[Federal Register Volume 89, Number 247 (Thursday, December 26, 2024)]
[Rules and Regulations]
[Pages 104859-104865]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-30274]
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DEPARTMENT OF ENERGY
10 CFR Part 431
[EERE-2024-BT-DET-0012]
RIN 1904-AE57
Energy Conservation Program: Commercial Warm Air Furnaces;
Notification of Tentative Determination and Request for Comment
AGENCY: Office of Energy Efficiency and Renewable Energy, Department of
Energy.
ACTION: Notification of tentative determination and request for
comment.
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SUMMARY: On June 2, 2023, the U.S. Department of Energy (``DOE'' or the
``Department'') published a test procedure final rule which established
test procedures for commercial warm air furnaces (``CWAFs''). The Air-
Conditioning, Heating, and Refrigeration Institute (``AHRI'') filed a
petition for review of the final rule in the United States Court of
Appeals for the Fourth Circuit on August 1, 2023. In a February 6,
2024, order, the Fourth Circuit granted a voluntary remand of the final
rule to the Department of Energy (``DOE'') to determine whether
establishment of the test procedure for the thermal efficiency two
(``TE2'') metric is supported by the specific provisions applicable to
CWAFs under the Energy Policy and Conservation Act (``EPCA''). More
specifically, DOE agreed in this voluntary remand to only establish the
TE2 test procedure if the Department makes a determination that the TE2
test procedure is consistent with the amended industry test procedure,
or a determination, supported by clear and convincing evidence, that
the amended industry test procedure fails to satisfy the statutory
requirements. This document provides DOE's tentative determination that
the amended industry test procedure fails to satisfy EPCA's statutory
requirements and requests comment on this topic.
DATES: DOE will accept comments, data, and information regarding this
document no later than January 8, 2025. See section V, ``Public
Participation,'' for details.
ADDRESSES: Interested persons are encouraged to submit comments using
the Federal eRulemaking Portal at www.regulations.gov under docket
number EERE-2024-BT-DET-0012. Follow the instructions for submitting
comments. Alternatively, interested persons may submit comments,
identified by docket numberEERE-2024-BT-DET-0012, by any of the
following methods:
(1) Email: [email protected]. Include the docket
number EERE-2024-BT-DET-0012in the subject line of the message.
(2) Postal Mail and Hand Delivery/Courier: Appliance and Equipment
Standards Program, U.S. Department of Energy, Building Technologies
Office, Mailstop EE-5B, 1000 Independence Avenue SW, Washington, DC
20585-0121. Telephone: (202) 287-1445. If possible, please submit all
items on a compact disc (``CD''), in which case it is not necessary to
include printed copies.
No telefacsimiles (``faxes'') will be accepted. For detailed
instructions on submitting comments and additional information on this
process, see section V of this document.
Docket: The docket for this activity, which includes Federal
Register notices, public meeting attendee lists and transcripts (if a
public meeting is held), comments, and other supporting documents/
materials, is available for review at www.regulations.gov. All
documents in the docket are listed in the www.regulations.gov index.
However, not all documents listed in the index may be publicly
available, such as information that is exempt from public disclosure.
The docket web page can be found at www.regulations.gov/docket/EERE-2024-BT-DET-0012. The docket web page contains instructions on how
to access all documents, including public comments, in the docket. See
section V for information on how to submit comments through
www.regulations.gov.
FOR FURTHER INFORMATION CONTACT: Ms. Julia Hegarty, U.S. Department of
Energy, Office of Energy Efficiency and Renewable Energy, Building
Technologies Office, EE-5B, 1000 Independence Avenue SW, Washington, DC
20585-0121. Telephone: (240) 597-6737. Email:
[email protected].
Mr. Pete Cochran, U.S. Department of Energy, Office of the General
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121.
Telephone: (240) 961-1189. Email: [email protected].
For further information on how to submit a comment or review other
public comments and the docket, contact the Appliance and Equipment
Standards Program staff at (202) 287-1445 or by email:
[email protected].
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Introduction
A. Authority
B. Energy Conservation Standards Rulemaking Process Under EPCA
C. Background
II. Discussion
A. ASHRAE Trigger
B. Appendix B Test Procedure for TE2
[[Page 104860]]
C. Industry Test Procedure (Appendix A Test Procedure for TE)
1. Jacket Loss
III. Procedural Issues and Regulatory Review
IV. Public Participation
V. Approval of the Office of the Secretary
I. Introduction
A. Authority
The Energy Policy and Conservation Act, Public Law 94-163, as
amended (``EPCA''),\1\ authorizes DOE to regulate the energy efficiency
of a number of consumer products and certain industrial equipment. (42
U.S.C. 6291-6317, as codified) Title III, Part C of EPCA, added by
Public Law 95-619, title IV, sec. 441(a), established the Energy
Conservation Program for Certain Industrial Equipment, which sets forth
a variety of provisions designed to improve energy efficiency. This
equipment includes CWAFs, the subject of this document. (42 U.S.C.
6311(1)(J))
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\1\ All references to EPCA in this document refer to the statute
as amended through the Energy Act of 2020, Public Law 116-260 (Dec.
27, 2020), which reflect the last statutory amendments that impact
Parts A and A-1 of EPCA.
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The energy conservation program under EPCA consists essentially of
four parts: (1) testing, (2) labeling, (3) Federal energy conservation
standards, and (4) certification and enforcement procedures. Relevant
provisions of EPCA include definitions (42 U.S.C. 6311), test
procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315),
energy conservation standards (42 U.S.C. 6313), and the authority to
require information and reports from manufacturers (42 U.S.C. 6316; 42
U.S.C. 6296).
The Federal testing requirements consist of test procedures that
manufacturers of covered equipment must use as the basis for: (1)
certifying to DOE that their equipment complies with the applicable
energy conservation standards adopted pursuant to EPCA (42 U.S.C.
6316(b); 42 U.S.C. 6296), and (2) making other representations about
the efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE
uses these test procedures to determine whether the equipment complies
with relevant standards promulgated under EPCA. DOE's test procedures
for CWAFs are currently prescribed at subpart D of part 431 of title 10
of the Code of Federal Regulations (``CFR'').
Federal energy efficiency requirements for covered equipment
established under EPCA generally supersede state laws and regulations
concerning energy conservation testing, labeling, and standards. (42
U.S.C. 6316(a) and 42 U.S.C. 6316(b); 42 U.S.C. 6297) DOE may, however,
grant waivers of Federal preemption for particular state laws or
regulations, in accordance with the procedures and other provisions of
EPCA. (42 U.S.C. 6316(b)(2)(D))
Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures
DOE must follow when prescribing or amending test procedures for
covered equipment. EPCA requires that any test procedures prescribed or
amended under this section must be reasonably designed to produce test
results that reflect energy efficiency, energy use, or estimated annual
operating cost of a given type of covered equipment during a
representative average use cycle (as determined by DOE) and requires
that test procedures not be unduly burdensome to conduct. (42 U.S.C.
6314(a)(2))
EPCA generally requires that, at least once every seven years, DOE
evaluate test procedures for each type of covered equipment, including
CWAFs, to determine whether amended test procedures would more
accurately or fully comply with the requirements for the test
procedures to not be unduly burdensome to conduct and be reasonably
designed to produce test results that reflect energy efficiency, energy
use, and estimated operating costs during a representative average use
cycle. (42 U.S.C. 6314(a)(1)-(3)) DOE refers to these provisions as the
``lookback'' provisions and rulemakings conducted under these
provisions as ``lookback'' rulemakings.
Specific to certain commercial equipment, including CWAFs, EPCA
required that the initial test procedures for this equipment be those
generally accepted industry testing procedures or rating procedures
developed or recognized by AHRI or ASHRAE, as referenced in ASHRAE
Standard 90.1, ``Energy Standard for Buildings Except Low-Rise
Residential Buildings'' (``ASHRAE Standard 90.1''), that were in effect
on June 30, 1992. (42 U.S.C. 6314(a)(4)(A)) Further, if such an
industry test procedure is amended, DOE must update its test procedure
to be consistent with the amended industry test procedure unless DOE
determines, by rule published in the Federal Register and supported by
clear and convincing evidence, that the amended test procedure would
not meet the requirements in 42 U.S.C. 6314(a)(2) and (3), in which
case DOE may establish an amended test procedure that does satisfy
those statutory provisions. (42 U.S.C. 6314(a)(4)(B) and (C)) DOE
refers to these provisions as the ``ASHRAE trigger'' provisions and
rulemakings conducted under these provisions as ``ASHRAE trigger''
rulemakings.
Whether pursuant to the lookback provision or the trigger
provision, if DOE determines that a test procedure amendment is
warranted, EPCA requires that the Department 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))
B. Energy Conservation Standards Rulemaking Process Under EPCA
The purpose of energy conservation standards issued under EPCA is
to reduce energy use by improving the energy efficiency of covered
products and equipment. (See 42 U.S.C. 6312(a)) The first step in
establishing new or amended energy conservation standards for any
covered product or equipment is to determine what energy use by a
covered product or equipment will be within the scope of the energy
conservation standard, i.e., what is the representative average use
cycle for the covered product or equipment. For example, prior to the
Energy Independence and Security Act of 2007 (``EISA 2007''), the
representative average use cycle for many covered products only
included active mode energy use, i.e., energy used while the product
was performing its main function. As such, the representative use cycle
did not include any energy used while the product was in a standby or
off mode. Thus, manufacturers had little incentive to reduce standby or
off mode energy use as it had no effect on whether a covered product
complied with the applicable energy conservation standards. But in EISA
2007, Congress required DOE to include standby and off mode energy use
as part of the representative average use cycle for any energy
conservation standard adopted after July 1, 2010. (42 U.S.C.
6295(gg)(3)).
Representative average use cycles for covered products and
equipment can also change over time as DOE's understanding of how the
product or equipment is used in the field improves, consumer habits
change, or technologies improve. For example, DOE recently issued an
amended test procedure for air-cooled commercial package air
conditioners and heat pumps that reflects how the representative
average use cycle for this equipment has changed over time. 89 FR 43986
(May 20, 2024). DOE adopted this new test procedure for air-cooled
commercial air conditioners and heat pumps with the
[[Page 104861]]
support of a cross-section of stakeholders, including the heating and
cooling industry, who recommended the details of the new test procedure
to DOE as part of a negotiated consensus recommendation. Id. at 89 FR
43991. The consensus recommendation recognized that the introduction of
innovative technologies in the market, such as the ability for
compressors to run at part-load values in response to different
operating conditions in the field, has contributed to changes in the
representative average use cycle for air-cooled commercial air
conditioners and heat pumps. The consensus recommendation also
recognized that air-cooled commercial air conditioners and heat pumps
operate in additional heating and cooling modes not encompassed by the
current representative average use cycle. As a result, the
representative use cycle for air-cooled commercial air conditioners and
heat pumps was updated to include, among other things, part-load
operation at a variety of outdoor temperature points and additional
modes of operation, e.g., integrated mechanical and economizer cooling,
economizer-only cooling, cooling season ventilation, and unoccupied no-
load hours. Id. at 89 FR 43997-43998.
Having determined a representative average use cycle for a covered
product or equipment, the next step in EPCA's energy conservation
standards rulemaking process is to prescribe a test procedure that is
reasonably designed to produce test results that measure energy use of
the covered product or equipment for that representative average use
cycle and that is not unduly burdensome to conduct. (42 U.S.C.
6293(b)(3); 42 U.S.C. 6314(a)(2)) For example, when Congress required
DOE to include standby and off mode energy use in standards for covered
products, it first directed DOE to amend test procedures for all
covered products to include provisions for measuring standby and off
mode energy use. (42 U.S.C. 6295(gg)(2)(A)) Congress then directed DOE
to use these amended test procedures when prescribing new or amended
standards that incorporate standby and off mode energy use. (42 U.S.C.
6295(gg)(3)(A)) As the new standards would be based on a different
representative use cycle, i.e., one that includes active mode, standby
mode, and off mode, Congress clarified that the amended test procedures
``shall not be used to determine compliance with product standards
established prior to the adoption of the amended test procedures.'' (42
U.S.C. 6295(gg)(2)(C)) It would have made little sense for Congress to
require manufacturers to use test procedures that measure active,
standby, and off mode energy when determining compliance with an energy
conservation standard that is only based on active mode energy use. DOE
takes the same approach when prescribing an amended test procedure for
use in evaluating new or amended energy conservation standards that are
based on an updated representative average use cycle. Use of the
amended test procedure is only required upon the compliance date of the
new or amended energy conservation standards. See sec. 8(f) of appendix
A to subpart C of 10 CFR part 430.
C. Background
Under EPCA's lookback provision, DOE initiated a test procedure
rulemaking for CWAFs by publishing a request for information (``RFI'')
in the Federal Register on May 5, 2020 (``May 2020 RFI''). 85 FR 26626.
The current energy conservation standards for CWAFs are based on a
representative average use cycle that assumes CWAFs always operate at
100% capacity in the field and that the only energy losses are from
flue exhaust gases. The May 2020 RFI solicited public comments, data,
and information on aspects of the existing DOE test procedure for CWAFs
at 10 CFR part 431, subpart D, appendix A (``appendix A''), which
measures Thermal Efficiency (``TE'') and is used for determining
compliance with the current energy conservation standards for CWAFs,
including whether there were any issues with the existing test
procedure at that time and whether it was in need of updates or
revisions. Id.
DOE subsequently published a notice of proposed rulemaking
(``NOPR'') for the CWAFs test procedure in the Federal Register on
February 25, 2022, which proposed amendments to the existing test
procedure for TE as well as a new test procedure based on DOE's
tentative determination that the representative average use cycle for
CWAFs should include jacket losses and part-load operation. 87 FR 10726
(``February 2022 NOPR''). DOE noted that CWAFs are typically installed
outdoors and, as a result, jacket losses can be a significant source of
energy loss. 87 FR 10726, 10735. DOE also noted that many CWAFs now
have multiple heating stages and performance for these CWAFs can vary
at different heating loads. id. As a result, DOE proposed that any new
or amended energy conservation standards for CWAFs should be based on a
representative average use cycle that includes jacket losses and part-
load operation, i.e., the TE2 metric. DOE proposed a new test procedure
in 10 CFR part 431, subpart D, appendix B (``appendix B''), to measure
energy efficiency under the TE2 metric. DOE tentatively determined that
the appendix B test procedure met the statutory criteria in 42 U.S.C.
6314(a)(2) and (3). 87 FR 10726, 10737-10738.
The February 2022 NOPR had a 60-day comment period and DOE held a
webinar public meeting on March 29, 2022. As directed by the remand
order from the Fourth Circuit, this document considers whether the
amended industry test procedure fails to satisfy the applicable
statutory requirements. In this document, DOE focuses on two discrete
issues related to whether the amended industry test procedure is
reasonably designed to product test results that reflect energy use
during a representative average use cyle: the lack of jacket loss and
part-load testing provisions in the amended industry test procedure.
DOE believes the comment period provided for in the DATES section is
more than sufficient for interested parties to provide comments on
these two issues and notes that DOE already satisfied the comment
period required in 42 U.S.C. 6314(b) for prescribing the appendix A and
appendix B test procedures with the 60-day comment period provided for
in the February 2022 NOPR.
Following publication of the February 2022 NOPR, the latest update
to ASHRAE Standard 90.1 was released in January 2023 (``ASHRAE Standard
90.1-2022''). ASHRAE Standard 90.1-2022 references CSA/ANSI Z21.47-
2021, Gas-fired central furnaces (``ANSI Z21.47-2021''), as the test
method for gas-fired CWAFs and Underwriters Laboratories (``UL'')
standard UL 727-2018, ``Standard for Safety Oil-Fired Central
Furnaces'' (``UL 727-2018''), as the test method for oil-fired CWAFs.
On June 2, 2023, DOE published a test procedure final rule for
CWAFs. 88 FR 36217 (``June 2023 Final Rule''). In the June 2023 Final
Rule, DOE amended the current test procedure for TE in appendix A and
incorporated by reference the latest industry test procedures
referenced in ASHRAE Standard 90.1-2022. The amendments to the industry
test procedure were relatively minor and not based on any updates to
the representative average use cycle for CWAFs. Rather, they were
clarifications to the existing test procedure intended to improve
clarity and help with the execution of the current test procedure. DOE
also finalized the proposed appendix B test procedure that is based on
an updated representative average use cycle that includes jacket losses
and part-load operation. Similar to other rulemakings
[[Page 104862]]
where DOE has determined that the representative average use cycle
should be updated, e.g., air-cooled commercial air conditioners and
heat pumps, the June 2023 Final Rule states that use of the appendix B
test procedure would not be required until such time as compliance is
required with amended energy conservation standards based on the new
metric, should DOE adopt such standards.
Following publication of the June 2023 Final Rule, the Air-
Conditioning, Heating, and Refrigeration Institute (``AHRI'') filed a
petition for review of the final rule in the United States Court of
Appeals for the Fourth Circuit on August 1, 2023. In its opening brief,
AHRI argued that DOE failed to provide notice and an opportunity for
comment after being triggered by the ASHRAE Standard 90.1-2022
publication prior to publishing the June 2023 Final Rule; DOE did not
undertake the required analysis under 42 U.S.C. 6314(a)(4)(B); and that
if DOE had conducted the correct analysis under 42 U.S.C.
6314(a)(4)(B), it would necessarily have concluded that it lacked clear
and convincing evidence that the industry test procedure did not meet
the statutory requirements. See Air-Conditioning, Heating, and
Refrigeration Institute v. United States Department of Energy, No. 23-
1793 (4th Cir. Oct. 23, 2023), 15-1.
On February 6, 2024, the Fourth Circuit granted the Department's
motion for voluntary remand. In its order, the Court granted DOE's
motion for voluntary remand to clarify that, in this particular
circumstance, where ASHRAE published an amended industry test procedure
during the pendency of a rulemaking under the 7-year lookback
provision, the Department will solicit public comment prior to making:
(1) a final determination that the test procedure in appendix B for the
TE2 metric is consistent with the amended industry test procedure; or
(2) a final determination, supported by clear and convincing evidence,
that the industry test procedure fails to satisfy the statutory
requirements. See Air-Conditioning, Heating, and Refrigeration
Institute v. United States Department of Energy, No. 23-1793 (4th Cir.
Feb. 6, 2024), 22-1. The remand order did not vacate the June 2023
Final Rule, nor did it require DOE to revisit its determination that
the appendix B test procedure meets the statutory requirements at 42
U.S.C. 6314(a)(2) and (3).
DOE is publishing this document in accordance with the order from
the Fourth Circuit. Specifically, DOE is presenting its tentative
determination, supported by clear and convincing evidence, that the
industry test procedure is not reasonably designed to produce test
results that reflect energy efficiency during a representative average
use cycle that, as determined by DOE, includes jacket losses and part-
load operation. DOE requests public comment on this tentative
determination.
II. Discussion
A. ASHRAE Trigger
As discussed, EPCA requires that if the industry test procedure for
CWAFs is amended, DOE must update its test procedure to be consistent
with the amended industry test procedure unless DOE determines, by rule
published in the Federal Register and supported by clear and convincing
evidence, that the amended test procedure would not meet the
requirements in 42 U.S.C. 6314(a)(2) and (3), in which case DOE may
establish an amended test procedure that does satisfy those statutory
provisions. (42 U.S.C. 6314(a)(4)(B) and (C)) The publication of ASHRAE
Standard 90.1-2022 represented an ASHRAE trigger for CWAFs. The test
procedure established in appendix A for the TE metric references the
industry test standards from the most recent version of ASHRAE Standard
90.1 (2022), which satisfies DOE's obligations under the ASHRAE trigger
provision with respect to the appendix A test procedure for the TE
metric. See 42 U.S.C. 6314(a)(4)(B). In this document, DOE is applying
the ASHRAE trigger provision to the appendix B test procedure for the
TE2 metric. In the following section, DOE discusses its tentative
determination, supported by clear and convincing evidence,\2\ that the
industry test procedure is not reasonably designed to produce test
results that reflect energy efficiency during a representative average
use cycle that, as determined by DOE, includes jacket losses and part-
load operation.
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\2\ ``[C]lear and convincing evidence requires a factfinder . .
. to have an `abiding conviction' that her findings . . . are
`highly probable' to be true.'' Am. Pub. Gas Ass'n v. United States
Dep't of Energy, 22 F.4th 1018, 1025 (D.C. Cir. 2022) (quoting
Colorado v. New Mexico, 467 U.S. 310, 316 (1984)).
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B. Appendix B Test Procedure for TE2
In the June 2023 Final Rule, DOE considered that the existing test
procedure and standards were based on a representative average use
cycle that did not include consideration of jacket losses or part-load
performance. 88 FR 36217, 36223-36227. CWAFs lose energy to the
environment through jacket losses and are capable of and do operate
differently under part-load conditions. As a result, DOE determined in
the June 2023 Final Rule that jacket losses and part-load performance
can contribute significantly to overall equipment energy use and should
be part of the representative average use cycle for CWAFs. Id. As such,
DOE established a new test procedure (appendix B) based on a
representative average use cycle that includes jacket losses and part-
load operation. The June 2023 Final Rule includes an extensive
discussion supporting DOE's determination that the appendix B test
procedure is reasonably designed to produce test results that reflect
energy efficiency during a representative average use cycle that, as
determined by DOE, includes jacket losses and part-load operation, and
is not unduly burdensome to conduct. Id. In that discussion, DOE
acknowledged that accounting for jacket losses and part-load operation
would increase test burden. Id. at 88 FR 36224. But after a thorough
analysis of the increased test costs, DOE concluded that the additional
costs are not unduly burdensome and the inclusion of jacket losses and
part-load operation provides for a more representative average use
cycle. Id. at 88 FR 36230.
C. Industry Test Procedure (Appendix A Test Procedure for TE)
As discussed previously, the industry test procedure, which is
referenced in appendix A and is used for determining compliance with
the current energy conservation standards, is based on a representative
average use cycle that assumes CWAFs only operate at 100 percent
capacity and that energy is only lost through flue exhaust gases. As
discussed previously, these assumptions are an over-simplification of
how CWAFs operate in the field. In this document, DOE evaluates the
industry test procedure in the context of the ASHRAE trigger provisions
and presents DOE's tentative determination, supported by clear and
convincing evidence, that the industry test procedure does not satisfy
all of the criteria in 42 U.S.C. 6314(a)(2) and (3). Specifically, DOE
has tentatively determined that the industry test procedure is not
reasonably designed to produce test results which reflect energy
efficiency during a representative average use cycle that, as
determined by DOE, includes jacket losses and part-load operation. As
such, DOE's adoption of the appendix B test procedure, which DOE
determined met the applicable statutory criteria in the June 2023 Final
Rule, is consistent with the ASHRAE
[[Page 104863]]
trigger provisions in 42 U.S.C. 6314(a)(4)(B) and (C).
As explained in more detail in the following sections, DOE
estimates that the test procedure for TE2 could produce a result that
is between 3.5 percent lower (in a model with high jacket loss and poor
part-load performance) to 1 percent higher (in a model with negligible
jacket loss and good part-load performance) than the industry test
procedure because the TE2 metric includes jacket loss and part-load
performance. This variation in efficiency is significant. For example,
when DOE last amended the standards for gas-fired CWAFs, the minimum
required efficiency went from 80 to 81 percent, which DOE determined
would result in significant additional conservation of energy. 81 FR
2420, 2430. Further, the average life-cycle cost savings to a consumer
from that 1 percent increase in efficiency was $284. Id. at 81 FR 2423.
Those already significant impacts are only magnified when larger
differences in measured efficiency are considered. Therefore, DOE has
tentatively determined, supported by clear and convincing evidence,
that the industry test procedures referenced in ASHRAE Standard 90.1-
2022 are not reasonably designed to produce test results which reflect
energy efficiency during a representative average use cycle that, as
determined by DOE, includes jacket losses and part-load operation. The
following sections discuss the significance of jacket loss and part-
load performance to overall energy use and efficiency during a
representative average use cycle in more detail.
1. Jacket Loss
As discussed, the current energy efficiency metric for CWAFs is TE.
10 CFR 431.77. TE for a CWAF is defined in 10 CFR 431.72 as 100 percent
minus the percent flue loss and is determined using the test procedure
in appendix A. Appendix A and the industry test procedure produce
results that are essentially a measure of combustion efficiency.
However, the energy efficiency of CWAFs in the field is influenced by
factors in addition to combustion efficiency (e.g., jacket loss).
Jacket losses are losses from the commercial warm air furnace to the
ambient environment that occur because heat is lost through the jacket,
i.e., the cabinet surrounding the heating section, of the CWAF during
operation. Jacket loss contributes to the overall energy use of a CWAF
and is, therefore, one of the parameters that determines a CWAF's
overall efficiency. In fact, table 6.8.1-5 of ASHRAE Standard 90.1-2022
includes performance requirements for CWAFs and specifies that units
must have jacket losses not exceeding 0.75 percent of the input rating,
indicating that jacket loss is an important aspect of CWAF operation.
Additionally, the test methods for similar products, such as consumer
furnaces, account for jacket loss further demonstrating that jacket
losses are an important factor in determining a furnace's efficiency.
Heat loss through the cabinet (i.e., jacket loss) is generally
proportional to the thickness of the insulation and/or insulative
material used in the cabinet. CWAFs with the same TE, as determined
under the current appendix A test procedure, could have different
performance in the field if, for example, one unit has different
insulation than the other (resulting in different levels of jacket
loss). DOE also notes that the vast majority of CWAFs are installed
within commercial unitary air conditioners (``CUACs'') located on
rooftops,\3\ and that these outdoor installations will result in
greater jacket loss than CWAFs installed indoors because of the colder
ambient air. As such, DOE has tentatively determined that energy use of
a CWAF will vary depending on installation location because of
different levels of jacket loss. Differences in energy use based on
differences in jacket loss are not captured by the industry test
procedure. Incorporating jacket loss into the representative average
use cycle and corresponding new metric, TE2, allows consumers to get a
more accurate picture of CWAF energy use in the field by capturing
differences in CWAF performance due to different levels of jacket loss
(which as previously described could be caused by different levels of
insulation, for example).
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\3\ On January 15, 2016, DOE published a direct final rule
amending energy conservation standards for various types of
commercial air conditioning equipment and CWAFs. 81 FR 2420. As
discussed in appendix 8D of the Direct Final Rule Technical Support
Document, DOE found that 95% of gas-fired CWAFs are installed
outdoors and packaged with a CUAC.
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While manufacturers currently complying with the ASHRAE Standard
90.1 requirements would have to limit jacket losses so as not to exceed
0.75 percent of the input rating, DOE notes that because the jacket
loss percentage would be multiplied by the jacket loss factor for
weatherized CWAFs designed to be installed outdoors (which represent
the majority of CWAFs on the market and which have a jacket loss factor
of 3.3), a jacket loss of 0.75 percent could result in a difference of
nearly 2.5 percent as compared to a unit with negligible jacket losses.
As discussed previously, even a 1 percent difference in efficiency is
significant both in terms of the national benefits of energy
conservation standards and benefits to individual consumers.
2. Part-Load Performance
DOE has reviewed the current CWAF market and found that the vast
majority of CWAFs have two or more stages of heating. DOE notes that
CWAFs with two or more stages can operate at reduced firing rates to
meet the building load. Part-load performance refers to the efficiency
of the CWAF when operating at a reduced firing rate (as opposed to
full-load performance which reflects the efficiency when operating at
the maximum firing rate).
Under the appendix A test procedure, TE reflects the efficiency of
the CWAF when firing at the maximum input rate (i.e., at full load).
When a CWAF burner operates at a reduced input rate (i.e., part load),
the ratio of heat exchanger surface area to burner input rate is
increased (in comparison to operation at the maximum input rate), which
could increase the efficiency of the CWAF compared to operating at full
load, if other aspects of operation are consistent. However, depending
on the air-fuel ratio or other factors impacting combustion efficiency,
the combustion efficiency could instead decrease when operating at a
reduced firing rate, especially if the air-fuel ratio is not maintained
at an optimal level. The change in performance, including whether
efficiency is improved or reduced at part-load, would vary from model
to model depending on the design and control strategies employed when
operating at input rates below the maximum input rate. Therefore, CWAF
part-load performance has the potential to be substantively different
from full-load performance and including part-load performance in the
measurement of CWAF efficiency would allow the efficiency metric to
account for this potential.
In previous testing of similar products, DOE has observed that the
efficiency when operating at the reduced input rate can be as much as 2
percent higher or lower than the efficiency when operating at the
maximum input rate.\4\ In a CWAF that exhibits similar performance
differences, the resulting difference in
[[Page 104864]]
TE2 would be 1 percent higher or lower than the TE of that unit
(depending on whether part load operation is more or less efficient
than at full load) when accounting for the weighting of 50 percent of
time operating at the reduced input rate. As discussed previously, such
a difference in efficiency is significant both in terms of the national
benefits of energy conservation standards and benefits to individual
consumers.
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\4\ In 2019, DOE conducted testing of consumer furnaces, which
included 2-stage, non-condensing furnaces. The consumer furnace test
method requires testing at both the maximum and minimum input rates
for 2-stage models, so DOE was able to compare the steady-state
efficiency at each input rate to determine the difference in
performance when operating at a reduced input rate.
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III. Conclusion
The potential difference in CWAF efficiency measured under the
industry test procedure and the appendix B test procedure is an
excellent example of why Congress updated representative use cycles for
covered products to include standby and off mode energy use in new or
amended energy conservation standards and why stakeholders, including
manufacturers, asked DOE to update the representative average use cycle
for air-cooled commercial air conditioners and heat pumps--consumers
and manufacturers are both better off when DOE test procedures and
energy conservation standards capture more energy use in the field. For
example, as discussed previously, a CWAF with a TE of 81 percent as
measured by the industry test procedure could, depending on jacket
losses and part-load operation, have an actual range of efficiencies
from 77.5 to 82 percent using the appendix B test procedure for TE2.
That is a significant difference in efficiency and corresponds to a
significant difference in fuel costs over the lifetime of the CWAF,
which is important information for consumers. The industry test
procedure also does not allow manufacturers to fully differentiate
their products in the market. For example, under the industry test
procedure, a manufacturer with a line of CWAF models with well-
insulated jackets has no way to advertise their improved efficiency in
the market. Under the industry test procedure, these models will have
the same advertised efficiency as similar models that lack insulation
and have higher jacket losses.
Having determined that any future, amended standards for CWAFs
should be based on a representative average use cycle that includes
jacket losses and part-load operation, DOE adopted the appendix B test
procedure in the June 2023 Final Rule. The appendix B test procedure
contains specific provisions for measuring jacket losses and energy use
during part-load operation and will be used by DOE to evaluate
potential amended standards for CWAFs. Use of the appendix B test
procedure by manufacturers would not be required until such time as
compliance is required with amended energy conservation standards based
on the new representative average use cycle, should DOE adopt such
standards.
In this document, DOE evaluated whether the industry test procedure
is reasonably designed to produce test results which reflect energy use
during a representative average use cycle that, as determined by DOE,
includes jacket losses and part-load operation. Unlike the appendix B
test procedure, the industry test procedure does not have provisions
for calculating jacket losses and changes in energy efficiency due to
part-load operation. As discussed previously, this results in the
industry test procedure producing test results that do not account for
significant variations in energy use across different CWAF models. As a
result, DOE has tentatively determined, supported by clear and
convincing evidence, that the industry test procedure is not reasonably
designed to produce test results which reflect energy efficiency during
a representative average use cycle. DOE requests comment on this
tentative determination.
III. Procedural Issues and Regulatory Review
DOE has concluded that the determinations made pursuant to the
various procedural requirements applicable to the June 2023 Final Rule
remain unchanged for this notification of tentative determination.
These determinations are set forth in the June 2023 Final Rule. 88 FR
36217, 36230-36233. DOE is publishing this document to present its
tentative determination, supported by clear and convincing evidence,
that the industry test procedure would not provide test results that
are representative of an average use cycle for the TE2 metric, and to
seek comment from interested parties.
IV. Public Participation
DOE will accept comments, data, and information regarding this
document no later than the date provided in the DATES section at the
beginning of this document. Interested parties may submit comments,
data, and other information using any of the methods described in the
ADDRESSES section at the beginning of this document.
Submitting comments via www.regulations.gov. The
www.regulations.gov web page will require you to provide your name and
contact information. Your contact information will be viewable to DOE
Building Technologies staff only. Your contact information will not be
publicly viewable except for your first and last names, organization
name (if any), and submitter representative name (if any). If your
comment is not processed properly because of technical difficulties,
DOE will use this information to contact you. If DOE cannot read your
comment due to technical difficulties and cannot contact you for
clarification, DOE may not be able to consider your comment.
However, your contact information will be publicly viewable if you
include it in the comment itself or in any documents attached to your
comment. Any information that you do not want to be publicly viewable
should not be included in your comment, nor in any document attached to
your comment. Otherwise, persons viewing comments will see only first
and last names, organization names, correspondence containing comments,
and any documents submitted with the comments.
Do not submit to www.regulations.gov information for which
disclosure is restricted by statute, such as trade secrets and
commercial or financial information (hereinafter referred to as
Confidential Business Information (``CBI'')). Comments submitted
through www.regulations.gov cannot be claimed as CBI. Comments received
through the website will waive any CBI claims for the information
submitted. For information on submitting CBI, see the Confidential
Business Information section.
DOE processes submissions made through www.regulations.gov before
posting. Normally, comments will be posted within a few days of being
submitted. However, if large volumes of comments are being processed
simultaneously, your comment may not be viewable for up to several
weeks. Please keep the comment tracking number that www.regulations.gov
provides after you have successfully uploaded your comment.
Submitting comments via email, hand delivery/courier, or postal
mail. Comments and documents submitted via email, hand delivery/
courier, or postal mail also will be posted to www.regulations.gov. If
you do not want your personal contact information to be publicly
viewable, do not include it in your comment or any accompanying
documents. Instead, provide your contact information in a cover letter.
Include your first and last names, email address, telephone number, and
optional mailing address. The cover letter will not be publicly
viewable as long as it does not include any comments.
[[Page 104865]]
Include contact information each time you submit comments, data,
documents, and other information to DOE. If you submit via postal mail
or hand delivery/courier, please provide all items on a CD, if
feasible, in which case it is not necessary to submit printed copies.
No telefacsimiles (``faxes'') will be accepted.
Comments, data, and other information submitted to DOE
electronically should be provided in PDF (preferred), Microsoft Word or
Excel, WordPerfect, or text (ASCII) file format. Provide documents that
are not secured, written in English, and that are free of any defects
or viruses. Documents should not contain special characters or any form
of encryption and, if possible, they should carry the electronic
signature of the author.
Campaign form letters. Please submit campaign form letters by the
originating organization in batches of between 50 to 500 form letters
per PDF or as one form letter with a list of supporters' names compiled
into one or more PDFs. This reduces comment processing and posting
time.
Confidential Business Information. Pursuant to 10 CFR 1004.11, any
person submitting information that he or she believes to be
confidential and exempt by law from public disclosure should submit via
email two well-marked copies: one copy of the document marked
``confidential'' including all the information believed to be
confidential, and one copy of the document marked ``non-confidential''
with the information believed to be confidential deleted. DOE will make
its own determination about the confidential status of the information
and treat it according to its determination.
It is DOE's policy that all comments may be included in the public
docket, without change and as received, including any personal
information provided in the comments (except information deemed to be
exempt from public disclosure).
V. Approval of the Office of the Secretary
The Secretary of Energy has approved publication of this
notification of tentative determination and request for comment.
Signing Authority
This document of the Department of Energy was signed on December
13, 2024, by Jeffrey Marootian, Principal Deputy Assistant Secretary
for Energy Efficiency and Renewable Energy, pursuant to delegated
authority from the Secretary of Energy. That document with the original
signature and date is maintained by DOE. For administrative purposes
only, and in compliance with requirements of the Office of the Federal
Register, the undersigned DOE Federal Register Liaison Officer has been
authorized to sign and submit the document in electronic format for
publication, as an official document of the Department of Energy. This
administrative process in no way alters the legal effect of this
document upon publication in the Federal Register.
Signed in Washington, DC, on December 16, 2024.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.
[FR Doc. 2024-30274 Filed 12-23-24; 8:45 am]
BILLING CODE 6450-01-P