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Rule2023-08128

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

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Published

May 4, 2023

Effective

June 5, 2023

Issuing agencies

Energy Department

Abstract

The U.S. Department of Energy (DOE) is amending the test procedures for walk-in coolers and walk-in freezers to harmonize with updated industry standards, revise certain definitions, revise the test methods to more accurately represent field energy use, and to accommodate a wider range of walk-in cooler and walk-in freezer component equipment designs.

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[Federal Register Volume 88, Number 86 (Thursday, May 4, 2023)]
[Rules and Regulations]
[Pages 28780-28871]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-08128]

[[Page 28779]]

Vol. 88

Thursday,

No. 86

May 4, 2023

Part III

Department of Energy

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10 CFR Parts 429 and 431

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

Federal Register / Vol. 88, No. 86 / Thursday, May 4, 2023 / Rules
and Regulations

[[Page 28780]]

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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: Final rule.

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SUMMARY: The U.S. Department of Energy (DOE) is amending the test
procedures for walk-in coolers and walk-in freezers to harmonize with
updated industry standards, revise certain definitions, revise the test
methods to more accurately represent field energy use, and to
accommodate a wider range of walk-in cooler and walk-in freezer
component equipment designs.

DATES: The effective date of this rule is June 5, 2023. The amendments
will be mandatory for product testing starting October 31, 2023.
Manufacturers will be required to use the amended test procedures until
the compliance date of any final rule establishing amended energy
conservation standards based on the newly established test procedures.
At such time, manufacturers will be required to begin using the newly
established test procedures.
The incorporation by reference of certain materials listed in the
rule is approved by the Director of the Federal Register on June 5,
2023. The incorporation by reference of certain other material listed
in the rule was approved by the Director of the Federal Register on
January 27, 2017.

ADDRESSES: The docket, which includes Federal Register notices, public
meeting attendee lists and transcripts, comments, and other supporting
documents/materials, is available for review at <a href="http://www.regulations.gov">www.regulations.gov</a>.
All documents in the docket are listed in the <a href="http://www.regulations.gov">www.regulations.gov</a>
index. However, not all documents listed in the index may be publicly
available, such as those containing information that is exempt from
public disclosure.
A link to the docket web page can be found at <a href="http://www.regulations.gov/docket/EERE-2017-BT-TP-0010">www.regulations.gov/docket/EERE-2017-BT-TP-0010</a>. The docket web page contains instructions
on how to access all documents, including public comments, in the
docket.
For further information on how to review the docket contact the
Appliance and Equipment Standards Program staff at (202) 287-1445 or by
email: <a href="/cdn-cgi/l/email-protection#bdfccdcdd1d4dcd3ded8eec9dcd3d9dccfd9ceecc8d8cec9d4d2d3cefdd8d893d9d2d893dad2cb">[email&#160;protected]</a>.

FOR FURTHER INFORMATION CONTACT: Ms. Catherine Rivest, U.S. Department
of Energy, Office of Energy Efficiency and Renewable Energy, Building
Technologies Office, EE-5B, 1000 Independence Avenue SW, Washington, DC
20585-0121. Telephone: (202) 586-7335. Email:
<a href="/cdn-cgi/l/email-protection#88c9f8f8e4e1e9e6ebeddbfce9e6ece9faecfbd9fdedfbfce1e7e6fbc8ededa6ece7eda6efe7fe">[email&#160;protected]</a>.
Mr. Matthew Schneider, U.S. Department of Energy, Office of the
General Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC
20585-0121. Telephone: (240) 597-6265. Email:
<a href="/cdn-cgi/l/email-protection#b3ded2c7c7dbd6c49dc0d0dbddd6dad7d6c1f3dbc29dd7dcd69dd4dcc5">[email&#160;protected]</a>.

SUPPLEMENTARY INFORMATION: DOE maintains a previously approved
incorporation by reference and incorporates by reference the following
industry standards into part 431:
AHRI Standard 1250-2020, ``2020 Standard for Performance Rating of
Walk-in Coolers and Freezers.''
Copies of AHRI 1250-2020 can be obtained from the Air-Conditioning,
Heating, and Refrigeration Institute, 2111 Wilson Blvd., Suite 400,
Arlington, VA 22201 or at <a href="http://www.ahrinet.org">www.ahrinet.org</a>.
ANSI/ASHRAE 16-2016, ``Method of Testing for Rating Room Air
Conditioners, Packaged Terminal Air Conditioners, and Packaged Terminal
Heat Pumps for Cooling and Heating Capacity''.
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''.
ANSI/ASHRAE 37-2009, ``Methods of Testing for Rating Electrically
Driven Unitary Air-Conditioning and Heat-Pump Equipment''.
ANSI/ASHRAE 41.1-2013, ``Standard Method for Temperature
Measurement''.
ANSI/ASHRAE 41.3-2014, ``Standard Methods for Pressure
Measurement''.
ANSI/ASHRAE 41.6-2014, ``Standard Method for Humidity
Measurement''.
ANSI/ASHRAE 41.10-2013, ``Standard Methods for Refrigerant Mass
Flow Measurement Using Flowmeters''.
Copies of ANSI/ASHRAE 16-2016, ANSI/ASHRAE 23.1-2010, ANSI/ASHRAE
37-2009, ANSI/ASHRAE 41.1-2013, ANSI/ASHRAE 41.3-2014, ANSI/ASHRAE
41.6-2014, and ANSI/ASHRAE 41.10-2013, can be obtained from the
American Society of Heating, Refrigerating and Air-Conditioning
Engineers, 180 Technology Parkway NW, Peachtree Corners, GA 30092, or
at <a href="http://www.ashrae.org">www.ashrae.org</a>.
ASTM C518-17, ``Standard Test Method for Steady-State Thermal
Transmission Properties by Means of the Heat Flow Meter Apparatus''.
ASTM C1199-14, ``Standard Test Method for Measuring the Steady-
State Thermal Transmittance of Fenestration Systems Using Hot Box
Methods.''
Copies of ASTM C518-17 and ASTM C1199-14 can be obtained from ASTM
International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken,
PA 19428-2959, or at <a href="http://www.astm.org">www.astm.org</a>.
NFRC 102-2020 [E0A0], ``Procedure for Measuring the Steady-State
Thermal Transmittance of Fenestration Systems''
Copies of NFRC 102-2020 can be obtained from the National
Fenestration Rating Council, 6305 Ivy Lane, Suite 140, Greenbelt, MD
20770, or at <a href="http://www.nfrc.org">www.nfrc.org</a>.
See section IV.N 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 Final Rule
III. Discussion
A. Scope and Definitions
1. Scope
2. Definitions
B. Updates to Industry Standards
1. Industry Standards for Determining Thermal Transmittance (U-
factor)
2. Industry Standard for Determining R-Value
3. Industry Standards for Determining AWEF
C. Amendments to Appendix A for Doors
1. Reference to NFRC 102-2020 in Place of NFRC 100-2010 and
Alternative Efficiency Determination Methods for Doors
2. Additional Definitions
3. Electrical Door Components
4. Percent Time Off Values
5. Energy Efficiency Ratio Values
6. Air Infiltration Reduction
D. Amendments to Appendix A for Display Panels
E. Amendments to the Appendix B for Panels and Non-Display Doors
1. 24-Hour Testing Window
2. Total Insulation and Test Specimen Thickness
3. Parallelism and Flatness
4. Insulation Aging
5. Overall Thermal Transmittance of Non-Display Panels
F. Amendments to Appendix C for Refrigeration Systems
1. Refrigeration Test Room Conditioning
2. Temperature Measurement Requirements
3. Hierarchy of Installation Instruction and Specified
Refrigerant Conditions for Refrigerant Charging and Setting
Refrigerant Conditions
4. Subcooling Requirement for Mass Flow Meters
5. Instrument Accuracy and Test Tolerances
6. CO<INF>2</INF> Unit Coolers
7. High-Temperature Unit Coolers

[[Page 28781]]

G. Establishing Appendix C1 for Refrigeration Systems
1. Off-Cycle Power Consumption
2. 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
8. 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 for
Refrigeration Systems
I. Sampling Plan for Enforcement Testing
J. Organizational Changes
K. Test Procedure Costs and Impact
1. Doors
2. Panels
3. Refrigeration Systems
L. Effective and Compliance Dates
IV. Procedural Issues and Regulatory Review
A. Review Under Executive Orders 12866 and 13563
B. Review Under the Regulatory Flexibility Act
C. Review Under the Paperwork Reduction Act of 1995
D. Review Under the National Environmental Policy Act of 1969
E. Review Under Executive Order 13132
F. Review Under Executive Order 12988
G. Review Under the Unfunded Mandates Reform Act of 1995
H. Review Under the Treasury and General Government
Appropriations Act, 1999
I. Review Under Executive Order 12630
J. Review Under Treasury and General Government Appropriations
Act, 2001
K. Review Under Executive Order 13211
L. Review Under Section 32 of the Federal Energy Administration
Act of 1974
M. Congressional Notification
N. Description of Materials Incorporated by Reference
V. Approval of the Office of the Secretary

I. Authority and Background

Walk-in coolers and walk-in freezers (collectively ``WICFs'' or
``walk-ins'') are included in the list of ``covered equipment'' for
which the U.S. Department of Energy (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, Public Law 94-163, as
amended (``EPCA''),\1\ authorizes DOE to regulate the energy efficiency
of a number of consumer products and certain industrial equipment. (42
U.S.C. 6291-6317) Title III, Part C of EPCA \2\ established the Energy
Conservation Program for Certain Industrial Equipment, which sets forth
a variety of provisions designed to improve energy efficiency. This
equipment includes WICFs, the subject of this document. (42 U.S.C.
6311(1)(G))
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\1\ All references to EPCA in this document refer to the statute
as amended through the Energy Act of 2020, Public Law 116-260 (Dec.
27, 2020), which reflect the last statutory amendments that impact
Parts A and A-1 of EPCA.
\2\ For editorial reasons, upon codification in the U.S. Code,
Part C was redesignated Part A-1.
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The energy conservation program under EPCA consists essentially of
four parts: (1) testing, (2) labeling, (3) Federal energy conservation
standards, 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 other 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 preemption for particular State laws or
regulations, in accordance with the procedures and other provisions of
EPCA. (42 U.S.C. 6316(b)(2)(D))
Under 42 U.S.C. 6314, 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 energy efficiency, energy use, or estimated annual
operating cost of a given type of covered equipment during a
representative average use cycle (as determined by the Secretary) and
requires that test procedures not be unduly burdensome to conduct. (42
U.S.C. 6314(a)(2))
EPCA also requires that, at least once every 7 years, DOE evaluate
test procedures for each type of covered equipment, including WICFs, to
determine whether amended test procedures would more accurately or
fully comply with the requirements for the test procedures to not be
unduly burdensome to conduct and be reasonably designed to produce test
results that reflect energy efficiency, energy use, and estimated
operating costs during a representative average use cycle. (42 U.S.C.
6314(a)(1)) DOE considers this rulemaking to be in satisfaction of the
7-year review requirement specified in EPCA.
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))

B. Background

For measuring walk-in energy use, DOE has established separate test
procedures for the principal components that may comprise 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. See 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

[[Page 28782]]

conduction, is determined using National Fenestration Rating Council
(NFRC) 100-2010, ``Procedure for Determining Fenestration U-factors''
(NFRC 100-2010), which is incorporated by reference at 10 CFR 431.303.
For walk-in non-display panels and non-display doors, in the final
rule published on April 15, 2011, DOE codified in the CFR the standards
established in EPCA based on the R-value metric,\3\ expressed in units
of (h-ft\2\-[deg]F/Btu),\4\ which is calculated as the thickness of the
panel in inches (in.) divided by the K-factor.\5\ See 10 CFR
431.304(b)(3) and 10 CFR part 431, subpart R, appendix B, ``Uniform
Test Method for the Measurement of R-Value for Envelope Components of
Walk-in Coolers and Walk-in Freezers'' (appendix B). (See also 42
U.S.C. 6314(a)(9)(A)) The K-factor is calculated based on ASTM
International (ASTM) C518, ``Standard Test Method for Steady-State
Thermal Transmission Properties by Means of the Heat Flow Meter
Apparatus'' (ASTM C518), which is incorporated by reference at 10 CFR
431.303. Id.
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\3\ The R-value is the thermal resistance, or the capacity of an
insulated material to resist heat flow. See section 3.3.3 of ASTM
C518. See 42 U.S.C. 6313(f)(1)(C) for the EPCA R-value requirements
for non-display panels and doors.
\4\ These symbols represent the following units of measurement--
h: hour; ft\2\: square foot; [deg]F: degrees Fahrenheit; Btu:
British thermal unit.
\5\ The K-factor represents the thermal conductivity of a
material, or its ability to conduct heat, in units of Btu-in/(h-
ft\2\-[deg]F). See section 3.3.1 of ASTM C518.
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For walk-in refrigeration systems, the efficiency metric is the
annual walk-in energy factor (``AWEF''), which is the ratio of the
total heat, not including the heat generated by the operation of
refrigeration systems, removed, in Btu, from a walk-in box during a
one-year period of usage for refrigeration to the total energy input of
refrigeration systems, in watt-hours, during the same period. AWEF is
determined by conducting the test procedure set forth in American
National Standards Institute (ANSI)/Air-Conditioning, Heating, and
Refrigeration Institute (AHRI) Standard 1250 (I-P), ``2009 Standard for
Performance Rating of Walk-in Coolers and Freezers'' (AHRI 1250-2009),
which is incorporated by reference in 10 CFR 431.303 with certain
adjustments specified in the CFR. See 10 CFR 431.304(b)(4) and 10 CFR
part 431, subpart R, appendix C, ``Uniform Test Method for the
Measurement of Net Capacity and AWEF of Walk-in Cooler and Walk-in
Freezer Refrigeration Systems'' (appendix C). A manufacturer may also
determine AWEF using an alternative efficiency determination method
(AEDM). 10 CFR 429.53(a)(2)(iii). An AEDM enables a manufacturer to
utilize computer-based or mathematical models for purposes of
determining an equipment's energy use or energy efficiency performance
in lieu of testing, provided certain prerequisites have been met. 10
CFR 429.70(f).
On August 5, 2015, DOE published its intention to establish a
working group under the Appliance Standards and Rulemaking Federal
Advisory Committee (ASRAC) to negotiate energy conservation standards
to replace the standards established in the final rule published on
June 3, 2014 (79 FR 32050, ``June 2014 ECS Final Rule''). 80 FR 46521.
The established working group (ASRAC Working Group) assembled its
recommendations into a term sheet \6\ (Docket No. EERE-2015-BT-STD-
0016, No. 56) that was presented to and approved by ASRAC on December
18, 2015 (ASRAC Term Sheet).
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\6\ Appliance Standards and Rulemaking Federal Advisory
Committee Refrigeration Systems Walk-in Coolers and Freezers Term
Sheet, available at <a href="http://www.regulations.gov/document/EERE">www.regulations.gov/document/EERE</a>-2015-BT-STD-
0016-0056.
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The ASRAC Term Sheet provided recommendations for energy
conservation standards to replace standards vacated by the United
States Court of Appeals for the Fifth Circuit in a controlling order
issued August 10, 2015. It also included recommendations regarding
definitions for a number of terms related to the WICF regulations, as
well as recommendations to amend the test procedure that the ASRAC
Working Group viewed as necessary to properly implement the energy
conservation standards recommendations. Consequently, in 2016 DOE
initiated both an energy conservation standards rulemaking and a test
procedure rulemaking to implement these recommendations. The ASRAC Term
Sheet also included recommendations for future amendments to the test
procedures intended to make DOE's test procedures more fully
representative of walk-in energy use.
On December 28, 2016, DOE published a final rule amending the WICF
test procedures (``December 2016 Final Rule''), consistent with the
ASRAC Term Sheet recommendations and including provisions to facilitate
implementation of energy conservation standards for walk-in components.
81 FR 95758.
In 2020, AHRI published an updated industry test standard for walk-
in refrigeration systems, ``2020 Standard for Performance Rating of
Walk-in Coolers and Freezers,'' (AHRI 1250-2020) updating the existing
AHRI standard ``AHRI 1250P (I-P)-2009.'' This new test procedure
included updated calculations for the determination of default values
for equipment with electric defrost and hot gas defrost. DOE published
a final rule for hot gas defrost unit coolers on March 26, 2021 (March
2021 Final Rule), that amended the test procedure to rate hot gas
defrost unit coolers using the modified default values for energy use
and heat load contributions in AHRI 1250-2020. These amendments ensure
that ratings for hot gas defrost unit coolers are consistent with those
of electric defrost unit coolers. 86 FR 16027.
Under 10 CFR 431.401, any interested person may submit a petition
for waiver from DOE's test procedure requirements. DOE will grant a
waiver from the test procedure requirements if DOE determines either
the basic model for which the waiver was requested contains a design
characteristic that prevents testing of the basic model according to
the prescribed test procedures, or the prescribed test procedures
evaluate the basic model in a manner so unrepresentative of its true
energy consumption characteristics as to provide materially inaccurate
comparative data. 10 CFR 431.401(f)(2). DOE may grant the waiver
subject to conditions, including adherence to alternate test procedures
specified by DOE. Id. DOE has granted interim waivers and/or waivers to
the manufacturers listed in Table I.1.

Table I.1--Manufacturers Who Received a Test Procedure Waiver/Interim Waiver From DOE
----------------------------------------------------------------------------------------------------------------
Waiver from
Manufacturer Subject Case No. appendix
----------------------------------------------------------------------------------------------------------------
Jamison Door Company......................... Percent Time Off (PTO) for Door 2017-009 A
Motors.
HH Technologies.............................. PTO for Door Motors............. 2018-001 A

[[Page 28783]]

Senneca Holdings............................. PTO for Door Motors............. 2020-002 A
Hercules..................................... PTO for Door Motors............. 2020-013 A
Heat Transfer Products Group, LLC (HTPG)..... CO2 Unit Coolers................ 2020-009 C
Hussmann Corporation (Hussmann).............. CO2 Unit Coolers................ 2020-010 C
KeepRite Refrigeration, Inc. (KeepRite)...... CO2 Unit Coolers................ 2020-014 C
RefPlus, Inc................................. CO2 Unit Coolers................ 2021-006 C
Refrigerated Solutions Group (RSG)........... Multi-Circuit Single-Package 2022-004 C
Dedicated Systems.
Store It Cold................................ Single-Packaged Dedicated 2018-002 C
Systems.
CellarPro.................................... Wine Cellar Refrigeration 2019-009 C
Systems.
Air Innovations.............................. Wine Cellar Refrigeration 2019-010 C
Systems.
Vinotheque................................... Wine Cellar Refrigeration 2019-011 C
Systems.
Vinotemp..................................... Wine Cellar Refrigeration 2020-005 C
Systems.
LRC Coil Company (LRC Coil).................. Wine Cellar Refrigeration 2020-024 C
Systems.
----------------------------------------------------------------------------------------------------------------

On June 17, 2021, DOE published a request for information (RFI) to
initiate a test procedure rulemaking for walk-ins (June 2021 RFI). 86
FR 32332. DOE published a notice of proposed rulemaking (NOPR) on April
21, 2022 (April 2022 NOPR), responding to comments received in response
to the June 2021 RFI and presenting DOE's proposals to amend the WICFs
test procedure--including amendments to eliminate the need for existing
test procedure waivers--and establish a new test procedure at 10 CFR
part 431, subpart R, appendix C1 (appendix C1), that would establish a
new energy efficiency metric, AWEF2. 87 FR 23920. DOE held a public
meeting related to the April 2022 NOPR on May 9, 2022.
DOE received comments in response to the April 2022 NOPR from the
interested parties listed in Table I.2.

Table I.2--List of Commenters With Written Submissions in Response to the April 2022 NOPR
----------------------------------------------------------------------------------------------------------------
Reference in this Final Comment No. in
Commenter(s) Rule the docket Commenter type
----------------------------------------------------------------------------------------------------------------
Air-Conditioning, Heating, & AHRI \7\.................. 30 Trade Association.
Refrigeration Institute.
Air-Conditioning, Heating, & AHRI-Wine \8\............. 30 Trade Association.
Refrigeration Institute.
Anthony International................... Anthony................... 31 Manufacturer.
Appliance Standards Awareness Project, Efficiency Advocates...... 37 Efficiency Organizations.
American Council for an Energy-
Efficient Economy, Natural Resources
Defense Council, Northwest Energy
Efficiency Alliance.
Bally Refrigerated Boxes, Inc........... Bally..................... 40 Manufacturer.
Heat Transfer Products Group, LLC....... HTPG...................... 32 Manufacturer.
Hussmann Corporation.................... Hussmann.................. 34, 38 Manufacturer.
KeepRite Refrigeration, Inc............. KeepRite.................. 36 Manufacturer.
Lennox International Inc................ Lennox.................... 35 Manufacturer.
National Refrigeration & Air National Refrigeration.... 39 Manufacturer.
Conditioning Canada Corp.
North American Association of Food NAFEM..................... 33 Trade Association.
Equipment.
Pacific Gas and Electric Company, San CA IOUs................... 42 Utility Association.
Diego Gas & Electric, and Southern
California Edison; collectively, the
California Investor-Owned Utilities.
Refrigerated Solutions Group............ RSG....................... 41 Manufacturer.
Senneca Holdings........................ Senneca................... 26 Manufacturer.
----------------------------------------------------------------------------------------------------------------

A parenthetical reference at the end of a comment quotation or
paraphrase provides the location of the item in the public record.\9\
To the extent that interested parties have provided written comments
that are substantively consistent with any oral comments provided
during the May 2022 public meeting, DOE cites the written comments
throughout this final rule.
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\7\ AHRI submitted two comment documents to the docket. The
first document in the docket includes AHRI's comments for
traditional walk-in manufacturers (i.e., medium- and low-temperature
walk-in components). The associated file name in the docket is: AHRI
Comments WICF NOPR EERE-2017-BT-TP-0010. These comments are
referenced in this document as ``AHRI'' comments.
\8\ AHRI submitted two comment documents to the docket. The
second document in the docket includes AHRI's comments supporting
wine cellar manufacturers (i.e., high-temperature walk-in
refrigeration systems). The associated file name in the docket is:
Comments WICF NOPR EERE-2017-BT-TP-0010 Wine. These comments are
referenced in this document as ``AHRI-Wine'' comments.
\9\ The parenthetical reference provides a reference for
information located in the docket of DOE's rulemaking to develop
test procedures for walk-ins (Docket No. EERE-2017-BT-TP-0010,
maintained at <a href="http://www.regulations.gov">www.regulations.gov</a>). The references are arranged as
follows: (commenter name, comment docket ID number, page of that
document).
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In response to the April 2022 NOPR, NAFEM commented that while the
April 2022 NOPR was not inconsistent with DOE's Process Rule,\10\ NAFEM
supports the U.S. Small Business Administration Office of Advocacy
request \11\ that DOE reopen public comment on the 2021 Process Rule
and

[[Page 28784]]

concurrent proposed rulemaking.\12\ (NAFEM, No. 33 at p. 2) The request
referenced by NAFEM specifically refers to a National Academies of
Sciences (``NAS'') report entitled ``Review of Methods Used by the U.S.
Department of Energy in Setting Appliance and Equipment Standards.''
Given that the recommendations in the NAS report pertain to the
processes by which DOE analyzes energy conservation standards, DOE will
consider this comment in a separate rulemaking that includes all
product categories.
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\10\ The term ``Process Rule'' refers to DOE's Procedures,
Interpretations, and Policies for Consideration of New or Revised
Energy Conservation Standards and Test Procedures for Consumer
Products and Certain Commercial/Industrial Equipment at 10 CFR part
430, subpart C, appendix A.
\11\ The U.S. Small Business Administration Office of Advocacy
request is available at <a href="http://cdn.advocacy.sba.gov/wp-content/uploads/2022/05/13104422/Comment-Letter-DOE-Process-Rule-Letter_5-13-22.pdf">cdn.advocacy.sba.gov/wp-content/uploads/2022/05/13104422/Comment-Letter-DOE-Process-Rule-Letter_5-13-22.pdf</a>.
\12\ DOE published a NOPR and request for comment on July 7,
2021, proposing changes to the Process Rule. 86 FR 35668.
---------------------------------------------------------------------------

II. Synopsis of the Final Rule

In this final rule, DOE is expanding the scope of its walk-in
coolers and freezers test procedure to include carbon dioxide
(CO<INF>2</INF>) unit coolers, multi-circuit single-packaged dedicated
systems, and ducted fan coil units. DOE has also determined that
liquid-cooled refrigeration systems are within the scope of DOE
coverage authority for walk-ins but is not adding an applicable test
procedure at this time.
In this final rule, DOE is amending the definitions of walk-in
cooler and walk-in freezer, door, door surface area, and single-
packaged dedicated systems. DOE is also adding new definitions for door
leaf, hinged vertical door, non-display door, roll-up door, sliding
door, high-temperature refrigeration systems, ducted fan coil units,
multi-circuit single-packaged dedicated systems, ducted multi-circuit
single-packaged dedicated systems, attached split systems, detachable
single-packaged dedicated systems, and CO<INF>2</INF> unit coolers.
In this final rule, DOE is revising appendix A as follows: (1)
incorporate by reference NFRC 102-2020 as the applicable test procedure
to determine door ``U-factor'' in place of NFRC 100-2010; \13\ (2)
provide further detail on and distinguish the area to be used for
calculating a thermal load from U-factor and determining compliance
with standards; (3) establish a percent time off (``PTO'') specific to
door motors; and (4) reorganize appendix A so it is easier to follow.
---------------------------------------------------------------------------

\13\ As discussed further in section III.C.1.b of this final
rule, DOE is also adopting AEDM provisions for doors in 10 CFR
429.53 to allow calculation of door energy use representations.
---------------------------------------------------------------------------

Additionally, DOE is modifying appendix B to improve test
representativeness and repeatability. Specifically, DOE is revising
appendix B as follows: (1) reference the updated industry standard ASTM
C518-17; (2) include more detailed provisions for determining measuring
insulation thickness and test specimen thickness; (3) provide
additional specifications for determining parallelism and flatness of a
test specimen; and (4) reorganize appendix B as a step-by-step
procedure to improve readability.
DOE is also including walk-in doors and walk-in panels in the list
of covered equipment in the same sampling plan for enforcement testing
that is used for walk-in refrigeration systems. (See 10 CFR
429.110(e)(2))
In this final rule, DOE is making two sets of changes to the
refrigeration system test procedure. One set of changes is grouped into
revisions to appendix C, and the other set of changes is included in a
new appendix C1. DOE has determined that the changes to appendix C will
not affect AWEF ratings and therefore will not require any retesting or
recertification. These changes will be required starting 180 days after
the test procedure final rule is published. DOE is also establishing a
new metric, AWEF2, in the new appendix C1, which will require retesting
and recertification. Use of appendix C1 will not be required until the
compliance date of amended energy conservation standards for WICFs that
DOE may ultimately adopt as part of a separate rulemaking.
DOE is revising appendix C, as follows:
(1) Specify refrigeration test room conditions.
(2) Provide for a temperature probe exception for small diameter
refrigerant lines.
(3) Incorporate a test setup hierarchy of installation instructions
for laboratories to follow when setting up a unit for test.
(4) Allow active cooling of the liquid line in order to achieve the
required 3 [deg]F subcooling at a refrigerant mass flow meter.
(5) Modify instrument accuracy and test tolerances.
(6) Address current test procedure waivers for CO<INF>2</INF> unit
coolers tested alone and high-temperature unit coolers tested alone by
incorporating amendments appropriate for this equipment.
The new appendix C1 includes these changes to appendix C, as well
as the following additional changes:
(1) Adopt AHRI 1250-2020.
(2) Provide for testing single-packaged dedicated systems,
detachable single-packaged dedicated systems; attached split systems;
CO<INF>2</INF>, variable-, two-, and multiple-capacity dedicated
condensing units; indoor variable-, two-, and multiple-capacity matched
pairs; matched refrigeration systems for high-temperature applications;
and multi-circuit single-packaged dedicated systems.
(3) Add a single-packaged dedicated system refrigerant enthalpy
test procedure.
(4) Add a new energy efficiency metric, AWEF2, to reflect the
changes in the test procedure that would result in a significant change
to energy use values compared to the AWEF metric in appendix C.
Table II.1 summarizes the current DOE test procedure, DOE's changes
to the test procedure, the attribution for each proposed change, and
the relevant test procedure appendix.

Table II.1--Summary of Changes in Test Procedure Relative to Current Test Procedure
----------------------------------------------------------------------------------------------------------------
DOE test procedure Amended test Relevant
WICF component(s) prior to amendment procedure Attribution appendix
----------------------------------------------------------------------------------------------------------------
Doors and Display Panels.......... Incorporates by Incorporates by Reduce test burden.. A
reference NFRC 100- reference NFRC 102-
2010 for 2020 for
determining U- determining U-
factor as part of factor and allows
determining energy AEDMs to be used
consumption. for determining
energy consumption.
Doors and Display Panels.......... Uses surface area of Requires that area Improve A
the door or display of the aperture or representative
panel external to surface area used values.
the walk-in to to determine U-
convert U-factor factor be used to
into a conduction convert U-factor
load. into a conduction
load.

[[Page 28785]]

Doors............................. Uses a PTO value of Establishes a PTO Improve A
25 percent for door value of 97 percent representative
motors (as they are specific to door values and address
considered ``other motors. inconsistent values
electricity- across waivers
consuming granted.
devices'').
Non-display Doors and Panels...... Incorporates by Incorporates by Update applicable B
reference ASTM C518- reference ASTM C518- industry test
04. 17. procedures.
Non-display Doors and Panels...... Does not include Includes detailed Ensure test B
detailed provisions provisions for repeatability.
for determining and determining and
measuring total measuring total
insulation insulation
thickness and test thickness and test
specimen thickness. specimen thickness.
Non-display Doors and Panels...... Requires that the Provides Ensure test B
test specimen meet specifications for repeatability.
a parallelism and determining
flatness tolerance parallelism and
of <plus-minus>0.03 flatness of the
inches but provides test specimen.
no guidance on
measurement.
Refrigeration Systems............. Does not include Includes guidance on Ensure test C
guidance on test test room repeatability.
room conditioning. conditioning.
Refrigeration Systems............. Does not include an Includes an Reduce test burden.. C
allowance for allowance for
measuring measuring
refrigerant refrigerant
temperatures with temperatures with
surface-mounted surface-mounted
measuring measuring
instruments. instruments for
small diameter
tubes.
Refrigeration Systems............. Does not include Includes guidance Ensure test C
guidance for unit for unit charging repeatability.
charging or a setup and a setup
condition hierarchy. condition hierarchy.
Refrigeration Systems............. Does not include Includes provisions Improve C
provisions for for testing CO2 representative
testing CO2 unit unit coolers. values.
coolers.
Refrigeration Systems............. Does not include Includes provisions Improve C
provisions for for testing high- representative
testing high- temperature unit values.
temperature unit coolers alone.
coolers alone.
Refrigeration Systems............. Incorporates by Incorporates by Update applicable C1
reference AHRI 1250- reference AHRI 1250- industry test
2009, ASHRAE 23.1- 2020, ASHRAE 37- procedures.
2010, and AHRI 420- 2009, and ASHRAE 16-
2008. 2016.
Refrigeration Systems............. Tests single- Includes multiple Improve C1
packaged dedicated methods for testing representative
systems using the single-packaged values.
refrigerant dedicated systems.
enthalpy method for
matched pairs.
Refrigeration Systems............. Does not include Includes provisions Improve C1
provisions for for testing representative
testing attached attached split values.
split systems or systems or
detachable single- detachable single-
packaged dedicated packaged dedicated
systems. systems.
Refrigeration Systems............. Does not include Includes provisions Improve C1
provisions for for testing multi- representative
testing multi- circuit single- values.
circuit single- packaged dedicated
packaged dedicated systems.
systems.
Refrigeration Systems............. Does not include Includes provisions Improve C1
provisions for for testing ducted representative
testing ducted fan fan coil units. values.
coil units.
Refrigeration Systems............. Does not include Includes provisions Improve C1
provisions for for testing high- representative
testing high- temperature matched- values.
temperature matched- pair and single-
pair and single- packaged dedicated
packaged dedicated systems.
systems.
Refrigeration Systems............. Does not include Includes provisions Improve C1
provisions for for testing of representative
testing of variable- variable, two-, and values.
and multiple- multiple-capacity
capacity dedicated dedicated
condensing units condensing units
nor variable- and and variable, two-,
multiple-capacity and multiple-
outdoor matched capacity outdoor
pairs. matched pairs.
----------------------------------------------------------------------------------------------------------------

DOE has determined that the amendments described in section III.C
and III.E of this final rule would not alter the measured energy
consumption of walk-in doors without motors or the R-value of walk-in
non-display doors and non-display panels. Therefore, retesting or
recertification would not be required solely as a result of DOE's
adoption of the amendments to the test procedures. Additionally, DOE
has determined that the amendments would not increase the cost of
testing.
For walk-in doors with motors, DOE has determined that the
amendments described in section III of this final rule would either not
change the measured energy consumption or would result in a lower
measured energy consumption and therefore, would not require retesting
or recertification as a result of DOE's adoption of the amendments to
the test procedures. New testing is only required if the manufacturer
wishes to make claims using the new, more efficient rating.
Additionally, DOE has determined the amendments would not increase the
cost of testing for doors with motors.

[[Page 28786]]

DOE has also determined that the amendments to appendix C,
described in section III.F of this final rule would not alter the
measured efficiency of walk-in refrigeration systems and would not
require retesting or recertification as a result of DOE's adoption of
the amendments to the test procedures. Additionally, DOE has determined
that the amendments would not increase the cost of testing.
Finally, DOE has determined that the provisions of the new appendix
C1 described in section III.G of this final rule would alter the
measured efficiency of walk-in refrigeration systems, in part because
the amended test procedure adopts a different energy efficiency metric
than in the current test procedure. However, the use of appendix C1 is
not required for use until the compliance date of any amended energy
conservation standards based on the test procedure in appendix C1.
Additionally, DOE has determined that the provisions in appendix C1
will increase the cost of testing. DOE's estimation of costs is
discussed in section III.K of this document.
The effective date for the amended test procedures adopted in this
final rule is 30 days after publication of this document in the Federal
Register. Representations of energy use or energy efficiency must be
based on testing in accordance with the amended appendices A, B, and C
test procedures beginning 180 days after the publication of this final
rule. Manufacturers will be required to certify compliance using the
new appendix C1 test procedures beginning on the compliance date of any
final rule establishing amended energy conservation standards for walk-
in refrigeration systems that are published after the effective date of
this final rule.

III. Discussion

A. Scope and Definitions

This final rule applies to the test procedures for ``walk-in
coolers and walk-in freezers.'' The following sections discuss DOE's
consideration of the scope of the test procedures and relevant
definitions.
1. Scope
The following sections discuss considerations and adopted changes
regarding the scope of equipment covered by DOE's test procedures for
walk-ins.
a. Liquid-Cooled Refrigeration Systems
A liquid-cooled refrigeration system rejects heat during the
condensing process to a liquid, and the liquid transports the heat to a
remote location. This contrasts with an air-cooled system, which
rejects heat to ambient air during the condensing process. 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 April 2022 NOPR, DOE tentatively
determined that liquid-cooled refrigeration systems represent a small
portion of the walk-in market, and thus DOE did not propose to amend
its test procedures to include liquid-cooled refrigeration systems. 87
FR 23920, 23927.
In response to the April 2022 NOPR, the Efficiency Advocates and CA
IOUs encouraged DOE to develop a test procedure for liquid-cooled
refrigeration systems. (Efficiency Advocates, No. 37 at p. 3; CA IOUs,
No. 42 at p. 5)
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. However, DOE maintains that liquid-cooled refrigeration
systems represent a small portion of the walk-in market, and the
potential for energy savings that could be realized through the
development of a test procedure and corresponding energy conservation
standards is likely limited at this time. Additionally, DOE is not
aware of an industry test standard for liquid cooled walk-in
refrigeration systems. Therefore, although liquid-cooled refrigeration
systems are covered within the scope of the walk-in coolers and walk-in
freezers definition, DOE is not adopting provisions specific to liquid-
cooled refrigeration systems in its test procedure 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 and 431.304 and appendix C. DOE understands that the current
test procedure, which is based on AHRI 1250-2009 (incorporated by
reference, 10 CFR 431.303(b)), specifies test conditions that may not
be consistent with the design and operation of carbon dioxide
(``CO<INF>2</INF>'') refrigeration systems (i.e., although AHRI 1250-
2009 does not specifically exclude CO<INF>2</INF> systems, the test
method is not designed to accommodate such systems).\14\
---------------------------------------------------------------------------

\14\ The DOE test procedure for unit coolers requires testing
with a liquid inlet saturation temperature of 105 [deg]F and a
liquid inlet subcooling temperature of 9 [deg]F, as specified by
Tables 15 and 16 of AHRI 1250-2009. However, CO<INF>2</INF> has a
critical temperature of 87.8 [deg]F; therefore, it does not coexist
as saturated liquid and gas above this temperature. The liquid inlet
saturation temperature of 105 [deg]F and the liquid inlet subcooling
temperature of 9 [deg]F specified in appendix C, are not achievable
by CO<INF>2</INF> unit coolers.
---------------------------------------------------------------------------

As a result, DOE has granted waivers or interim waivers to
manufacturers from appendix C, for specific basic models of
CO<INF>2</INF> unit coolers.\15\ The alternate test procedure granted
in these waivers and DOE's amendments with respect to refrigeration
systems utilizing CO<INF>2</INF> as a refrigerant are further discussed
in section III.F.6 of this document.
---------------------------------------------------------------------------

\15\ HTPG Decision and Order, 86 FR 14887 (Mar. 19, 2021);
Hussmann Decision and Order, 86 FR 24606 (May 7, 2021); KeepRite
Decision and Order, 86 FR 24603 (May 7, 2021); RefPlus Interim
Waiver, 86 FR 43633 (Aug. 10, 2021).
---------------------------------------------------------------------------

In the April 2022 NOPR, DOE tentatively determined that walk-in
refrigeration equipment utilizing CO<INF>2</INF> as a refrigerant meets
the definition of a walk-in refrigeration system. In the April 2022
NOPR, DOE proposed test procedure provisions specific to (1) single-
packaged dedicated systems and (2) unit cooler variants of
CO<INF>2</INF> refrigeration systems. DOE did not propose test
procedure provisions specific to CO<INF>2</INF>-dedicated condensing
units.\16\
---------------------------------------------------------------------------

\16\ As discussed in the April 2022 NOPR, DOE preliminarily
found that, in the North American market, CO<INF>2</INF> is
primarily used in large rack systems, and there do not appear to be
any CO<INF>2</INF> dedicated condensing units available. Hence, DOE
tentatively found that adopting a test procedure for CO<INF>2</INF>
dedicated condensing units is currently not warranted. 87 FR 23920,
23928.
---------------------------------------------------------------------------

In response to the April 2022 NOPR, the CA IOUs and HTPG stated
that CO<INF>2</INF>-dedicated condensing units are available on the
market in the United States. (CA IOUs, No. 42 at p. 4; HTPG, No. 32 at
p. 2) The CA IOUs, HTPG, and the Efficiency Advocates encouraged DOE to
develop a test procedure for CO<INF>2</INF>-dedicated condensing units.
(CA IOUs, No. 42 at p. 4; HTPG, No. 32 at p. 2; Efficiency Advocates,
No. 37 at p. 2)
DOE has conducted additional market research and determined that
while CO<INF>2</INF> dedicated condensing units are currently available
in the United States the market is small. In addition, due to COVID
supply constraints, DOE has not been able to procure a CO<INF>2</INF>
dedicated condensing unit to evaluate for testing. Therefore, DOE is
not adopting a test procedure for CO<INF>2</INF> dedicated condensing
units at this time. The test procedures for CO<INF>2</INF> unit coolers
and single-packaged dedicated systems that use CO<INF>2</INF> as a
refrigerant are discussed in

[[Page 28787]]

more detail in sections III.F.6 and III.G.2.g of this document,
respectively.
c. Multi-Circuit Single-Packaged Dedicated Systems
DOE published an interim test procedure waiver for Refrigerated
Solutions Group (RSG) on July 22, 2022. 87 FR 43808. In its petition
for waiver and interim waiver, RSG stated that the current walk-in test
procedure does not address multiple refrigeration circuits enclosed in
a single unit. DOE has determined that refrigeration systems with
multiple refrigeration circuits that share a single evaporator and a
single condenser and that are used in walk-in applications meet the
definition of ``walk-in cooler and walk-in freezer.'' Thus, DOE is
adding a definition for ``multi-circuit single-packaged dedicated
system,'' as discussed in section III.A.2.e of this document, and
adopting a test procedure for such systems, as discussed in section
III.G.2.f of this document.
d. Ducted Units
As discussed in the April 2022 NOPR, DOE is aware that some walk-in
evaporators and/or dedicated condensing units are sold with provisions
to be installed with ducting to circulate air between the walk-in and
the refrigeration system; however, unit cooler and single-packaged
systems sold for ducted installation are not addressed by either the
definition for ``single-packaged dedicated system'' or ``unit cooler.''
87 FR 23920, 23928. 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. In addition, the current test procedure
does not include provisions for the setup of ductwork. While the
definition of ``condensing unit'' does not exclude systems intended for
ducted installation, the current test procedure also does not include
provisions for setup of ductwork for these components.
DOE has granted waivers from the test procedure in appendix C, to
CellarPro, Air Innovations, Vinotheque, and Vinotemp, and an interim
waiver to LRC Coil, for walk-ins marketed for use as wine cellar
refrigeration systems.\17\ Relevant to the present discussion of scope,
the specific basic models for which waivers have been granted include
equipment sold as ducted units.
---------------------------------------------------------------------------

\17\ CellarPro Decision and Order, 86 FR 26496 (May 14, 2021);
Air Innovations Decision and Order, 86 FR 23702 (May 4, 2021);
Vinotheque Decision and Order, 86 FR 26504 (May 14, 2021); Vinotemp
Decision and Order, 86 FR 36732 (July 13, 2021); LRC Coil Interim
Waiver, 86 FR 47631 (Aug. 26, 2021).
---------------------------------------------------------------------------

In this final rule, DOE is revising the single-packaged dedicated
system definition to clarify that such systems may have provisions for
ducted installation. DOE is adding a definition for ``ducted fan coil
unit,'' the ducted equivalent of a unit cooler, as discussed in section
III.A.2.d of this document. In doing so, DOE preserves the industry
standard definition of a unit cooler while expanding the scope of the
test procedure to ducted units. DOE is also adding provisions in the
test procedures to address setup of ductwork and the external static
pressure that it imposes on refrigeration system fans--all to improve
the representativeness of the test procedure for ducted units. These
test procedure revisions are addressed in section III.G.6 of this
document.
2. Definitions
a. Walk-In Cooler and Walk-In Freezer
DOE currently defines the term ``walk-in cooler and walk-in
freezer'' as an enclosed storage space 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 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))
To align the definition of walk-in cooler and walk-in freezer with
the regulatory scheme adopted by DOE--which establishes separate test
procedures and energy conservation standards for the principal
components that make up a walk-in: panels, doors, and refrigeration
systems--in the April 2022 NOPR, DOE proposed to amend the definition
to specify that a walk-in may comprise these principal components. DOE
requested comment on this proposed change. 87 FR 23920, 23928.
AHRI, Anthony, RSG, HTPG, KeepRite, Lennox, and National
Refrigeration agreed with DOE's proposed changes to the definition of
walk-in cooler and walk-in freezer. (AHRI, No. 30 at p. 2; Anthony, No.
31 at p. 1; RSG, No. 41 at p. 1; HTPG, No. 32 at p. 2; KeepRite, No. 36
at p. 1; Lennox, No. 35 at p. 2; National Refrigeration, No. 39 at p.
1) For the reasons discussed in the previous paragraph and the April
2022 NOPR, DOE is adopting the definition proposed in the April 2022
NOPR that ``walk-in cooler and walk-in freezer'' means 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.
The Efficiency Advocates commented that refrigerated shipping
containers should be within the scope of the walk-in test procedures.
(Efficiency Advocates, No. 37 at p. 4) DOE notes that based on its
initial research, neither the previous definition of walk-in cooler and
walk-in freezer nor the amended definition adopted in this final rule
would specifically exclude refrigerated shipping containers. However,
DOE has not evaluated refrigerated shipping containers to determine if
current walk-in test procedures would produce test results that reflect
energy efficiency, energy use, or estimated operating costs during a
representative average use cycle, without being unduly burdensome to
conduct. Therefore, DOE has determined that refrigerated shipping
containers are not currently subject to the DOE test procedure or
energy conservation standards for WICFs. DOE may consider whether test
procedures and energy conservation standards should be applied to
refrigerated shipping containers in future rulemakings.
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, mullions, and any other elements that form the
door or part of its connection to the wall. 10 CFR 431.302.
(1) Door, Door Leaf, and Door Plug
In the April 2022 NOPR, DOE discussed that the current definition
of ``door'' does not explicitly address that walk-in door assemblies
may contain multiple door openings within one frame. 87 FR 23920,
23929. DOE also

[[Page 28788]]

noted that NFRC 100-2010 includes several defined terms relating to
door components (e.g., door leaf), which differ from the terms used in
DOE's definition of ``door.'' Id. Additionally, certain stakeholders
commented that they are unfamiliar with the term ``door plug,'' whereas
others used it to describe different components of the door assembly.
Id.\18\
---------------------------------------------------------------------------

\18\ In response to the June 2021 RFI, 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) In response to the June 2021
RFI, Imperial Brown and Hussmann commented that they used the term
``door plug'' to describe different components of the door assembly.
(Imperial Brown, No. 15 at p. 1; Hussmann, No. 18 at p. 3)
---------------------------------------------------------------------------

In the April 2022 NOPR, DOE proposed to amend the definition of
``door'' to address doors with multiple openings within one frame, to
include terminology that generally aligns with that used by the
industry, and to remove use of the term ``door plug.'' Id.
Specifically, DOE proposed to define ``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 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 proposed to define the term ``door
leaf'' to mean the pivoting, rolling, sliding, or swinging portion of a
door. Id.
Regarding the proposed definition of ``door,'' Senneca considered
the proposed definition of ``door'' to refer to the door system (i.e.,
includes the door leaf, frame, casings, header, tracks, and all
necessary components and hardware). (Senneca, No. 26 at p. 1) AHRI
commented that its members find DOE's current definition unclear and
recommended that DOE not use what AHRI referred to as the ``single
door'' interpretation. (AHRI, No. 30 at p. 2) DOE interprets AHRI's
comment to mean that a door with multiple openings within a single
frame should not be treated as a single basic model. DOE notes that the
proposed definition of ``door'' is consistent with Senneca's
understanding. Additionally, DOE notes that the proposed definition
intends to clarify the definition of ``door'', particularly, that a
``door'' consists of a single frame and includes all parts of the door
assembly attached to the single frame, including multiple door openings
where applicable.
Anthony stated that the definition of ``door'' does not accurately
reflect the use of the term ``door'' in the 2014 final rule engineering
analysis spreadsheet.\19\ (Anthony, No. 31 at pp. 1-3) Specifically,
Anthony commented that when applying the same formula to a single door
with multiple openings, there is a 20 to 30 percent reduction in energy
allowance per door. Id. DOE notes that this comment refers to the
representative units used to evaluate and adopt energy conservation
standards in a final rule published on June 3, 2014 (79 FR 32050). DOE
has determined that the representative units used in 2014 met the
definition of ``door'' at the time of the analysis and would continue
to meet the definition of ``door'' as amended by this final rule.-- The
amended definition of ``door'' adopted in this final rule provides
additional clarity that a door contains a single frame with one or
multiple door openings. Regarding the energy impacts of doors with
multiple openings, DOE recommends that stakeholders provide feedback on
the representative unit characteristics in response to the ongoing
energy conservation standards rulemaking which is the appropriate venue
to address such concerns (see docket EERE-2017-BT-STD-0009).
---------------------------------------------------------------------------

\19\ Anthony is referring to the engineering analysis for
display doors as part of the June 2014 ECS Final Rule, which can be
found at <a href="http://regulations.gov">regulations.gov</a> under docket number EERE-2008-BT-STD-0015-
0084.
---------------------------------------------------------------------------

For the reasons discussed in the preceding paragraphs and the April
2022 NOPR, this final rule adopts the revised definition of ``door'' as
proposed.
Bally agreed with the term ``door leaf'' and stated that the term
as defined would be easily understood. (Bally, No. 40 at p. 1) AHRI
stated that DOE's proposed definition of ``door leaf'' is clear. (AHRI,
No. 30 at p. 2) Senneca commented that it considers ``door leaf'' to be
a movable, insulated portion of the assembly. (Senneca, No. 26 at p.
10) DOE has concluded that Senneca's comment is consistent with the
proposed definition of ``door leaf.'' This final rule adopts the
definition of ``door leaf'' as proposed in the April 2022 NOPR. 87 FR
23920, 23929.
DOE did not receive any comments regarding its proposal to remove
use of the term ``door plug.'' For the reasons discussed in the April
2022 NOPR, this final rule removes the term ``door plug'' as proposed.
Id.
(2) Non-Display Door
DOE also proposed to define the term ``non-display door'' in the
April 2022 NOPR. 87 FR 23920, 23930. 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. DOE proposed to define a
``non-display door'' as a door that is not a display door.\20\
---------------------------------------------------------------------------

\20\ DOE defines ``display door'' as a door that (1) is designed
for product display; or (2) has 75 percent or more of its surface
area composed of glass or another transparent material. 10 CFR
431.302.
---------------------------------------------------------------------------

In response to the April 2022 NOPR discussion of non-display doors,
Hussmann stated that although its Heavy Duty Door products and ABC Beer
Cave sliding door products are made largely of glass, it does not
believe these doors meet the display door definition because they are
designed to be used as passage doors (i.e., passage of people).
(Hussmann, No. 34 at p. 2) In response, DOE notes that the display door
definition references the physical characteristics of the door (i.e.,
the portion of surface area composed of glass or another transparent
material), and is not contingent on door application. Any door(s) that
meets this criteria is considered a display door, even those not
necessarily designed for product display.
In this final rule, DOE is adopting the definition of ``non-display
door'' as proposed in the April 2022 NOPR.
(3) Hinged Vertical Door, Roll-Up Door, and Sliding Door
In the April 2022 NOPR, DOE tentatively determined that
differentiating walk-in doors based on opening characteristics would
better align with industry terminology and proposed to define three
terms to further differentiate all walk-in doors (including both
display and non-display doors): ``hinged vertical door,'' ``roll-up
door,'' and ``sliding door.'' 87 FR 23920, 23930.
DOE proposed to define ``hinged vertical door'' as a door with a
door leaf (or leaves) with a hinge (or hinges) connecting one vertical
edge of the door leaf (or leaves) to a frame or mullion of the door.
This includes doors that swing open in one direction (i.e., into or out
of the walk-in) and free-swinging doors that open both into and out of
the walk-in. 87 FR 23920, 23991.
DOE proposed to define ``roll-up door'' as a door that bi-
directionally rolls open and closed in a vertical and horizontal manner
and may include vertical jamb tracks. Id.
DOE proposed to define ``sliding door'' as a door having one or
more manually operated or motorized door leaves within a common frame
that slide horizontally or vertically. Id.

[[Page 28789]]

In the April 2022 NOPR, DOE requested feedback on the proposed
definitions for ``hinged vertical door,'' ``roll-up door,'' and
``sliding door.'' Id. Senneca and AHRI agreed with DOE's proposed
definitions. (Senneca, No. 26 at p. 1; AHRI, No. 30 at p. 2)
DOE recognizes that these definitions are not used in the adopted
test procedure amendments. In the preliminary analysis for the walk-in
standards energy conservation rulemaking, DOE stated that it was
interested in differentiating its analysis by door opening
characteristics. See page ES-36 of the preliminary analysis technical
support document (EERE-2017-BT-STD-0009-0024). DOE is not adopting
definitions for the terms ``hinged vertical door,'' ``roll-up door,''
and ``sliding door'' and will consider the potential adoption of these
terms in the ongoing energy conservation standards rulemaking for
WICFs.
As discussed in the April 2022 NOPR, DOE currently differentiates
non-display doors by whether they are passage doors or freight doors.
87 FR 23920, 23929. 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. After reviewing comments submitted in response to the June
2021 RFI, DOE did not propose to amend the definition of freight door
or passage door. DOE again received comments, however, on the
definitions of freight and passage doors. 87 FR 23920, 23930.
Bally commented that specifying the way a door leaf is moved would
not aid in defining a door nor clarify whether a non-display door is a
passage or a freight door. (Bally, No. 40 at p. 1) Additionally, Bally
disagreed with the current distinction of freight doors by size,
stating that it manufactures doors with a width greater than or equal
to 4 feet that are often the only door in the WICF; therefore, it
considers these doors to be passage doors rather than freight doors.
Id. Senneca stated that it views opening size as a determinant to
whether a non-display door is designated as a passage or freight door
and reiterated that a freight door has a width-in clear \21\ (``WIC'')
greater than or equal to 4 feet and a height-in-clear \22\ (``HIC'')
greater than or equal to 8 feet. (Senneca, No. 26 at p. 1)
---------------------------------------------------------------------------

\21\ In their comment in response to the June 2021 RFI, Imperial
Brown defined WIC as the clear opening width, typically from left
frame jamb to right frame jamb. See EERE-2017-BT-TP-0010-0015 at p.
1.
\22\ In their comment in response to the June 2021 RFI, Imperial
Brown defined HIC as the clear opening height, typically from door
sill to frame header. See EERE-2017-BT-TP-0010-0015 at p. 1.
---------------------------------------------------------------------------

DOE acknowledges that stakeholder comments demonstrate that factors
other than size may be used to differentiate between a passage and
freight door. However, DOE concludes that size is currently the most
suitable way to differentiate between a passage door and a freight
door. Therefore, DOE is not amending these definitions.
c. High-Temperature Refrigeration System
As mentioned previously, DOE has granted several manufacturers
waivers and interim waivers from the current test procedure in appendix
C for basic models of refrigeration systems marketed as wine cellar
refrigeration systems (see section III.A.1.d of this document). These
manufacturers stated that walk-ins used for wine storage are intended
to operate at a temperature range of 45 to 65 [deg]F and 50 to 70
percent relative humidity, rather than the 35 [deg]F and less than 50
percent relative humidity test conditions prescribed in appendix C.
In the April 2022 NOPR, DOE proposed to define ``high-temperature
refrigeration system'' as a walk-in refrigeration system that is not
designed to operate below 45 [deg]F. 87 FR 23920, 23930. DOE did not
receive any feedback from stakeholders on the proposed definition;
however, the CA IOUs commented that they support DOE including a test
method for high-temperature unit coolers (CA IOUs, No. 42 at p. 6). DOE
is adopting the definition for ``high-temperature refrigeration
system'' as proposed in the April 2022 NOPR. Section III.G.6 provides
further details of the corresponding test procedure provisions.
d. Ducted Fan Coil Unit and Ducted Single-Packaged Dedicated System
As discussed in the April 2022 NOPR, the definitions for single-
packaged dedicated systems and unit coolers currently exclude ducted
units. 87 FR 23920, 23931. As a part of the high-temperature
refrigeration system waivers discussed in section III.A.2.c, DOE has
granted waivers to Air Innovations, Vinotheque, CellarPro, 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.
To clarify that refrigeration systems with provision for ducted
installation are included in the DOE test procedure, DOE proposed to
adopt the new term ``ducted fan-coil unit,'' 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. 87 FR 23920, 23931.
DOE also proposed 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. Id.
In the April 2022 NOPR, DOE requested comment on its proposed
definition for ``ducted fan coil unit'' and on the proposed
modification to the definition of ``single-packaged dedicated system.''
Id. RSG agreed with the proposed definitions. (RSG, No. 41 at p. 1)
AHRI and HTPG suggested separate definitions for ducted and non-ducted
single-packaged dedicated systems. (AHRI, No. 30 at pp. 2-3; HTPG, No.
32 at p. 2)
After consideration of stakeholder comments, and to maintain
consistency with industry terminology, DOE is adopting a separate
definition for ``ducted single-packaged dedicated system'' that means a
refrigeration system (as defined in 10 CFR 431.302) that is a single-
packaged assembly designed for use with ducts, 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. As such, DOE is maintaining its current definition of a
``single-packaged dedicated system,'' and clarifying that it describes
non-ducted units.
DOE received no feedback from stakeholders on the proposed
definition for the new term ``ducted fan coil unit.'' DOE is adopting
the definition for ``ducted fan coil unit'' as proposed in the April
2022 NOPR.
e. Multi-Circuit Single-Packaged Dedicated System
In the April 2022 NOPR, DOE proposed to define a ``multi-circuit
single-packaged dedicated 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. DOE requested comment on this proposed definition. 87 FR 23920,
23931.
RSG agreed with the proposed definition. (RSG, No. 41 at p. 1) AHRI
and HTPG suggested that the proposed definition is too specific and
should be

[[Page 28790]]

broader. (AHRI, No. 30 at p. 3; HTPG, No. 32 at p. 3) However, AHRI and
HTPG did not provide alternative definitions or other additional
information that might support broadening the definition.
In this final rule, DOE is adopting the definition for ``multi-
circuit single-packaged dedicated refrigeration system'' as proposed in
the April 2022 NOPR.
As discussed in section III.A.2.d, DOE proposed to adopt the new
term ``ducted fan-coil unit'' to clarify that refrigeration systems
with provision for ducted installation are included in the DOE test
procedure. 87 FR 23920, 23931. In response to the April 2022 NOPR,
several stakeholders suggested creating separate definitions for ducted
and non-ducted single-packaged dedicated systems. (AHRI, No. 30 at pp.
2-3; HTPG, No. 32 at p. 2) DOE's current definition for a ``single-
packaged dedicated system'' applies only to non-ducted units. As
discussed in section III.A.2.d, after consideration of stakeholder
comments, and to maintain consistency with industry terminology, DOE is
adopting a definition for ducted single-packaged dedicated systems
Since ducted multi-circuit single-packaged dedicated systems are a
derivative of ducted single-packaged dedicated systems, DOE is also
defining ``ducted multi-circuit single-packaged dedicated systems'' to
mean a ducted single-packaged dedicated system that contains two or
more refrigeration circuits that refrigerate a single stream of
circulated air. DOE believes these amendments are consistent with the
intent of proposed changes in the April 2022 NOPR while being
responsive to stakeholder feedback.
f. Attached Split System
As discussed in the April 2022 NOPR, 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. 87 FR 23920, 23931. 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
proposed to define ``attached split system'' as a matched-pair
refrigeration system 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. Id.
In the April 2022 NOPR, DOE requested comment on the proposed
definition for ``attached split system.'' Id. AHRI, HTPG, Hussmann, and
Lennox agreed with the proposed definition. (AHRI, No. 30 at p. 3;
HTPG, No. 32 at p. 3; Hussmann, No. 38 at p. 2; Lennox, No. 35 at p. 2)
In this final rule, DOE is adopting the proposed definition for
``attached split system.'' The provisions for testing such units are
discussed in section III.G.4 of this document.
g. Detachable Single-Packaged System
As discussed in the April 2022 NOPR, DOE had tentatively determined
that detachable single-packaged systems are a type of single-packaged
dedicated system, and proposed to define ``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. 87 FR 23920, 23931. The current DOE test procedure does not
define such systems or provide testing provisions specific to this
configuration.
In the April 2022 NOPR, DOE requested comment on the proposed
definition for ``detachable single-packaged dedicated system.'' Id.
AHRI, HTPG, Lennox, and RSG agreed with the proposed definition. (AHRI,
No. 30 at p. 3; HTPG, No. 32 at p. 3; Lennox, No. 35 at p. 2; RSG, No.
41 at p. 1)
In this final rule, DOE is adopting the definition for ``detachable
single-packaged dedicated system'' as proposed in the April 2022 NOPR.
h. CO<INF>2</INF> Unit Cooler
In the April 2022 NOPR, DOE proposed a test procedure for
CO<INF>2</INF> unit coolers. 87 FR 23920, 23952. To clarify the scope
of the proposed CO<INF>2</INF> unit cooler test procedure, DOE proposed
to define a ``CO<INF>2</INF> unit cooler'' as one that includes a
nameplate listing only CO<INF>2</INF> as an approved refrigerant. 87 FR
23920, 23932.
In the April 2022 NOPR, DOE requested comment on the proposed
definition of CO<INF>2</INF> unit coolers. Id. AHRI, HTPG, Hussmann,
Lennox, National Refrigeration, and RSG agreed with the proposed
definition. (AHRI, No. 30 at p. 3; HTPG, No. 32 at p. 3; Hussmann, No.
38 at p. 2; Lennox, No. 35 at p. 2; National Refrigeration, No. 39 at
p. 1; RSG, No. 41 at p. 1)
DOE also requested comment on whether any distinguishing features
of CO<INF>2</INF> unit coolers exist that could reliably be used as an
alternative approach to differentiate them from those unit coolers
intended for use with conventional refrigerants. 87 FR 23920, 23932.
AHRI, HTPG, Lennox, and National Refrigeration all stated that they
were not aware of any features that distinguish CO<INF>2</INF> unit
coolers from those that use traditional refrigerants. (AHRI, No. 30 at
p. 3; HTPG, No. 32 at p. 3; Lennox, No. 35 at p. 2; National
Refrigeration, No. 39 at p. 1)
Given that stakeholders are not aware of any features that
distinguish CO<INF>2</INF> unit coolers from those that use traditional
refrigerants, this information must be provided on the unit in some
way. Therefore, DOE is adopting the ``CO<INF>2</INF> unit cooler''
definition proposed in the April 2022 NOPR which requires a nameplate
listing only CO<INF>2</INF> as an approved refrigerant for this
equipment.
i. Hot Gas Defrost
In the April 2022 NOPR, DOE proposed that manufacturers of
equipment with hot gas defrost installed at the factory may make market
representations of performance with hot gas defrost activated, in
addition to the current required calculation-based approach using
default electric defrost parameters, and proposed a definition for
``hot gas defrost'' to clarify the scope of the voluntary
representation. 87 FR 23920, 23932.
AHRI, HTPG, KeepRite, Lennox, National Refrigeration, and RSG all
recommended changes to the definition as proposed. (AHRI, No. 30 at p.
3; HTPG, No. 32 at p. 3; KeepRite, No. 36 at p. 1; Lennox, No. 35 at p.
2; National Refrigeration, No. 39 at p. 1; RSG, No. 41 at p. 4) In
particular, AHRI, HTPG, and Lennox stated that not all hot gas defrost
systems are factory installed. (AHRI, No. 30 at pp. 3-4; HTPG, No. 32
at p. 3; Lennox, No. 35 at p. 2)
DOE intended for the voluntary hot gas defrost representation
provisions proposed in the April 2022 NOPR to apply only to factory-
installed hot gas defrost systems. 87 FR 23920, 23970. Considering the
comments received, DOE recognizes that the proposed provisions would
not apply to many hot gas defrost applications, thus negating the
purpose and intent of DOE's proposal. Therefore, DOE has determined not
to adopt provisions allowing representations of performance with hot
gas defrost activated at this

[[Page 28791]]

time and consequently is not adopting a definition for ``hot gas
defrost.''

B. Updates to Industry Standards

The current DOE test procedures for walk-in coolers and freezers
incorporate the following industry test standards: NFRC 100-2010 into
appendix A; ASTM C518-04 into appendix B; and AHRI 1250-2009, AHRI 420-
2008,\23\ and ASHRAE 23.1-2010 \24\ into appendix C. The following
sections discuss the industry standards DOE is incorporating by
reference in this final rule and the relevant provisions of those
industry standards that DOE is adopting.
---------------------------------------------------------------------------

\23\ AHRI 420-2008, ``Performance Rating of Forced-Circulation
Free-Delivery Unit Coolers for Refrigeration'' (``AHRI 420-2008'').
\24\ 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. Industry Standards for Determining Thermal Transmittance (U-Factor)
As discussed in the April 2022 NOPR, appendix A to subpart R of
part 431 references NFRC 100-2010 as the method for determining the U-
factor of doors and display panels, which references NFRC 102-2010. 87
FR 23920, 23932. NFRC has published updates to NFRC 102-2010, the most
recent being NFRC 102-2020, which contains the following substantive
changes from NFRC 102-2010:
1. Added a list of required calibrations for primary measurement
equipment;
2. Added metering box wall transducer and surround panel flanking
loss characterization and annual verification procedure;
3. Incorporated a calibration transfer standard continuous
characterization procedure; and
4. Revised the provisions regarding air velocity distribution to be
more specific to the type of fans used.
DOE proposed to adopt by reference in appendix A the following
sections of NFRC 102-2020 in place of NFRC 100-2010 for determining U-
factor:

<bullet> 2. Referenced Documents
<bullet> 3. Terminology
<bullet> 5. Apparatus
<bullet> 6. Calibration
<bullet> 7. Experimental Procedure (excluding 7.3. Test Conditions)
<bullet> 8. Calculation of Thermal Transmittance
<bullet> 9. Calculation of Standardized Thermal Transmittance
<bullet> Annex A1. Calibration Transfer Standard Design
<bullet> Annex A2. Radiation Heat Transfer Calculation Procedure
<bullet> Annex A4. Garage Panel and Rolling Door Installation

87 FR 23920, 23932.
DOE also proposed to incorporate by reference ASTM C1199-14, as it
is referenced in NFRC 102-2020. Specifically, in the appendix A test
procedure, DOE proposed 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 did not propose to
reference any other sections of NFRC 102-2020 or ASTM C1199-14, as
either they do not apply or they are in direct conflict with other test
procedure provisions included in appendix A.
In this final rule, DOE is incorporating by reference NFRC 102-2020
and ASTM C1199-14 in appendix A as proposed in the April 2020 NOPR. DOE
further discusses the reference to NFRC 102-2020 in place of NFRC 100-
2010 and addresses stakeholder comments in section III.C.1 of this
document.
2. Industry Standard for Determining R-Value
As discussed in the April 2022 NOPR, section 4.2 of appendix B to
subpart R of part 431 references ASTM C518-04 \25\ to determine the
thermal conductivity, or K-factor, of panel insulation. 87 FR 23920,
23932. ASTM published a revision of ASTM C518 in July 2017 (``ASTM
C518-17''). Id.
---------------------------------------------------------------------------

\25\ ASTM C518-04 is the version of the industry test procedure
specified by EPCA as the basis for calculating the K-factor.
---------------------------------------------------------------------------

In the April 2022 NOPR, DOE tentatively determined that the updates
in ASTM C518-17 do not substantively change the test method and do not
impact test burden compared to ASTM C518-04. Therefore, DOE proposed to
amend its test procedure for determining insulation R-value for non-
display doors and panels by incorporating by reference ASTM C518-17.
Specifically, in the test procedure in appendix B, DOE proposed to
reference the following sections of ASTM C518-17:

<bullet> 2. Referenced Documents
<bullet> 3. Terminology
<bullet> 5. Apparatus
<bullet> 6. Calibration
<bullet> 7. Test Procedures (excluding 7.3. Specimen Conditioning)
<bullet> 8. Calculation
<bullet> Annex A1. Equipment Design

87 FR 23920, 23933.
DOE did not propose to reference any other sections of ASTM C518-
17, as either they do not apply or they are in direct conflict with
other test procedure provisions included in appendix B. Because ASTM
C518-17 is an updated version of ASTM C518-04, DOE stated in the April
2022 NOPR that the test procedure for determining the K-factor would
effectively remain based on ASTM C518-04 as specified by EPCA (42
U.S.C. 6314(a)(9)(A)(ii)).
In response to the April 2022 NOPR, Anthony supported the proposal
to reference the latest version of the industry test procedure, ASTM
C518-17. (Anthony, No. 31 at p. 3)
In this final rule, DOE is incorporating by reference the sections
of ASTM C518-17 as proposed in the April 2022 NOPR.
3. Industry 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 walk-in cooler and freezer
refrigeration systems, including unit coolers and dedicated condensing
units sold separately, as well as matched pairs. 81 FR 95758,
95798.\26\ 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.
---------------------------------------------------------------------------

\26\ Available at <a href="http://www.ahrinet.org">www.ahrinet.org</a>.
---------------------------------------------------------------------------

The DOE test procedure for walk-in refrigeration systems
incorporates by reference the test procedure in AHRI 1250-2009
(excluding Tables 15 and 16), with certain enumerated modifications.
See appendix C to subpart R of part 431.
In April 2020, AHRI published AHRI 1250-2020, which incorporates
many of the modifications and additions to AHRI 1250-2009 that DOE
currently prescribes in its test procedure at appendix C. 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. AHRI 1250-2020 also includes
test methods for single-packaged dedicated systems.
The following sections discuss the amendments being adopted in
appendix

[[Page 28792]]

C and appendix C1 with respect to the aforementioned industry test
methods.
a. Appendix C
In the April 2022 NOPR, DOE proposed minor modifications to
appendix C that improve test procedure accuracy and repeatability,
while maintaining equivalent measurements of AWEF. 87 FR 23920, 23933.
As discussed further in the section that follows, DOE also proposed to
establish a new appendix C1 to subpart R that would incorporate
substantive changes that would result in different measured values of
efficiency, AWEF2, compared to appendix C. DOE proposed that the use of
appendix C with the proposed amendments would be required 180 days
after this test procedure final rule is published and would remain
required for use until the compliance date of any future amended energy
conservation standards based on appendix C1.
Within appendix C, DOE proposed to maintain reference to AHRI 1250-
2009. DOE proposed to adopt certain instrument accuracy and test
tolerances from AHRI 1250-2020 that would not change the measured AWEF
value, as discussed further in section III.F.5 of this document.
DOE received no comments on its proposal to maintain appendix C,
with modification, until the compliance date of any future amended
energy conservation standards based on appendix C1.
In this final rule, DOE maintains the required use of appendix C,
as amended by this final rule, including the incorporation by reference
of AHRI 1250-2009, until the compliance date of any future amended
energy conservation standards based on appendix C1.
b. Appendix C1
As discussed, in the April 2022 NOPR, DOE proposed to establish a
new appendix C1 to subpart R that incorporates by reference AHRI 1250-
2020. 87 FR 23920, 23933. DOE tentatively determined that the changes
proposed in appendix C1 through the incorporation of AHRI 1250-2020
would increase the representativeness of the DOE test procedure for
walk-ins. DOE also tentatively determined that several of the changes
in AHRI 1250-2020 would change the measured AWEF value. These changes
can be grouped into five categories: off-cycle tests, single-packaged
dedicated systems, defrost calculations, variable capacity, and default
unit cooler parameters. These changes and the comments received on
these proposed changes are discussed in detail in section III.G. Since
these changes would result in a change to measured AWEF, DOE proposed
to establish a new metric called ``AWEF2.''
In the April 2022 NOPR, DOE proposed to incorporate AHRI 1250-2020
for use in appendix C1, with the following exclusions:

<bullet> Section 1 Purpose
<bullet> Section 2 Scope
<bullet> Section 9 Minimum Data Requirements for Published Ratings
<bullet> Section 10 Marking and Nameplate Data
<bullet> Section 11 Conformance Conditions
<bullet> Section C10.2.1.1 Test Room Conditioning Equipment under
section C10--Defrost Calculation and Test Methods

87 FR 23920, 23933.
DOE proposed to exclude these sections of AHRI 1250-2020 because
they either do not apply or conflict with other test procedure
provisions included in appendix C1.
Further, DOE proposed to reference ASHRAE 16-2016 in appendix C1,
as it is referenced in AHRI 1250-2020, with the following exclusions:

<bullet> Section 1 Purpose
<bullet> Section 2 Scope
<bullet> Section 4 Classifications
<bullet> Normative Appendices E-M
<bullet> Informative Appendices N-R

87 FR 23920, 23934.
DOE did not propose to reference these sections of ASHRAE 16-2016,
as either they do not apply or they conflict with other test procedure
provisions that are included as part of appendix C1.
Similarly, DOE proposed to reference ASHRAE 37-2009 in appendix C1,
as it is referenced in AHRI 1250-2020, with the following exclusions:

<bullet> Section 1 Purpose
<bullet> Section 2 Scope
<bullet> Section 4 Classifications
<bullet> Informative Appendix A Classifications of Unitary Air-
conditioners and Heat Pumps

Id.
DOE did not propose to reference these sections of ASHRAE 37-2009,
as either they do not apply, or they conflict with other test procedure
provisions that are included as part of appendix C1.
As discussed in the April 2022 NOPR, AHRI 1250-2020 incorporates
many of the modifications and additions to AHRI 1250-2009 that DOE
currently prescribes in its appendix C test procedure. Id. Since DOE
proposed to adopt AHRI 1250-2020, DOE did not propose to carry over the
sections listed in Table III.1 from appendix C to appendix C1.

Table III.1--List of Sections in Appendix C Not Proposed To Be Included
in Appendix C1
------------------------------------------------------------------------
Appendix C Summary
------------------------------------------------------------------------
Section 3.1.1..................... Modifies Table 1 (Instrumentation
Accuracy) in AHRI 1250-2009.
Section 3.1.2..................... Provides guidance on electrical
power frequency tolerances.
Section 3.1.3..................... 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..................... 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..................... Provides tables to use in place of
AHRI 1250-2009 Tables 15 and 16,
which are excluded from the
reference in 10 CFR 431.303.
Section 3.2.1..................... Provides specific guidance on how to
measure refrigerant temperature.
Section 3.2.2..................... Removes the requirement to perform a
refrigerant composition and oil
concentration analysis.
Section 3.2.5..................... Provides insulation and
configuration requirements for
liquid and suction lines used for
testing.
Section 3.3.1..................... Gives direction for how to test and
rate unit coolers tested alone.
Section 3.3.2..................... Clarifies that the 2008 version of
AHRI Standard 420 should be used
for unit coolers tested alone.
Section 3.3.3..................... Modifies the allowable reduction in
fan speed for off-cycle evaporator
testing.
Section 3.4.1..................... 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.
Section 3.4.2..................... Provides instruction on how to
calculate AWEF and net capacity for
dedicated condensing units.
Section 3.5....................... Provides guidance on how to rate
refrigeration systems with hot gas
defrost.
------------------------------------------------------------------------

[[Page 28793]]

AHRI 1250-2020 does not incorporate all the modifications and
additions to AHRI 1250-2009 that DOE currently prescribes in its test
procedure. Therefore, DOE proposed that the modifications in sections
3.2.3, 3.3.4, 3.3.5, and 3.3.7 of appendix C be incorporated into
appendix C1.
In response to the April 2022 NOPR, DOE received several general
comments about the incorporation of AHRI 1250-2020 for use in appendix
C1. AHRI and National Refrigeration commented that they disagreed with
DOE aligning appendix C1 with AHRI 1250-2020 and requested further
clarification on the proposal. (AHRI, No. 30 at p. 7; National
Refrigeration, No. 39 at p. 2) Neither AHRI nor National Refrigeration
provided detail about what specifically they disagreed with, or which
aspects of DOE's proposal required further clarification.
In response to the April 2022 NOPR, HTPG requested details on the
changes in the new appendix C1 that may impact the determination of
AWEF for unit coolers and variable-capacity systems. (HTPG, No. 32 at
p. 2) These topics are discussed in detail in sections III.G.7 and
III.G.11 of this document, respectively.
As discussed in this section and in more detail in section III.G,
DOE has concluded that the changes in AHRI 1250-2020 improve the
representativeness of the walk-in refrigeration systems test procedure.
Therefore, DOE is incorporating AHRI 1250-2020, ASHRAE 37-2009, ASHRAE
16-2016 for use in appendix C1 as proposed in the April 2022 NOPR.
c. Additional Amendments
AHRI 1250-2020 includes additional amendments that are inconsistent
with AHRI 1250-2009 but are either not referenced in the DOE test
procedure or serve to make aspects of the test procedure more explicit
or clear. None of these changes impact measured AWEF. These additional
amendments are discussed in the paragraphs below.
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. As mentioned
previously, DOE is not incorporating section 2 of AHRI 1250-2020 into
appendix C1.
AHRI 1250-2020 includes an updated list of references and the
applicable versions of certain test standards in appendix A,
``References--Normative.'' DOE does not expect these changes to impact
measured AWEF apart from ways discussed in section III.G. AHRI 1250-
2020 added specifications for refrigerant temperature measurement
locations for unit coolers tested alone, matched pairs, and dedicated
condensing systems tested alone in sections C3.1.3.1, C3.1.3.2, and
C3.1.3.3. DOE has determined that these specifications will not affect
measured AWEF.
AHRI 1250-2020 revised section C7.5.1 to provide more detailed
instructions for calculating system capacity beginning with measured
temperatures and pressures instead of calculated enthalpies, which is
what was done in AHRI 1250-2009. Section C7.5.1 also includes the
determination of capacity from enthalpy calculation results. The
addition of these sections provides clarity and further instruction but
does not affect measured AWEF.
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 ASHRAE 23.1-2010. AHRI 1250-2020 now
provides specific methods for testing dedicated condensing units tested
alone. DOE has 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 measured AWEF.
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. DOE has 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 measured AWEF. As a result, DOE is not
incorporating by reference AHRI 420-2008 in new appendix C1.

C. Amendments to Appendix A for Doors

Appendix A provides test procedures for measuring walk-in envelope
component energy consumption. 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 (see section III.D for
discussion of display panels).
In the April 2022 NOPR, DOE proposed several changes to appendix A
specific to display doors and non-display doors. 87 FR 23920, 23936-
23943. DOE determined that these changes would improve test
representativeness and repeatability. DOE stated in the April 2022 NOPR
that it did not expect the changes it proposed to have a substantive
impact on measured energy consumption calculations for display doors or
non-display doors, except in the case of testing doors with motors.
The following sections describe the modifications that DOE proposed
to appendix A with respect to walk-in display and non-display doors.
1. Reference to NFRC 102-2020 in Place of NFRC 100-2010 and Alternative
Efficiency Determination Methods for Doors
a. NFRC 102-2020 in Place of NFRC 100-2010
Appendix A references NFRC 100-2010 as the method for determining
the U-factor of doors and display panels. NFRC 100-2010 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 100-2010.\27\
---------------------------------------------------------------------------

\27\ Section 4.7.1 of NFRC 100-2010 requires that the accepted
difference between the tested U-factor and the simulated U-factor be
(a) 0.03 Btu/(h-ft\2\-[deg]F) for simulated U-factors that are 0.3
Btu/(h-ft\2\-[deg]F) or less, or (b) 10 percent of the simulated U-
factor for simulated U-factors greater than 0.3 Btu/(h-ft\2\-
[deg]F). This agreement must match for the baseline product in a
product line. Per NFRC 100, the baseline product is the individual
product selected for validation; it is not synonymous with ``basic
model'' as defined in 10 CFR 431.302.
---------------------------------------------------------------------------

As discussed in the April 2022 NOPR, DOE is aware there has been
limited success using the computational method in NFRC 100-2010 to
simulate U-factors of non-display doors. 87 FR 23920, 23936-23937.
Thus, DOE proposed to remove reference to NFRC 100-2010 (i.e., the
computational method) and instead reference NFRC 102-2020 (i.e., the
physical test method) for determining U-factor. Id. Consistent with
that proposal, and with stakeholder concerns regarding test burden
given the highly customizable nature of the walk-in door market, DOE
also proposed to allow use of alternative efficiency determination
methods (AEDMs) to determine the represented value of energy
consumption of walk-in doors at 10 CFR 429.53(a)(3). 87 FR 23920,
23972.
In response, Bally stated that it looks forward to using AEDMs to
rate its walk-in doors. (Bally, No. 40 at p. 5) RSG also agreed with
the proposal to allow for AEDMs. (RSG, No. 41 at p. 2)

[[Page 28794]]

Hussmann noted that, although it is ``not pleased'' with the
current NFRC 100-2010 test method, it does not support use of an AEDM
because it believes rating with an AEDM creates an opportunity for
``approved non-compliance.'' (Hussmann, No. 34 at pp. 3-4)
DOE acknowledges Hussmann's concern but notes that rating a basic
model with an AEDM does not excuse a manufacturer from complying with
the relevant energy conservation standards. DOE has several
requirements pertaining to AEDM records retention; the ability to
provide analyses, conduct simulations, or conduct certification testing
of basic models rated with the AEDM at DOE's request; and verification
testing of an AEDM by DOE. These requirements can be found in 10 CFR
429.70(f)(3) through (5). DOE enforces all these requirements.
DOE notes that despite the limited success historically with using
the computational method in NFRC 100-2010, to the extent that
manufacturers have successfully used the simulation method in NFRC 100-
2010 to produce accurate results, such results would be acceptable as
an AEDM. AEDMs and the specific provisions DOE is adopting pertaining
to AEDMs for doors are explained and discussed in the following
section.
b. Alternative Efficiency Determination Methods for Doors
Pursuant to the requirements of 10 CFR 429.70, DOE may permit use
of an AEDM in lieu of testing equipment for which testing burden may be
considerable and for which that equipment's energy efficiency
performance may be well predicted by such alternative methods. Although
specific requirements vary by product or equipment, use of an AEDM
entails development of a mathematical model that estimates energy
efficiency or energy consumption characteristics of the basic model, as
would be measured by the applicable DOE test procedure. The AEDM must
be based on engineering or statistical analysis, computer simulation or
modeling, or other analytic evaluation of performance data. A
manufacturer must perform validation of an AEDM by demonstrating that
the performance, as predicted by the AEDM, agrees with the performance
as measured by actual testing in accordance with the applicable DOE
test procedure. The validation procedure and requirements, including
the statistical tolerance, number of basic models, and number of units
tested vary by product or equipment.
Once developed and validated, an AEDM may be used to rate and
certify the performance of untested basic models in lieu of physical
testing. Use of an AEDM for any basic model is always at the option of
the manufacturer. One potential advantage of AEDM use is that it may
free a manufacturer from the burden of physical testing. One potential
risk is that the AEDM may not perfectly predict performance, and the
manufacturer could be found responsible for having an invalid rating
for the equipment in question or for having distributed a noncompliant
basic model. The manufacturer, by using an AEDM, bears the
responsibility and risk of the validity of the ratings.
For walk-ins, DOE currently permits the use of AEDMs for
refrigeration systems only. 10 CFR 429.70(f). As discussed previously,
DOE proposed to allow the use of AEDMs for rating walk-in doors in the
April 2022 NOPR. 87 FR 23920, 23972. Concurrent with this proposal, DOE
proposed a number of provisions specific to the validation and use of
an AEDM. First, DOE proposed to include walk-in door validation classes
at 10 CFR 429.70(f)(2)(iv) and to require that two basic models per
validation class be tested using the proposed test procedure in
appendix A, which is consistent with the number of basic models
required to be tested per validation class for walk-in refrigeration
systems. Id.
Second, DOE proposed to include a 5 percent individual model
tolerance, which aligns with the individual model tolerance applicable
to walk-in refrigeration systems, to validate the measured energy
consumption result of an AEDM with the appendix A test result at 10 CFR
429.70(f)(2)(ii). Id. The individual model tolerance is used to
validate the AEDM. This means that when validating the AEDM for use,
the predicted daily energy consumption for each model calculated by
applying the AEDM may not be more than 5 percent less than the daily
energy consumption determined from the corresponding test of the model.
DOE also proposed that an AEDM for doors can only simulate or model
characteristics of the door that are required to be tested by the DOE
test procedure--i.e., for the doors test procedure, the AEDM would be
used to simulate or model the U-factor, which is the only part of the
appendix A test procedure that is not a calculation. The AEDM cannot be
used to simulate or model the energy consumption due to conduction
thermal load, or the direct and indirect electrical energy consumption
of electricity-consuming devices sited on the door--those must be
calculated using the appendix A test procedure. However, when
validating the AEDM, the comparison between a door that has been
physically tested versus a door that has been modeled or simulated must
be done using the complete metric (i.e., total daily energy
consumption). In other words, the AEDM can only be used to determine
the U-factor, but the total daily energy consumption using an AEDM must
be carried out using the calculations in appendix A for the energy
consumption due to conduction thermal load, and the direct and indirect
electrical energy consumption. Then, the validation of an AEDM would
compare the energy consumption calculated using a simulated U-factor
with the energy consumption calculated using a tested U-factor.
Lastly, DOE proposed to include a 5 percent tolerance applicable to
the maximum daily energy consumption metric for AEDM verification
testing conducted by DOE at 10 CFR 429.70(f)(5)(vi), which aligns with
the tolerance applicable to AWEF of walk-in refrigeration systems. Id.
DOE may randomly select and test a single unit of a basic model to
assess whether a basic model is in compliance with the applicable
energy conservation standards pursuant to 10 CFR 429.104, which extends
to all DOE covered products and equipment, including those certified
using an AEDM. As part of the AEDM requirements, DOE may use the test
data from an assessment test for a given model to verify the certified
rating determined by an AEDM. This is called verification testing. See
10 CFR 429.70(f)(5). For doors using an energy consumption metric, the
result from a DOE verification test must be less than or equal to the
certified rating multiplied by (1 plus the applicable tolerance); i.e.,
the DOE verification test result must be less than or equal to 105
percent of the certified rating.
In the April 2022 NOPR, DOE requested comment on the specific
proposals pertaining to the validation and use of AEDMs for doors. Id.
RSG agreed with the proposals. (RSG, No. 41 at p. 2)
Anthony disagreed with DOE removing the reference to NFRC 100-2010
for NFRC 102-2020 and allowing AEDMs because it believes an AEDM would
require more testing and result in an increased financial and physical
burden on manufacturers without achieving an additional energy benefit.
(Anthony, No. 31 at pp. 3, 8-9) Additionally, Anthony stated that if
NFRC 100-2010 is able to be used as an AEDM, the application of the 5
percent

[[Page 28795]]

tolerance on the energy consumption metric, E<INF>dd</INF>, would
conflict with the NFRC 100-2010 standard without achieving an
additional energy benefit. Id. AHRI commented that the AEDM strategy
with respect to U-factor is unclear and requested clarification of what
the proposed 5 percent model tolerance applies to. (AHRI, No. 30 at p.
11)
DOE is clarifying that to use an AEDM, the manufacturer must first
validate the AEDM. To validate the AEDM, the manufacturer must select
at least the minimum number of basic models for each validation class
(specified in table 1 to 10 CFR 429.70(f)(2)(iv)(A)) and physically
test a single unit of each basic model. Thus, for a single validation
class, where DOE proposed two basic models be tested per validation
class, only two physical tests would be required, although more testing
may be conducted at the manufacturer's discretion. The manufacturer
would be required to conduct the physical U-factor tests according to
NFRC 102-2020 referenced by appendix A and carry out the energy
consumption calculations as done in appendix A. For the AEDM, the
manufacturer would model or simulate the U-factor using a method of
their choice, and then carry out the energy consumption calculations as
done for the physical test, only deviating by using the simulated U-
factor in the calculations. All other parts of the energy consumption
calculations shall be done according to appendix A and may not be
modeled. To validate the AEDM, the energy consumption output using the
physical test must be compared with the energy consumption output using
the AEDM for each basic model used for validation. If the output using
the AEDM is lower than the physical test output by more than the
individual model tolerance (i.e., 5 percent), then the AEDM is not
valid. If the output using the AEDM is greater than or equal to 95
percent of the output using physical testing and meets the standard for
at least two basic models, then the AEDM has been validated for that
validation class.
To illustrate the minimum number of physical tests required,
consider an example of a display door manufacturer that produces models
in two validation classes: medium-temperature and low-temperature. This
manufacturer would need to, at a minimum, physically test the U-factor
and calculate the energy consumption of two basic models per validation
class, thus requiring a total of four physical tests: two for the
medium-temperature display door validation class and two for the low-
temperature display door validation class. The manufacturer would use
the U-factor test results to calculate the total daily energy
consumption each door. Then, the manufacturer would use their AEDM to
model or simulate the U-factor of each door and calculate each door's
total daily energy consumption. Each basic model's simulated and tested
total daily energy consumption results would be compared using the
tolerance of 5 percent in order to validate the AEDM. DOE stresses that
this 5 percent tolerance used to validate the AEDM would only apply to
the comparison of tested and simulated energy consumption for the
minimum number of models physically tested for validation of the AEDM.
If the AEDM is validated, the manufacturer could then use the AEDM to
rate the remainder of the basic models it manufacturers in those
validation classes. The 5 percent tolerance would not be used for any
models simulated without a physical test because the AEDM was validated
and thus no physical test would be further required.
DOE emphasizes that allowing use of an AEDM would provide
manufacturers with the flexibility to use an alternative method (i.e.,
besides NFRC 100-2010) that yields the best agreement with a physical
test for their doors. Additionally, DOE notes that the change in test
burden associated with the use of an AEDM is dependent on a
manufacturer's product offerings. If a manufacturer does not have
success with NFRC 100-2010 and is currently required to physically test
all basic models, the AEDM option may reduce the test burden by
requiring only two basic models per validation class to be tested. DOE
is aware there has been limited success using the computational method
in NFRC 100-2010 to simulate U-factors of non-display doors. Therefore,
DOE expects a reduction of test burden across the industry since
allowing AEDMs generally provides manufacturers, particularly those
that manufacture non-display doors, the flexibility to use an alternate
method that works best for them and meets the AEDM criteria established
by DOE. However, if a manufacturer currently has success using NFRC
100-2010, there could be an increase in test burden, but only if the
manufacturer currently validates the use of the simulation method with
less than two basic models per validation class. Test burden and costs
are discussed further in section III.K.1 of this document. The
inclusion of AEDM provisions would enable manufacturers to continue
using NFRC 100-2010, provided that manufacturers meet the AEDM
requirements in 10 CFR 429.53 and 429.70(f). Therefore, DOE is removing
reference to NFRC 100-2010 from its test procedure and is instead
referencing NFRC 102-2020 and adopting provisions that allow
manufacturers to use an AEDM, as proposed in the April 2022 NOPR.
c. Exceptions to the Industry Test Method for Determining U-Factor
Section 5.3 of appendix A references NFRC 100-2010 for determining
U-factor, and section 5.3(a) of appendix A specifies four exceptions to
that industry standard. The first exception implements a tolerance on
the surface heat transfer coefficients (no such tolerance is specified
in NFRC 100-2010); specifically, that the average surface heat transfer
coefficients during a test must be within <plus-minus> 5 percent of the
values specified through NFRC 100-2010 in ASTM C1199. The second and
third exceptions modify the cold and warm-side conditions from the
standard conditions prescribed in NFRC 100-2010. The fourth exception
specifies the direct solar irradiance be 0 Btu/(h-ft\2\).
Sections 6.2.3 and 6.2.4 of ASTM C1199 specify the standardized
heat transfer coefficients and their tolerances as part of the
procedure to set the surface heat transfer conditions of the test
facility using the Calibration Transfer Standard (``CTS'') test. The
warm-side surface heat transfer coefficient must be within <plus-minus>
5 percent of the standardized warm-side value of 1.36 Btu/(h-ft\2\-
[deg]F), and the cold-side surface heat transfer coefficient must be
within <plus-minus> 10 percent of the standardized cold-side value of
5.3 Btu/(h-ft\2\-[deg]F) during the CTS test (ASTM C1199, sections
6.2.3 and 6.2.4). ASTM C1199 does not require that the measured surface
heat transfer coefficients match or be within a certain tolerance of
standardized values during the official sample test--although test
facility operational (e.g., cold-side fan settings) conditions would
remain identical to those set during the CTS test. ASTM C1199 also does
not require measurement of the warm-side surface temperature of the
door. Rather, this value is calculated based on the radiative and
convective heat flows from the test specimen's surface to the
surroundings, which are driven by values determined from the
calibration of the hot box using the CTS test (e.g., the convection
coefficient). See ASTM C1199, section 9.2.1.
As discussed in the April 2022 NOPR, DOE has found that obtaining
the standardized heat transfer values within the <plus-minus> 5 percent
tolerance specified in section 5.3(a)(1) of appendix A on the

[[Page 28796]]

warm side and cold side may not be achievable depending on the thermal
transmittance through the door. 87 FR 23920, 23937. In the April 2022
NOPR, DOE proposed to remove the exceptions specified in section
5.3(a)(1) of appendix A regarding the surface heat transfer
coefficients and the tolerances on them during testing.
DOE did not receive any comments on its proposal to remove the
exceptions specified in section 5.3(a)(1) of appendix A.
For the reasons discussed in the preceding paragraphs and the April
2022 NOPR, DOE is removing the exceptions listed in section 5.3(a)(1)
of appendix A regarding the surface heat transfer coefficients and the
tolerances on them during testing. 87 FR 23920, 23937-23938. By
removing these exceptions, the requirements pertaining to the surface
heat transfer coefficients would apply as they are specified in the
referenced industry standards.
Relatedly, Anthony commented on the specific values used to define
the surface heat transfer coefficients. Specifically, Anthony commented
that it disagrees with the current surface heat transfer coefficient
applied to the cold side during testing and simulation of U-factors for
display doors. (Anthony, No. 31 at pp. 4-5) Anthony presented data from
field testing at several different public locations showing that the
actual measured wind speed is on average 84 percent less than specified
in NFRC 102-2020 and NFRC 100-2010, as well as a measured wind speed
from their test cell showing an average of 1.1 miles per hour
(``mph''). Anthony recommended that DOE adopt a cold-side heat transfer
coefficient corresponding to a conservative wind speed value of 5 mph.
Id.
DOE notes that deviating from the existing surface heat transfer
coefficients would require test labs to change their test chamber
calibration procedures and would require manufacturers to retest and
rerate all envelope components subject to the energy consumption test
procedure in appendix A. DOE has evaluated the data and information
provided by Anthony but is unable to establish at this time whether
such changes to the heat transfer coefficient would be nationally
representative, nor the extent to which any such improvement in
representativeness of the test result would outweigh the test burden
associated with changing the heat transfer coefficient value. DOE has
therefore determined it is not appropriate to amend the heat transfer
coefficients in this final rule.
Additionally, section 5.3(a)(1) of appendix A currently specifies a
direct solar irradiance \28\ of 0 Btu/h-ft\2\. Consistent with DOE's
removal of its reference to NFRC 100-2010, DOE is removing the
requirement of direct solar irradiance of 0 Btu/h-ft\2\ in section
5.3(a)(4) of appendix A. DOE received no comment on solar irradiance in
response to the April 2022 NOPR and notes that the removal of this
requirement would not affect measured values. 87 FR 23920, 23938.
---------------------------------------------------------------------------

\28\ Solar irradiance is the power per unit area received from
the sun in the form of electromagnetic radiation.
---------------------------------------------------------------------------

2. Additional Definitions
a. Surface Area for Determining Compliance With Standards
Surface area of a door is used in two ways in the regulations at
subpart R of 10 CFR431: (1) to convert the tested U-factor of the door
into a conduction load as part of the energy consumption test
procedure, and (2) to determine compliance with the maximum energy
consumption standards. As currently defined in section 3.4 of appendix
A, surface area means 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. The definition does not provide detail on how to determine
the boundaries of the walk-in door from which height and width are
determined to calculate surface area. Additionally, the definition does
not specify if these measurements are to be strictly in-plane with the
surface of the wall or panel that the walk-in door would be affixed to,
or if troughs and other design features on the exterior surface of the
walk-in door should be included in the measured surface area.
In the April 2022 NOPR, DOE proposed that the surface area bounds
of both display doors and non-display doors be the outer edge of the
frame. 87 FR 23920, 23939. DOE proposed to change the term from
``surface area'' to ``door surface area,'' and to define the term as
meaning the product of the height and width of a walk-in door measured
external to the walk-in. Id. 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 leaf is affixed, and the
surface area of a display door and non-display door would be
represented as A<INF>dd</INF> and A<INF>nd,</INF> respectively.
In addition, DOE proposed to move the defined term from the test
procedure in appendix A to the definition section in 10 CFR 431.302
with the other definitions that are broadly applicable to subpart R.
Id. DOE proposed this move because, as revised and in light of the
following section III.C.2.b of this document, this term would no longer
be used to convert the tested U-factor of the door into a conduction
load as part of the energy consumption test procedure and is only
relevant for determining compliance with the energy conservation
standards. Id.
Anthony agreed with the proposed revision of using the external
frame dimensions, which includes the flange, for determining
A<INF>dd</INF> and for determining the maximum energy consumption
standard. (Anthony, No. 31 at p. 5)
Bally suggested that the surface area definition should include
electrical conduit and pressure relief vents, not pieces of the door
with low conductivity. (Bally, No. 40 at pp. 1-2) Bally also commented
that it disagrees with DOE's discussion in the April 2022 NOPR that if
the surface area of a door is measured without the frame, then it
should be considered a panel. (Id.) Senneca stated that the outside
dimensions of the frame should not be included in the surface area
measurement because the frame mounts directly to the insulated panel
and, therefore, the backside of the frame is not exposed directly to
the cold-side temperature. (Senneca, No. 26 at p. 2) Additionally,
Senneca described that a door with a longer track would require a
longer frame and therefore would have a larger surface area; however,
it stated that the larger frame would have no bearing on the energy
consumption because, as mentioned, the backside of the frame is not
exposed directly to the cold-side temperature. (Id.)
Senneca also stated that with the proposal for the door frame to be
included in the surface area, it believes there is ambiguity in
measuring sliding doors that have a track extending past the door
frame. (Id.) DOE has considered Senneca's comment specific to sliding
doors and acknowledges that the track of a horizontal sliding door may
extend significantly beyond the width of the door leaf and door frame
or casings and attach to the panels adjacent to the door, which would
result in a significant increase in ``door surface area'' if the track
width were to be included in the area measurement. Therefore, DOE has
concluded that the portion of the track that extends beyond the
external width (for a horizontal sliding door) or external height (for
a vertical sliding door) of the door leaf or

[[Page 28797]]

leaves and its frame or casings should be excluded from the surface
area measurement used to determine compliance with the standards. DOE
notes that given the equipment it is aware of on the market, this
additional instruction will likely only impact the bounds of sliding
non-display doors. DOE notes that sliding display doors typically have
tracks that are integrated completely into the frame of the entire door
system, thus the entire track is expected to be included in the
determination of surface area.
DOE has considered stakeholder opposition to including the frame in
the door surface area measurement but has determined that the
definition of ``door'' includes the frame for consistent comparison
across door products offered. DOE recognizes that non-display doors may
have variations in the frames used, where some look similar to panels
but tend to have electrical components wired through them, while others
look more like casings used in replacement installations. DOE also
recognizes that non-display doors may have variations in the
installation of doors, where parts of the door frame may or may not be
in direct contact with the cold side of the walk-in. However, DOE
intends to consistently evaluate different products and sees a need to
have consistent instructions on determining the bounds of surface area
for all walk-in doors. DOE has determined that all parts of the door
that impact the operation of the door shall be included in the
determination of the surface area, with the exception of extended track
area for sliding doors as discussed previously. Therefore, the bounds
of the ``door surface area'' dimensions also include the frame.
As proposed in the April 2022 NOPR, in this final rule, DOE is
defining ``door surface area'' as the product of the height and width
of a walk-in door measured external to the walk-in. The height and
width dimensions shall be perpendicular to each other and parallel to
the wall or panel of the walk-in to which the door is affixed. The
height and width measurements shall extend to the edge of the frame and
frame flange (as applicable) to which the door is affixed. For sliding
doors, the height and width measurements shall include the track;
however, the width (for horizontal sliding doors) or the height (for
vertical sliding doors) shall be truncated to the external width or
height of the door leaf or leaves and its frame or casings. The surface
area of a display door is represented as A<INF>dd</INF>, and the
surface area of a non-display door is represented as A<INF>nd</INF>.
b. Surface Area for Determining U-Factor
As stated previously, appendix A currently references NFRC 100-
2010, which in turn references NFRC 102 for the determination of U-
factor through a physical test. When conducting physical testing, the
U-factor (U<INF>s</INF>) is calculated using projected surface area
(A<INF>s</INF>) and then converted to the final standardized U-factor
(U<INF>ST</INF>). See ASTM C1199, sections 8.1.3 and 9.2.7, as
referenced through NFRC 102. Projected surface area (A<INF>s</INF>) 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 (A<INF>dd</INF>) and non-display doors
(A<INF>nd</INF>), 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 amending the definitions
of A<INF>nd</INF> and A<INF>dd</INF> to be specific to the exterior
dimensions of the door, including the frame and frame flange as
appropriate. Defining the bounds of the door through this definition is
inconsistent with the defined area (A<INF>s</INF>) used to calculate U-
factor in NFRC 102-2020.
In the April 2022 NOPR, DOE proposed to specify that the projected
area of the test specimen, A<INF>s</INF>, as defined in ASTM C1199, or
the area used to determine U-factor is the area used for converting the
standardized tested U-factor, U<INF>ST</INF>, into a conduction load in
appendix A. 87 FR 23920, 23940. DOE recognizes that this may not change
ratings for some doors, where A<INF>s</INF> is equivalent to
A<INF>nd</INF> or A<INF>dd</INF>, but it may result in slightly lower
ratings of energy consumption for other doors, where A<INF>s</INF> is
less than A<INF>nd</INF> or A<INF>dd</INF>. DOE expects that since this
proposed detail would either result in a reduced measured energy
consumption or have no impact, there will likely be no need for
manufacturers to retest or rerate. Additional details on how this
detail impacts retesting and rerating are further discussed in section
III.K.1 of this document.
Anthony commented that it agrees with the proposed revision to use
the area of the test specimen, A<INF>s</INF>, to calculate the
conduction load. (Anthony, No. 31 at p. 6) Bally reiterated comments
from AHRI, Hussmann, and Imperial Brown in response to the June 2021
RFI which suggested they did not see a distinction that warranted
changing the definition. (Bally, No. 40 at p. 1) See summary of these
comments at 87 FR 23920, 23939.
DOE reiterates that the door surface area defined in section
III.C.2.a differs from the surface area used to calculate U-factor in
NFRC 102-2020. Thus, despite stakeholder comments, DOE sees a need to
resolve this discrepancy. Otherwise, the conduction load determined
from the physical U-factor test may inflate the actual conduction load.
In the April 2022 NOPR, DOE also proposed to specify in appendix A
that the physical U-factor test should include all components of the
door that aid in the operation of the door, including the frame, rather
than just the door leaf, to improve consistency in application of the
test procedure across all walk-in doors. 87 FR 23920, 23940. Bally
commented that it does not believe the frame of the door should be
included in the U-factor test and suggested that including the frame in
the U-factor test was minimal in comparison to the electrical
components. (Bally, No. 40 at pp. 2-3) As stated in the April 2022
NOPR, DOE's testing of non-display doors has demonstrated that
including the frame in the U-factor test has a measurable impact on the
thermal performance of the door assembly relative to the increase in
the total area, and so DOE is adopting the specification that the
physical U-factor test should include the door frame.
3. Electrical Door Components
Sections 4.4.2 and 4.5.2 of appendix A currently include provisions
for calculating the direct energy consumption of electrical components
of display doors and non-display doors, respectively. Electrical
components associated with doors could include, for example, heater
wire (for anti-sweat or anti-freeze applications), lights (including
display door lighting systems), control system units, or sensors. 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) on the device's product
data sheet if the device does not have a nameplate or such nameplate
does not list the device's power.
As discussed in the April 2022 NOPR, DOE has observed issues that
make calculating a door's total energy consumption a challenge. 87 FR
23920, 23940. These issues include using a

[[Page 28798]]

single nameplate for all door electrical components rather than
individual nameplates for all electricity-consuming devices,
specification of voltage and amperage rather than wattage on the
nameplate, and no specification of whether the nameplate represents the
maximum or steady-state operating conditions. DOE is aware that
measuring direct power consumption of each electrical component could
alleviate some of these issues. In response to the April 2022 NOPR, the
Efficiency Advocates stated that they support an option for direct
measurement of door component electrical power in the test procedure
(Efficiency Advocates, No. 37 at p. 4). DOE acknowledges the comment
but has concluded that additional investigation is needed to develop a
test procedure for such measurements. Therefore, DOE is not adopting
provisions requiring measurement of power consumption of each
electrical door component in appendix A.
Furthermore, 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 proposed in the
April 2022 NOPR to specify in appendix A that the rated power of each
electrical component, P<INF>rated,u,t</INF>, would be the rated input
power of each component because the input power represents power
consumption. The Efficiency Advocates also supported the clarification
that the certified door motor power should be the input power. Id.
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. In
the April 2022 NOPR, DOE proposed that for the purposes of enforcement
testing, in 10 CFR 429.134(q), 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. Anthony agreed with the proposal to use nameplate values
for determining energy consumption unless physical testing results in a
power value that exceeds what is depicted on the nameplate. (Anthony,
No. 31 at p. 6) Bally stated that adjusting nameplate values based on
measurement results requires door manufacturers to be responsible for
the quality assurance of their vendors. (Bally, No. 40 at p. 3) In
response, DOE notes that the door manufacturer is ultimately
responsible for certifying that the walk-in door, when outfitted with
all necessary components, meets the applicable DOE energy conservation
standards.
Given DOE's observations during testing, DOE sees a need to provide
a way to calculate energy consumption using a measured value of
electrical component power. DOE recognizes that there may be minor
variations in measured power as compared to the rated power and has
determined that a tolerance of 10 percent accounts for such variation.
DOE is adopting this provision at 10 CFR 429.134(q)(4) only for the
purposes of enforcement testing to aid the Department in determining
non-compliance with energy conservation standards.
4. Percent Time Off Values
The current test procedure assigns percent time off (``PTO'')
values to various walk-in door components to reflect the hours in a day
that an electricity-consuming device operates at its full rated or
certified power. PTO values are not incorporated in the rated or
certified power of an electricity-consuming device. Table III.2 lists
the PTO values in the current DOE test procedure for walk-in door
components.

Table III.2--Assigned PTO Values for Walk-In Door Components
------------------------------------------------------------------------
Percent time
Component type Off (PTO) (%)
------------------------------------------------------------------------
Lights without timers, control system, or other demand- 25
based control..........................................
Lights with timers, control system, or other demand- 50
based control..........................................
Anti-sweat heaters without timers, control system, or 0
other demand-based control.............................
Anti-sweat heaters on walk-in cooler doors with timers, 75
control system, or other demand-based control..........
Anti-sweat heaters on walk-in freezer doors with timers, 50
control system, or other demand-based control..........
All other electricity-consuming devices without timers, 0
control system, or other auto-shut-off system..........
All other electricity-consuming devices for which it can 25
be demonstrated that the device is controlled by a
preinstalled timer, control system, or auto-shut-off
system.................................................
------------------------------------------------------------------------

As mentioned in the April 2022 NOPR, DOE has granted waivers to
several door manufacturers with motorized door openers, allowing the
use of a different PTO for motors.\29\ 87 FR 23920, 23941. DOE proposed
a single PTO for use with door motors to create consistency in the test
procedure among doors with motors. 87 FR 23920, 23941-23942. DOE
calculated an average PTO value based on the information in the waivers
to determine a single representative PTO value. Considering the waivers
and its calculations, DOE proposed to adopt a door motor PTO value of
97 percent for all walk-in doors with motors. Id. Senneca and the
Efficiency Advocates agreed with the proposed PTO. (Senneca, No. 26 at
p. 2; Efficiency Advocates, No. 37 at p. 2) Bally suggested that the
power consumption of the motor be completely removed from the energy
consumption calculation, but ultimately supported the proposed PTO
value. (Bally, No. 40 at p. 3) DOE has determined that motor power
consumption contributes to direct and total energy consumption of the
door and aids in the operation of the door. Therefore, the motor power
should be included in the determination of energy consumption.
Additionally, 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 to eliminate any need for the continuation of such waiver.
10 CFR 431.401(l). For the reasons stated above, DOE is adopting the
PTO value of 97 percent

[[Page 28799]]

for door motors in appendix A. DOE notes that the adoption of this PTO
value would not require retesting or recertification because calculated
daily energy consumption will be equal to or lower than currently
certified values. New testing would only be required if the
manufacturer wishes to make claims using the new, more efficient
rating.
---------------------------------------------------------------------------

\29\ See HH Technologies, 83 FR 53457; Jamison Door Company, 83
FR 53460; Senneca Holdings, 86 FR 75; Hercules, 86 FR 17801.
---------------------------------------------------------------------------

5. Energy Efficiency Ratio Values
As discussed in the April 2022 NOPR, the energy efficiency ratio
(``EER'') values used in appendix A differ from the EER values in
appendix C. 87 FR 23920, 23942. The values in appendix A are used to
calculate the daily energy consumption associated with heat loss
through a walk-in door, and the values in appendix C correspond to
adjusted dew point temperature when testing refrigeration systems of
walk-in unit coolers alone. In the July 2021 RFI, DOE requested comment
on the difference in EER values used in appendices A and C and based on
stakeholder feedback, DOE concluded in the April 2022 NOPR that there
is no advantage to harmonizing the two values. Id. As discussed in the
April 2022 NOPR, an envelope component manufacturer cannot control what
refrigeration equipment is installed and the EER values are intended to
provide a nominal means of comparison rather than reflect an actual
walk-in installation. Additionally, the difference between the EER
values used in appendix A for doors and those used in appendix C for
unit coolers is seven percent for coolers and five percent for
freezers; however, changing the EER values would require manufacturers
to retest and rerate energy consumption without necessarily providing a
more representative test procedure. Id. Therefore, in the April 2022
NOPR, DOE did not propose to harmonize the EER values between
appendices A and C.
In response to the April 2022 NOPR, Anthony suggested that DOE
adopt the EER values specified in AHRI 1250 to align all components of
a WICF and stated that the modification of EER values would not require
additional testing, as these values are only used in the mathematical
energy calculations. (Anthony, No. 31 at pp. 6-7) DOE notes that
Anthony's suggested approach would require recalculation and
recertification of every basic model and would do so without
necessarily providing a more representative test procedure. As such,
DOE has determined that changing the reference EER values in either
appendix A or C would be unduly burdensome. Therefore, DOE is not
harmonizing the EER values in appendices A and C.
6. Air Infiltration Reduction
As discussed in the April 2022 NOPR, EPCA includes prescriptive
requirements for doors used in walk-in applications intended to reduce
air infiltration. 87 FR 23902, 23943. Specifically, walk-ins must have
(A) automatic door closers that firmly close all walk-in doors that
have been closed to within 1 inch of full closure (excluding doors
wider than 3 feet 9 inches or taller than 7 feet), and (B) strip doors,
spring-hinged doors, or other method of minimizing infiltration when
doors are open. (42 U.S.C. 6313(f)(1)(A)-(B)) DOE previously proposed
methods for determining the thermal energy leakage due to steady-state
infiltration through the seals of a closed door and door opening
infiltration. 75 FR 186, 196-197; 75 FR 55068, 55084-55085. DOE did not
ultimately adopt these methods as part of the final test procedure
because DOE concluded that steady state infiltration was primarily
influenced by on-site assembly practices rather than the performance of
individual components. 76 FR 21580, 21594-21595 (April 15, 2011).
Similarly, DOE stated that, based on its experience with the door
manufacturing industry, door opening infiltration is primarily reduced
by incorporating a separate infiltration reduction device at the
assembly stage of the complete walk-in. Id.
In the April 2022 NOPR, DOE did not propose to include air
infiltration in the test procedure. 87 FR 23920, 23943. However, the
Efficiency Advocates encouraged DOE to incorporate a measurement of air
infiltration for walk-in doors because it would improve the
representativeness and encourage the development and deployment of
technologies that can save energy. (Efficiency Advocates, No. 37 at p.
4) DOE did not receive any data or recommendations for how to
incorporate the measurement of air infiltration for walk-in doors into
the test procedure in response to either the June 2021 RFI or the April
2022 NOPR. DOE has concluded that additional investigation is needed to
adopt a test procedure that considers air infiltration for walk-in
doors and thus is not adopting provisions pertaining to air
infiltration at this time. DOE intends to consider data on the
magnitude of air infiltration for walk-ins as it becomes available for
appropriate evaluation of the representativeness of including it in the
test procedure for walk-in doors.
As previously mentioned, EPCA requires air infiltration limiting
devices on all doors. (42 U.S.C. 6313(f)(1)(A)-(B)) Even though air
infiltration is not currently evaluated as part of the current test
procedure and thus not part of the performance standard, all walk-in
doors are subject to the prescriptive requirements in the energy
conservation standard pertaining to air infiltration limiting devices.
(10 CFR 431.306(a)(1)-(2))

D. Amendments to Appendix A for Display Panels

Appendix A specifies the test procedure to determine energy
consumption of walk-in display panels, which are not currently subject
to any daily energy consumption performance standards but are subject
to the prescriptive requirements at 10 CFR 431.306. The existing test
procedure for walk-in display panels is very similar to that of walk-in
doors in that it requires a U-factor test using NFRC 100-2010, which is
used to determine the thermal conduction through the display panel and
ultimately the total daily energy consumption. The existing display
panel test procedure differs, however, from that of walk-in doors in
that direct and indirect electrical energy consumption are not included
in the test procedure.
In the April 2022 NOPR, DOE proposed to apply all the test
requirements proposed for determining display door conduction load and
energy consumption to determining display panel conduction load and
energy consumption, except for the provisions applicable to electrical
components and PTO values. 87 FR 23920, 23943.
Anthony agreed that the test procedure for display panels should be
similar to the test procedure for display doors, but it disagreed with
DOE's proposal that provisions applicable to electrical components and
PTO values should be excluded from the test procedure for display
panels. (Anthony, No. 31 at p. 7) Anthony stated that display panels
can have heaters and lights. (Id.)
DOE acknowledges Anthony's feedback regarding display panels;
however, DOE does not currently have sufficient information on display
panel electrical components and PTO values to adopt provisions for
electrical components for display panels. DOE may do so in a future
rulemaking, however at this time, DOE is adopting the changes to
section III.C of appendix A for determining display panel conduction
load and energy consumption as proposed in the April 2022 NOPR.

[[Page 28800]]

E. Amendments to Appendix B for Panels and Non-Display Doors

The insulation R-value of walk-in non-display panels and non-
display doors is determined using appendix B. In the April 2022 NOPR,
DOE proposed to modify appendix B to improve test representativeness
and repeatability. 87 FR 23920, 23943. Specifically, DOE proposed to
make the following revisions to appendix B: (1) reference the updated
industry standard ASTM C518-17; (2) include more detailed provisions on
measuring insulation thickness and test sample thickness; (3) provide
additional guidance on determining parallelism and flatness of test
specimen; and (4) reorganize appendix B so it is easier for
stakeholders to follow as a step-by-step test procedure. Id.
In response to the appendix B proposals, Bally commented that the
proposed regulations will be burdensome for laboratories to conduct.
(Bally, No. 40 at p. 4) DOE acknowledges Bally's comment; however, DOE
has concluded that the proposed amendments would not be unduly
burdensome and would improve test representativeness and repeatability
as discussed in sections III.E.1 through III.E.5 of this document. Test
procedure costs and impacts because of the adopted changes are further
discussed in section III.K.2 of this document. DOE does not expect that
the adopted changes to appendix B, discussed further, will alter
measured R-values; therefore, no retesting or recertification is
required.
Additionally, AHRI commented generally that they would like to
understand if display doors, non-display doors, and panels use the same
calculation. (AHRI, No. 30 at p. 4) DOE defines each of these
components separately (see subpart R of 10 CFR 431.302) and their
respective test procedures are described in appendix A, and appendix B.
The procedure for determining energy consumption of display doors
begins at section 4.4 of appendix A. The procedure for determining
energy consumption of non-display doors begins at section 4.5 of
appendix A. Sections 4.4 and 4.5 of appendix A follow the same
methodology of accounting for thermal conduction through the door
(represented in the form of additional refrigeration system energy),
the direct electrical energy consumption of electricity-consuming
devices sited on the door, and the indirect electrical energy
consumption of electricity-consuming devices represented in the form of
additional refrigeration system energy consumption. Panels not
classified as display panels follow the test procedure in appendix B,
which determines the R-value of insulation for only the foam of the
panel.
Furthermore, DOE clarifies that in the following sections, the
changes discussed are specifically in the context of walk-in panels;
however, DOE notes that non-display doors are also subject to the
prescriptive R-value requirement at 10 CFR 431.306(a)(3) and that the
R-value for walk-in door insulation is determined using appendix B. The
following sections describe the modifications that DOE is adopting in
appendix B.
1. 24-Hour Testing Window
As mentioned in the April 2022 NOPR, DOE is aware that the test
specimen and conditioning instruction and example given in section 7.3
of ASTM C518-04 and ASTM C518-17 conflict with the provision in section
4.5 of the DOE test procedure at appendix B. The DOE test procedure
requires testing be completed within 24 hours of specimens being cut
for the purpose of testing, while ASTM C518-04 and ASTM C518-17 require
that specimens be conditioned prior to testing based on material
specifications, which could be longer than 24 hours. 87 FR 23920,
23942.
Bally commented that a cut sample should not be exposed to air for
longer than 8 hours because foam samples become irreversibly de-
conditioned once removed from a panel. (Bally, No. 40 at pp. 3-4) Bally
included a technical bulletin from 1984 that states that, in general, a
1-inch cut section of foam can increase in K-factor about 5 to 10
percent in a few days. (Bally, No. 40, Attachment 2) \30\
---------------------------------------------------------------------------

\30\ The Bally comment included two supplemental attachments:
Attachment 1, ``Solid and Opaque Eval,'' and Attachment 2, ``BTB--
Aging of Foam.'' DOE will reference as ``Attachment 1'' and
``Attachment 2'' throughout this document. Both attachments are
available on the docket.
---------------------------------------------------------------------------

It is DOE's understanding that since the technical bulletin
referenced by Bally was published, there have been changes to the
blowing agents used in polyurethane foam, the most common foam
insulation type used in walk-in panels. Additionally, no specific data
on the change in K-factor beyond 8 hours was provided. Recent tests
conducted by DOE demonstrate that there is no measurable difference in
K-factor for specimens tested immediately after extraction from the
complete panel as compared to specimens tested 24 hours after
extraction from the complete panel. DOE has not evaluated changes to K-
factor of a test specimen beyond 24 hours of extraction from the panel.
Given the existing technology on the market today, DOE believes 24
hours is an appropriate limit that balances K-factor representativeness
with test burden, and therefore DOE is maintaining the current
requirement that testing be completed within 24 hours of cutting a test
specimen from the envelope component. Correspondingly, DOE is not
referencing Section 7.3 of ASTM C518-17 regarding specimen conditioning
as part of its update to appendix B.
2. Total Insulation and Test Specimen Thickness
Section 4.5 of appendix B currently requires that K-factor of a 1
<plus-minus> 0.1-inch sample of insulation be determined according to
ASTM C518-04.
To make the test procedure in appendix B more repeatable, DOE
proposed in the April 2022 NOPR to include instructions for determining
both the total insulation thickness as well as the test specimen
insulation thickness prior to conducting the test to determine K-factor
using ASTM C518-17, which is substantively the same as determining the
K-factor according to ASTM C518-04. 87 FR 23920, 23944. DOE also
proposed step-by-step instructions for specimen preparation, including
detailed instructions of the number and locations of thickness and area
measurements and from where the test specimen should be removed from
the overall envelope component. Id. DOE proposed to require the
following for determining the total thickness of the foam,
t<INF>foam</INF>, from which the final R-value is calculated:
<bullet> The thickness around the perimeter of the envelope
component is determined as the average of at least 8 measurements taken
around the perimeter that avoid the edge region.\31\
---------------------------------------------------------------------------

\31\ Edge region means a region of the panel that is wide enough
to encompass any framing members. If the panel contains framing
members (e.g., a wood frame), then the width of the edge region must
be as wide as any framing member plus an additional 2 in. <plus-
minus> 0.25 in. See section 3.1 of appendix B.
---------------------------------------------------------------------------

<bullet> The area of the entire envelope component is calculated as
the width by the height of the envelope component.
<bullet> A sample is cut from the center of the envelope component
relative to the envelope component's width and height. The specimen to
be tested using ASTM C518-17 will be cut from the center sample.
<bullet> The thickness of the sample cut and removed from the
center of the envelope component is determined as the average of at
least 8 measurements, with at least 2 measurements taken in each
quadrant.

[[Page 28801]]

<bullet> The area of the sample cut and removed from the center of
the envelope component is determined as the width by the height of the
cut sample.
<bullet> Any facers on the sample cut from the envelope component
shall be removed while minimally disturbing the foam, and the thickness
of each facer shall be the average of at least 4 measurements.
<bullet> The average total thickness of the foam shall then be
determined by calculating an area-weighted average thickness of the
complete envelope component less the thickness of the facers.

Id.
For preparing and determining the thickness of the 1-inch test
specimen, DOE proposed the following:
<bullet> A 1 <plus-minus> 0.1-inch-thick specimen shall be cut from
the center of the cut envelope sample removed from the center of the
envelope component.
<bullet> Prior to testing, the average of at least 9 thickness
measurements at evenly spaced intervals around the test specimen shall
be the thickness of the test specimen, L.
Id.
In the April 2022 NOPR, DOE requested feedback on the proposed
provisions relating to test specimen and total insulation thickness and
test specimen preparation prior to conducting the ASTM C518-17 test.
Anthony agreed with both of the proposals. (Anthony, No. 31 at p. 7)
Bally referenced the EPCA calculation for R-value and recommended that
R-value remain calculated with that formula. (Bally, No. 40 at p. 3)
Bally commented that it believes the tolerance of 1 <plus-minus> 0.1
inch is not necessary because the sample preparation process would need
to be restarted, but a smaller sample could have been used to determine
K-factor. (Bally, No. 40 at p. 4)
In response to Bally's comment, DOE is not adopting any changes to
the R-value formula; rather, DOE is providing additional instruction so
that the inputs to the R-value formula, namely the K-factor, are
determined in a consistent and more repeatable manner. At this time,
DOE has determined that the 1 <plus-minus> 0.1 inch tolerance is still
necessary to appropriately and consistently measure K-factor.
Therefore, DOE is adopting the provisions outlined in the April 2022
NOPR for determining test specimen and total thickness of insulation in
appendix B.
3. Parallelism and Flatness
The test procedure for determining R-value requires that the two
surfaces of the tested sample that contact the hot plate assemblies (as
defined in ASTM C518-04 and ASTM C518-17) maintain a flatness tolerance
of <plus-minus>0.03 inches and maintain parallelism of one another with
a tolerance of <plus-minus>0.03 inches.\32\ See section 4.5 of appendix
B. As discussed in the April 2022 NOPR, the current test procedure does
not provide direction to measure or calculate flatness and parallelism.
DOE believes, however, that accurate and repeatable determination of a
specimen's R-value requires the specimen under test to be both flat and
parallel. 87 FR 23920, 23944.
---------------------------------------------------------------------------

\32\ Maintaining a flatness tolerance means that no part of a
given surface is more distant than the tolerance from the ``best-fit
perfectly flat plane'' representing the surface. Maintaining
parallelism tolerance means that the range of distances between the
best-fit perfectly flat planes representing the two surfaces are no
more than twice the tolerance (e.g., for square surfaces, the
distance between the most distant corners of the perfectly flat
planes minus the distance between the closest corners is no more
than twice the tolerance).
---------------------------------------------------------------------------

In the April 2022 NOPR, DOE proposed to include several steps for
determining the parallelism and flatness of the test specimen in
appendix B:
<bullet> Prior to determining the specimen thickness, the specimen
would be placed on a flat surface and gravity used determine the
specimen's position on the surface. As specified previously, a minimum
of nine thickness measurements would be taken at equidistant positions
on the specimen. These measurements would be associated with side 1 of
the specimen.
<bullet> The least squares plane of side 1 is determined based on
the height measurements taken. The theoretical height of the least
squares plane is determined at each measurement location in the x and y
(length and width) direction of the specimen.
<bullet> The difference at each measurement location between actual
height measurement and theoretical height measurement based on the
least squares plane is calculated. The maximum value minus the minimum
value is the flatness associated with this side (side 1). For each side
of the specimen to be considered flat, this value would need to be less
than or equal to 0.03 inches.
<bullet> Flip the specimen so that side 1 is now on the flat
surface and let gravity determine the specimen position on the surface.
Repeat the steps above for side 2 of the specimen.
<bullet> To determine if each side of the specimen is parallel, the
theoretical height at the four corners (i.e., at points (0,0), (0,12),
(12,0), and (12,12)) of the specimen must be calculated using the least
squares plane. The difference in the maximum and minimum heights would
represent the parallelism of one side and would need to be less than or
equal to 0.03 inches for the specimen to be considered parallel.

87 FR 23920, 23945.
AHRI and Anthony agreed with the proposed provisions relating to
determining parallelism and flatness of the test specimen. (AHRI, No.
30 at p. 4; Anthony, No. 31 at p. 8) Bally stated that commercial
devices used to measure K-factor using ASTM C518 have an internal check
on flatness and parallelism so a sample that is out of tolerance will
be flagged. (Bally, No. 40 at pp. 4-5)
DOE acknowledges Bally's comment, however, it is DOE's
understanding that not all manufacturers or laboratories use the same
commercial device to measure K-factor. Regardless of the device used, a
consistent procedure for determining parallelism and flatness is
necessary. DOE is adopting the method for determining parallelism and
flatness in appendix B as described in the April 2022 NOPR. 87 FR
23920, 23945.
4. Insulation Aging
The current test procedure for determining panel R-value does not
account for insulation aging. ``Aging'' of foam insulation refers to
how diffusion of blowing agents out of the foam and diffusion of air
into the foam impacts thermal resistance of insulation materials. The
gaseous blowing agents contained in the foam provide it with much of
its insulating performance, represented by the R-value of the foam
material. Because air has a lower insulating value than the blowing
agents used in foam insulation, the increased ratio of air to blowing
agent reduces the foam insulation performance, which reduces the R-
value of the foam material over time. The building industry uses long-
term thermal resistance (``LTTR'') to represent the R-value of foam
material over its lifetime by describing the insulating performance
changes due to diffusion over time. The presence of impermeable facers
on a foam structure may delay the rate of aging or reduce the decrease
in R-value when compared to a foam structure that is unfaced or has
permeable facers. Blowing agents and temperature and humidity
conditions may also affect the amount or rate of aging that occurs in a
foam structure.
In the April 2022 NOPR, DOE discussed its previous adoption and
subsequent removal of a test procedure that considered aging of foam
insulation. 87 FR 23920, 23945-23946. DOE rescinded the method that
evaluated aging because of stakeholder concerns regarding test burden
and the availability of laboratories to conduct the adopted test
procedure. 79 FR 23788, 27405-27406. As such, DOE did

[[Page 28802]]

not propose to add test procedure provisions regarding aging in the
April 2022 NOPR. 87 FR 23920, 23945-23946. DOE also did not propose to
consider the effects of aging in assessment and enforcement testing
because a recent study at Oak Ridge National Laboratory (``ORNL'')
found the effects of foam insulation aging for panels sold with facers
to be minimal when panel facers remain attached to the foam (i.e., when
the panel remains intact).\33\ Id. In the April 2022 NOPR, DOE
requested comment on other comparable data or studies of foam panel
aging that are representative of the foam insulation, blowing agents,
and panel construction currently used in the manufacture of walk-in
panels. Id. DOE also requested comment on whether manufacturers have
been certifying R-value at time of manufacture or after a period of
aging. Id.
---------------------------------------------------------------------------

\33\ A presentation on ORNL's study can be found online at
<a href="http://www.osti.gov/biblio/1844325-impact-thermal-bridging-imperfections-agingeffective-value-walk-cooler-freezer-panels">www.osti.gov/biblio/1844325-impact-thermal-bridging-imperfections-agingeffective-value-walk-cooler-freezer-panels</a>. DOE acknowledges
that panels are shipped for assembly in walk-ins with the foam
already in final chemical form between facers. Thus, the most
applicable evaluation of change in insulation R-value over time is
demonstrated by the red data points (labeled ``2'') for the foam
that remained intact with the facers on slides 26 through 30 of
ORNL's presentation.
---------------------------------------------------------------------------

In response, AHRI suggested that any aging criteria should be based
on the conditioning requirements in ASTM C518. (AHRI, No. 30 at p. 4)
AHRI also stated that typical aging periods to ensure dimensional
stability of finished foam has been reached vary between 14 and 28
days. Id. Bally stated that it tests its foam without aging. (Bally,
No. 40 at p. 5) RSG commented that it would like to limit the time
between manufacture and testing as much as possible. (RSG, No. 41 at
pp. 1, 11) RSG stated that it has conducted its own test, where it
calculated R-value every 2 weeks for 6 months after manufacture; it
found that R-value drops sharply at the beginning, followed by a slower
rate of decline. (Id.)
In response to AHRI's suggestion regarding aging criteria, DOE
testing has shown that there is no measurable difference in K-factor
for specimens tested immediately after extraction from the complete
panel as compared to specimens tested 24 hours after extraction from
the complete panel, even though it would be expected that aging of a
thinner sample without facers would be more significant than a fully
intact panel. Therefore, DOE expects the aging of an intact panel to be
negligible after 24 hours.
Bally's and RSG's comments suggest that manufacturers are rating R-
value without considering the effects of aging and would prefer to
limit the amount of time between manufacture and test. As stated
previously, DOE has found that there are minimal effects of foam
insulation aging for panels sold with facers when panel facers remain
attached to the foam. For assessment and enforcement testing conducted
to support the enforcement of DOE's energy conservation standards, DOE
is generally able to test samples within one to three months after
receipt. The time lag from when the panel is manufactured and when
testing is conducted at a laboratory is typically significantly shorter
than that evaluated in the ORNL study. Therefore, DOE expects any
reduction in R-value to be minimal from date of manufacture to
assessment or enforcement test date. Additionally, walk-in panels
received by DOE for assessment and enforcement testing are evaluated
upon arrival to ensure that they are received intact (i.e., with
facers) and undamaged, and testing of the specimen is completed within
24 hours of sample removal from the panel, as specified in section 4.5
of the DOE test procedure in appendix B. DOE does not expect any
reduction in R-value within 24 hours of the sample being cut from the
panel. Therefore, at this time, DOE will not consider insulation aging
in the test procedure nor in the Department's assessment and
enforcement testing based on the available data. DOE may consider
additional data on this issue as it becomes available.
5. Overall Thermal Transmittance of Non-Display Panels
The current test procedure for non-display panels does not measure
the overall thermal transmittance of a walk-in panel. 87 FR 23920,
23946. DOE previously adopted a test method for measuring overall
thermal transmittance of a walk-in panel, including the impacts of
thermal bridges \34\ and edge effects (e.g., due to structural
materials and fixtures used to mount cam locks). 76 FR 21580. However,
after receiving comments concerning test and cost burden and the lack
of availability of laboratories to conduct the test procedure, DOE
rescinded this portion of the walk-in panel test procedure. 79 FR
27388, 27405-27406. Based on past concerns, DOE did not propose any
provisions to evaluate overall thermal transmittance of non-display
panels in the April 2022 NOPR. 87 FR 23920, 23946.
---------------------------------------------------------------------------

\34\ Thermal bridging occurs when a more conductive material
allows an easy pathway for heat flow across a thermal barrier.
---------------------------------------------------------------------------

In response, the Efficiency Advocates encouraged DOE to investigate
appropriate methods to capture the overall thermal transmittance of
walk-in panels. (Efficiency Advocates, No. 37 at p. 4) DOE did not
receive any other feedback on its proposal or specific suggestions on
how to implement a procedure that would measure overall thermal
transmittance while minimizing the test cost burdens previously
identified.
DOE continues to have the same concerns regarding test burden and
lack of availability of test facilities to conduct any potential
overall thermal transmittance testing of walk-in panels. Therefore, DOE
is not including a test procedure in appendix B for determining overall
thermal transmittance of non-display panels at this time.

F. Amendments to Appendix C for Refrigeration Systems

Appendix C provides test procedures to determine the AWEF and net
capacity of walk-in refrigeration systems. DOE does not expect that the
adopted changes to appendix C will alter measured capacity values or
AWEF. Therefore, DOE expects no retesting or recertification will be
required. Rather, the revisions for appendix C address repeatability
issues that DOE has observed through its testing of walk-in
refrigeration systems.
The following sections describe the modifications that DOE is
making to appendix C, in this final rule.
1. Refrigeration Test Room Conditioning
The DOE test procedure for walk-in refrigeration systems specifies
temperature and/or humidity conditions for the test chambers. (See,
e.g., Tables 3 through 16 of AHRI 1250-2009, which is incorporated by
reference in the DOE test procedure.) Section C6.2 of AHRI 1250-2009
requires that the environmental chambers ``be equipped with essential
air handling units and controllers to process and maintain the enclosed
air to any required test conditions.'' This requirement is also in
section C5.2.2 of AHRI 1250-2020. However, DOE is aware that some test
facilities may rely on the test unit to cool and dehumidify the test
room. When the test unit is used to cool and dehumidify the test room,
frost accumulation on the test unit's coils during pretest conditioning
is possible and can affect the results of the capacity test. 87 FR
23920, 23947. Section C5.1 of AHRI 1250-2020 states that the unit
cooler under test may be used to aid in

[[Page 28803]]

achieving the required test chamber ambient temperatures prior to
beginning a steady-state test but requires the unit under test to be
free from frost before initiating steady-state testing. In the April
2022 NOPR, DOE proposed to specify that for applicable system
configurations (matched pairs, single-packaged systems, and unit
coolers tested alone), the unit under test may be used to help achieve
the required test chamber conditions prior to beginning any steady-
state test. 87 FR 23920, 23947. Additionally, DOE proposed to require a
visual inspection of the test unit coils for frost before the steady-
state test begins. Id. 87 FR 23920, 23947. DOE requested comment on the
proposed pretest coil inspection requirement and asked for feedback on
current chamber conditioning practices within the industry. 87 FR
23920, 23947.
AHRI, HTPG, Hussmann, KeepRite, Lennox, and National Refrigeration
disagreed with allowing the unit under test to condition the test room
because it cannot sufficiently remove humidity from the room. (AHRI,
No. 30 at p. 4; HTPG, No. 32 at p. 4; Hussmann, No. 38 at p. 3;
KeepRite, No. 36 at p. 1; Lennox, No. 35 at pp. 2-3; National
Refrigeration, No. 39 at p. 1) The same group of commenters also stated
that the requirement for the unit to be ``free from frost'' is too
subjective. (Id.) Hussmann mentioned that defrost could reduce the
frost present, but that would result in a frosted-coil test instead of
a dry-coil test. (Hussmann, No. 38 at p. 3) AHRI and Hussmann suggested
that, if the unit under test is used to condition the test chamber, the
unit's capacity be tested both before and after the test to ensure that
the unit's capacity is not decreasing due to frost load. (AHRI, No. 30
at pp. 4-5; Hussmann, No. 38 at p. 3) Lennox recommended that
environmental chambers be equipped with air handlers to maintain test
conditions. (Lennox, No. 35 at pp. 2-3) RSG agreed with the DOE's
proposed inspection requirement. (RSG, No. 41 at p. 1)
2. DOE notes that the proposed test procedure allows the unit under
test to aid in achieving the required test chamber conditions This
implies that other conditioning equipment may be necessary and that the
unit under test should never be the sole conditioner. In addition, DOE
notes that the amendments to test procedure are in alignment with
section C5 of AHRI 1250-2020, the most current industry test procedure.
DOE has determined that a visual inspection is the most practical way
to confirm that coils are free from frost and that while such an
inspection may include subjective judgement about the presence of
frost, it is better than no inspection at all. DOE has therefore
determined that a visual inspection of the coils is sufficient. DOE
also notes that the operating tolerances discussed in section III.F.5
of this document, appendix C to subpart R of 10 CFR part 431, and AHRI
420-2007 ensure that any significant impact of frost collection during
a test would invalidate the test unless the unit capacity remains
steady throughout a test.\35\ These requirements make the pre- and
post-test measurement of capacity unnecessary. Therefore, DOE is
adopting the test procedure as proposed in the April 2022 NOPR. DOE is
adding the new requirement to appendix C, which also carries over to
appendix C1. Temperature Measurement Requirements
---------------------------------------------------------------------------

\35\ For dedicated condensing units and matched pairs, new mass
flow operating tolerances are adopted as discussed in section
III.F.5, and existing refrigerant temperature tolerances are
specified in section 3.1.1 of appendix C to subpart R of 10 CFR part
431. These two measurements would drift out of tolerance during a
test if frost conditions were significantly affecting capacity
measurements for such systems. Similarly, table C3 of AHRI 420-2007
includes a refrigerant mass flow tolerance and table C4 of AHRI 420-
2007 includes inlet and outlet saturation temperature operating
tolerances. These measurements would drift out of tolerance during a
test if frost conditions were significantly affecting capacity
measurements of unit coolers tested alone.
---------------------------------------------------------------------------

a. Suction Line Temperature Measurement
The current DOE test procedure requires measuring refrigerant
temperature entering or leaving the unit cooler using either
thermometer wells or immersed sensors to determine refrigerant enthalpy
as part of the capacity measurement for matched pairs and unit coolers
tested alone (see 10 CFR part 431, subpart R, appendix C, section
3.2.1). The capacity determination for dedicated condensing units
tested alone is based on the refrigerant conditions leaving the
condensing unit and standardized conditions leaving the unit cooler, as
specified in section 3.4.2.1 of appendix C. In the April 2022 NOPR, DOE
proposed to clarify that, when testing dedicated condensing units,
thermometer wells or immersed sensors can be used only at the
condensing unit liquid outlet and are not required to be used for the
suction line. 87 FR 23920, 23947.
AHRI, KeepRite, Lennox, National Refrigeration, and HTPG all
commented that they do not support the proposal to forgo temperature
measuring requirements for the suction line when testing dedicated
condensing units. (AHRI, No. 30 at p. 5; KeepRite, No. 36 at p. 1;
Lennox, No. 35 at p. 3; National Refrigeration, No. 39 at p. 1; HTPG,
No. 32 at p. 4) AHRI also stated that legacy calculation and simulation
systems use existing temperature measurements of the suction discharge.
(AHRI, No. 30 at p. 5)
DOE acknowledges that existing systems and calculations may depend
on suction line temperature measurements. For this reason, DOE retracts
its proposal from the April 2022 NOPR and in this final rule maintains
the requirements for thermometer wells or immersed sensors for both the
suction and liquid lines when testing dedicated condensing units alone.
AHRI-Wine also commented that wine cellar manufacturers are
concerned that the wells are not large enough for temperature
measurements. (AHRI-Wine, No. 30 at p. 2) DOE notes that thermometer
wells are required in the current DOE test procedure for temperature
measurement. DOE addresses these concerns in the remainder of this
section.
b. Surface-Mount Temperature Measurement Allowances for Small Diameter
Tubing
As mentioned in the April 2022 NOPR, DOE has found that
implementing the current thermometer well requirement for refrigerant
lines with an outer diameter of 1-2 inch or less can restrict the
refrigerant flow and thus affect temperature measurements. To rectify
this issue and to ensure that all walk-in refrigeration systems can be
tested according to the DOE test procedure, DOE proposed allowing an
alternative approach when the refrigerant line tubing diameter is 1-2
inch or less, in which the temperature measurement would be made using
two surface-mounted measuring instruments with a minimum accuracy of
<plus-minus>0.5 [deg]F, which would be averaged to obtain the reading.
Additionally, DOE proposed that the two measuring instruments must be
mounted on the pipe separated by 180 degrees around the refrigerant
tube circumference. To ensure

[[Page 28804]]

measurements are not affected by changes in ambient temperature, DOE
proposed requiring use of 1-inch-thick insulation around the measuring
instruments that extends 6 inches up- and downstream of the measurement
locations. Where this technique is used to measure temperature at the
expansion valve inlet, DOE proposed to require that the measurement be
within 6 inches of the device.
With respect to tube surface measurements, AHRI and KeepRite stated
that the temperature measurements on the tube surface are not accurate
enough, and that this measurement is too critical to allow this. (AHRI,
No. 30 at p. 5; KeepRite, No. 36 at p. 1) AHRI and KeepRite also stated
that a low-temperature reading resulting from surface-mounted
temperature measurement devices could lead to bubbling upstream of the
expansion valve, resulting in inflated AWEF values. (AHRI, No. 30 at p.
5; KeepRite, No. 36 at p. 2) Lennox supported DOE's proposal to allow
surface-mounted temperature sensors but encouraged DOE to work with
industry to ensure the full scope of applications can be covered with
these requirements. (Lennox, No. 35 at p. 3) Additionally, AHRI and
KeepRite suggested allowing transition to a pipe large enough for a
thermometer well. Id. National Refrigeration also recommended
maintaining the thermometer well requirement for small diameter tubing
and allowing for larger diameter tubing to accommodate thermometer
wells. (National Refrigeration, No. 39 at p. 1) Regarding location of
the temperature measurement, AHRI and KeepRite agreed with the
allowance to locate the temperature sensor within 6 inches; however,
they suggested that the test procedure should further clarify if the
measurement is from the body of the expansion valve or the joint with
the liquid line. (AHRI, No. 30 at p. 5; KeepRite, No. 36 at p. 2)
KeepRite further suggested allowing the dual liquid temperature
measurements to be further upstream in a thermometer well with a
secondary surface measurement 6 inches from the expansion valve and
with sufficient insulation such that the surface temperature reading
does not differ by more than 2 [deg]F from the thermometer well
measurements. (KeepRite, No. 36 at p. 2)
Specific to the liquid line temperature measurement location, DOE
clarifies that the measurement is from the center of the body of the
expansion valve.
AHRI-Wine and HTPG agreed with the proposal to allow two external
temperature measurements for small diameter tubing. (AHRI-Wine, No. 30
at p. 2; HTPG, No. 32 at p. 4)
DOE acknowledges the concerns from stakeholders regarding the use
of surface measurements and will consider data from industry on this
issue in future rulemakings. DOE has conducted testing using the
approach proposed in the April 2022 NOPR and has determined that the
approach provides representative measurements and prevents bubbling.
Therefore, DOE is adopting the surface mount temperature measurement
test provisions as proposed in the April 2022 NOPR. These requirements
will be added to appendix C, and will also carry over to appendix C1.
3. Hierarchy of Installation Instruction and Specified Refrigerant
Conditions for Refrigerant Charging and Setting Refrigerant Conditions
As discussed in the April 2022 NOPR, DOE is aware that sometimes
multiple installation instructions may be available for a unit, and
different test results could be obtained based on which instructions
are used. 87 FR 23920, 23948. DOE proposed a hierarchy for installation
instructions and setup of refrigerant conditions to improve test
repeatability by indicating which manufacturer-specified conditions
would be prioritized during setup.
Setup conditions or instructions may be stamped on the unit
nameplate or otherwise affixed to the unit, shipped with the unit, or
available online. DOE has encountered walk-in refrigeration units for
which these three sources of instruction provide different values or
conflicting directions. To ensure consistent setup during testing, DOE
proposed in the April 2022 NOPR that instructions or conditions stamped
on or adhered to a test unit take precedence, followed by instructions
shipped with the unit. Id. Because online instructions can be easily
revised, DOE proposed that instructions or other setup information
found online would not be used to set up the unit for testing.
Furthermore, setting of refrigerant charge level or refrigerant
conditions is a key aspect of setup of refrigeration systems, whether
for field use or testing. In the April 2022 NOPR, DOE proposed that
units be charged and set up at operating conditions specified in the
test procedure (for outdoor refrigeration systems, DOE proposed use of
operating condition A) based on the installation instructions, using
the proposed hierarchy (i.e., prioritizing instructions stamped or
adhered to unit over instructions included in a manual shipped with the
unit). Id. In cases where instructions for refrigerant charging or
refrigerant conditions are provided only online or not at all, DOE
proposed that a generic charging approach be used instead. If the
installation instructions specify operating conditions to set up the
refrigerant charge or refrigerant conditions, those conditions would be
used rather than the conditions specified in the test procedure. Id.
DOE determined that in some cases, a manufacturer specifies a range
of conditions for superheat,\36\ subcooling, and/or refrigerant
pressure. In these instances, DOE proposed to treat the midpoint of
that range as the target temperature/pressure, and a test condition
tolerance would be applied to the parameter that is equal to half the
range. For example, if a manufacturer specifies a target superheat of 5
to 10 [deg]F, the target for test would be 7.5 [deg]F and the average
value during operation at the setup operating conditions would have to
be 7.5 [deg]F <plus-minus> 2.5 [deg]F. Alternatively, installation
instructions may specify a refrigerant condition value without a range
or without indicated tolerances. In such cases, DOE proposed that
standardized tolerances be applied as indicated in Table III.3. These
tolerances depend on the kind of refrigerant expansion device used.
---------------------------------------------------------------------------

\36\ Superheat is the difference between vapor-phase refrigerant
temperature and the dew point corresponding to the pressure level.

[[Page 28805]]

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

DOE also notes that zeotropic \37\ refrigerants have become more
common. When charging with such refrigerants (i.e., any 400 series
refrigerant), DOE proposed that the refrigerant charged into the system
must be in liquid form. 87 FR 23920, 23948. Charging a system in liquid
form is standard practice for charging of such refrigerants because the
concentrations of the components of the blend present in the vapor
phase of the charging cylinder are often skewed from the intended
concentrations of the refrigerant blend.
---------------------------------------------------------------------------

\37\ A zeotropic refrigerant is a blend of two or more
refrigerants that have different boiling points. Each refrigerant
will evaporate and condense at different temperatures.
---------------------------------------------------------------------------

If the installation instructions on the label affixed to (or
shipped with) the unit do not provide instructions for setting
subcooling or otherwise how to charge with refrigerant for a condensing
unit tested alone or as part of a matched pair, DOE proposed requiring
testing the unit in a way that is consistent with the DOE test
procedure and the installation instructions and that also does not
cause the unit to stop operating during testing, e.g., by shutoff by
the high-pressure switch. DOE believes that such installation would be
most representative of the way a technician would set up a system in
the field if there were no refrigerant charge or subcooling
instructions. 87 FR 23920, 23948.
AHRI and Lennox commented that they agree with the hierarchy of
charging methods, however, they recommended that DOE allow use of
online documentation. (AHRI, No. 30 at p. 6; Lennox, No. 35 at p. 3)
HTPG also suggested that electronic instructions be allowed in addition
to paper. (HTPG, No. 32 at p. 5)
As discussed previously, DOE proposed in the April 2022 NOPR not to

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