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Proposed Rule2022-06423

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

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Published

April 21, 2022

Issuing agencies

Energy Department

Abstract

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

Full Text

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

[[Page 23919]]

Vol. 87

Thursday,

No. 77

April 21, 2022

Part II

Department of Energy

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10 CFR Parts 429 and 431

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

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

[[Page 23920]]

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DEPARTMENT OF ENERGY

10 CFR Parts 429 and 431

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

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

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

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

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

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

ADDRESSES: Interested persons are encouraged to submit comments using
the Federal eRulemaking Portal at <a href="http://www.regulations.gov">www.regulations.gov</a>, under docket
number EERE-2017-BT-TP-0010. Follow the instructions for submitting
comments. Alternatively, interested persons may submit comments by
email to <a href="/cdn-cgi/l/email-protection#a7f0eee4e195979690f3f797979697e7c2c289c3c8c289c0c8d1">[email&#160;protected]</a>. Include docket number EERE-2017-BT-
TP-0010 in the subject line of the message.
No telefacsimiles (``faxes'') will be accepted. For detailed
instructions on submitting comments and additional information on this
process, See section V of this document.
Although DOE has routinely accepted public comment submissions
through a variety of mechanisms, including postal mail and hand
delivery/courier, the Department has found it necessary to make
temporary modifications to the comment submission process in light of
the ongoing coronavirus 2019 (``COVID-19 pandemic''). DOE is currently
suspending receipt of public comments via postal mail and hand
delivery/courier. If a commenter finds that this change poses an undue
hardship, please contact Appliance Standards Program staff at (202)
586-1445 to discuss the need for alternative arrangements. Once the
COVID-19 pandemic health emergency is resolved, DOE anticipates
resuming all of its regular options for public comment submission,
including postal mail and hand delivery/courier.
Docket: The docket, which includes Federal Register notices, public
meeting attendee lists and transcripts (if a public meeting is held),
comments, and other supporting documents/materials, is available for
review at <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, some documents listed in the
index, such as those containing information that is exempt from public
disclosure, may not be publicly available.
The docket web page can be found at <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. See
section V for information on how to submit comments through
<a href="http://www.regulations.gov">www.regulations.gov</a>.

FOR FURTHER INFORMATION CONTACT:
Dr. Stephanie Johnson, U.S. Department of Energy, Office of Energy
Efficiency and Renewable Energy, Building Technologies Office, EE-2J,
1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone:
(202) 287-1943. Email <a href="/cdn-cgi/l/email-protection#4a0b3a3a26232b24292f193e2b242e2b382e391b3f2f393e232524390a2f2f642e252f642d253c">[email&#160;protected]</a>.
Mr. Michael Kido, U.S. Department of Energy, Office of the General
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121.
Telephone: (202) 586-8145. Email: <a href="/cdn-cgi/l/email-protection#eba68288838a8e87c5a0828f84ab839ac58f848ec58c849d">[email&#160;protected]</a>.
For further information on how to submit a comment, review other
public comments and the docket, or participate in a public meeting (if
one is held), contact the Appliance and Equipment Standards Program
staff at (202) 287-1445 or by email:
<a href="/cdn-cgi/l/email-protection#95d4e5e5f9fcf4fbf6f0c6e1f4fbf1f4e7f1e6c4e0f0e6e1fcfafbe6d5f0f0bbf1faf0bbf2fae3">[email&#160;protected]</a>.

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

[[Page 23921]]

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

Table of Contents

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

I. Authority and Background

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

A. Authority

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

[[Page 23922]]

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

B. Background

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

[[Page 23923]]

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

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

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

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

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

[[Page 23924]]

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

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

\7\ The parenthetical reference provides a reference for
information located in the docket of DOE's rulemaking to develop
test procedures for walk-ins. (Docket No. EERE-2017-BT-TP-0010,
which is maintained at <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.
---------------------------------------------------------------------------

II. Synopsis of the Notice of Proposed Rulemaking

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

[[Page 23925]]

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

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

[[Page 23926]]

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

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

III. Discussion

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

A. Scope and Definitions

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

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

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

[[Page 23927]]

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

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

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

[[Page 23928]]

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

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

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

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

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

[[Page 23929]]

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

[[Page 23930]]

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

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

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

[[Page 23931]]

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

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

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

[[Page 23932]]

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

B. Industry Standards

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

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

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

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

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

[[Page 23933]]

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

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

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

[[Page 23934]]

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

[[Page 23935]]

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

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

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

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

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

[[Page 23936]]

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

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

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

[[Page 23937]]

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

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

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

[[Page 23938]]

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

[[Page 23939]]

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

[[Page 23940]]

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

[[Page 23941]]

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

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

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

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

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

[[Page 23942]]

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

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

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

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

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

[[Page 23943]]

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

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

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

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

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

[[Page 23944]]

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

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

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

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

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

[[Page 23945]]

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

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

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

\26\ A presentation on ORNL's study can be found online at
<a href="https://www.osti.gov/biblio/1844325-impact-thermal-bridging-imperfections-aging-effective-value-walk-cooler-freezer-panels">https://www.osti.gov/biblio/1844325-impact-thermal-bridging-imperfections-aging-effective-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.
---------------------------------------------------------------------------

Based on DOE evaluation of product literature, there are two common
ways to manufacture walk-in panels: (1) Foaming metal skins in place
using closed cell polyurethane foam (``PUF'') or (2) gluing layers of
previously-hardened foam to metal skins. DOE research suggests that PUF
is the most common insulation used in walk-ins. To manufacture PUF
panels, the PUF is injected and hardened using jigs that firmly
maintain exterior panel dimensions until the foam has cooled and
hardened. This process encourages standardization of panel dimensions
as jigs are expensive and typically have limited adjustability.
Extruded polystyrene (``XPS'') is used by some manufacturers to
construct walk-in panels. XPS-based walk-ins are built in layers of
XPS, a previously-hardened foam material that is shipped in sheets to
the original equipment manufacturer (``OEM''), where it is cut to the
desired shape and assembled. Customization is more common with XPS
panels. XPS strongly resists water absorption, preventing panels from
losing their insulative properties should water or condensation leaks
develop. Other layered panel assembly materials include
polyisocyanurate and expanded polystyrene (``EPS'') which are used less
but are still offered by so

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