI, No. 11 at p. 11) Lennox and AHRI both urged DOE to work with the ASHRAE 210P committee to find an appropriate solution. (Lennox, No. 9 at p. 7; AHRI, No. 11 at p. 12)

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (“ASHRAE”) has formed the ASHRAE Standard Project Committee 210 (“ASHRAE 210P”) to evaluate and revise its “Method of Testing and Rating Commercial Walk-in Refrigerators and Freezers.”

See spc210.ashraepcs.org/.

To clarify that refrigeration systems that have provision for ducted installation are indeed included in the DOE test procedure, DOE is proposing an appropriate term and a definition for the term “ducted unit cooler” mentioned by commenters and is also proposing to revise the definition for single-packaged dedicated system to clarify that such a system can have provision for ducted installation. DOE proposes to adopt the new term, “ducted fan-coil unit,” which would be defined as an assembly including means for forced air circulation capable of moving air against both internal and non-zero external flow resistance, and elements by which heat is transferred from air to refrigerant to cool the air, with provision for ducted installation. DOE is also proposing to revise the current single-packaged dedicated system definition to mean a refrigeration system (as defined in 10 CFR 431.302) that is a single-packaged assembly that includes one or more compressors, a condenser, a means for forced circulation of refrigerated air, and elements by which heat is transferred from air to refrigerant.

Issue 3: DOE requests comment on the proposed definition of “ducted fan coil unit” and on the proposed modification to the “single-packaged dedicated system” definition.

e. Multi-Circuit Single-Packaged Refrigeration Systems

As discussed in section III.A.1.c, DOE is proposing to include a test procedure for evaluating the energy consumption of single-packaged units that contain multiple refrigeration circuits. As discussed, these units differ from larger multi-circuit refrigeration systems in that the refrigeration circuits are housed within an assembly and share a single condenser and a single evaporator. DOE proposes to define a “multi-circuit single-packaged refrigeration system” as a single-packaged dedicated system (as defined in 10 CFR 431.302) that contains two or more refrigeration circuits that refrigerate a single stream of circulated air.

Issue 4: DOE requests comment on the proposed definition for multi-circuit single-packaged dedicated refrigeration systems.

f. Attached Split Systems

DOE is aware of some refrigeration systems that are sold as matched pairs in which the dedicated condensing unit and unit cooler are permanently attached to each other with structural beams. When these units are mounted to the refrigerated box, these beams extend through the wall of the walk-in, connecting the unit cooler inside the refrigerated box with the dedicated condensing unit outside the refrigerated box. The functionality of an attached split system may be similar to that of a matched pair system but may also have similarities to a single-packaged dedicated system, since they are single assemblies. The DOE test procedure does not currently define such systems, nor does it provide any unique test provisions for them—thereby affecting the ability of manufacturers to provide test results reflecting the energy efficiency of this equipment during a representative average use cycle. DOE discusses its proposal for testing such units in section III.G.4 of this document. DOE has initially determined that attached split systems are a type of matched pair system and proposes to define these systems as matched pair refrigeration systems designed to be installed with the evaporator entirely inside the walk-in enclosure and the condenser entirely outside the walk-in enclosure, and the evaporator and condenser are permanently connected with structural members extending through the walk-in wall.

Issue 5: DOE requests comment on the proposed definition for attached split system.

g. Detachable Single-Packaged System

DOE is aware of some refrigeration systems that are designed to be installed with the evaporator unit exchanging air through the wall or ceiling of the walk-in as would be the case in a single-packaged system, but with the condensing unit installed either next to the evaporator unit or installed remotely and connected to the evaporator with refrigerant lines as is done in split systems. The current DOE test procedure does not define such systems or provide testing provisions specific to this configuration. DOE discusses its proposal for testing such units in section III.G.3 of this document. DOE has initially determined that these units are a type of single-packaged dedicated system, and proposes to define a detachable single-packaged system as a system consisting of a dedicated condensing unit and an insulated evaporator section in which the evaporator section is designed to be installed external to the walk-in enclosure and circulating air through the enclosure wall, and the condensing unit is designed to be installed either attached to the evaporator section or mounted remotely with a set of refrigerant lines connecting the two components.

Issue 6: DOE requests comment on the proposed definition for detachable single-packaged dedicated system.

h. CO

Unit Coolers

As discussed in section III.A.1.b, DOE is proposing to adopt test procedures for unit coolers designed for use in CO

refrigeration systems, these proposals are discussed in detail in section III.F.6 of this document. CO

systems are designed and built to operate using CO

as a refrigerant, which has the potential to reach pressures much higher than conventional refrigerants. With the air enthalpy test method, CO

single-packaged refrigeration systems would use the same test methods as conventional-refrigerant single-packaged dedicated systems (

see

DOE's proposal discussed in section III.G.2.f). However, the proposed test procedure for CO

unit coolers would alter the inlet refrigerant test conditions as compared to conventional refrigerants (

see

section III.F.6). To clarify the scope

of the proposed unit cooler test procedure, DOE is proposing to define a CO

unit cooler as one that includes a nameplate listing only CO

as an approved refrigerant.

Issue 7: DOE requests comment on the proposed definition of CO

unit coolers. DOE also requests comment on whether any distinguishing features of CO

unit coolers exist that could reliably be used as an alternative approach that can differentiate them from those unit coolers intended for use with conventional refrigerants.

i. Hot Gas Defrost

As discussed previously, DOE published a final rule that amended the test procedure to rate hot gas defrost unit coolers using the modified default values for energy use and heat load contributions in AHRI 1250-2020. 86 FR 16027. At that time, DOE did not adopt a definition for “hot gas defrost.” However, as discussed in more detail in section III.G.8.b, DOE is proposing that equipment with hot gas defrost installed at the factory may be marketed using representations of performance with hot gas defrost activated. This would be a voluntary representation by the manufacturer. To ensure that the scope of this voluntary representation is clear, DOE is proposing to define “hot gas defrost” as a factory-installed system where refrigerant is used to transfer heat from ambient outside air, the compressor, and/or a thermal storage component that stores heat when the compressor is running and uses this stored heat to defrost the evaporator coils.

Issue 8: DOE requests comment on the proposed definition for hot gas defrost. Specifically, DOE requests comment on if this proposed definition is sufficient to identify which equipment is sold with hot gas defrost capability installed and which is not.

B. Industry Standards

The current DOE test procedure for walk-in coolers and freezers incorporates the following industry test standards: NFRC 100-2010 into appendix A; ASTM C518 into appendix B; and AHRI 1250-2009, AHRI 420-2008,

and ASHRAE 23.1-2010

into subpart R, appendix C. The following sections detail the industry standards DOE is proposing to incorporate by reference in the NOPR and the relevant provisions of those industry standards that DOE is proposing to adopt.

AHRI 420-2008, “Performance Rating of Forced-Circulation Free-Delivery Unit Coolers for Refrigeration” (“AHRI 420-2008”).

ANSI/ASHRAE 23.1-2010, “Methods of Testing for Rating the Performance of Positive Displacement Refrigerant Compressors and Condensing Units that Operate at Subcritical Temperatures of the Refrigerant” (“ASHRAE 23.1-2010”).

1. Standards for Determining Thermal Transmittance (U-Factor)

Appendix A references NFRC 100 as the method for determining the U-factor of doors and display panels. NFRC 100 allows for computational determination of U-factor by simulating U-factor using Lawrence Berkeley National Lab's (“LBNL”) WINDOW and THERM software, provided that the simulated value for the baseline product in a product line is validated with a physical test of that baseline product and the simulated value is within the accepted agreement with the physical test value as specified in section 4.7.1 of NFRC 100.

Section 4.3.2.1 of NFRC 100 references NFRC 102-2010, “Procedure for Measuring the Steady state Thermal Transmittance of Fenestration Systems” (“NFRC 102-2010”), as the physical test procedure for determining U-factor. NFRC 102-2010 is based on ASTM C1199-09, “Standard Test Method for Measuring the Steady state Thermal Transmittance of Fenestration Systems Using Hot Box Methods” (“ASTM C1199-09”) with some modifications.

Section 4.7.1 of NFRC 100 requires that the accepted difference between the tested U-factor and the simulated U-factor be (a) 0.03 Btu/(h-ft

-°F) for simulated U-factors that are 0.3 Btu/(h-ft

-°F) or less, or (b) 10 percent of the simulated U-factor for simulated U-factors greater than 0.3 Btu/(h-ft

-°F). This agreement must match for the baseline product in a product line. Per NFRC 100, the baseline product is the individual product selected for validation; it is not synonymous with “basic model” as defined in 10 CFR 431.302.

Since DOE adopted this test procedure for determining U-factor of doors and display panels in 2011, NFRC has published updates to NFRC 102, the most recent being NFRC 102-2020, which supersedes all previous versions of NFRC 102. The following are the identified substantive changes and additions in NFRC 102-2020 as compared to NFRC 102-2010, which is referenced in the current Federal test procedure via NFRC 100-2010:

1. Added a list of required calibrations for primary measurement equipment, including metering box wall transducer and surround panel flanking loss characterization and annual verification procedure, and incorporated a calibration transfer standard (“CTS”) calibration continuous characterization procedure; and

2. The provisions regarding air velocity distribution were revised to be more specific to the type of fans used.

Additionally, NFRC 102-2020 references the updated version of ASTM C1199 (ASTM C1199-14) instead of ASTM C1199-09. Based on a review of ASTM C1199-14, DOE has tentatively determined that the differences between editions are editorial.

DOE is proposing to adopt by reference in appendix A, the following sections of NFRC 102-2020 for determining U-factor:

• 2. Referenced Documents,

• 3. Terminology,

• 5. Apparatus,

• 6. Calibration,

• 7. Experimental Procedure (excluding 7.3. Test Conditions),

• 8. Calculation of Thermal Transmittance,

• 9. Calculation of Standardized Thermal Transmittance,

• Annex A1. Calibration Transfer Standard Design,

• Annex A2. Radiation Heat Transfer Calculation Procedure, and

• Annex A4. Garage Panel and Rolling Door Installation.

DOE is also proposing to incorporate by reference ASTM C1199-14, as it is referenced in NFRC 102-2020. Specifically, in the proposed test procedure in appendix A, DOE is proposing to reference the following sections of ASTM C1199-14 as referenced through NFRC 102-2020: Sections 2, 3, 5, 6, 7 (excluding 7.3), 8, 9, and Annexes A1 and A2. DOE is not proposing to reference any other sections of NFRC 102-2020 or ASTM C1199-14 as they either do not apply or they are in direct conflict with other test procedure provisions included in the subpart R.

2. Standard for Determining R-Value

As mentioned previously, section 4.2 of appendix B references ASTM C518 to determine the thermal conductivity, or K-factor, of panel insulation. EPCA requires that the measurement of the K-factor used to calculate the R-value be based on ASTM C518-2004 (“ASTM C518-04”). (42 U.S.C. 6314(a)(9)(A)(ii)) In December 2015, ASTM published a revision of this standard (“ASTM C518-15”). ASTM C518-15 removed references to ASTM Standard C1363, “Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus” (“ASTM C1363”), and added references to ASTM Standard E456, “Terminology Relating to Quality and Statistics.” Additionally, ASTM C518-15 relies solely on the International System of Units (“SI units”), with paragraph 1.13 clarifying that these SI unit values are to be regarded as standard. In July 2017, ASTM published another revision of ASTM C518 (“ASTM C518-17”). ASTM

C518-17 added a summary of precision statistics from an interlaboratory study from 2002-2004 in section 10 “Precision and Bias.”

As part of the June 2021 RFI, DOE requested comment on what issues, if any, would be present if DOE were to adopt the most current version of the standard, ASTM C518-17, for measuring panel K-factor. 86 FR 32332, 32336. NFRC stated that the updates to ASTM C518-17 as compared to what is in ASTM C518-04 would have no substantial impact on the results of testing and no impact on test burden. NFRC also stated that adopting ASTM C518-17 would bring DOE test procedures in line with current industry methods and practice. (NFRC, No. 10 at p. 2) DOE did not receive any additional comments on potentially adopting ASTM C518-17 for measuring panel K-factor.

DOE has tentatively determined that the updates to ASTM C518-2004 (the version of the industry test procedure specified by EPCA as the basis for calculating the K-factor) made in 2015 and 2017 do not substantively change the test method nor would adoption of the latest version in the DOE test procedure increase test burden. Therefore, DOE is proposing to amend its test procedure for determining R-value of insulation for non-display doors and panels by incorporating by reference ASTM C518-17. Specifically, in the proposed test procedure in appendix B, DOE is proposing to reference the following sections of ASTM C518-17:

• 2. Referenced Documents,

• 3. Terminology,

• 5. Apparatus,

• 6. Calibration,

• 7. Test Procedures (excluding 7.3. Specimen Conditioning),

• 8. Calculation, and

• Annex A1. Equipment Design.

DOE is not proposing to reference any other sections of ASTM C518-17 as they either do not apply or they are in direct conflict with other test procedure provisions included in subpart R. As ASTM C518-17 is an updated version of ASTM C518-2004, the DOE test procedure for determining the K-value remains based on ASTM C518-2004.

3. Standards for Determining AWEF

DOE's current test procedure for WICF refrigeration systems is codified in appendix C to subpart R of part 431 and incorporates by reference AHRI 1250-2009, AHRI 420-2008, and ASHRAE 23.1-2010. AHRI 1250-2009 is the industry test standard for refrigeration systems for walk-in coolers and freezers, including unit coolers and dedicated condensing units sold separately, as well as matched pairs. 81 FR 95758, 95798.

The procedure describes the method for measuring the refrigeration capacity and the electrical energy consumption for a condensing unit and a unit cooler, including off-cycle fan and defrost subsystem contributions. Using the refrigeration capacity and electrical energy consumption, AHRI 1250-2009 provides a calculation methodology to compute AWEF, the applicable energy-performance metric for refrigeration systems.

Available at

www.ahrinet.org.

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

The DOE test procedure for walk-in refrigeration systems adopts by reference the test procedure in AHRI 1250-2009 (excluding Tables 15 and 16), with certain enumerated modifications. Generally, DOE's modifications to AHRI 1250-2009 address specific test conditions, tolerances, and instrumentation requirements, as well as specific instructions for how to address defrost energy use, unit coolers tested alone, and dedicated condensing units tested alone.

See

appendix C to subpart R of part 431.

In 2014, AHRI published an update to AHRI Standard 1250 (“AHRI 1250-2014”) which supersedes AHRI 1250-2009. After publication of AHRI 1250-2014, DOE and other stakeholders supported the AHRI 1250 committee in its update of AHRI Standard 1250. Subsequently, in April 2020, AHRI published AHRI 1250-2020, which supersedes AHRI 1250-2014. AHRI 1250-2020 incorporates many of the modifications and additions to AHRI 1250-2009 that DOE currently prescribes in its test procedure. It also includes test methods for unit coolers and dedicated condensing units tested alone, rather than incorporating by reference updated versions of AHRI 420-2008 and/or ASHRAE 23.1-2010, and also includes test methods for single-packaged dedicated systems. Sections III.B.3.a to III.B.3.d detail the changes made to AHRI 1250-2020 as compared to AHRI 1250-2009.

In the June 2021 RFI, DOE requested comment on what issues, if any, would be present if DOE were to adopt AHRI 1250-2020 into the DOE test procedure. 86 FR 32332, 32336. The CA IOUs and NEEA stated their general support for the adoption of AHRI 1250-2020. (CA IOUs, No. 14 at p. 1; NEEA, No. 16 at pp. 1-2) Lennox, AHRI, and Hussmann supported the adoption of AHRI 1250-2020 with some reservations associated with the retest burden it may create. (Lennox, No. 9 at p. 2; AHRI, No. 11 at p. 4; Hussmann, No. 18 at p. 6) Lennox, AHRI, and Hussmann asked DOE to evaluate if a full revision of the test standards was appropriate at this time. (Lennox, No. 9 at p. 2; AHRI, No. 11 at p. 4; Hussmann, No. 18 at p. 6) DOE acknowledges the potential burden of a new test procedure and notes that a full cost evaluation of the proposed test procedure changes has been conducted and is discussed in section III.J. Therefore, DOE is proposing two sets of changes for the refrigeration system test procedure. One set of changes would be included as proposed revisions to subpart R, appendix C, and the other group would be proposed through the establishment of an appendix C1. DOE has tentatively determined that the changes to subpart R, appendix C, would not affect AWEF ratings and therefore not require retesting or recertification. These proposed changes, if adopted, would be required 180 days after the test procedure final rule is published. DOE has also tentatively determined that the proposed provisions included in appendix C1 would affect the determination of energy use and would therefore require retesting and recertification of the proposed AWEF2. The provisions proposed in appendix C1, if adopted, would be required to be followed in conjunction with the compliance date of any amended energy conservation standards that DOE may end up adopting as part of a separate standards rulemaking.

In this test procedure NOPR DOE is proposing to reference AHRI 1250-2020 for use in appendix C1, but excluding:

• Section 1 Purpose,

• Section 2 Scope,

• Section 9 Minimum Data Requirements for Published Ratings,

• Section 10 Marking and Nameplate Data,

• Section 11 Conformance Conditions, and

• Section C10.2.1.1 Test Room Conditioning Equipment under section C10—Defrost Calculation and Test Methods.

DOE is not proposing to reference these sections of AHRI 1250-2020 since they either do not apply or conflict with other test procedure provisions included in the proposed appendix C1. Additionally, DOE is not proposing to reference ASHRAE 23.1-2010 or AHRI 420-2008 in the proposed appendix C1, as the materials referenced in these standards by AHRI 1250-2009 are now included within AHRI 1250-2020.

Further, DOE is proposing to reference ASHRAE 16-2016 in the proposed appendix C1, as it is referenced in AHRI 1250-2020, but excluding:

• Section 1 Purpose

• Section 2 Scope

• Section 4 Classifications

• Normative Appendices E-M

• Informative Appendices N-R

DOE is not proposing to reference these sections of ASHRAE 16-2016 as they either do not apply or conflict with other test procedure provisions that would be included as part of the newly proposed appendix C1.

Similarly, DOE is proposing to reference ASHRAE 37-2009 in the proposed appendix C1, as it is referenced in AHRI 1250-2020, but excluding:

• Section 1 Purpose,

• Section 2 Scope,

• Section 4 Classifications,

• Informative appendix A Classifications of Unitary Air-conditioners and Heat Pumps.

DOE is not proposing to reference these sections of ASHRAE 37-2009 as they either do not apply or conflict with other test procedure provisions that would be included as part of the newly proposed appendix C1.

a. Changes Consistent With Subpart R, Appendix C

As mentioned previously, AHRI 1250-2020 incorporates many of the modifications and additions to AHRI 1250-2009 that DOE currently prescribes in its test procedure. The modifications in the following sections of subpart R, appendix C, were incorporated into AHRI 1250-2020. Thus, if DOE were to adopt AHRI 1250-2020, DOE would remove the following sections from subpart R, appendix C:

• Section 3.1.1, which modifies Table 1 (Instrumentation Accuracy) in AHRI 1250-2009;

• Section 3.1.2, which provides guidance on electrical power frequency tolerances;

• Section 3.1.3, which states that in Table 2 of AHRI 1250-2009, the test operating tolerances and test condition tolerances for air leaving temperatures shall be deleted;

• Section 3.1.4, which states that in Tables 2 through 14 in AHRI-1250-2009, the test condition outdoor wet bulb temperature requirement and its associated tolerance apply only to units with evaporative cooling;

• Section 3.1.5, which provides tables to use in place of AHRI 1250-2009 Tables 15 and 16, which are excluded from the IBR in 10 CFR 431.303. The update in AHRI 1250-2020 to Tables 15 and 16 would allow DOE to incorporate the AHRI 1250-2020 tables by reference if DOE were to adopt AHRI 1250-2020;

• Section 3.2.1, which provides specific guidance on how to measure refrigerant temperature;

• Section 3.2.2, which removes the requirement to perform a refrigerant composition and oil concentration analysis;

• Section 3.2.4, which provides voltage requirements for unit cooler fan power measurements;

• Section 3.2.5, which provides insulation and configuration requirements for liquid and suction lines used for testing;

• Section 3.3.1, which gives direction for how to test and rate unit coolers tested alone;

• Section 3.3.2, which clarifies that the 2008 version of AHRI Standard 420 should be used for unit coolers tested alone;

• Section 3.3.3, which modifies the allowable reduction in fan speed for off-cycle evaporator testing;

• Section 3.4.1, which specifies that the 2010 version of ASHRAE 23.1 should be used and that “suction A” condition test points should be used when testing dedicated condensing units and,

• Section 3.5, which provides guidance on how to rate refrigeration systems with hot gas defrost.

The entirety of section 3.4.2 of subpart R, appendix C, which provides instruction on how to calculate AWEF and net capacity for dedicated condensing units, would also be removed if AHRI 1250-2020 were to be adopted, but the text in AHRI 1250-2020 that would replace it alters the text currently in section 3.4.2, which would result in a change to the current test procedure.

b. CFR Language Not Adopted in AHRI 1250-2020

As mentioned previously, AHRI 1250-2020 incorporates many, but not all, of the modifications and additions to AHRI 1250-2009 that DOE currently prescribes in its test procedure. For example, section 3.2.3, which modifies the requirements in Section C3.4.5 of AHRI 1250-2009 to require only a sight glass and a temperature sensor located on the tube surface under the insulation to verify sub-cooling downstream of mass flow meters, was not incorporated into AHRI 1250-2020. DOE is proposing, however, to carry over this section into the newly proposed appendix C1.

With respect to other current sections in subpart R, appendix C, sections that were not adopted by AHRI 1250-2020, DOE is proposing to revise those sections as part of this NOPR in the following manner:

• Sections 3.3.4 and 3.3.5, which modify the defrost test procedure in AHRI 1250-2009, would not be carried over into the newly proposed appendix C1. This NOPR proposes a revised approach to account for defrost heat load and energy use. This topic and DOE's proposals are discussed in sections III.G.8.a and III.G.8.b; and

• Section 3.3.7, which provides guidance on how to rate refrigeration systems with variable-speed evaporator fans would also not be carried over into the newly proposed appendix C1.

c. Changes That May Impact the Determination of AWEF

Several changes in AHRI 1250-2020 may impact the AWEF calculation. These changes can be grouped into five categories, discussed in the following paragraphs: Off-cycle tests, single-packaged dedicated systems, defrost calculations, variable capacity, and unit coolers.

Off-Cycle Tests

AHRI 1250-2020 updated the off-cycle tests in Sections C3.5 and C4.2 such that the total input wattage of the test unit is measured during the off cycle, rather than just the unit cooler fan input wattage. This change accounts for ancillary power from components such as crank case heaters and would deliver more representative off-cycle power results. As a result, if DOE were to incorporate this provision into its test procedure, it would affect the AWEF measurement for dedicated condensing units, matched pairs, and single-packaged dedicated systems by accounting for additional energy usage in the measured off-cycle power consumption value. In addition, updates made in AHRI 1250-2020 require that the measurement of unit cooler off-cycle power include the total electric power input to pan heaters and controls as well as the fan motors. AHRI 1250-2020 requires that off-cycle fan speed be at least 50% of full speed or that duty cycle for cycling fans be at least 50%, consistent with the current requirements of section 3.3.3 of subpart appendix C.

Single-Packaged Units

AHRI 1250-2020 added Section C9.1, which includes test methods for single-packaged refrigeration units. These methods allow for testing of single-packaged units with indoor and outdoor air enthalpy methods as specified in ASHRAE 37 and ASHRAE 16. These methods account for the heat leakage

that single-packaged dedicated systems are prone to experience by design. The inclusion of this heat leakage would lower single-packaged dedicated systems' net capacities and therefore lower their AWEFs. It would also make their net capacities more representative of field performance.

Defrost Calculations

AHRI 1250-2020 combined the defrost calculations and test methods into Section C10 to AHRI 1250-2020. For systems using electric defrost, the defrost calculations for defrost heat contributed to the box load (Q

) have been changed to three different equations depending on the system's gross capacity. In addition, new calculation methods for estimating the defrost energy of units with hot gas defrost have been added. The new default equations for electric and hot gas defrost heat and energy contributions are based on testing and analysis work conducted by AHRI and DOE, and therefore these values are expected to be more representative than previous equations for the default values.

AHRI 1250-2020 also added two optional challenge

tests for adaptive and hot gas defrost in appendices E and F, respectively. Both tests evaluate whether a unit has a system that functions as either an adaptive or hot gas defrost system. For compliance purposes, DOE requires that units are tested without activating adaptive defrost or hot gas defrost; therefore, neither challenge test included in AHRI 1250-2020 would affect the calculation of AWEF. The defrost challenge tests and calculations are discussed in detail in sections III.G.8.a, and III.G.8.b of this document.

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

d. Additional Amendments

In addition to those changes enumerated in sections III.B.3.a through III.B.3.c of this document, AHRI 1250-2020 includes additional amendments that are inconsistent with the current DOE test procedure and would not be expected to impact calculated AWEF. This section discusses those changes.

AHRI 1250-2020 added exclusions for liquid-cooled condensing systems in section 2.2.4. and excludes systems that use carbon dioxide, glycol, or ammonia as refrigerants in section 2.2.5. The current DOE test procedure is neutral with respect to refrigerant, and DOE considers all walk-in refrigeration systems to be covered equipment regardless of the refrigerant used. However, DOE recognizes that modifications may be necessary to the test method for different refrigerants (for example, see discussion in section III.F.6 for CO

As discussed in section III.B.3.a, AHRI 1250-2020 updated many of the tolerances in Table 2 of section 4. Some of these updates are not included in the current CFR language. DOE proposes to adopt the tolerances in AHRI 1250-2020, Table 2 of section 4 in subpart R, appendix C. As discussed later, DOE expects that the updated tolerance values would improve the repeatability of the test procedure with no impact on test cost.

AHRI 1250-2020 includes an updated list of references and the applicable versions of certain test standards in appendix A, “References—Normative.” DOE proposes to reference AHRI 1250-2020 appendix A in subpart R, appendix C. DOE expects that this modification would have no impact on test cost, while ensuring that more recent test standards are referenced.

Both AHRI 1250-2009 appendix C and AHRI 1250-2020 appendix C provide specific test methods for testing walk-in cooler and freezer systems, whereas the body of the standard specifies test requirements and calculations for walk-in box load and for determining AWEF. Additionally, AHRI 1250-2020 includes the following updated provisions: Section C3 of AHRI 1250-2009 lists requirements for measuring temperature (Section C3.1), measuring pressure (Section C3.2), measuring refrigerant properties (Section C3.3), determining refrigerant flow (Section C3.4), determining unit cooler fan power (Section C3.5), and specifies measurement and recording intervals (Section C3.6). In AHRI 1250-2020, Section C3 has been expanded to include requirements for measuring off-cycle power (Section C3.5) and determining steady state refrigeration capacity and energy consumption (Section C3.6), which are applicable to all tests unless otherwise specified. Aside from single-packaged dedicated system tests and the off-cycle power tests discussed in the previous section and in Sections III.G.2 and III.G.1, respectively, of this document, DOE does not expect that the revisions made to Section C3 in AHRI 1250-2020 would impact test duration and is therefore proposing to incorporate these sections (except for Section C3.5)

into subpart R, appendix C.

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

Sections C3.1.3.1, C3.1.3.2, and C3.1.3.3 of AHRI 1250-2020 specified refrigerant temperature measurement locations for unit coolers tested alone, matched pairs, and dedicated condensing systems tested alone. Specific changes include:

• For unit coolers tested alone: Refrigerant entering temperature is measured within six pipe diameters upstream of the control device (Section C3.1.3.1).

• For matched pairs, but not single-packaged dedicated systems: Refrigerant entering temperature is measured within the first six inches of the refrigerant pipe entering the unit cooler conditioned space, and the leaving temperature is measured within the last six inches of the refrigerant pipe leaving the unit cooler conditioned space (Section C3.1.3.2); and

• For dedicated condensing units tested alone: Entering and leaving refrigerant temperatures are measured at the inlet and outlet of the unit using two independent measuring systems (Section C3.1.3.3).

The modifications for measuring refrigerant temperature in AHRI 1250-2020 are expected to improve the repeatability and reproducibility of the test procedure, but do not impact test setup or test duration; therefore, DOE is proposing to reference these sections in subpart R, appendix C.

AHRI 1250-2020 added Section C7.5.1.1 to provide more detailed instructions for calculating system capacity beginning with measured temperatures instead of calculated enthalpies, which is what was done in AHRI 1250-2009. Section C7.5.1 also includes the determination of enthalpy from capacity test results.

AHRI 1250-2020 added Section C9.2, which specifies an allowable heat balance of ± 6 percent for single-packaged refrigeration capacity testing. AHRI 1250-2009 required a heat balance of ± 5 percent for all systems. This change was made to align with ASHRAE 37, which AHRI 1250-2020 incorporates by reference for single-packaged testing.

AHRI 1250-2009 included Section C12 “Method of Testing Condensing Units for Walk-In Cooler and Freezer Systems for Use in Mix-Match System Ratings,” which referenced AHRAE 23.1-2010. AHRI 1250-2020 now provides specific test methods for testing dedicated condensing units

tested alone. DOE has tentatively determined that the test procedure incorporated into AHRI 1250-2020 is the same as that in ASHRAE 23.1-2010 and therefore does not impact test setup or burden. As a result, DOE proposes to no longer incorporate ASHRAE 23.1-2010 by reference.

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

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

Appendix A provides the test procedures to measure the energy consumption of the components of envelopes of walk-ins. Specifically, appendix A provides the test procedures to determine the U-factor, conduction load, and energy use of walk-in display panels and to determine the energy use of walk-in display doors and non-display doors. DOE notes that display panels are also subject to the energy consumption test procedure in appendix A. Display panels are discussed in section III.D of this document.

In this NOPR, DOE is proposing to make the following revisions to appendix A, specific to display doors and non-display doors: (1) Reference NFRC 102-2020 in place of NFRC 100 and adopt AEDM provisions; (2) provide further detail on and distinguish the area to be used for determining compliance with standards and the area used to calculate a thermal load from U-factor; (3) establish a percent time off value specific to door motors; and (4) reorganize the test method so that it is easier to follow. The organizational changes include moving the test methods and measurement provisions for determining U-factor up before the provisions for calculating energy consumption and moving the percent time off values for all electrical components into a table. DOE has preliminarily determined that these changes would improve test representativeness and repeatability.

DOE does not expect that the changes it is proposing in this section would have a substantive impact on energy consumption calculations for display doors or non-display doors, except in the case of testing doors with motors as described in the following paragraphs.

The following sections describe the modifications that DOE is proposing to appendix A with respect to walk-in display doors and walk-in non-display doors.

1. Procedure for Determining Thermal Transmittance (U-Factor)

a. Reference to NFRC 102 in Place of NFRC 100

As discussed in section III.B.1 of this document, section 5.3 of appendix A requires manufacturers to determine thermal transmittance, or “U-factor,” according to NFRC 100. As also mentioned previously, NFRC 100 includes a computational method for determining U-factor, which involves simulating the U-factor using LBNL's WINDOW and THERM software. Section 4.1.1 of NFRC 100 provides validation requirements so that simulation, rather than a physical test, can be used for rating U-factor for a product line. This approach may be less costly but can result in a different, and potentially less accurate, thermal transmittance value than the thermal transmittance value determined by physical test using NFRC 102. NFRC 100 defines a “product line” as a series of individual products of the same product type, and a “product type” as a designation used to differentiate between fenestration products based on fixed and operable sash and frame members. Section 4.2.1 of NFRC 100 lists the allowable changes from product to product within a product line. DOE notes that “product line” is not synonymous with “basic model” as defined in 10 CFR 431.302. DOE understands that simulated U-factors of non-display doors using NFRC 100 have generally not been accurately determined when compared to a physical test.

In the June 2021 RFI, DOE noted it was considering incorporating by reference NFRC 102 as the test method for determining U-factor of walk-in doors in place of NFRC 100 and adopting AEDM provisions for walk-in doors to replace the computational methodology in NFRC 100. 86 FR 32332, 32336. As part of the June 2021 RFI, DOE requested comment on the accuracy of the computational method in NFRC 100 to predict U-factor for display and non-display doors, the magnitude of the difference in U-factor determined using the computational method and using the physical test method, and whether the computational method could be modified to more closely match the results obtained from physical testing. DOE also sought comment on whether manufacturers are using the computational method in NFRC 100 to rate U-factors, whether there are other alternative methods for computationally determining U-factor, and the costs associated with NFRC 100 or other computational methods compared to physical testing. 86 FR 32332, 32336.

NFRC stated that the NFRC 100 computational method has been used to accurately simulate U-factors for display doors because the physical characteristics of a display door are similar to the windows and glass doors for which the NFRC 100 computational method was developed. NFRC also stated, however, that there has been limited success validating NFRC 100 simulations with physical tests for non-display doors because non-display doors, unlike windows and glass doors, have high amounts of insulation and significant thermal bypasses along the door perimeter. (NFRC, No. 10 at p. 1) Similarly, AHRI commented that while NFRC 100 is appropriate and accurate for display doors, it was not designed for non-display doors, but it is not aware of an industry test method better suited for non-display doors. (AHRI, No. 11 at p. 4) NFRC stated that while refinements to the computational method in NFRC 100 may be possible for more accurately determining U-factor of non-display doors, they have not yet been addressed due to limited usage of this method for specimens like non-display doors. NFRC also stated that the computational method does not always result in higher or more conservative U-factors than the U-factors determined through physical test, and that the test and simulation agreement vary in either direction. (NFRC, No. 10 at p. 1)

Anthony and Hussmann stated that in their experience, the U-factors generated using the computational method in NFRC 100 generally align with the U-factors obtained from the physical test method, NFRC 102. (Anthony, No. 8 at p. 2; Hussmann, No. 18 at p. 5) Imperial Brown stated that it is possible to simulate U-factor of non-display doors if the door frame is included in the simulation and provided example simulation cross-sections. (Imperial Brown, No. 15 at p. 2)

The CA IOUs recommended that the physical test method ASTM C1199 be

used for doors and window assemblies to provide a measured approach that can be compared to the current calculated method. (CA IOUs, No. 14 at p. 5) Hussmann recommended using the computational method exclusively, except for the physical testing of one model per product line required for validation, stating that physical testing imposes an unnecessary burden on a manufacturer. (Hussmann, No. 18 at p. 5) Imperial Brown asserted that NFRC 102 is costly and time consuming to conduct, and that it is unrealistic to test all of the models they offer since the walk-in door market is highly customizable. Imperial Brown supported continuing to use NFRC 100 and recommended a “safety factor” be included to make up for potential inaccuracies of the computational method. (Imperial Brown, No. 15 at pp. 1-2)

Anthony urged DOE to eliminate the requirement for a physical test, stating that there is no added value for it and that physical testing is more than two times the cost of the computational method. Anthony also stated, however, that if NFRC 100 remains the referenced industry test method, the test procedure should specify a course of action if the computational method results fall outside the 10 percent acceptance criteria. (Anthony, No. 8 at p. 2)

NFRC stated that developing an AEDM would be inefficient as the computational method described in NFRC 100 has been shown to be accurate. (NFRC, No. 10 at p. 1) Additionally, NFRC estimated a cost of $2,000 for simulating U-factors for a typical product line of display doors (about 35-50 U-factor values). NFRC emphasized that there is no economy of scale in performing more physical tests because each sample must be tested on its own and requires its own specific setup and time to run. NFRC suggested that given the U-factors of non-display doors cannot typically be simulated within the agreement specified by NFRC 100, the most economical way to determine U-factor for a product line would be to pick a few sizes within the range of offerings and use the worst-case U-factors to represent a range of sizes. (

Id.

At p. 2)

In response to comments received on the accuracy of the computational method, DOE understands that there has been limited success in accurately simulating the U-factor of non-display doors using NFRC 100. Although stakeholders asserted that NFRC 100 can accurately simulate display door U-factors, the recommendation by one stakeholder that instruction be provided when the simulated value and tested value do not agree within the limits specified by NFRC 100 suggests there may be instances when the computational method does not provide sufficiently accurate results. DOE recognizes that if display or non-display door manufacturers are unable to simulate U-factor using NFRC 100, they are currently required to physically test every door basic model, which may be unduly burdensome given the highly customizable nature of the market and thus high number of basic models to test.

In this NOPR, DOE is proposing to remove reference to NFRC 100 from its test procedure and instead reference NFRC 102 and adopt provisions allowing manufacturers to use an AEDM. DOE emphasizes that allowing use of an AEDM would provide manufacturers with the flexibility to use an alternative method that yields the best agreement with a physical test for their doors. If manufacturers have had success using the computational method in NFRC 100, inclusion of AEDM provisions would enable manufacturers to continue using NFRC 100, provided that manufacturers meet the proposed AEDM requirements in 10 CFR 429.53 and 10 CFR 429.70(f). Particularly, under the proposals, manufacturers would need to ensure that the output result of energy consumption from the AEDM is within the proposed 5 percent tolerance of an energy consumption result that includes a physical U-factor test. The proposed adoption of an AEDM is discussed in more detail in section III.H.1.

b. Exceptions to Industry Test Method for Determining U-Factor

Section 5.3 of appendix A references NFRC 100 for determining U-factor with the specific modifications to the industry standard listed in section 5.3(a). The first modification specifies that the average surface heat transfer coefficients during a test must be within ± 5 percent of the values specified through NFRC 100 in ASTM C1199. The second and third items modify the cold and warm side conditions from the standard conditions prescribed in NFRC 100. The final provision listed specifies the direct solar irradiance

be 0 Btu/(h-ft

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

As discussed in the June 2021 RFI, DOE has found that obtaining the standardized heat transfer values within the tolerances specified in section 5.3(a)(1) of appendix A on the warm-side and cold-side may not be achievable depending on the thermal transmittance through the door. 86 FR 32332, 32340. Specifically, the warm-side heat transfer is dominated by natural convection and radiation and the heat transfer coefficient varies as a function of surface temperature. When testing doors with higher thermal resistance, less heat is transferred across the door from the warm-side to the cold-side, so the warm-side surface temperature is closer to the warm-side air temperature.

Sections 6.2.3 and 6.2.4 of ASTM C1199 specify the standardized heat transfer coefficients and their tolerances as part of the procedure to set the surface heat transfer conditions of the test facility using the Calibration Transfer Standard (“CTS”) test. The warm-side surface heat transfer coefficient must be within ± 5 percent of the standardized warm-side value of 1.36 Btu/(h-ft

-°F), and the cold-side surface heat transfer coefficient must be within ± 10 percent of the standardized cold-side value of 5.3 Btu/(h-ft

-°F) during the CTS test (ASTM C1199, Sections 6.2.3 and 6.2.4). ASTM C1199 does not require that the measured surface heat transfer coefficients match or be within a certain tolerance of standardized values during the official sample test—although test facility operational (

e.g.,

cold side fan settings) conditions would remain identical to those set during the CTS test. ASTM C1199 also does not require measurement of the warm-side surface temperature of the door. Rather, this value is calculated based on the radiative and convective heat flows from the test specimen's surface to the surroundings, which are driven by values determined from the calibration of the hot box using the CTS test (

e.g.,

the convection coefficient).

See

ASTM C1199, Section 9.2.1. When testing doors with extremely high- or low-thermal resistance, the resulting change in warm-side surface temperature can shift the warm-side heat transfer coefficient out of the tolerance specified in the DOE test procedure. To ensure that these coefficients are within tolerance during the test would require recalibration of the hot box for each specific door.

As part of the June 2021 RFI, DOE requested feedback on the tolerances currently specified in section 5.3(a)(1) of appendix A applied to the surface heat transfer coefficients used to measure thermal transmittance and whether they should be increased or omitted. 86 FR 32332, 32340.

In response, NFRC asserted that applying the surface heat transfer coefficient tolerances to the surface heat

transfer coefficients determined in the actual U-factor test is not a correct application of the NFRC 102 test method and recommended that the tolerances be removed from section 5.3(a)(1) of appendix A. NFRC additionally stated that the idea behind the CTS calibration tests is to set up a consistent set of fan speeds on both sides of the chamber or to create consistent cold and warm side environments for testing of all products. NFRC further stated that the convection currents will be influenced during sample testing by the surface temperatures of the test sample and that this is an expected and natural occurrence. (NFRC, No. 10 at pp. 3-4)

Given DOE's experience with testing walk-in doors and the comments provided by NFRC, DOE is proposing to remove the requirement listed in section 5.3(a)(1) regarding the surface heat transfer coefficients and the tolerances on them during testing.

Additionally, while DOE did not request specific comment on the surface heat transfer coefficients themselves (

i.e.,

the warm side value of 1.36 Btu/(h-ft

-°F) and cold side value of 5.3 Btu/(h-ft

-°F)), Anthony commented that the heat transfer coefficient applied to the cold side of the test specimen correlates to a wind speed roughly equivalent to 12.3 miles per hour (“mph”). Anthony stated that their field testing has demonstrated that the wind speed interior to the walk-in is below 5 mph. (Anthony, No. 8 at pp. 3-4)

DOE is not proposing to deviate from the surface heat transfer coefficients specified in NFRC 102-2020 for calibration because additional investigation is needed. Deviating from these surface heat transfer coefficients would require test labs to change their test chamber calibration procedures and would require manufacturers to retest and re-rate all envelope components subject to the energy consumption test procedure in appendix A. DOE may consider changes to the surface heat transfer coefficients specified in NFRC 102-2020 for calibration in the future if more data became available regarding the internal and external conditions of walk-ins in various installations. At this time however, more data and Departmental analysis would need to be conducted to support any changes to the surface heat transfer coefficients specified in NFRC 102-2020.

DOE also received comment on the direct solar irradiance requirement. NFRC stated that direct solar irradiance of 0 Btu/(h-ft

) listed in section 5.3(a)(4) of appendix A is not an exception to NFRC 100 and should be removed from appendix A. (NFRC, No. 10 at p. 4) Consistent with DOE's proposal to remove reference to NFRC 100, DOE proposes to remove this requirement in section 5.3(a)(4) of appendix A.

c. Calibration of Hot Box for Measuring U-Factor

As stated previously, NFRC 100 references NFRC 102 as the physical test method for measuring U-factor, which in turn incorporates by reference ASTM C1199. ASTM C1199 references ASTM C1363-05, “Standard Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus” (“ASTM C1363”). Section 6.1 of ASTM C1199 and Annexes 5 and 6 of ASTM C1363 include calibration requirements to characterize metering box wall loss and surround panel flanking loss, but the frequency at which these calibrations should occur is not specified in these test standards. As part of the June 2021 RFI, DOE sought comment on the frequency at which test laboratories perform each of the calibration procedures referenced in ASTM C1199 and ASTM C1363,

e.g.,

those used to determine the calibration coefficients for calculating metering box wall loss and surround panel flanking loss. 86 FR 32332, 32340. DOE also requested comment on the magnitude of variation in the calibration coefficients measured during successive calibrations.

Id.

NFRC stated that because the referenced ASTM standards (

i.e.,

ASTM C1199 and ASTM C1363) do not specify frequency of calibration, NFRC 102 includes calibration frequency requirements in section 6.1. NFRC stated that section 6.1 requires that metering box wall loss and surround panel flanking loss be determined once and verified annually as these values would not inherently change over time. It noted that the verification of the metering box wall loss and surround panel flanking loss requires results to be within 2 Watts of previous characterization results. NFRC added that their experience shows that these results repeat well over time and that an increase in calibration frequency is unnecessary. (NFRC, No. 10 at p. 3)

As NFRC stated, the most recent version of NFRC 102, NFRC 102-2020, includes calibration frequencies and requirements in section 6.1(A). The currently referenced version of NFRC 102, NFRC 102-2010, does not include these calibration requirements. For this reason and because of the comments provided by NFRC, DOE is proposing to adopt the calibration requirements in Section 6.1(A) of NFRC 102-2020.

2. Additional Definitions

a. Surface Area for Determining Compliance With Standards

The surface area of display doors and non-display doors (designated as

and

respectively) are used to determine maximum energy consumption (“MEC”) in kWh/day of a walk-in door. 10 CFR 431.306(c)-(d). Surface area is currently defined in section 3.4 of appendix A as “the area of the surface of the walk-in component that would be external to the walk-in cooler or walk-in freezer as appropriate.” As currently written, the definition does not provide further detail on how to determine the boundaries of the walk-in door from which height and width are determined to calculate surface area. Additionally, the definition does not specify if these measurements are to be strictly in-plane with the surface of the wall or panel that the walk-in door would be affixed to, or if troughs and other design features on the exterior surface of the walk-in door should be included in the measured surface area. Inconsistent determination of surface area, specifically with respect to the measurement boundaries, may result in unrepresentative and inconsistent MEC values. Additionally, walk-in doors with antisweat heaters are subject to prescriptive standards for power use of antisweat heaters per square foot of door opening. 10 CFR 431.306(b)(3)-(4). DOE considers the area of the “door opening” to be consistent with the surface area used to determine MEC.

Display doors are fundamentally different from non-display doors in terms of their overall construction. For example, display door assemblies contain a larger frame that can encompass multiple door openings or leaves, and the entire assembly fits into an opening within a walk-in wall. Non-display doors differ in that they often are affixed to a panel-like structure that more closely resembles a walk-in wall rather than a traditional door frame.

In the June 2021 RFI, DOE described how it applies the current test procedure definition for surface area when determining compliance with standards. 86 FR 32332, 32337. As part of the June 2021 RFI, DOE requested comment on how manufacturers determine surface area for the purpose of evaluating compliance with the MEC performance standards and with the prescriptive standards pertaining to antisweat heaters for both display and non-display doors.

Id.

AHRI and Hussmann stated that they determine surface area consistent with DOE, and that they do not see any

distinctions between display doors and non-display doors that warrant determining surface area differently. (AHRI, No. 11 at p. 7; Hussmann, No. 18 at p. 9) Anthony stated that they include the frame and frame flange as part of the door assembly when determining door surface area. Anthony also stated that, contrary to how they determine surface area, Figure 4-2 of NFRC 100-2017 excludes frame flanges. (Anthony, No. 8 at pp. 2-3) Imperial Brown stated that the area for non-display doors,

, should be the clear opening area, or WIC by HIC, which excludes the door frame portion of the door assembly. They also stated that the clear opening area may be smaller than the swinging or sliding portion of the door, which typically overlaps a portion of the door frame. (Imperial Brown, No. 15 at p. 2)

With regard to the prescriptive anti-sweat heater standards, Anthony agreed that the power use of anti-sweat heat per square foot is consistent with the surface area used to determine MEC. (Anthony, No. 8 at pp. 2-3) AHRI and Hussmann stated that they do not see a need to change requirements for the prescriptive standards pertaining to anti-sweat heaters. (AHRI, No. 11 at p. 7; Hussmann, No. 18 at p. 9)

In response to comments received, DOE notes that the description of surface area for determining MEC in the June 2021 RFI considers the structural differences between display and non-display doors and assumes different bounds for determining the surface area of display doors and non-display doors. As described previously, DOE includes the frame in the surface area calculation for display doors, whereas the panel-like frame of non-display doors has not been included in the surface area calculation. However, DOE has observed that many electrical components of non-display doors are sited on or within the frame to which the door is attached. If the non-display door frame is not considered as part of the non-display door, the frame would fall under the category of a walk-in panel. However, the current test procedure for panels does not account for electrical energy consumption. Many of the electrical components sited on the non-display door frame serve a function for operation of the door itself. For example, to keep non-display doors from freezing shut, anti-sweat heaters are used to prevent condensation from accumulating around the edge of the door.

Comments received regarding surface area determination suggest that the approach provided in appendix A may result in inconsistent interpretations as to how to determine this measurement. To clarify this issue, DOE is proposing additional specification on how the surface area is measured. DOE is proposing that the surface area bounds of both display doors and non-display doors be the outer edge of the frame. Specifically, DOE proposes to revise the term “surface area” to “door surface area,” and to define the new term as meaning the product of the height and width of a walk-in door measured external to the walk-in. Under this definition, the height and width dimensions would be perpendicular to each other and parallel to the wall or panel of the walk-in to which the door is affixed, the height and width measurements would extend to the edge of the frame and frame flange (as applicable) to which the door is affixed, and the surface area of a display door and non-display door would be represented as

and

, respectively. In addition, DOE proposes to move the defined term from the test procedure in appendix A because, as revised and in light of the following proposal in section III.C.2.b, this term does not apply to the proposed test procedure and is only relevant for determining compliance with the standards. Instead, DOE proposes to include the amended term and revised definition with the other definitions that are broadly applicable to subpart R in 10 CFR 431.302.

b. Surface Area for Determining U-Factor

As stated previously, appendix A currently references NFRC 100, which in turn references NFRC 102 for the determination of U-factor through a physical test. When conducting a simulation, the U-factor is calculated using the projected fenestration product area (

), or the area of the rough opening in the wall or roof, for the fenestration product, less installation clearances.

See

NFRC 100, section 3. When conducting physical testing, the U-factor (

) is calculated using projected surface area (

) and is then converted to the final standardized U-factor (

See

ASTM C1199, sections 8.1.3 and 9.2.7 as referenced through NFRC 102. Projected surface area (

) is defined as “the projected area of test specimen (same as test specimen aperture in surround panel).”

See

ASTM C1199, section 3.3 as referenced through NFRC 102.

Currently, equations 4-19 and 4-28 of appendix A specify that surface area of display doors (

) 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 is transferred from the exterior to the interior of the walk-in.

As discussed in section III.C.2.a, DOE is proposing to amend the definitions of

and

to be specific to the exterior plane of the door, including the frame and frame flange as appropriate. Defining the area in this manner is inconsistent with the area (

) used to calculate U-factor in NFRC 102-2020.

As part of the June 2021 RFI, DOE sought comment on this inconsistency and feedback on specifying additional detail for the surface area used to determine thermal conduction through a walk-in door to differentiate it from the surface area used to determine the maximum energy consumption of a walk-in door. 86 FR 32332, 32337.

NFRC stated that the area used to convert U-factor into energy use and the area used to determine U-factor must be consistent when calculating conduction load from thermal transmittance. (NFRC, No. 10 at pp. 2-3) NFRC also observed that NFRC 100, NFRC 102, ASTM C1199 and ASTM C1363 all define the area for U-factor based “n “projec”ed” specimen “r “open”ng” area in the wall through which the door is installed.

Id.

NFRC further asserted that since the surface area as defined by

and

are different from the projected area, heat flow is miscalculated when the tested U-factor is inserted into equations 4-19 and 4-28.

Id.

AHRI and Hussmann declared that they determine surface area in a manner consistent with the DOE regulations in 10 CFR parts 429 and 431 and that they do not see a distinction that warrants determining surface area differently in these instances. (AHRI, No. 11 at p. 7; Hussmann, No. 18 at p. 9)

Imperial Brown stated that for a non-display door, the outer frame is equivalent to a walk-in panel and therefore the frame would have a limited impact on the U-factor calculation of the swinging or sliding portion of the door. (Imperial Brown, No. 15 at p. 2) Imperial Brown separately defined the two types of non-display doors they manufacture, defining a “panel frame” as a frame that is connected in-line with other walk-in panels and a “flat frame” as a frame that is typically used in retrofit applications or by door-only manufacturers which are non-insulating and mount over and are fastened to walk-in panels. (

Id.

at p. 1) Imperial Brown suggested that manufacturers not be required to separately test basic models for U-factor which differ in their frame type because they believe “panel” frames and “flat” frames to be equivalent in performance

once mounted. Imperial Brown recommended that the same U-factor determined for a door with a “panel frame” be used for an otherwise the same door with a “flat frame.” (

Id.

at p. 2)

Based on this feedback, DOE has preliminarily determined that using the same area that is used to determine U-factor (

in NFRC 102 and ASTM C1199 as referenced) to convert U-factor into a conduction load, rather than the proposed revised term for door surface area in section III.C.2.a (

) results in a more representative conduction load and provides for improved consistency in application of the test procedure across all walk-in doors. As such, DOE proposes to specify that the projected area of the test specimen,

as defined in ASTM C1199, or the area used to determine U-factor is the area used for converting the tested U-factor,

into a conduction load in appendix A. DOE recognizes that this may not change ratings for some doors, where

is equivalent to

but it may result in slightly lower ratings of energy consumption for other doors, where

is less than

. DOE expects that since this proposed detail would either result in a reduced energy consumption or have no impact, there would be no need for manufacturers to retest or re-rate. Additional details on how this proposed detail impacts retesting and re-rating are further discussed in section III.J.1.

In response to Imperial Brown's assertion that the frame has a limited impact on the thermal performance of the door, DOE testing of non-display doors found that inclusion of the frame in the U-factor test (which resulted in a 34 to 52 percent increase in total door area) increased the heat transferred through the door assembly by 23 to 139 percent compared to heat transfer through the door leaf alone. This implies that including the frame in the U-factor test does have a measurable impact on the thermal performance of the door assembly. Therefore, DOE also proposes to specify in appendix A that the U-factor test includes the frame of the door to improve consistency in application of the test procedure across all walk-in doors.

3. Electrical Door Components

Sections 4.4.2 and 4.5.2 of appendix A include provisions for calculating the direct energy consumption of electrical components of display doors and non-display doors, respectively. For example, electrical components associated with doors could include, but are not limited to: Heater wire (for anti-sweat or anti-freeze application); lights (including display door lighting systems); control system units; and sensors.

See

appendix A, sections 4.4.2 and 4.5.2. For each electricity-consuming component, the calculation of energy consumption is based on the component's “rated power” rather than a measurement of its power draw. Section 3.5 of appendix A defines “rated power” as the electricity consuming device's power as specified (1) on the device's nameplate or (2) from the device's product data sheet if the device does not have a nameplate or such nameplate does not list the device's power.

DOE has observed that walk-in doors often provide a single nameplate for the door, rather than providing individual nameplates for each electricity-consuming device. In many cases, the nameplate does not provide separate power information for the different electrical components. Also, the nameplate often specifies voltage and amperage (a measure of current) ratings without providing wattage (a measure of power) ratings, as is referenced by the definition of “rated power.” While the wattage is equal to voltage multiplied by the current for many components, this may not be true for all components that may be part of a walk-in door assembly. Furthermore, nameplate labels typically do not specify whether any listed values of rated power or amperage represent the maximum operation conditions or continuous steady state operating conditions, which could differ for components such as motors that experience an initial surge in power before power use levels off. These issues make calculating a door's total energy consumption a challenge for a test facility that does not have in-depth knowledge of the electrical characteristics of the door components.

As part of the June 2021 RFI, DOE requested comment on whether, and if so how, an option for direct component power measurement could be included in the test procedure or DOE's CCE provisions to allow for a more accurate accounting of the direct electrical energy consumption of WICF doors. 86 FR 32332, 32338.

ASAP supported adding an option for direct measurement of power consumed by door electrical components. (ASAP, No. 13 at p. 1) The CA IOUs also supported direct measurement of power used by door components, but more specifically for components designed to operate at partial nameplate power such as door motors or powered door closers. The CA IOUs stated that, in their experience, power measurement for resistance components like lighting and door heaters are not necessary if these components are designed to operate at full nameplate power. They recommended that the electrical energy consumption of door motors be reported per door opening and that the electrical energy consumption be calculated as the actual power consumption of the motor multiplied by the duration of the door opening and closing. (CA IOUs, No. 14 at p. 4) Hussmann and Imperial Brown supported maintaining the current approach of using rated power for calculating direct electrical energy consumption and did not see a need for the measurement option. (Hussmann, No. 18 at p. 10; Imperial Brown, No. 15 at pp. 2-3) Imperial Brown also stated that control components are typically rated at 5 Watts or less and that they should be excluded from the calculation of direct electrical energy consumption. (Imperial Brown, No. 15 at pp. 2-3)

DOE is not proposing to include provisions requiring measurement of power consumption of electrical door components in the test procedure in appendix A because additional investigation is needed. However, DOE has observed that some manufacturers may be certifying door motor power as the output power rating of the motor, rather than the input power of the motor. Thus, DOE is proposing to specify in appendix A that the rated power of each electrical component,

rated,u,t

would be the rated input power of each component because the input power represents power consumption.

Additionally, DOE has observed through testing that the measured power of some walk-in door electrical components exceeds either the certified or nameplate power values of these electrical components. For the purposes of enforcement testing, DOE is proposing in 10 CFR 429.134(q) that DOE may validate the certified or nameplate power values of an electrical component by measuring the power when the device is energized using a power supply that provides power within the allowable voltage range listed on the nameplate. If the measured input power is more than 10 percent higher than the power listed on the nameplate or the rated input power in a manufacturer's certification, then the measured input power would be used in the energy consumption calculation. For electrical components with controls, the maximum input wattage observed while energizing the device and activating the control would be considered the measured input power.

4. Percent Time Off Values

The test procedure also assigns percent time off (“PTO”) values to various walk-in door components. PTO

values are applied to reflect the hours in a day that an electricity-consuming device operates at its full-rated or certified power (

i.e.,

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

Table III.3—Assigned PTO Values for Walk-in Door Components

Component type

Percent

time off

(PTO)

(%)

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

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

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

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

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

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

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

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

Table III.4—PTO Values Granted in Decision and Orders for Manufacturers of Doors With Motorized Door Openers

Manufacturer

Percent

time off

(PTO)

(%)

Decision and order

Federal Register

citation

HH Technologies

83 FR 53457. (Oct. 23, 2018).

Jamison Door Company

93.5

83 FR 53460. (Oct. 23, 2018).

Senneca Holdings

86 FR 75. (Jan. 4, 2021).

Hercules

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

In the June 2021 RFI, DOE requested comment on the current PTO values for all electricity-consuming devices, whether these values should be amended, and whether specific values should be added for certain electrical components, such as motors. 86 FR 32332, 32339.

In response, Hussmann stated that they determine energy consumption consistent with DOE's regulations in parts 429 and 431 and do not see a need to change the current PTO values. (Hussmann, No. 18 at p. 10) ASAP supported adding specific PTO values for motorized door openers because they believe it will provide similar treatment for these components as for other electrical components and eliminate the need for ongoing test procedure waivers. (ASAP, No. at p. 1) The CA IOUs recommended that DOE reduce the usage factor of door opening motors from 75 percent to 5 percent or less (

i.e.,

implement a PTO of 95 percent or greater). In their comments, the CA IOUs provided anecdotal data for two food service sites where doors were open an average of 20 and 40 minutes per day. The CA IOUs observed that if these doors had motors, the motor on time would be even less than the time recorded in the open position. Additionally, the CA IOUs recommended that DOE explore the differences in opening patterns among passage, freight, and display doors and potentially adjust the door motor PTO based on door opening pattern for each corresponding class. (CA IOUs, No. 14 at pp. 5-6)

As shown in Table III.4, each manufacturer requested a PTO value specific to their door and motor characteristics, resulting in four different PTO values. For this proposal, DOE evaluated a PTO that could be used to consistently evaluate energy consumption of doors with motors and would be sufficiently representative. Recognizing that the PTO values requested in the waivers are relatively close to one another, DOE calculated an average PTO value based on the information received in the waivers and is proposing to specify one PTO value for all basic models of doors with motors to use. This approach results in a more representative test procedure for doors with motors as compared to the current value specified for other electricity-consuming devices in appendix A. The intent of the PTO value is not to reflect behaviorally-related energy consumption of each individual installation of a door with a motor, but to provide a more representative means for comparison of walk-in door performance.

DOE calculated an average PTO value, as follows. For each motorized door offering from manufacturers that were granted waivers, DOE used the cycle rating as specified in the product literature. When a cycle rating was not provided in the product literature, DOE used its previously estimated number of door openings per day of 60 for passage doors and 120 for freight doors, respectively.

75 FR 55068, 55085.

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

DOE's previously estimated door openings per day were relevant for a proposal to address door opening infiltration in the test procedure introduced in a supplemental notice of proposed rulemaking from September 9, 2010. Ultimately, DOE did not adopt test procedure provisions addressing door opening infiltration, having determined that a typical door manufacturer has very few direct means for reducing the door

infiltration on its own. 76 FR 21580, 21595 (Apr. 15, 2011).

Considering the waivers granted, DOE's own calculations, and comments received, DOE is proposing to adopt a door motor PTO value of 97 percent for display doors with motors and non-display doors with motors.

As discussed in the June 2021 RFI, DOE is aware that some manufacturers design and market walk-in cooler display doors for high humidity applications. Ratings from the CCMS database show these doors have more anti-sweat heater power per door opening area than standard cooler display doors. 86 FR 32332, 32339. Section 4.4.2(a)(2) of appendix A requires a PTO value of 50 percent be used when determining the direct energy consumption for anti-sweat heaters with timers, control systems, or other demand-based controls situated within a walk-in cooler door (which would include walk-in cooler doors marketed for high humidity applications). This approach assumes that the anti-sweat heaters are not operating for 50 percent of the time. DOE recognizes that anti-sweat heaters may be in operation for a different amount of time in high humidity installations than in standard installations. In the June 2021 RFI, DOE requested comment on whether the current PTO of 50 percent is appropriate for evaluating direct energy consumption of anti-sweat heaters with controls for walk-in cooler doors marketed for high humidity applications and the amount of time per day or per year that anti-sweat heaters with controls are off for high humidity doors.

Id.

In response, DOE received comments from Anthony, AHRI, and Hussmann regarding the maximum energy consumption of high humidity doors. (Anthony, No. 8 at p. 3; AHRI, No. 11 at pp. 7-8; Hussmann, No. 18 at p. 10) However, as the responses of these comments were more focused on the standards, DOE plans to address these comments as part of a separate standards rulemaking for this equipment. DOE did not receive any comments regarding whether the PTO in the test procedure for anti-sweat heaters with controls sited on high humidity doors should be modified nor any data on the amount of time the anti-sweat heaters operate on high-humidity doors as compared to standard doors (

i.e.,

cooler display doors). DOE is not proposing any changes to the PTO values for anti-sweat heaters sited on high humidity doors at this time.

5. EER Values

To calculate the daily energy consumption associated with heat loss through a walk-in door, appendix A requires dividing the calculated heat loss rate by specified energy efficiency ratio (“EER”) values of 12.4 Btu per Watt-hour (“Btu/W-h”) for coolers and 6.3 Btu/(W-h) for freezers. Appendix A, sections 4.4.4(a) and 4.5.4(a). DOE selected EER values of 12.4 Btu/(W-h) for coolers and 6.3 Btu/(W-h) for freezers because these are typical EER values of walk-in cooler and walk-in freezer refrigeration systems, respectively.

75 FR 186, 209 (Jan. 4, 2010); 76 FR 21580, 21593-21594 (Apr. 15, 2011). The DOE test procedure in subpart R, appendix C, also assigns nominal EER values, which correspond to the appropriate adjusted dew point temperature in Table 17 of AHRI 1250-2009,

when testing the refrigeration systems of walk-in unit coolers alone. The resulting EER values for unit coolers tested alone are 13.3 Btu/(W-h) for coolers and 6.6 Btu/(W-h) for freezers, which are different than the EER values of 12.4 Btu/(W-h) and 6.3 Btu/(W-h), respectively, applied to walk-in doors, as described previously. In the June 2021 RFI, DOE sought feedback on the EER values specified in appendix A used to calculate daily energy consumption for walk-in doors and the values used to test unit coolers as specified in subpart R, appendix C. Specifically, DOE requested comment on whether the EER values used for door testing and unit cooler testing consistent with each other, and if so, which values are more representative. 86 FR 32332, 32339.

The difference in EER values between coolers and freezers reflects the relative efficiency of the refrigeration equipment for the associated application. 75 FR 186, 197. As the temperature of the air surrounding the evaporator coil drops (that is, when considering a freezer relative to a cooler), thermodynamics dictates that the system effectiveness at removing heat per unit of electrical input energy decreases.

Id.

The dewpoint temperature to be used for testing unit coolers alone is defined in section 3.3.1 of appendix C to be the Suction A saturation condition provided in Tables 15 or 16 of appendix C (for refrigerator unit coolers and freezer unit coolers, respectively). Table 15 for refrigerator unit coolers defines the Suction A saturation condition (

i.e.,

dewpoint temperature) as 25 °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 coolers 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.

Anthony responded that the EER values referenced in subpart R, appendix C (

i.e.,

13.3 Btu/(W-h) for coolers and 6.6 Btu/(W-h) for freezers), better reflect current compressor efficiency for walk-in refrigeration systems. (Anthony, No. 8 at p. 3) National Refrigeration encouraged DOE to keep the current EER values, stating that they believe the values are accurate, but did not specify if they were referring to walk-in door or refrigeration system EER values. (National Refrigeration, No. 17 at p. 1) Keeprite, Lennox, and AHRI all supported maintaining the EER values applicable to unit coolers in subpart R, appendix C. (Keeprite, No. 12 at p. 2; Lennox, No. 9 at p. 4; AHRI, No. 11 at p. 8)

Based on the comments received, it is not clear that there is an advantage to harmonizing the EER values between appendix A and subpart R, appendix C. Therefore, DOE is not proposing to change the subpart R, appendix C, EER values pertaining to walk-in refrigeration systems.

Additionally, with respect to envelope components, DOE is not proposing to align the EER values in appendix A for calculating the energy consumption of envelope components with the EER values used for testing unit coolers alone in subpart R, appendix C, at this time. DOE originally defined nominal EER values in appendix A because an envelope component manufacturer generally cannot control what refrigeration equipment is installed, and the defined EER value is intended to provide a nominal means of comparison rather than reflecting an actual walk-in installation. 76 FR 21580, 21593 (Apr. 15, 2011). In other words, the EER values used to estimate energy consumption of the envelope components is a constant. DOE notes that the difference between the EER values used in appendix A for doors and those used in subpart R, appendix C, for unit coolers is seven percent for coolers and five percent for freezers, which would have minimal impact on rated values but would require manufacturers to retest and re-rate energy consumption without necessarily providing a more representative test procedure.

6. Air Infiltration Reduction

EPCA includes prescriptive requirements for doors used in walk-in applications which are intended to reduce air infiltration. Specifically, walk-ins must have (A) automatic door closers that firmly close all walk-in doors that have been closed to within 1 inch of full closure (excluding doors wider than 3 feet 9 inches or taller than 7 feet), and (B) strip doors, spring-hinged doors, or other method of minimizing infiltration when doors are open. (42 U.S.C. 6313(f)(1)(A)-(B)) DOE previously propo

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