[Federal Register Volume 87, Number 134 (Thursday, July 14, 2022)]
[Proposed Rules]
[Pages 42270-42295]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-14687]
[[Page 42269]]
Vol. 87
Thursday,
No. 134
July 14, 2022
Part II
Department of Energy
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10 CFR Part 430
Energy Conservation Program: Test Procedure for Consumer Water Heaters
and Residential-Duty Commercial Water Heaters; Proposed Rule
Federal Register / Vol. 87 , No. 134 / Thursday, July 14, 2022 /
Proposed Rules
[[Page 42270]]
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DEPARTMENT OF ENERGY
10 CFR Part 430
[EERE-2019-BT-TP-0032]
RIN 1904-AE77
Energy Conservation Program: Test Procedure for Consumer Water
Heaters and Residential-Duty Commercial Water Heaters
AGENCY: Office of Energy Efficiency and Renewable Energy, Department of
Energy.
ACTION: Supplemental notice of proposed rulemaking and request for
comment.
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SUMMARY: The U.S. Department of Energy (``DOE'') is publishing this
supplemental notice of proposed rulemaking (``SNOPR'') to amend the
test procedure for consumer water heaters and residential-duty
commercial water heaters. This SNOPR updates the proposals presented in
a notice of proposed rulemaking published in the Federal Register on
January 11, 2022. In this SNOPR, DOE proposes additional amendments
that would provide additional specificity regarding flow rate
tolerances for water heaters with a rated storage volume of less than 2
gallons; allow for voluntary representations at certain additionally
specified test conditions for heat pump water heaters; revise the
proposed specifications regarding separate storage tank requirements
for certain types of water heaters; provide instructions for testing
certain water heaters that store water at a temperature higher than the
delivery setpoint; establish a metric and method for determining the
effective storage volume of certain storage-type water heaters; and
update the proposed methodology for estimating the internal tank
temperature of water heaters which cannot be directly measured. DOE is
seeking comment from interested parties on these proposals.
DATES: DOE will accept comments, data, and information regarding this
SNOPR no later than August 4, 2022. See section IV, ``Public
Participation,'' for details.
ADDRESSES: Comments: Interested persons are encouraged to submit
comments using the Federal eRulemaking Portal at www.regulations.gov,
under docket number EERE-2019-BT-TP-0032. Follow the instructions for
submitting comments. Alternatively, interested persons may submit
comments, identified by docket number EERE-2019-BT-TP-0032 and/or RIN
1904-AE77, by any of the following methods:
(1) Email: [email protected]. Include docket number
EERE-2019-BT-TP-0032 in the subject line of the message.
(2) Postal Mail: 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.
(3) Hand Delivery/Courier: Appliance and Equipment Standards
Program, U.S. Department of Energy, Building Technologies Office, 950
L'Enfant Plaza SW, 6th Floor, Washington, DC 20024. Telephone: (202)
287-1445. If possible, please submit all items on a 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 (Public Participation).
Docket: The docket for this activity, which includes Federal
Register notices, public meeting/webinar attendee lists and
transcripts, 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?D=EERE-2019-BT-TP-0032. The docket web page contains
instructions on how to access all documents, including public comments,
in the docket. See section V (Public Participation) 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: (202) 597-6737. Email:
[email protected].
Mr. Eric Stas, U.S. Department of Energy, Office of the General
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121.
Telephone: (202) 586-5827. Email: [email protected].
For further information on how to submit a comment, 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. Authority and Background
A. Authority
B. Background
II. Synopsis of Proposed Amendments
III. Discussion
A. Flow Rate Tolerance Requirements
B. Optional Test Conditions
C. Storage Tank Over-Heating
1. Testing in Over-Heated Mode
2. Effective Storage Volume
D. Separate Storage Tank Requirements
E. Method for Determining Internal Tank Temperature for Certain
Water Heaters
IV. Procedural Issues and Regulatory Review
A. Review Under Executive Orders 12866 and 13563
B. Review Under the Regulatory Flexibility Act
C. Review Under the Paperwork Reduction Act of 1995
D. Review Under the National Environmental Policy Act of 1969
E. Review Under Executive Order 13132
F. Review Under Executive Order 12988
G. Review Under the Unfunded Mandates Reform Act of 1995
H. Review Under the Treasury and General Government
Appropriations Act, 1999
I. Review Under Executive Order 12630
J. Review Under Treasury and General Government Appropriations
Act, 2001
K. Review Under Executive Order 13211
L. Review Under Section 32 of the Federal Energy Administration
Act of 1974
V. Public Participation
VI. Approval of the Office of the Secretary
I. Authority and Background
Consumer water heaters are included in the list of ``covered
products'' for which DOE is authorized to establish and amend energy
conservation standards and test procedures. (42 U.S.C. 6292(a)(4))
DOE's energy conservation standards and test procedures for consumer
water heaters are currently prescribed respectively at Title 10 of the
Code of Federal Regulations (``CFR''), part 430 section 32(d), and 10
CFR part 430, subpart B, appendix E (``appendix E''), Uniform Test
Method for Measuring the Energy Consumption of Water Heaters.
Residential-duty commercial water heaters, for which DOE is also
authorized to establish and amend energy conservation standards and
test procedures (42 U.S.C. 6311(1)(K)), must also be tested according
to appendix E. 10 CFR 431.106(b)(1) (See 42 U.S.C. 6295(e)(5)(H)).
DOE's energy conservation standards for residential-duty commercial
water heaters are currently prescribed at 10 CFR
[[Page 42271]]
431.110(b)(1). The following sections discuss DOE's authority to
establish and amend test procedures for consumer water heaters and
residential-duty commercial water heaters, as well as relevant
background information regarding DOE's consideration of test procedures
for these products and 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. 6291-
6317, as codified) Title III, Part B \2\ of EPCA established the Energy
Conservation Program for Consumer Products Other Than Automobiles,
which sets forth a variety of provisions designed to improve energy
efficiency. (42 U.S.C. 6291-6309, as codified) These products include
consumer water heaters, one of the subjects of this document. (42
U.S.C. 6292(a)(4)) Title III, Part C \3\ of EPCA, added by Public Law
95-619, Title IV, section 441(a), established the Energy Conservation
Program for Certain Industrial Equipment, which again sets forth a
variety of provisions designed to improve energy efficiency. (42 U.S.C.
6311-6317, as codified) This equipment includes residential-duty
commercial water heaters, which are also the subject of this document.
(42 U.S.C. 6311(1)(k))
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\1\ All references to EPCA in this document refer to the statute
as amended through Energy Act of 2020, Pub. L. 116-260 (Dec. 27,
2020), which reflect the last statutory amendments that impact Parts
A and A-1 of EPCA.
\2\ For editorial reasons, upon codification in the U.S. Code,
Part B was redesignated Part A.
\3\ For editorial reasons, upon codification in the U.S. Code,
Part C was redesignated Part A-1.
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The energy conservation program under EPCA consists essentially of
four parts: (1) testing, (2) labeling, (3) Federal energy conservation
standards, and (4) certification and enforcement procedures. Relevant
provisions of EPCA specifically include definitions (42 U.S.C. 6291; 42
U.S.C. 6311), test procedures (42 U.S.C. 6293; 42 U.S.C. 6314),
labeling provisions (42 U.S.C. 6294; 42 U.S.C. 6315), energy
conservation standards (42 U.S.C. 6295; 42 U.S.C. 6313), and the
authority to require information and reports from manufacturers (42
U.S.C. 6296; 42 U.S.C. 6316).
The Federal testing requirements consist of test procedures that
manufacturers of covered products and commercial equipment must use as
the basis for: (1) certifying to DOE that their products/equipment
comply with the applicable energy conservation standards adopted
pursuant to EPCA (42 U.S.C. 6295(s); 42 U.S.C. 6296; 42 U.S.C. 6316(a)-
(b)), and (2) making other representations about the efficiency of
those consumer products (42 U.S.C. 6293(c); 42 U.S.C. 6314(d)).
Similarly, DOE must use these test procedures to determine whether the
products comply with relevant standards promulgated under EPCA. (42
U.S.C. 6295(s))
Federal energy efficiency requirements for covered products and
equipment established under EPCA generally supersede State laws and
regulations concerning energy conservation testing, labeling, and
standards. (42 U.S.C. 6297(a)-(c); 42 U.S.C. 6316(a)-(b)) DOE may,
however, grant waivers of Federal preemption in limited circumstances
for particular State laws or regulations, in accordance with the
procedures and other provisions of EPCA. (42 U.S.C. 6297(d); 42 U.S.C.
6316(a); 42 U.S.C. 6316(b)(2)(D))
Under 42 U.S.C. 6293, EPCA sets forth the criteria and procedures
DOE must follow when prescribing or amending test procedures for
covered products. Specifically, EPCA requires that any test procedures
prescribed or amended shall be reasonably designed to produce test
results which measure energy efficiency, energy use, or estimated
annual operating cost of a covered product during a representative
average use cycle or period of use and not be unduly burdensome to
conduct. (42 U.S.C. 6293(b)(3)) Under 42 U.S.C. 6314, the statute sets
forth the criteria and procedures DOE must follow when prescribing or
amending test procedures for covered equipment, reciting similar
requirements at 42 U.S.C. 6314(a)(2).
In addition, the Energy Independence and Security Act of 2007 (EISA
2007) amended EPCA to require that DOE amend its test procedures for
all covered consumer products to integrate measures of standby mode and
off mode energy consumption. (42 U.S.C. 6295(gg)(2)(A)) Standby mode
and off mode energy consumption must be incorporated into the overall
energy efficiency, energy consumption, or other energy descriptor for
each covered product unless the current test procedures already account
for and incorporate standby and off mode energy consumption or such
integration is technically infeasible. (42 U.S.C. 6295(gg)(2)(A)(i)-
(ii)) If an integrated test procedure is technically infeasible, DOE
must prescribe a separate standby mode and off mode energy use test
procedure for the covered product, if technically feasible. (42 U.S.C.
6295(gg)(2)(A)(ii)) Any such amendment must consider the most current
versions of the International Electrotechnical Commission (IEC)
Standard 62301 \4\ and IEC Standard 62087,\5\ as applicable. (42 U.S.C.
6295(gg)(2)(A))
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\4\ IEC 62301, Household electrical appliances--Measurement of
standby power (Edition 2.0, 2011-01).
\5\ IEC 62087, Methods of measurement for the power consumption
of audio, video, and related equipment (Edition 3.0, 2011-04).
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The American Energy Manufacturing Technical Corrections Act
(AEMTCA), Pub. L. 112-210, further amended EPCA to require that DOE
establish a uniform efficiency descriptor and accompanying test methods
to replace the energy factor (EF) metric for covered consumer water
heaters and the thermal efficiency (TE) and standby loss (SL) metrics
for commercial water-heating equipment \6\ within one year of the
enactment of AEMTCA. (42 U.S.C. 6295(e)(5)(B)-(C)) The uniform
efficiency descriptor and accompanying test method were required to
apply, to the maximum extent practicable, to all water-heating
technologies in use at the time and to future water-heating
technologies, but could exclude specific categories of covered water
heaters that do not have residential uses, can be clearly described,
and are effectively rated using the TE and SL descriptors. (42 U.S.C.
6295(e)(5)(F) and (H)) In addition, beginning one year after the date
of publication of DOE's final rule establishing the uniform descriptor,
the efficiency standards for covered water heaters were required to be
denominated according to the uniform efficiency descriptor established
in the final rule (42 U.S.C. 6295(e)(5)(D)); and for affected covered
water heaters tested prior to the effective date of the test procedure
final rule, DOE was required to develop a mathematical factor for
converting the measurement of their energy efficiency from the EF, TE,
and SL metrics to the new uniform energy
[[Page 42272]]
descriptor. (42 U.S.C. 6295(e)(5)(E)(i)-(ii))
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\6\ The initial thermal efficiency and standby loss test
procedures for commercial water heating equipment (including
residential-duty commercial water heaters) were added to EPCA by the
Energy Policy Act of 1992 (EPACT 1992), Public Law 102-486, and
corresponded to those referenced in the ASHRAE and Illuminating
Engineering Society of North America (IESNA) Standard 90.1-1989
(i.e., ASHRAE Standard 90.1-1989). (42 U.S.C. 6314(a)(4)(A)) DOE
subsequently updated the commercial water heating equipment test
procedures on two separate occasions--once in a direct final rule
published on October 21, 2004, and again in a final rule published
on May 16, 2012. These rules incorporated by reference certain
sections of the latest versions of American National Standards
Institute (ANSI) Standard Z21.10.3, Gas Water Heaters, Volume III,
Storage Water Heaters with Input Ratings Above 75,000 Btu Per Hour,
Circulating and Instantaneous, available at the time (i.e., ANSI
Z21.10.3-1998 and ANSI Z21.10.3-2011, respectively). 69 FR 61974,
61983 (Oct. 21, 2004) and 77 FR 28928, 28996 (May 16, 2012).
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EPCA also requires that, at least once every 7 years, DOE evaluate
test procedures for each type of covered product or equipment,
including consumer water heaters and residential-duty commercial water
heaters, 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 (or, additionally, period of use for consumer products). (42
U.S.C. 6293(b)(1)(A); 42 U.S.C. 6314(a)(1)(A))
If the Secretary determines, on her own behalf or in response to a
petition by any interested person, that a test procedure should be
prescribed or amended, the Secretary shall promptly publish in the
Federal Register proposed test procedures and afford interested persons
an opportunity to present oral and written data, views, and arguments
with respect to such procedures. (42 U.S.C. 6293(b)(2); 42 U.S.C.
6314(b)) The comment period on a proposed rule to amend a test
procedure shall be at least 60 days \7\ and may not exceed 270 days.
(42 U.S.C. 6293(b)(2)) In prescribing or amending a test procedure, the
Secretary shall take into account such information as the Secretary
determines relevant to such procedure, including technological
developments relating to energy use or energy efficiency of the type
(or class) of covered products involved. (42 U.S.C. 6293(b)(2)) If DOE
determines that test procedure revisions are not appropriate, DOE must
publish in the Federal Register its determination not to amend the test
procedures. (42 U.S.C. 6293(b)(1)(A)(ii) and 42 U.S.C.
6314(a)(1)(A)(ii))
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\7\ For covered, equipment, 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))
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DOE is conducting this rulemaking in satisfaction of the 7-year-
lookback review requirement specified in EPCA. (42 U.S.C. 6293(b)(1)(A)
and 42 U.S.C. 6314(a)(1)(A))
B. Background
On January 11, 2022, DOE published in the Federal Register a notice
of proposed rulemaking (``January 2022 NOPR'') in which the Department
proposed to update appendix E, and related sections of the CFR, as
follows:
(1) Incorporate by reference current versions of industry
standards referenced by the current and proposed DOE test
procedures: American Society of Heating, Refrigerating, and Air-
Conditioning Engineers (ASHRAE) Standard 41.1,\8\ ASHRAE Standard
41.6,\9\ the pending update to ASHRAE Standard 118.2 \10\
(contingent on it being substantively the same as the draft which
was under review), ASTM International (ASTM) D2156,\11\ and ASTM
E97.\12\
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\8\ ASHRAE Standard 41.1-2020, ``Standard Methods for
Temperature Measurement,'' approved June 30, 2020.
\9\ ASHRAE Standard 41.6-2014, ``Standard Method for Humidity
Measurement,'' ANSI approved July 3, 2014.
\10\ ASHRAE Standard 118.2-2022, ``Method of Testing for Rating
Residential Water Heaters and Residential-Duty Commercial Water
Heaters,'' ANSI approved March 1, 2022.
\11\ ASTM Standard D2156-09 (RA 2018), ``Standard Test Method
for Smoke Density in Flue Gases from Burning Distillate Fuels,''
reapproved October 1, 2018.
\12\ ASTM Standard E97-1987 (W 1991), ``Standard Test Methods
for Directional Reflectance Factor, 45-Deg 0-Deg, of Opaque
Specimens by Broad-Band Filter Reflectometry,'' approved January
1987, withdrawn 1991. Referenced by ASTM Standard D2156-09 (RA
2018).
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(2) Add definitions for ``circulating water heater,'' ``low
temperature water heater,'' and ``tabletop water heater.''
(3) Specify how a mixing valve should be installed when the
water heater is designed to operate with one.
(4) Modify flow rate requirements during the FHR test for water
heaters with a rated storage volume less than 20 gallons.
(5) Modify timing of the first measurement in each draw of the
24-hour simulated-use test.
(6) Clarify the determination of the first recovery period.
(7) Clarify the mass of water to be used to calculate recovery
efficiency.
(8) Modify the terminology throughout appendix E to explicitly
state ``non-flow activated'' and ``flow-activated'' water heater,
where appropriate.
(9) Clarify the descriptions of defined measured values for the
standby period measurements.
(10) Modify the test condition specifications and tolerances,
including electric supply voltage tolerance, ambient temperature,
ambient dry bulb temperature, ambient relative humidity, standard
temperature and pressure definition, gas supply pressure, and
manifold pressure.
(11) Add provisions to address gas-fired water heaters with
measured fuel input rates that deviate from the certified input
rate.
(12) Clarify provisions for calculating the volume or mass
delivered.
(13) Add specifications for testing for the newly defined ``low
temperature water heaters.''
(14) Clarify testing requirements for the heat pump part of a
split-system heat pump water heater.
(15) Define the use of a separate unfired hot water storage tank
for testing water heaters designed to operate with a separately sold
hot water storage tank.
(16) Clarify that any connection to an external network or
control be disconnected during testing.
(17) Add procedures for estimating internal stored water
temperature for water heater designs in which the internal tank
temperature cannot be directly measured.
(18) Modify the provisions for untested water heater basic
models within 10 CFR 429.70(g) to include electric instantaneous
water heaters.
87 FR 1554, 1558.\13\
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\13\ A correction was published in the Federal Register on
January 19, 2022, to properly reflect the date of the public meeting
to discuss the test procedure NOPR. 87 FR 2731.
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DOE received written comments in response to the January 2022 NOPR
pertinent to the issues discussed in this SNOPR from the interested
parties listed in Table III.1 of this document. In this SNOPR, DOE is
maintaining the proposals from the January 2022 NOPR with modifications
as discussed in this SNOPR and will address comments on any remaining
topics in a future test procedure final rule.
Table III.1--List of Commenters With Written Submissions in Response to the January 2022 NOPR Relevant to Topics
Covered in This SNOPR
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Comment No. in
Commenter(s) Reference in this SNOPR Docket Commenter type
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A.O. Smith Corporation............... A.O. Smith...................... 37 Manufacturer.
Air Conditioning, Heating, and AHRI............................ 40 Trade Association.
Refrigeration Institute.
Appliance Standards Awareness Joint Advocates................. 34 Efficiency Advocacy
Project, American Council for and Organizations.
Energy-Efficient Economy, National
Consumer Law Center.
Bradford White Corporation........... BWC............................. 33 Manufacturer.
[[Page 42273]]
Pacific Gas and Electric Company, San CA IOUs......................... 36 Utilities.
Diego Gas and Electric, and Southern
California Edison; collectively, the
California Investor-Owned Utilities.
Jim Lutz............................. Lutz............................ 35 Individual.
New York State Energy Research and NYSERDA......................... 32 State Agency.
Development Authority.
Northwest Energy Efficiency Alliance. NEEA............................ 30 Efficiency Advocacy
Organization.
Rheem Manufacturing Company.......... Rheem........................... 31 Manufacturer.
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As discussed, this SNOPR addresses only those comments related to
the proposals laid out in this document; all other relevant comments
will be addressed in a future stage of the rulemaking. A parenthetical
reference at the end of a comment quotation or paraphrase provides the
location of the item in the public record.\14\
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\14\ The parenthetical reference provides a reference for
information located in the docket of DOE's rulemaking to develop
test procedures for consumer water heaters and residential-duty
commercial water heaters. (Docket No. EERE-2019-BT-TP-0032, which is
maintained at www.regulations.gov). The references are arranged as
follows: (commenter name, comment docket ID number, page of that
document).
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II. Synopsis of Proposed Amendments
DOE's proposed actions in this SNOPR are summarized in Table II.1
of this document as compared to the January 2022 TP NOPR. Reasons for
each proposed change are also explained in summary.
Table II.1--Summary of Proposed Changes Addressed in This SNOPR
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January 2022 NOPR proposal SNOPR Attribution
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Proposed that flow rates for Additionally Improve
all water heaters with proposes that for repeatability and
rated storage volume less water heaters with reproducibility of
than 2 gallons must be rated storage the test procedure.
maintained within a volume less than 2
tolerance of 0.25 gallons per Max GPM of less
minute. than 1 gallon per
minute, the flow
rate tolerance
shall be 25 percent of
the rated Max GPM.
Did not propose to allow for Proposes to allow Harmonize with
optional efficiency for optional current industry
representations at efficiency testing practices.
alternative test conditions representations at
for heat pump water heaters. alternative test
conditions for heat
pump water heaters.
Did not propose a definition Proposes a Provide additional
for split-system heat pump definition for clarity to
water heaters. split-system heat application of test
pump water heaters conditions for heat
to distinguish pump water heaters.
these from heat
pump-only water
heaters.
Proposed to define Proposes that gas- Improve
``circulating water fired circulating representativeness
heaters'' and require that water heaters be of test methodology
such products be tested tested using a for circulating
using an 80 gallon (1 gallon) unfired hot storage volume
water storage tank between 80 and 120
(``UFHWST'') that meets the gallons and an R-
energy conservation value exactly at
standards for an unfired the minimum R-value
hot water storage tank at required at 10 CFR
10 CFR 431110(a). 431110(a), and that
heat pump
circulating water
heaters be tested
using a 40-gallon
electric resistance
water heater at the
minimum UEF
standard required
at 10 CFR 43032(d).
Proposed to continue to Proposes that water Improve
specify that water heaters heaters (with the representativeness
with multiple modes of exception of demand- of test methodology
operation be tested in the response water for water heaters
``default'' or other heaters) with user- with user-
similarly named mode as selectable modes to selectable
currently required by ``over-heat'' the overheated storage
Appendix E. water stored in the tank modes.
tank to increase
effective capacity
be tested at the
highest internal
tank temperature
that can be
achieved while
maintaining the
outlet water
temperature at 125
5
[deg]F If no such
over-heated mode
exists, the unit is
to be tested in a
default mode.
Did not include a definition Proposes to define Clarify the test
for ``demand-response water ``demand-response methods for
heater''. water heater'' products with
based on the ENERGY demand-response
STAR specification utility,
v5.0 definition for
connected water
heating product,
with the additional
requirement that
demand-response
water heaters
cannot over-heat as
a result of user-
initiated operation.
Did not include any proposal Proposes to Adopt a metric to
related to the effective establish a metric provide additional
storage volume of storage- and method for information to
type water heaters. determining the consumers on
effective storage product
volume of storage- performance.
type water heaters.
[[Page 42274]]
Proposed a method of Proposes a method of Adopt a test method
determining the internal determining the for certain water
storage tank temperature internal storage heaters which
(for water heaters with tank temperature cannot be directly
rated storage volume using draws at the measured.
greater than or equal to 2 beginning and end
gallons which cannot be of the 24-hour
directly measured) based on simulated use test.
an assumption that the mean
tank temperature is
approximately the average
of the inlet water
temperature and the outlet
water temperature.
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III. Discussion
A. Flow Rate Tolerance Requirements
In this SNOPR, DOE proposes to supplement the proposal presented in
the January 2022 NOPR regarding specified flow rate tolerances for
water heaters with a rated storage volume under 2 gallons.
Section 5.4 of appendix E provides instructions for conducting the
24-hour simulated-use test for the determination of the uniform energy
factor (``UEF''). Section 5.4.1 of appendix E specifies directions for
determination of the draw pattern of the water heater under test;
section 5.4.2 of appendix E specifies the test sequence for water
heaters with rated storage volume greater than or equal to 2 gallons;
and section 5.4.3 of appendix E specifies the test sequence for water
heaters with rated storage volume less than 2 gallons. These test
sequences specify the timings of each water draw during the 24-hour
simulated-use test, the flow rates at which the draws must occur, and
condition tolerances for these draws.
In particular, section 5.4.2 of appendix E, Test Sequence for Water
Heaters with Rated Storage Volumes Greater Than or Equal to 2 Gallons,
provides that all draws during the 24-hour simulated-use test must be
made at the flow rates specified in the applicable draw pattern table
in section 5.5 of this appendix, within a tolerance of 0.25
gallons per minute (0.9 liters per minute). Section 5.4.3
of appendix E, Test Sequence for Water Heaters with Rated Storage
Volume Less Than 2 Gallons, currently does not provide explicit
instruction for the tolerance on the flow rate.
Within the proposed amendments to the regulatory text provided in
the January 2022 NOPR, DOE included a proposed amendment to section
5.4.3 of appendix E to specify that flow rates for water heaters with
rated storage volume less than 2 gallons must be maintained within a
tolerance of 0.25 gallons per minute. 87 FR 1554, 1603
(Jan. 11, 2022). The preamble to the January 2022 NOPR did not include
discussion of this topic, nor did DOE specifically request for comment
on this topic.
Adopting these proposed tolerances at section 5.4.3 of appendix E
would ensure repeatability and reproducibility of test results for
water heaters with rated storage volume less than 2 gallons. Most water
heaters with storage volume less than 2 gallons are flow-activated
devices, meaning that burner or heating element activation is
controlled based on sensing the flow rate when hot water is called for.
As such, significant variations in the flow rate from test to test
could affect the measured efficiency of these products.
In this SNOPR, DOE is updating its proposal to include additional
specificity for water heaters with flow rates less than 1 gallon per
minute. In section III.C.6 of the January 2022 NOPR, DOE discussed
water heaters on the market with maximum gallon per minute (``Max
GPM'') delivery capacities below 1 gallon per minute. 87 FR 1554, 1582
(Jan. 11, 2022). For these models, the ``very small'' draw pattern for
the 24-hour simulated-use test would be applicable. Section 5.5 of
appendix E states that, for the very small draw pattern, if the water
heater has a Max GPM rating less than 1 gallon per minute (3.8 L/min),
then all draws shall be implemented at a flow rate equal to the rated
Max GPM. For products with Max GPM less than 1 gallon per minute, an
allowable flow rate tolerance of 0.25 gallon per minute
would represent a significant variation of flow rate in comparison to
the rated Max GPM. For example, for a water heater with Max GPM of 0.5
gallon per minute, a tolerance of 0.25 gallon per minute
would represent a 50 percent difference from the rated flow
rate. Furthermore, in its review of publicly certified water heater
ratings,\15\ DOE identified models with rated Max GPM delivery
capacities as low as 0.20 gallon per minute. For such products, a flow
rate tolerance of 0.25 gallon per minute would allow for
either flow rates close to zero or flow rates that are more than twice
the rated Max GPM; either case would lead to results unrepresentative
of actual product usage. Therefore, in this SNOPR, DOE proposes further
amending section 5.4.3 of appendix E to specify that for water heaters
with a rated Max GPM of less than 1 gallon per minute, the flow rate
tolerance shall be 25 percent of the rated Max GPM. For
such products, a flow rate tolerance of 25 percent would
represent the same level of variation (on a percentage basis) as for
products rated at 1.0 gallon per minute and subject to a tolerance of
0.25 gallon per minute.
---------------------------------------------------------------------------
\15\ DOE consulted its public Certification Compliance Database
(Available at: www.regulations.doe.gov/certification-data/CCMS-4-Water_Heaters.html#q=Product_Group_s%3A%22Water%20Heaters%22).
---------------------------------------------------------------------------
By way of example, under the proposal, for a water heater with a
rated Max GPM flow rate of 0.5 gallon per minute, the required
tolerance would be 0.125 gallon per minute. For a water
heater with a rated Max GPM flow rate of 0.20 gallon per minute, the
required tolerance would thus be 0.05 gallon per minute.
As discussed, EPCA requires that test procedures be reasonably
designed to produce test results which measure energy efficiency,
energy use, or estimated annual operating cost of a covered product
during a representative average use cycle or period of use and not be
unduly burdensome to conduct. (42 U.S.C. 6293(b)(3)) DOE expects that
laboratories may require high-precision water flow rate instrumentation
(e.g., Coriolis flow meters) in order to maintain the tolerances
discussed, in particular for water heaters with rated Max GPM flow
rates less than 1 gallon per minute. DOE is aware through its testing
activities that multiple third-party laboratories already use Coriolis
flow meters. In reviewing water heater test data previously collected,
DOE has observed third-party laboratories maintaining flow rate
condition tolerances as low as 0.05 gallon per minute. For
these reasons, DOE has initially determined that the proposed
tolerances would generally not require additional capital investments
for test
[[Page 42275]]
laboratories and, therefore, would not be unduly burdensome to conduct.
DOE also has tentatively determined that the proposed amendment
would not alter the measured efficiency of consumer water heaters and
residential-duty commercial water heaters, nor require retesting or
recertification solely as a result of DOE's adoption of the proposed
amendments to the test procedure, if made final. In the absence of an
explicit instruction for the flow rate tolerance applicable to water
heaters with rated storage volume under 2 gallons, DOE expects that
general industry best practice is to apply the flow rate tolerances
being proposed for section 5.4.3 of appendix E for water heaters with
rated storage volume less than 2 gallons (based on DOE's review of
third-party laboratory test data), such that this proposal is expected
to be consistent with current methodology.
With the addition of these proposed amendments to section 5.4.3 of
appendix E, DOE maintains the proposals set forth in the January 2022
NOPR.
DOE seeks comment on the proposed amendment to specify flow rate
tolerances for the 24-hour simulated use test for water heaters with
rated storage volume under 2 gallons, and in particular to specify the
tolerance as 25 percent for water heaters with a rated
maximum flow rate of less than 1 gallon per minute. DOE is particularly
interested in test data or information that would indicate the
technical feasibility of maintaining the tolerances proposed with
instrumentation that is used in general practice, as well as the
potential impacts on test burden.
B. Optional Test Conditions
Section 2.2 of appendix E specifies that the ambient air
temperature shall be maintained between 65.0 [deg]F and 70.0 [deg]F
(18.3 [deg]C and 21.1 [deg]C) on a continuous basis during the test.
Additionally, for heat pump water heaters, that test procedure
provision provides that the dry-bulb temperature shall be maintained at
67.5 [deg]F 1 [deg]F (19.7 [deg]C 0.6 [deg]C)
and that the relative humidity shall be maintained at 50 percent 2 percent throughout the test.\16\
---------------------------------------------------------------------------
\16\ DOE proposed amendments to the ambient air tolerance
requirements in the January 2022 NOPR. 87 FR 1554, 1577-1578 (Jan.
11, 2022).
---------------------------------------------------------------------------
In the January 2022 NOPR, DOE discussed comments previously
received on the April 2020 RFI suggesting that DOE explore the usage of
NEEA's Advanced Water Heating Specification for voluntary climate-
specific efficiency representations of heat pump water heaters. 87 FR
1554, 1580 (Jan. 11, 2022). In response to those comments, DOE stated
that it did not have data to indicate what conditions would be
representative for regional representations, and, thus, DOE tentatively
decided not to allow optional representations of additional efficiency
ratings at test conditions other than those found in the DOE test
procedure, such as those made in accordance with NEEA's Advanced Water
Heating Specification. Id.
In response to the January 2022 NOPR, DOE received additional
comments regarding optional representations that have led the
Department to reconsider its tentative decision not to allow optional
representations.
The CA IOUs stated that water heater installation practices vary
regionally, and that similar units installed in the same region can
experience different ambient conditions. The CA IOUs further stated
that the direct relationship between the diverse ambient conditions and
efficiency make it impossible to choose a single representative value
for ambient conditions for the consumer water heaters test procedure
that will yield useful energy consumption estimates for heat pump water
heaters. The CA IOUs asserted that in the case of a split-system heat
pump water heater, the condenser is almost always located in an
unconditioned space (e.g., outdoors), such that the ambient conditions
specified in the current DOE test procedure are not representative. The
CA IOUs recommended that DOE clarify whether manufacturers may provide
information on the performance of heat pump water heaters at ambient
temperatures other than 67.5 [deg]F 1 [deg]F. The CA IOUs
reiterated their recommendation to allow manufacturers to provide
representations for more than one ambient condition, stating that
allowing manufacturers to state performance under different conditions
would allow them to introduce heat pump water heater models optimized
for different applications, would help keep performance claims
consistent, and would help consumers select the most appropriate
products. (CA IOUs, No. 36 at p. 2)
The Joint Advocates stated that the value of having test data at
both colder and warmer conditions than those specified in the current
test procedure is that they would allow for calculating UEFs for any
climate regardless of whether the specific optional test conditions are
representative of any region. The Joint Advocates reiterated its
recommendation that DOE allow voluntary reporting of ratings at two
additional test conditions. The Joint Advocates asserted that allowing
optional reporting would help provide a better understanding of the
differences in heat pump water heater performance at various conditions
without increasing test burden for manufacturers who do not wish to
report these additional rating. (Joint Advocates, No. 34 at p. 1)
NYSERDA requested that DOE require heat pump water heater
performance data at a range of operating conditions. NYSERDA stated
that demonstrating performance at different ambient temperatures is a
commonly applied approach for heat pumps that serve HVAC loads, and
that similar treatment for heat pump water heaters is appropriate.
NYSERDA stated that in order for heat pump water heaters to provide
utility in all climates, including the colder temperatures in New York,
consumers and installers will need to understand the expected
performance at a range of operating conditions. NYSERDA encouraged DOE
to allow manufacturers to provide performance data at conditions
representative of where heat pump water heaters will be installed
throughout the country. NYSERDA specifically referenced NEEA's Advanced
Water Heating Specification as an example resource. (NYSERDA, No. 32 at
p. 3)
BWC stated that voluntary representations would potentially
increase burden and not increase representativeness for performance on
a national basis. BWC expressed its support for DOE's tentative
determination not to allow additional voluntary representations. (BWC,
No. 33 at p. 8)
After considering these comments, the Department once again notes
that EPCA requires that the DOE test procedure must be reasonably
designed to produce test results which measure energy efficiency during
a representative average use cycle or period of use. (42 U.S.C.
6293(b)(3)) While the test conditions in the current appendix E test
procedure must remain representative for the nation as a whole,
comments from interested parties have demonstrated that allowing
additional representations of efficiency at alternative ambient
conditions could provide consumers with additional information about
the expected performance of heat pump water heaters at conditions that
are representative of their specific installation circumstances. For
other types of covered products and equipment, DOE has adopted optional
metrics for voluntary representations where it was determined that the
primary efficiency metric would not be representative for certain
installation
[[Page 42276]]
conditions common for the product or equipment. For heat pump water
heaters, both the efficiency and the heating capacity of the product
are sensitive to the ambient conditions, and in general will be lower
at colder ambient temperatures and higher at warmer ambient
temperatures. For example, at lower ambient temperatures, the reduction
in heating capacity of the heat pump could result in back-up electric
resistance heating elements operating more frequently than at the
current DOE rating conditions. Differences in ambient conditions also
would affect integrated heat pump water heaters installed in
unconditioned spaces (e.g., garage or attic) and split-system heat pump
water heaters for which the heat pump components are located outdoors.
Depending on the installation location, the ambient conditions may vary
significantly from the conditions in the DOE test method, thereby
resulting in significantly different performance for such products. For
these reasons, in this SNOPR, DOE has tentatively determined to allow
for certain optional representations for additional ambient conditions,
as described further in the following paragraphs. DOE understands this
to be the intent in NYSERDA's request (however, NYSERDA's comment
discusses both a requirement for optional representations as well as an
allowance for optional representations). In response to BWC's concerns
regarding a potential increase in test burden, DOE proposes that any
testing at multiple ambient conditions would be optional, and DOE is
not proposing to require testing at the alternative ambient conditions.
In summary, DOE is proposing to define new metrics for optional
representations based primarily upon the test conditions provided in
NEEA's Advanced Water Heating Specification version 8.0 (``AWHS
v8.0'').
AWHS v8.0 was published by NEEA on March 1, 2022. Though early
editions of the AWHS focused primarily on providing more representative
performance metrics for heat pump water heaters in cold climates, the
latest editions are now more broadly focused on providing
representative performance metrics for heat pump water heaters across
all climates. Performance metrics in the AWHS are generally calculated
by measuring energy efficiency at multiple (two or more) ambient test
conditions, linearly interpolating between the test results, and
finally calculating an ambient temperature-weighted efficiency metric
using temperature bin data. The metric is a cold climate efficiency
(``CCE'') rating for integrated heat pump water heaters installed in
semi-conditioned (i.e., garage, basement) spaces and a seasonal
coefficient of performance (``SCOP'') for split-system heat pump water
heaters (where the heat pump is separated from the storage tank and
located outdoors).
NEEA maintains a Qualified Products List for heat pump water
heaters tested by manufacturers to the AWHS.\17\ As of February 2022,
the Qualified Products List contains CCE and SCOP representations from
seventeen heat pump water heater brands. As such, DOE notes that
manufacturers are already conducting testing per the AWHS and are
providing representations in accordance with its test methods. On this
basis, DOE has tentatively determined that adopting these test points
for voluntary testing and representations would not significantly
increase test burden for manufacturers who choose to provide these
ratings.
---------------------------------------------------------------------------
\17\ Available at: neea.org/img/documents/residential-unitary-HPWH-qualified-products-list.pdf (Last accessed on May 11, 2022).
---------------------------------------------------------------------------
In its review of the AWHS v8.0, DOE determined that there are
several differences between the test conditions provided and those
present in the appendix E test procedure. These differences include
ambient dry bulb temperatures, relative humidity conditions, and supply
water temperatures.
For integrated heat pump water heaters, AWHS v8.0 determines
CCE50 at ambient air conditions of 50 [deg]F dry bulb
temperature and 58 percent relative humidity, with a supply water
temperature of 50 [deg]F. An additional high-temperature condition of
95 [deg]F is also included but noted as optional in appendix B.1.1 to
AWHS v8.0. DOE is proposing adopt the low ambient air conditions (50
[deg]F and 58 percent relative humidity) and the high ambient air
conditions (95 [deg]F and 40 percent relative humidity) for optional
representations of integral heat pump water heaters. Additionally, AWHS
v8.0 modifies the inlet water temperatures at these ambient conditions
to reflect the corresponding mains water temperature expected at each
outdoor air temperature. At the 50 [deg]F ambient condition, the
specified inlet water temperature is also 50 [deg]F, and at the 95
[deg]F ambient condition, the specified inlet water temperature is 67
[deg]F. Although NEEA's AWHS v8.0 specifies these air and water
conditions only for integrated heat pump water heaters, DOE has
tentatively determined that these conditions could also be used for
heat pump-only water heaters, which typically do not have any outdoor
components.
For split-system heat pump water heaters, Appendix B.4 to AWHS v8.0
includes a note that the test method and calculation procedure is ``in
progress,'' and test conditions are labeled as ``draft testing
conditions.'' Appendix B.4 to AWHS v8.0 states, ``broadly, the method
will consist of calculating an efficiency for each test in Table 8
following the Uniform Energy Factor calculation method but substituting
in appropriate temperature conditions.'' For split-system heat pump
water heaters, AWHS v8.0 determines SCOP at ambient air conditions
ranging from 5 [deg]F dry bulb temperature and 30 percent relative
humidity to 95 [deg]F dry bulb temperature and 25 percent relative
humidity. Similar to the requirements in AWHS v8.0 for integrated heat
pump water heaters, the supply water temperature requirement varies
with ambient dry bulb temperature. The four standard test conditions
for SCOP in AWHS v8.0 are shown in Table 8 of AWHS v8.0 and in Table
III.1 in this SNOPR.
Table III.1--AWHS v8.0 Standard Test Conditions for Split-System Heat Pump Water Heaters
--------------------------------------------------------------------------------------------------------------------------------------------------------
Outdoor conditions Water Indoor conditions
-------------------------------------------------------------------------------------------------------------
Test point Outdoor dry- Outdoor wet-
bulb bulb Relative Supply water Dry-bulb Relative humidity
temperature temperature humidity (%) temperature temperature
--------------------------------------------------------------------------------------------------------------------------------------------------------
A......................................... 5 [deg]F 2 [deg]F 30 42 [deg]F 67.5 [deg]F Not specified.
B......................................... 34 [deg]F 31 [deg]F 72 47 [deg]F
[[Page 42277]]
C......................................... 68 [deg]F 57 [deg]F 50 58 [deg]F
D......................................... 95 [deg]F 69 [deg]F 25 67 [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
Test point C in AWHS v8.0 most closely resembles the current test
condition in appendix E. In this SNOPR, DOE is proposing to adopt the
three additional outdoor air conditions (A, B, and D in AWHS v8.0) for
optional representations of split-system heat pump water heaters. Where
indoor relative humidity is not currently specified in AWHS v8.0 for
split-system heat pump water heaters, DOE is proposing to use the 50-
percent relative humidity requirement from the current appendix E test
procedure in order to maintain the consistency and comparability of
results. Tolerances on these conditions would be the same as those
required for the standard UEF test conditions.
DOE proposes to adopt the optional test conditions as stand-alone
metrics in sections 2.8 and 5.6 of appendix E. DOE proposes to adopt a
new metric, EX (where ``X'' represents the air temperature
under which the test was conducted if not 67.5 [deg]F), at sections
1.16 and 6.5 of appendix E for optional representations only. The
metric EX would represent the result of a test done in
accordance with the UEF test procedure but at a different set of
ambient test conditions. With the exception of the different
temperature (both air and water) and humidity conditions, all other
aspects of the test procedure would remain identical to those used to
determine the regulated metric, UEF. The draw pattern used to determine
EX would be the same draw pattern used to determine UEF. The
proposed optional test conditions for heat pump water heaters are shown
in Table III.2.
Table III.2--Proposed Optional Test Conditions for Heat Pump Water Heaters
--------------------------------------------------------------------------------------------------------------------------------------------------------
Outdoor air conditions Indoor air conditions
---------------------------------------------------------------- Supply water
Heat pump type Metric Dry-bulb Relative Dry-bulb Relative temperature
temperature humidity (%) temperature humidity (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Split-System............................................ E5 5.0 [deg]F 30 67.5 [deg]F 50 42.0 [deg]F
E34 34.0 [deg]F 72 47.0 [deg]F
E95 95.0 [deg]F 25 67.0 [deg]F
Integrated or Heat Pump-Only............................ E50 N/A N/A 50.0 [deg]F 58 50.0 [deg]F
E95 N/A N/A 95.0 [deg]F 40 67.0 [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
DOE seeks information and comments on its proposal to allow
optional representations of EX in the appendix E test
procedure to indicate efficiency at different inlet air and water
conditions. DOE also welcomes feedback on its proposal to use the same
temperature measurement tolerances for optional Ex
conditions and the required UEF condition. DOE is interested in data
which can be used to determine the range of indoor ambient air
conditions typical in semi-conditioned spaces in different geographical
regions in the United States, and how these conditions typically
correlate to outdoor air conditions. DOE is also interested in data
which may be used to correlate consumer hot water usage patterns with
different seasonal conditions.
In order to avoid any potential confusion between heat pump-only
water heaters and split-system water heaters, DOE is also proposing to
define ``split-system heat pump water heater'' in section 1.14 of
appendix E. Specifically, DOE proposes to adopt the definition in AWHS
v8.0 with minor modifications:
Split-system heat pump water heater means a heat pump-type water
heater with an indoor storage tank and outdoor heat pump component.
DOE welcomes comment on its proposed definition of ``split-system
heat pump water heater.''
DOE has tentatively determined that this proposal would not lead to
additional testing costs or burden for manufacturers or test labs
because these optional metrics would remain voluntary for
representations.
C. Storage Tank Over-Heating
As discussed in the January 2022 NOPR, DOE proposed amendments
pertaining to water heaters that are designed to, or have operational
modes that, raise the temperature of the stored water significantly
above the outlet water temperature requirements specified in section
2.4 of appendix E. 87 FR 1554, 1580 (Jan. 11, 2022). These water
heaters are meant to be used with a mixing valve (which may or may not
be provided with, or be built into, the unit) to temper the outlet
water to a typical outlet water temperature. Generally, raising the
temperature of the water in the storage tank significantly above the
target output temperature (i.e., ``over-heating'' the water) would
effectively increase the amount of hot water that a given size water
heater can deliver (e.g., a 50-gallon water heater with an over-heated
storage tank temperature could provide the same amount of hot water as
an 80-gallon water heater with a more typical storage tank
temperature). An FHR test performed at an over-heated storage tank
temperature would result in a higher FHR than a test performed at a
lower, more conventional storage tank temperature. The installation
instructions in section 4 of appendix E do not address when a separate
mixing valve should be installed, and the operational mode selection
instructions in section 5.1 of appendix E do not specifically address
when the water heater has an operational mode that can over-heat the
water in the storage tank.
[[Page 42278]]
However, section 5.1 of appendix E requires that the water heater be
tested in its default mode, and where a default mode is not specified,
to test the unit in all modes and rate the unit using the results of
the most energy-intensive mode. Id.
For this type of water heater, DOE proposed in the January 2022
NOPR to add instructions for the installation of a mixing valve similar
to what is published in section 4.1 of the ENERGY STAR Connected Test
Method.\18\ 87 FR 1554, 1580 (Jan. 11, 2022).
---------------------------------------------------------------------------
\18\ The ENERGY STAR program published a Test Method to Validate
Demand Response for connected residential water heaters on April 5,
2021 (the ``ENERGY STAR Connected Test Method''). Section 4.1 of the
ENERGY STAR Connected Test Method addresses the test set-up in which
a separate mixing valve is required. The Energy Star Test Method to
Validate Demand Response for connected residential water heaters is
available at: www.energystar.gov/sites/default/files/ENERGY%20STAR%20Connected%20Residential%20Water%20Heaters%20Test%20Method%20to%20Validate%20Demand%20Response_0.pdf (Last accessed May
19, 2022).
---------------------------------------------------------------------------
In response to the January 2022 NOPR, several commenters requested
that DOE consider further amendments to the appendix E test procedure
to provide more representative efficiency results for such storage-type
water heaters that ``over-heat'' the stored water beyond the delivery
temperature. These comments are summarized and responded to in the
paragraphs that follow. In consideration of these comments, DOE is
proposing additional testing requirements to further address water
heaters that have an operational mode (or modes) that over-heat the
stored water.
NYSERDA commented that DOE should ensure that all test procedure
requirements surrounding FHR enable comparison between products and
accurately reflect the in-field performance of water heaters, including
those which may augment capacity through the use of a mixing valve or
other approaches. (NYSERDA, No. 32 at p. 4)
NEEA commented that it supports DOE's proposal to specify
instructions for the installation of a mixing valve, stating that the
proposal would improve repeatability and comparability of test results
by providing clarity on the pipe, valve, and measurement locations.
(NEEA, No. 30 at p. 2) The commenter further asserted that ensuring
that inlet temperature is measured before supplying cold water to the
mixing valve and that outlet temperature is measured after heating and
mixing would produce the most representative and repeatable test
results. (Id.) NEEA also recommended that DOE consider ways to account
for the increased effective capacity enabled by a mixing valve (either
separate or integrated). (Id.) According to NEEA, products that store
water at a higher temperature in a mode other than default would have
an increased effective capacity and lower UEF in this high temperature
mode. (Id.) NEEA encouraged DOE to consider ways to account for the
increased effective capacity for products with integrated mixing valves
and those designed to be used with a mixing valve. (Id.)
The Joint Advocates expressed support for DOE's proposal to include
instructions for the installation of a mixing valve and encouraged DOE
to amend the test procedure to capture the associated increase in
effective hot water storage volume for water heaters designed to be
used with a mixing valve. (Joint Advocates, No. 34 at pp. 1-2) The
Joint Advocates stated that raising the temperature of the stored water
above the outlet water temperature requirements essentially increases
the amount of hot water delivered without increasing the size of the
water heater, and that this is not reflected in the test procedure or
standards because water heater ratings are calculated based on the
rated storage volume, not the actual effective volume. (Id.) Therefore,
the Joint Advocates recommended that DOE amend the test procedure to
account for the additional effective storage volume enabled by a higher
operating temperature and mixing valve. Specifically, the Joint
Commenters encouraged DOE to consider specifying how to calculate the
effective storage volume for water heaters designed to be installed
with a mixing valved based on the highest possible temperature setpoint
and requiring such water heaters to be tested at both 125 5
[deg]F and at their highest setpoint. (Id.) Furthermore, the Joint
Advocates commented that water heaters designed to be installed with a
mixing valve should be subject to the DOE standards based on both their
rated storage volume (and FHR at the 125 5 [deg]F
setpoint) and their effective storage volume (and FHR at their highest
setpoint). (Id.)
The CA IOUs stated that storage volume and first hour rating are
often correlated; however, with the increased use of thermostatic
mixing valves, this correlation has decreased, and FHR has become a
better representation of hot water delivery than storage volume. (CA
IOUs, No. 36 at p. 3) The CA IOUs asserted that the FHR metric best
defines consumer amenity, and that the current standards--which are
differentiated by storage volume--allow for less-efficient performance
for larger volume tanks within a given test procedure bin despite
delivering similar service to the consumer. (Id.) With regard to mixing
valves specifically, the CA IOUs supported DOE's proposal to require
the fitting of thermostatic mixing valves between the inlet and outlet
temperature measurement points when they are not an integral component
of the water heater and in the absence of manufacturer instructions.
(Id. at p. 5) The CA IOUs stated that this requirement would align with
product designs, as manufacturers typically direct the integration of a
valve or its installation, making it the correct choice to ensure
comparability of results and to accurately represent real-world energy
use. (Id.)
In order to further examine the potential impact of storage tank
over-heating, DOE performed testing on one 50-gallon electric
resistance storage water heater that includes built-in mixing valve and
multiple user-selectable modes to boost the delivery capacity by over-
heating the storage tank. DOE collected data at three different storage
tank temperatures, each of which provided an outlet water temperature
at 125 5 [deg]F through the use of the built-in mixing
valve. The maximum measured mean tank temperature after cut-out
following the first draw of the 24-hour simulated use test
(Tmax,1) and the average outlet water temperature during the
second draw (Tdel,2) were used as indicators of over-
heating. Data from this testing is shown in Table III.3 of this
document. The first row of data (with maximum mean tank temperature
value of 124.3) represents the unit as tested according to the current
test procedure.
[[Page 42279]]
Table III.3--Storage Tank Over-Heating Test Data
----------------------------------------------------------------------------------------------------------------
Tdel,2 **
Tmax,1 * ([deg]F) ([deg]F) Corresponding FHR Corresponding UEF
----------------------------------------------------------------------------------------------------------------
124.3.................................................. 121.3 77 gal 0.94
144.5.................................................. 124.3 81 gal 0.90
159.6.................................................. 124.3 95 gal 0.88
----------------------------------------------------------------------------------------------------------------
* Tmax,1 represents the maximum measured mean tank temperature after cut-out following the first draw of the 24-
hour simulated-use test.
** Tdel,2 represents the average outlet water temperature during the second draw of the 24-hour simulated-use
test.
The test results support NEEA's assertion that storage tank over-
heating could lead to reductions in UEF. The test configuration
corresponding to the current DOE test procedure produced a UEF value of
0.94, which surpasses the threshold for compliance with the current
minimum energy conservation applicable to this unit (minimum UEF of
0.93). The over-heated configurations with mean tank temperatures of
144.5 and 159.6 produced UEF values of 0.90 and 0.88, respectively,
both of which are below the applicable minimum energy conservation
standard for this unit.
In addition, the test results indicate that storage tank over-
heating leads to an increase in the measured FHR value. The test
configuration corresponding to the current DOE test procedure produced
an FHR value of 77 gallons. The over-heated configurations with mean
tank temperatures of 144.5 and 159.6 produced FHR values of 81 and 95
gallons, respectively. DOE notes that an FHR of 95 gallons is
comparable to that of a 100-gallon electric storage water heater.\19\
By comparison, the current minimum energy conservation standard that
applies to 100-gallon consumer water heaters in the high draw pattern
is a UEF of 2.13 (which currently can only be achieved through heat
pump technology).
---------------------------------------------------------------------------
\19\ For example, DOE's Compliance Certification Database
includes a 107-gallon electric storage water heater with an FHR
rating of 94 gallons.
---------------------------------------------------------------------------
From its review of publicly available product literature, products
that utilize storage tank over-heating generally offer user-selectable
operating modes that result in tank temperatures ranging from 100
[deg]F to 170 [deg]F. Based on DOE's test data, should consumers choose
to operate these products to a high-capacity mode (which maintains the
storage tank at, for example, 140 [deg]F while delivering water at 125
[deg]F), the water heater would likely perform significantly worse than
a rating determined based on testing without storage tank over-heating
(i.e., the rated efficiency at the rated delivery capacity would not be
representative of an average use cycle or period of use when operated
in a high-capacity mode). Hence, DOE has tentatively determined that
revisions to the method for determination of UEF and FHR are necessary
to yield results representative of an average use cycle for these
products. These proposed amendments are discussed in detail in the
following sections.
1. Testing in Over-Heated Mode
Most conventional storage-type water heaters do not include a
mixing valve and offer a range of temperature setpoints that would, in
typical installations, deliver outlet water at the temperature
corresponding to the setpoint temperature (e.g., a 140 [deg]F setting
on the water heater will deliver a 140 [deg]F outlet temperature).
Whereas, as discussed previously, water heaters that include a mixing
valve and provide ``over-heating'' capability offer a range of internal
temperature setpoints, although the outlet water remains at nominally
at 125 [deg]F regardless of internal setpoint. For the remainder of
this discussion, DOE refers to a user-initiated mode that results in an
elevated internal water temperature without increasing the delivered
water temperature as ``over-heated mode.''
Currently, section 5.1 of appendix E states, ``For water heaters
that allow for multiple user-selected operational modes, all procedures
specified in this appendix shall be carried out with the water heater
in the same operational mode (i.e., only one mode). This operational
mode shall be the default mode (or similarly-named, suggested mode for
normal operation) as defined by the manufacturer in its product
literature for giving selection guidance to the consumer.'' An
``overheated mode'' in storage-type water heaters is distinct from a
high-temperature setpoint because the outlet water temperature is
unaffected by the internal temperature setpoint. DOE surmises that
consumers who purchase a water heater that provides over-heating
capability would do so with the intent to use such capability; as such,
these consumers would be expected to use the over-heated mode some
portion of the time, ranging from occasional use (e.g., switching
between the normal mode and the over-heated mode depending on the hot
water capacity needed at any particular time) to regular use.
Accordingly, for such products, DOE expects that a representative
average use cycle would include some portion of time in over-heated
mode. For this reason, DOE has tentatively concluded that testing only
in the default mode would not produce results that are representative
of an average use cycle or period of use for products with this
capability if the default mode does not provide over-heat capability.
Considering these factors, DOE has tentatively determined that
testing storage-type water heaters that offer user-selectable over-
heated modes in the over-heated mode would provide a more
representative result than testing in the default mode. Therefore, DOE
proposes to amend section 5.1 of appendix E to require that for water
heaters that offer a user-selected operational mode(s) in which the
storage tank is maintained at a temperature higher than the delivery
temperature, the operational mode shall be that which results in the
highest mean tank temperature while maintaining an outlet temperature
of 125 5 [deg]F.
DOE recognizes that the aforementioned proposal would likely cause
UEF ratings for these products to decrease if they are currently
certified using a default operational mode that does not initiate over-
heating. In order to limit potential re-testing and re-certification
burden for manufacturers, DOE is proposing that the requirement to test
these products in the over-heated mode go into effect only once DOE
completes its ongoing review of potential amended energy conservation
standards for consumer water heaters and residential-duty commercial
water heaters.\20\
---------------------------------------------------------------------------
\20\ DOE is concurrently evaluating potential amended energy
conservation standards for consumer water heaters (Docket No. EERE-
2017-BT-STD-0019) and residential-duty commercial water heaters
(Docket No. EERE-2021-BT-STD-0027).
---------------------------------------------------------------------------
Electric storage water heaters with demand-response capabilities
may undergo utility-initiated over-heating during certain periods in
order to store additional energy in the water heater for
[[Page 42280]]
use during peak demand periods. This over-heating, when initiated by
the electric utility company, serves an important purpose for energy
storage and grid flexibility. Products that offer the ability to
respond to utility-initiated over-heating requests are distinct in
function from products that offer user-initiated over-heating, because
demand-response water heaters do not over-heat to increase the overall
daily capacity of the water heater. Instead, the capacity is only
temporarily boosted to counteract the deactivation of the heating
elements for extended periods of time when demand curtailment is
occurring. As such, demand-response water heaters with the capability
to undergo utility-initiated over-heating would not be expected
increase the capacity of the water heater over a typical average use
cycle in the same way that a water heater with user-initiated over-
heating would, so DOE has tentatively concluded that testing demand-
response water heaters in the default/normal mode would be the most
representative for demand-response water heaters.
In order to clarify which products with over-heating capability
should be tested in the operational mode that results in the highest
mean tank temperature while maintaining an outlet temperature of 125
5 [deg]F and which products with over-heating capability
should be tested in default/normal mode, DOE is proposing to define
``demand-response water heater'' in section 1.3 of appendix E. Products
meeting that definition would be tested in normal/default mode, while
all other products capable of over-heating the stored water in the tank
would be tested in the in the operational mode that results in the
highest mean tank temperature while maintaining an outlet temperature
of 125 5 [deg]F. The proposed definition for ``demand-
response water heater'' is based on the ENERGY STAR definitions for
``connected water heater product,'' ``demand response management
system,'' and ``demand response'' in specification version 5.0, with
certain modifications made by DOE.\21\ More specifically, DOE proposes
to define ``demand-response water heater'' as follows:
---------------------------------------------------------------------------
\21\ The ENERGY STAR Version 5.0 Residential Water Heater Final
Draft Specification was published on June 1, 2022 and is available
online at: www.energystar.gov/products/spec/residential_water_heaters_specification_version_5_0_pd (Last
accessed on June 4, 2022).
Demand-response water heater means a storage-type water heater
that--
(1) Has integrated communications hardware and additional
hardware and software required to enable connected functionality
with a utility or third party, which dispatches signals with demand
response instructions and/or price signals to the product and
receives messages from the demand-response water heater;
(2) Meets the communication and equipment standards for Consumer
Technology Association Standard (CTA) 2045-B (ANSI/CTA-2045-B); \22\
---------------------------------------------------------------------------
\22\ ANSI/CTA-2045-B, ``Modular Communications Interface for
Energy Management,'' published February 2021.
---------------------------------------------------------------------------
(3) Automatically heats the stored water above the delivery
temperature setpoint only in response to instructions received from
a utility or third party.
DOE welcomes comment on its proposed definition of ``demand-
response water heater,'' including the specification for ANSI/CTA-2045-
B to demonstrate connected functionality (as it is the latest version
of the CTA-2045 standard).
DOE seeks comment on the proposal to specify that water heaters,
except demand-response water heaters, that offer an operational mode
(or modes) causing water to be stored at a temperature higher than the
delivery temperature must be tested in the ``over-heated mode'' that
results in the highest internal tank temperature while still while
maintaining an outlet temperature of 125 5 [deg]F. DOE also
welcomes feedback on its proposal to require testing in this manner
only after compliance with amended energy conservation standards for
consumer water heaters and residential-duty commercial water heaters is
required. DOE further seeks information and consumer use data to
identify how often the over-heated mode is used in field installations.
2. Effective Storage Volume
As discussed in section III.C of this document, the Joint Advocates
and the CA IOUs both recommended that the increase in water heating
capacity attained through over-heating the storage tank be considered
for energy conservation standards. The Joint Advocates suggested that
compliance with standards should be based on an ``effective storage
volume,'' whereas the CA IOUs advocated for FHR to be used for
standards instead of a representation of storage volume.
The current energy conservation standards at 10 CFR 430.32(d)
define the minimum required UEF as a function of rated storage volume.
These standards have been amended over time but are based on the
original standards prescribed by EPCA at 42 U.S.C. 6295(e)(1), which
also correlated the efficiency metric to storage volume. In doing so,
these standards account for differences in standby losses (i.e., heat
transfer from the hot, stored water to the ambient surroundings) for
storage tanks of varying sizes. For storage-type water heaters, the
amount of hot water immediately available for consumer use has
typically been governed by the storage tank size, with increased tank
size resulting in a corresponding increase in standby losses. Standby
losses are primarily dependent upon three factors: (1) surface area of
the tank; (2) temperature of the stored water, and (3) tank insulation.
As storage tank volume increases, so do the expected standby losses
(all else being equal). Similarly, an increased water temperature would
also increase standby losses. The standards originally prescribed by
EPCA and subsequently amended by DOE did not contemplate storage tank
over-heating and its potential impact on standby losses and the amount
of hot water that is immediately available for consumer use. Therefore,
DOE has initially concluded that a capacity metric that combines
information about the tank volume and storage temperature may be more
appropriate.
Similar to standby loss, the thermal energy stored in a water
heater is a function of both the volume and the temperature of the
water being stored in the tank. The ability to over-heat the tank
increases the effective thermal energy storage of the tank to that
equivalent to a larger tank that has been heated to a more
conventional, lower temperature (i.e., approximately 125 5
[deg]F). DOE has tentatively determined that a measure of ``effective
storage volume'' (as suggested by the Joint Advocates) that reflects
the thermal energy stored in the water heater would allow for a better
comparison between a smaller water heater with over-heating and a
larger water heater storing water at a lower temperature.
Lutz stated that the test procedure should be able to distinguish
and measure the ability of a water heater to deliver hot water with
enough energy and to deliver a high enough temperature. Lutz provided
the example of a bath, where the temperature at every point during the
draw is not important; contrasted with a shower, where the temperature
is crucial. (Lutz, No. 35 at p. 1)
DOE notes that for activities such as filling a bathtub, consumers
would benefit more from knowing the effective storage volume (i.e., the
volume of immediately available hot water) of a water heater, whereas
for activities such as taking a shower, consumers could benefit more
from knowing the FHR (i.e., ability to deliver hot water for an
extended period of time). In particular,
[[Page 42281]]
FHR represents one full hour of delivery and does not necessarily
describe immediate hot water availability, as FHR is also impacted by
the rate of recovery. Hence, in addition to FHR, DOE has tentatively
determined that effective storage volume would be a meaningful
performance metric for consumers. In this SNOPR, DOE proposes a method
to determine effective storage volume, Veff (expressed in
gallons or liters), at section 6.3.1.1 of appendix E. For water heaters
storing water no higher than the delivery temperature, DOE proposes
that the effective storage volume be equivalent to the measured storage
volume. DOE proposes that to determine whether the stored water
temperature is higher than the delivery temperature, the maximum mean
tank temperature measured after cut-out following the first draw of the
24-hour simulated-use test (Tmax,1) is to be compared to the
average outlet water temperature during the second draw of the 24-hour
simulated-use test (Tdel,2). If Tmax,1 is less
than or equal to Tdel,2, then the unit would be determined
to not be capable of over-heating the stored water, and the effective
storage volume would be set equal to the measured storage volume. DOE
has tentatively chosen Tmax,1 to represent the temperature
of the stored water. Based on DOE's review of its own test data,
Tmax,1 is typically the highest mean tank temperature
achieved by the water heater, and Tmax values throughout the
test (i.e., all maximum mean tank temperatures following element cut-
out) typically do not vary significantly. DOE has tentatively chosen
Tdel,2 to represent the delivered water temperature because
it corresponds to the first draw after Tmax,1 is observed.
By contrast, for water heaters capable of over-heating water (as
determined by Tmax,1 being greater than Tdel,2),
DOE proposes to calculate the effective storage volume based on a
volume scaling factor and data already collected during the appendix E
test. The volume scaling factor would be determined as follows, which
is based on the relative heat transfer rates calculated from the
temperature data collected during the test:
[GRAPHIC] [TIFF OMITTED] TP14JY22.000
Where:
kV is the dimensionless volume scaling factor;
[rho](T) is the density of water evaluated at temperature T;
CP(T) is the heat capacity of water evaluated at
temperature T, and
67.5 [deg]F is the average ambient temperature.
DOE proposes to determine the effective storage volume by
multiplying the measured storage volume by kV.
DOE notes that this approach to calculating effective storage
volume would allow all calculations to be based on data collected
during a single 24-hour simulated use test, but it would yield
meaningful results only if water heaters capable of over-heating are
required to be tested in an over-heated mode, which is discussed in
section III.C.1 of this document.
This SNOPR does not propose to require representations of effective
storage volume, but DOE may consider such requirements as part of a
future energy conservation standards rulemaking, should this proposal
be finalized.
With respect to the comment from the CA IOUs suggesting that the
energy conservation standards be based on FHR rather than storage
volume, DOE notes that changes to the energy conservation standards are
outside the scope of this test procedure rulemaking. However, this
recommendation, along with the Joint Advocates' recommendation that
standards be based on an effective volume, will be considered further
in DOE's concurrent energy conservation standards rulemaking.
DOE seeks comment on its tentative determination that effective
storage volume would be a meaningful performance metric for consumers
and is a more appropriate measure of thermal energy storage than FHR.
DOE seeks comment on the proposed equations and approach to
calculating effective storage volume for water heaters.
D. Separate Storage Tank Requirements
Some water heaters on the market require a volume of water,
typically contained in either a storage tank (or tanks) or in a piping
distribution system of sufficient volume, to operate. These products
operate by circulating water stored either in the piping system or from
a separate tank (or multiple separate tanks) to the water heater to be
heated then back to the piping system or tank until hot water is
needed. In the January 2022 NOPR, DOE identified two types of products
that require a volume of water to operate--heat pump-only water heaters
that require installation with a separate storage tank and circulating
gas-fired instantaneous water heaters that require installation with a
separate storage tank or a piping system of sufficient volume. 87 FR
1554, 1583-1585 (Jan. 11, 2022). Circulating gas-fired instantaneous
water heaters are distinct from other types of gas-fired instantaneous
water heaters in that they are not designed to operate independent of a
storage tank or hot water system, as other gas-fired instantaneous
water heaters are. This applies generally to circulating water heaters;
however, DOE has tentatively determined that there are no electric
resistance or oil-fired circulating water heaters on the market today.
The current test procedure does not have procedures in place to
appropriately test circulating water heaters. As such, in the January
2022 NOPR, DOE proposed to define ``circulating water heater''
(including both heat pump-only and gas-fired instantaneous circulating
water heaters) and to require that such products be tested using an 80
gallon ( 1 gallon) unfired hot water storage tank
(``UFHWST'') that meets the energy conservation standards for an
unfired hot water storage tank at 10 CFR 431.110(a). 87 FR 1554, 1583-
1585 (Jan. 11, 2022).
In response to the January 2022 NOPR, DOE received a number of
comments regarding the separate storage tank requirements, primarily
related to the 1 gallon tolerance, the representativeness
of an 80-gallon unfired hot water storage tank, and the lack of a
specification for the upper bound on thermal insulation for the unfired
hot water storage tank. These comments are summarized and addressed in
the paragraphs that follow.
NYSERDA commented that an 80-gallon UFHWST may not be the correct
tank to use to increase repeatability and represent real world
conditions. (NYSERDA, No. 32 at p. 2)
Rheem commented that because a circulating water heater can be
paired with multiple sizes of tanks (e.g., 40-, 60-, and 80-gallon
tanks), DOE should consider multiple tank sizes for testing circulating
water heaters instead of just one 80-gallon storage tank. Rheem also
suggested that DOE increase the
[[Page 42282]]
tolerance on the volume of the storage tank to match the tolerance
prescribed by product safety standards,\23\ noting that a 1
gallon tolerance on an 80-gallon storage volume is too tight. Rheem
also requested clarification on whether the separately sold storage
tank may have backup heating (e.g., if the circulating water heater is
designed to be used with a tank that has backup heating) and whether
the two products could be rated together as a system. (Rheem, No. 40 at
pp. 3-4)
---------------------------------------------------------------------------
\23\ DOE understands this to be a reference to the 10 percent by
volume tolerances prescribed by UL Standard 174 (``Household
Electric Storage Tank Water Heaters'') and UL Standard 1453
(``Standard for Electric Booster and Commercial Storage Tank Water
Heaters''). These standards can be found online at
www.shopulstandards.com (Last accessed on June 21, 2022).
---------------------------------------------------------------------------
AHRI recommended that DOE not adopt a 1 gallon
tolerance requirement for the storage tank used in the test for a heat
pump-only water heater, stating that DOE should instead apply 10
percent volume tolerance, consistent with UL standard 174 or UL
standard 1453. AHRI also suggested that manufacturers be allowed to
specify the storage tank used to determine ratings for circulating and
heat pump-only water heaters. (AHRI, No. 40 at pp. 3-5)
A.O. Smith stated that it would not be unduly burdensome to use an
80-gallon tank for heat pump-only water heater testing. However, A.O.
Smith stated that tank insulation, inlet and outlet connection
locations, internal tank baffling, and inlet tube designs could impact
the UEF result, and accordingly, these variables should be addressed in
the DOE test procedure. A.O. Smith recommended that, to minimize as
many variables as possible, manufacturers be required to provide the
model number of the specific tank as part of its certification data,
and that the test tank should be defined as a part of the test
apparatus. (A.O. Smith, No. 37 at p. 3) DOE understands this to mean
that A.O. Smith recommends that the UFHWST model number used for
testing UEF be certified to DOE by the manufacturer, and that appendix
E should indicate that the specific UFHWST model certified to DOE must
be used in the test set-up.
The CA IOUs stated that the proposed 80-gallon tank size may not
reflect real-world applications. Additionally, the CA IOUs argued that
because the proposed requirement would impose a minimum R-value for the
tank, but no maximum, it could lead to variations in test outcomes. The
CA IOUs suggested that heat pump-only water heater manufacturers should
be allowed to test their products with a manufacturer-specified storage
tank and certify the information about the tank used for testing. The
CA IOUs also suggested that for heat-pump-only water heaters, DOE
should specify a traditional consumer electric storage water heater
tank, as it may be more representative of actual use. (CA IOUs, No. 36
at p. 5; CA IOUs, No. 27 at p. 31)
BWC commented that not all storage tanks are designed identically,
and differences in tank design may lead to differences in ratings for
circulating and heat pump-only water heaters. BWC also urged DOE to not
adopt a 1-gallon tolerance on the volume of an 80-gallon storage tank,
but instead to use a 10-percent tolerance. BWC requested that DOE
clarify whether the 80-gallon requirement would pertain to nominal
capacity. (BWC, No. 33 at p. 9)
After considering the issues raised by commenters, DOE is proposing
several updates to its earlier proposals (in section 4.10 of appendix
E) for testing circulating water heaters as initially presented in the
January 2022 NOPR.
First, after re-evaluating the market for heat-pump-only water
heaters, DOE tentatively agrees with the CA IOUs that testing such
products with a conventional electric storage water (i.e., an electric
water heater that uses only electric resistance heating elements) would
be more representative than testing with an UFHWST. Therefore, DOE is
proposing that heat-pump-only water heaters be tested in the medium
draw pattern using a 40-gallon traditional electric storage tank (i.e.,
that provides heat only with electric resistance heating elements) that
has a UEF rating at the minimum required at 10 CFR 430.32(d). DOE chose
a 40-gallon tank in the medium draw pattern because that size and draw
pattern combination has the highest number of models currently
available on the market.\24\ DOE is also proposing that, for heat pump-
only water heaters, the test be carried out using a tank that does not
``over-heat'' the stored water (see discussion of over-heating in
section III.C of this document; Tmax,1 (maximum measured
mean tank temperature after the first recovery period of the 24-hour
simulated-use test) must be less than or equal to Tdel,2
(average outlet water temperature during the 2nd draw of the 24-hour
simulated-use test)). This would ensure that the electric storage tanks
are not overheating during the test, thereby ensuring consistency
across tests.
---------------------------------------------------------------------------
\24\ See Figure 3A.2.8 of the Preliminary Analysis Technical
Support Document for consumer water heaters (Docket No. EERE-2017-
BT-STD-0019-0018).
---------------------------------------------------------------------------
In contrast, DOE is maintaining its earlier proposal that a UFHWST
be used for testing of circulating gas-fired water heaters, as those
products are more likely to be installed with a UFHWST in the field.
Therefore, DOE tentatively concludes that testing with an UFHWST would
be representative for such units.
In response to AHRI's suggestion that DOE allow manufacturers to
specify the storage tank used for testing, DOE notes that this approach
could lead to additional test burden for third-party testing labs, who
may need to acquire more than one storage tank if they are performing
tests for multiple manufacturers, each of whom may specify a different
storage tank for testing. In order to avoid creating the potential for
additional test burden, DOE has tentatively determined not to allow
manufacturers to specify the electric storage water heater or unfired
hot water storage tank used respectively for testing the heat pump-only
or gas-fired instantaneous circulating water heaters. Additionally, DOE
will consider relevant amendments to certification and reporting
requirements in a separate rulemaking.
After considering the comments regarding the tolerance on the
storage tank initially proposed in the January 2022 NOPR, DOE has
tentatively determined that a wider tolerance would reduce potential
testing burden while still providing representative and reproducible
results. In other words, DOE tentatively concludes that a 10-percent
tolerance would increase flexibility for manufacturers by increasing
the number of tanks that could be used for testing, while not
materially impacting the UEF test results. Therefore, consistent with
the recommendations provided by commenters, DOE is proposing to adopt a
10 percent tolerance (10 percent, allowing products with
rated storage volumes between 36 gallons and 44 gallons) for the
electric storage water heater used for testing heat-pump-only water
heaters.
In addition, after further review of the market for circulating
gas-fired instantaneous water heaters and unfired hot water storage
tanks, DOE is proposing to allow testing with a tank at any storage
volume between 80- and 120-gallons. Based on further analysis, DOE has
tentatively determined that variations in the tank size should not
significantly impact the result of the test. During a water draw, the
internal tank temperature decreases as hot water exits the tank and is
replenished by colder water entering the tank.
[[Page 42283]]
Generally, different tank sizes will result in different rates of
internal temperature decrease during a water draw (e.g., during a
specified water draw, a smaller tank will generally experience a faster
decrease in temperature compared to a larger tank). During a test, any
potential differences in the tank water temperature due to the use of
different size tanks would be accompanied by a corresponding
proportional difference in burner on-time, such that the impact on
measured efficiency (i.e., the ratio of energy output to energy input)
would be negligible. DOE also recognizes that a larger tank would
likely have more standby losses than a smaller tank; however, DOE has
tentatively determined that the impact this would have on measure
efficiency would also not be significant.
Providing a range of allowable tank volumes would reduce potential
burden by providing manufacturers with more tank options, thereby
allowing them to pair their circulating gas-fired instantaneous water
heaters with an existing UFHWST model. This approach is also likely to
be more representative of how the units would be installed in the field
as opposed to testing with a custom-made tank for testing or a
competitor's tank that meets a specific volume requirement.
DOE notes that, as suggested by the CA IOUs and A.O. Smith, the
lack of an upper bound on the thermal insulation value for the UFHWST
could lead to differences in measured efficiency that reflect
differences in tank performance, rather than reflecting differences in
water heater performance. Therefore, DOE has tentatively determined
that more specific constraints on tank performance are warranted to
ensure more comparable test results across the subject water heater
models. Thus, DOE is proposing to require that UFHWSTs used for testing
circulating gas-fired instantaneous water heaters exactly meet the
baseline energy conservation standard for UFHWSTs.\25\ As stated
previously, A.O. Smith raised the concern that differences in the
UFHWST's design (insulation, inlet and outlet connection locations,
internal tank baffling, and inlet tube designs) could lead to variation
in UEF results; however, A.O. Smith and other commenters did not
provide suggestions on specific UFHWST designs which should be
standardized in order to improve representativeness and repeatability
of the test method. A.O. Smith did not provide any data to demonstrate
these to be significant concerns. While the variations in insulation
would most significantly impact the standby losses of the tank (and
therefore the UEF rating of the circulating water heater), these
variations would already be minimized by specifying the R-value of the
UFHWST to be the baseline requirement in the energy conservation
standards for UFHWSTs. Regarding the other design options, over-
specifying the design of the UFHWST--given the impacts on the UEF
rating are minimal--could result in a very narrow range of UFHWST
models which can be used for testing circulating water heaters, thereby
potentially introducing significant barriers to testing these products
at third-party laboratories. Additionally, DOE does not currently have
sufficient information on specifications for the inlet and outlet
connection locations, internal tank baffling, and inlet tube designs
for the UFHWST; therefore, DOE is not including these specifications in
its proposed requirements.
---------------------------------------------------------------------------
\25\ Currently, baseline energy conservation standards for
UFHWSTs require a thermal insulation of R-12.5. 10 CFR 431.110(a).
---------------------------------------------------------------------------
As noted previously, DOE is similarly proposing that the electric
storage water heater used for testing heat-pump-only water heaters have
a rated UEF corresponding to the minimum standard found at 10 CFR
430.32(d), thereby helping to ensure more comparable results.
In summary, in this SNOPR, DOE proposes to further amend the
separate storage tank requirements proposed in the January 2022 NOPR
for heat pump-only and gas-fired circulating water heaters. DOE
proposes that heat pump-only water heaters be tested with a 40-gallon
( 4 gallons) electric storage water heater that has a UEF
value corresponding to the minimum standard for such products; and that
gas-fired circulating water heaters be tested with an 80- to 120-gallon
unfired hot water storage tank that is rated equal to the energy
conservation standard for such equipment.
DOE requests comment on its proposed separate tank requirements for
heat pump-only and gas-fired circulating water heaters. DOE also seeks
comment on whether any additional tank characteristics should be
specified.
For gas-fired circulating water heaters, these proposed changes
could require a one-time purchase of an 80- to 120-gallon unfired hot
water storage tank. DOE research indicates that such tanks are readily
commercially available for approximately $2,000. For heat pump-only
water heaters, the proposed changes could result in a one-time purchase
of a 40-gallon ( 4 gallons) electric storage water heater.
DOE research indicates that such water heaters are readily available
for approximately $500. These estimates reflect costs for third-party
laboratory testing (i.e., assuming these tanks would have to be
purchased at retail price).
DOE seeks comment on the estimated potential increase in costs for
testing heat pump-only and gas-fired circulating water heaters
according to this proposal.
Finally, although this SNOPR does not propose changes to the
certification requirements, DOE may consider a requirement to certify
the UFHWST and electric storage water heater models and/or
characteristics in a future rulemaking.
E. Method for Determining Internal Tank Temperature for Certain Water
Heaters
As discussed in the January 2022 NOPR, section 4.5 of appendix E
specifies that the thermocouples be inserted into the storage tank of a
water heater through either the anodic device opening, the temperature
and pressure relief valve, or the outlet water line. DOE has identified
consumer water heaters with physical attributes that make measuring
internal storage tank temperature using any of these means difficult,
such as water heaters that have a built-in mixing valve and no anodic
device, or have a large heat exchanger that does not accommodate
insertion of a thermocouple tree. 87 FR 1554, 1586 (Jan. 11, 2022).
Commenters on the April 2020 RFI suggested an approach whereby the tank
would be drained down to measure the temperature of the water inside.
Id. In the January 2022 NOPR, DOE explained how draining down the tank
would not be possible in the middle of the 24-hour simulated use test,
when mean tank temperature data is required. Id. Therefore, DOE
proposed that the internal tank temperature for these products would be
approximated as the average between the inlet and outlet temperatures
(i.e., a ``linear temperature gradient'' assumption). Id.
Rheem agreed with DOE's proposed methodology to estimate the mean
tank temperature for products for which the internal tank temperature
cannot be directly measured. (Rheem, No. 31 at p. 4)
[[Page 42284]]
However, several commenters indicated that the linear temperature
gradient assumption inherent to the proposed methodology in the January
2022 NOPR is incorrect. AHRI commented that the proposed procedure
incorrectly assumes a linear temperature gradient in the tank, which
can lead to inaccurate calculation of temperature and stored energy in
the tank.\26\ (AHRI, No. 40 at p. 5)
---------------------------------------------------------------------------
\26\ Additionally, AHRI stated that the procedure should require
measurements to be taken 15 seconds after the initial draw to be
consistent with other proposals.
---------------------------------------------------------------------------
A.O. Smith commented that it has conducted testing using the
proposed test method and has found that the assumption of a linear
temperature gradient is inaccurate when compared to actual temperature
readings conducted with thermocouples. Accordingly, A.O. Smith
concluded that it would be premature to incorporate the proposed test
method into the DOE test procedure at this time. (A.O. Smith, No. 37 at
pp. 5-6) BWC indicated that, based on its own testing, the proposed
methodology could record artificially lower tank temperatures, with
errors as high as 10 to 25 percent. (BWC, No. 33 at p. 10)
In the final rule that established the current test procedure for
commercial water heaters, DOE noted that using the average of the
supply and outlet water temperature as an estimate for the stored water
temperature is only valid if the water temperature inside the heat
exchanger has a linear increase in temperature as it moves from the
inlet to the outlet. 81 FR 79261, 79295 (Nov. 10, 2016). In order to
estimate the internal tank temperature for commercial instantaneous
water heaters and hot water supply boilers, DOE adopted a method that
uses the outlet water temperature as an approximation, because it was
consistent with the industry-adopted test method for flow-activated
instantaneous water heaters, found at Annex E.3 of ANSI Standard
Z21.10.3-2015. Id.
However, as discussed in section III.C of this SNOPR, DOE is aware
of consumer water heaters that can store water at temperatures that are
significantly higher than the outlet temperature, so the method used
for commercial instantaneous water heaters and hot water supply boilers
would not be applicable to all types of products covered under this
rulemaking. Furthermore, outlet water temperature would only be
representative of the internal tank temperature for consumer water
heaters and residential-duty commercial water heaters with very limited
storage volume, where the small volume prevents internal temperature
stratification.\27\
---------------------------------------------------------------------------
\27\ Currently, mean tank temperature measurements are not
required for consumer water heaters or residential-duty commercial
water heaters less than 2 gallons in rated storage volume.
---------------------------------------------------------------------------
Based on further consideration of comments received in response to
the January 2022 NOPR and at previous stages of this rulemaking, DOE is
proposing in this SNOPR that, for water heaters with rated storage
volumes greater than or equal to 2 gallons that are unable to have
their internal tank temperatures measured using thermocouples, the
internal tank temperature shall be estimated by removing water from the
water heater, as described in detail in the following paragraphs. This
method, proposed in a new section 5.4.2.2 of appendix E, is partially
based on the approaches suggested by Rheem and BWC prior to the January
2022 NOPR (see Document No. EERE-2019-BT-TP-0032-0012 at p. 5 and
Document No. EERE-2019-BT-TP-0032-0014 at p. 9), with certain
modifications.
As discussed in the January 2022 NOPR, throughout the 24-hour
simulated-use test, internal tank thermocouples are used to determine
the mean tank temperature. Mean tank temperatures are required at the
start and end of the test, the start and end of the standby period, and
the after the first recovery period (i.e., T0,
T24, Tsu,0, Tsu,f, and
Tmax,1, respectively). Also, an average mean tank
temperature throughout the standby period is required (i.e.,
Tt,stby,1). 87 FR 1554, 1586 (Jan. 11, 2022). DOE performed
an analysis on data collected from its own testing and has initially
concluded that, for typical storage-type water heaters, T0,
, Tsu,0, and Tmax,1 are similar in that they
represent temperatures near the cut-out control temperature. Removing
the heated water from the tank and measuring the temperature, as
described in detail below, immediately after cut-out may reasonably
estimate these temperatures. The mean tank temperature at the end of
the standby period, Tsu,f, can also be measured by removing
water and measuring its temperature at the end of a sufficiently long
standby period at the end of the test, and this value could also
approximate T24.
In this SNOPR, DOE is proposing the following methodology for water
heaters with rated storage volumes greater than or equal to 2 gallons
that are unable to have their internal tank temperatures measured using
thermocouples:
(1) After the FHR test (for non-flow-activated products) or Max GPM
test (for flow-activated products), allow the water heater to fully
recover.
(2) When cut-out occurs, deactivate the burner, compressor, and/or
electrical heating elements.
(3) Remove the hot water from the tank by performing a continuous
draw, while measuring the outlet water temperature at 3-second
intervals, until the outlet water temperature is within 2 [deg]F of the
inlet water temperature for five consecutive readings. Perform the draw
at a flow rate of 3.0 gallons per minute (0.25 gallons per
minute). Compute the mean tank temperature, Tst, as follows
and assign this value as T0, Tsu,0, and
Tmax,1:
[GRAPHIC] [TIFF OMITTED] TP14JY22.001
Where:
Tst = the estimated average internal storage tank
temperature.
Tp = the average of the inlet and the outlet water
temperatures at the end of the period defined by [tau]p.
vout,p = the average flow rate during the period.
Vst = the rated storage volume of the water heater.
[tau]p = the duration of the period, determined by the
length of time taken for the outlet water temperature to be within 2
[deg]F of the inlet water temperature for 15 consecutive seconds.
The duration of the period shall include the 15-second stabilization
period.
Tin,p = the average of the inlet water temperatures
during the period.
Tout,p = the average of the outlet water temperatures
during the period.
(4) Re-activate the burner, compressor, and/or electrical elements
and perform the 24-hour simulated use
[[Page 42285]]
test as instructed in section 5.4 of appendix E.
(5) The standby period will start at five minutes after the end of
the first recovery period after the last draw of the simulated-use
test. The standby period shall last eight hours, so testing will extend
beyond the 24-hour duration of the simulated-use test. At the end of
the final standby measurement, remove water from the tank once again as
in step #3, including computing the value of mean tank temperature.
This calculated mean tank temperature is then assigned as
Tsu,f and T24.
(6) Determine Tt,stby,1 as the average of
Tsu,0 and Tsu,f.
DOE seeks comment on its revised proposed test method to determine
the internal tank temperature for water heaters that cannot be directly
measured and are greater than or equal to 2 gallons in rated storage
volume.
DOE estimates that, at maximum, the proposed method for estimating
the internal tank temperature would increase the test duration by 8
hours (corresponding to the final standby period appended to the
current 24-hour simulated use test). DOE estimates that the testing a
water heater to the 24-hour simulated use test currently costs $3,000
for a fossil-fuel-fired or electric water heater and $4,500 for a heat
pump water heater. By extending the duration of the test by up to 8
hours (or 33 percent), this amendment, if finalized, could increase
testing costs by $1,000 to $1,500 per basic model for water heaters
with rated storage volume greater than or equal to 2 gallons which
cannot have their internal storage tank directly measured. However,
these products are designed in such a way that instruments for
measuring the internal water temperature cannot be installed, and,
thus, these products cannot be tested to the current version of
appendix E.
IV. Procedural Issues and Regulatory Review
A. Review Under Executive Orders 12866 and 13563
Executive Order (``E.O.'')12866, ``Regulatory Planning and
Review,'' 58 FR 51735 (Oct. 4, 1993), as supplemented and reaffirmed by
E.O. 13563, ``Improving Regulation and Regulatory Review,'' 76 FR 3821
(Jan. 21, 2011), requires agencies, to the extent permitted by law, to:
(1) propose or adopt a regulation only upon a reasoned determination
that its benefits justify its costs (recognizing that some benefits and
costs are difficult to quantify); (2) tailor regulations to impose the
least burden on society, consistent with obtaining regulatory
objectives, taking into account, among other things, and to the extent
practicable, the costs of cumulative regulations; (3) select, in
choosing among alternative regulatory approaches, those approaches that
maximize net benefits (including potential economic, environmental,
public health and safety, and other advantages; distributive impacts;
and equity); (4) to the extent feasible, specify performance
objectives, rather than specifying the behavior or manner of compliance
that regulated entities must adopt; and (5) identify and assess
available alternatives to direct regulation, including providing
economic incentives to encourage the desired behavior, such as user
fees or marketable permits, or providing information upon which choices
can be made by the public. DOE emphasizes as well that E.O. 13563
requires agencies to use the best available techniques to quantify
anticipated present and future benefits and costs as accurately as
possible. In its guidance, the Office of Information and Regulatory
Affairs (``OIRA'') in the Office of Management and Budget (``OMB'') has
emphasized that such techniques may include identifying changing future
compliance costs that might result from technological innovation or
anticipated behavioral changes. For the reasons stated in the preamble,
this proposed regulatory action is consistent with these principles.
Section 6(a) of E.O. 12866 also requires agencies to submit
``significant regulatory actions'' to OIRA for review. OIRA has
determined that this proposed regulatory action does not constitute a
``significant regulatory action'' under section 3(f) of E.O. 12866.
Accordingly, this action was not submitted to OIRA for review under
E.O. 12866.
B. Review Under the Regulatory Flexibility Act
The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires
preparation of an initial regulatory flexibility analysis (``IRFA'')
for any rule that by law must be proposed for public comment, unless
the agency certifies that the rule, if promulgated, will not have a
significant economic impact on a substantial number of small entities.
As required by Executive Order 13272, ``Proper Consideration of Small
Entities in Agency Rulemaking,'' 67 FR 53461 (August 16, 2002), DOE
published procedures and policies on February 19, 2003, to ensure that
the potential impacts of its rules on small entities are properly
considered during the DOE rulemaking process. 68 FR 7990. DOE has made
its procedures and policies available on the Office of the General
Counsel's website: www.energy.gov/gc/office-general-counsel. DOE
reviewed this test procedure SNOPR under the provisions of the
Regulatory Flexibility Act and the policies and procedures previously
published on February 19, 2003.
The following sections detail DOE's IRFA for this test procedure
rulemaking.
1. Description of Reasons Why Action Is Being Considered
DOE is proposing to amend test procedures for consumer water
heaters and residential-duty commercial water heaters. DOE is
publishing this rulemaking in satisfaction of the 7-year-lookback
review requirement specified in EPCA. (42 U.S.C. 6293(b)(1)(A);
6314(a)(1)) Further, amending test procedures for consumer and
residential-duty commercial water heaters assists DOE in fulfilling its
statutory deadline for amending energy conservation standards for
products and equipment that achieve the maximum improvement in energy
efficiency that is technologically feasible and economically justified.
(42 U.S.C. 6295(o)(2)(A); 42 U.S.C. 6313(a)(6)) Additionally, amending
test procedures for consumer and residential-duty commercial water
heaters allows manufacturers to produce measurements of energy
efficiency that are representative of an average use cycle and uniform
for all manufacturers.
On January 11, 2022, DOE published a test procedure NOPR (``January
2022 NOPR'') in the Federal Register proposing to amend the test
procedure for consumer water heaters and residential-duty commercial
gas water heaters. See 87 FR 1554, 1590-1592. In this SNOPR, DOE
proposes modifications to the January 2022 NOPR.
2. Objectives of, and Legal Basis for, Rule
EPCA authorizes DOE to regulate the energy efficiency of a number
of consumer products and certain industrial equipment, including the
consumer and residential-duty commercial water heaters that are the
subject of this proposed rulemaking. (42 U.S.C. 6292(a)(4) and 42
U.S.C. 6311(1)(K))
3. Description and Estimate of Small Entities Regulated
For manufacturers of consumer water heaters and residential-duty
commercial water heaters, the Small Business Administration (SBA) has
set a size threshold, which defines those entities classified as
``small businesses'' for the
[[Page 42286]]
purposes of the statute. DOE used the SBA's small business size
standards to determine whether any small entities would be subject to
the requirements of the rule. (See 13 CFR part 121.) The size standards
are listed by North American Industry Classification System (``NAICS'')
code and industry description and are available at: www.sba.gov/
document/support--table-size-standards. Manufacturing of consumer water
heaters and residential-duty commercial water heaters is classified
under NAICS 335220, ``Major Household Appliance Manufacturing.'' The
SBA sets a threshold of 1,500 employees or fewer for an entity to be
considered as a small business for this category. DOE used available
public information to identify potential small manufacturers. DOE
accessed CCMS,\28\ the certified product directory of the AHRI,\29\
company websites, and manufacturer literature to identify companies
that import, private label, or produce the consumer water heaters and
residential-duty commercial water heaters covered by this proposal.
Using these sources, DOE identified a total of 27 manufacturers of
consumer water heaters and residential-duty commercial water heaters.
Of these 27 manufacturers, DOE identified one domestic small business
that manufactures products covered by the proposed test procedure
amendments in this SNOPR.
---------------------------------------------------------------------------
\28\ U.S. Department of Energy Compliance Certification
Management System, available at: www.regulations.doe.gov/ccms. (Last
accessed March 1, 2022).
\29\ AHRI Directory of Certified Product Performance, available
at: www.ahridirectory.org/Search/SearchHome. (Last accessed March 1,
2022).
---------------------------------------------------------------------------
4. Description and Estimate of Compliance Requirements
As noted previously, DOE conducted an initial regulatory
flexibility analysis (``IRFA'') as part of the January 2022 NOPR, in
which it determined that there is one domestic, small business that
manufactures residential water heaters impacted by the January 2022
NOPR. Id. at 87 FR 1591. Under the proposed amendments in the January
2022 NOPR, DOE anticipated the small business would incur third-party
re-testing costs of $4,500 for one basic model as result of DOE's
proposal to require the use of a separate unfired hot water storage
tank for testing water heaters designed to operate with a separately
sold hot water storage tank. DOE estimated the compliance burden to
represent less than 0.01 percent of the company's revenue. Id.
This SNOPR serves to: (1) provide additional specificity for the
existing test procedure for water heaters with a rated storage volume
of less than 2 gallons; (2) propose optional rating conditions and
associated metrics for voluntary representations of heat pump water
heaters; (3) revise the separate storage tank requirements for
circulating water heaters proposed in the January 2022 NOPR; (4)
provide instructions for testing water heaters which store water at a
temperature higher than the delivery setpoint and for determining the
effective storage volume of such products, and (5) revise the testing
requirements for water heaters which are greater than or equal to 2
gallons in rated storage volume but cannot have the temperature of
their internal storage tanks directly measured. Each of these proposed
amendments will be discussed in turn to assess their potential impacts
in light of the Regulatory Flexibility Act.
First, DOE proposes to add flow rate tolerances for the 24-hour
simulated-use test for water heaters with a rated storage volume of
less than 2 gallons. DOE expects that laboratories may utilize high-
precision water flow rate instrumentation (e.g., Coriolis flow meters)
to meet the proposed flow rate tolerances. DOE is aware of multiple
third-party laboratories which already incorporate Coriolis flow meters
for DOE compliance testing. Further, DOE expects that general industry
best practice is already applying the flow rate tolerances being
proposed for section 5.4.3 of appendix E for water heaters with rated
storage volume less than 2 gallons; therefore, this proposal is
expected to be consistent with current methodology and practice.
Additionally, DOE has tentatively determined that the proposed
amendment would not alter the measured efficiency of consumer water
heaters and residential-duty commercial water heaters, nor require
retesting or recertification solely as a result of DOE's adoption of
the proposed amendments to the test procedure. For these reasons, DOE
has initially determined that the proposed tolerances would generally
not impose additional testing burden.
Second, DOE is proposing to adopt optional test conditions and
metrics for voluntary representations of heat pump water heater energy
efficiency at test conditions other than the standard rating
conditions. If adopted in a final rule, these metrics will not be
required for reporting or compliance with standards for consumer water
heaters and residential-duty commercial water heaters. Therefore, DOE
has initially determined that testing for these optional metrics would
not be unduly burdensome to conduct.
Third, DOE previously proposed separate storage tank requirements
for testing circulating water heaters in the January 2022 NOPR. 87 FR
1554, 1589 (Jan. 11, 2022). In the January 2022 NOPR, DOE proposed that
circulating water heaters (including heat pump-only water heaters) be
tested paired with 80-gallon unfired hot water storage tanks which
meets the energy conservation standard requirements at 10 CFR
431.110(a). Id. In this SNOPR, DOE is instead proposing to require
circulating gas-fired instantaneous water heaters and heat pump-only
water heaters to be paired with different types of tanks to be more
representative of field installations.
For circulating gas-fired instantaneous water heaters, DOE proposes
that these products be paired with UFHWSTs that exactly meet baseline
energy conservation standards (as required at 10 CFR 431.110(a)) and
rated at a capacity between 80 gallons and 120 gallons. Compared to the
January 2022 NOPR, DOE applied additional specificity to the tank
performance constraints to improve reproducibility of the test method
and increased the range of acceptable capacities after reviewing market
data on which capacities are commercially available at the baseline
energy conservation standard level.
DOE estimates that the cost of running the amended test procedure
for circulating gas-fired instantaneous water heaters should be the
same as testing a comparable water heater with storage volume (i.e.,
third-party testing of a fossil fuel-fired or electric storage water
heater would cost approximately $3,000 and third-party testing of an
electric storage water heater which uses heat pump technology would
cost approximately $4,500). However, DOE is not aware of any domestic
small manufacturers of circulating gas-fired instantaneous water
heaters at this time.
For heat pump-only water heaters, DOE is updating its proposal to
propose that these products be paired with electric storage water
heaters that have a rated storage volume of 40 gallons 4
gallons, have an FHR that results in classification at the medium draw
pattern, and be rated at exactly the minimum required UEF. Compared to
the January 2022 NOPR, DOE is proposing a different type and size of
product to be paired with a heat pump-only water heater to better
reflect how heat pump-only water heaters may be installed in the field.
DOE estimates that the cost of running the amended test procedure
for heat pump-only water heaters should be the same as testing a
comparable water
[[Page 42287]]
heater with storage volume. For this estimate, DOE utilized a third-
party test estimate of $4,500. DOE believes this to represent the high-
end range of the testing cost burden compared to in-house testing.
DOE is aware of one domestic small manufacturer which has a single
model that would be affected by this amendment. DOE expects the cost to
test that model per the test method proposed in this SNOPR to be
$4,500. This represents less than 0.01 percent of company revenue, and,
therefore, DOE has tentatively determined that it would not be unduly
burdensome to conduct.
Fourth, DOE is proposing to require that water heaters, except for
demand-response water heaters, which can store water at a temperature
higher than the delivery setpoint as a result of a user-selected
operating mode be tested using the setting that provides the highest
internal mean tank temperature while delivering water at a temperature
of 125 [deg]F 5 [deg]F, and that an ``effective storage
volume''--which quantifies the increase in energy storage due to this
mode of operation--be calculated for all storage water heaters based on
data that is already being collected per the current appendix E test
procedure. This proposal, if adopted, would improve representativeness
and reproducibility for water heaters with such a capability.
The proposed amendment to test in an ``over-heated'' mode could
potentially lead to re-testing and re-certification costs for
manufacturers of such water heaters, as it would impact the UEF rating
of such products. Should a manufacturer be required to re-testing, DOE
estimates re-testing costs to be up to $4,500 per basic model using
third-party testing. DOE believes this to represent the high-end range
of the testing cost burden compared to in-house testing.
DOE is not proposing to require compliance with this provision
until compliance with amended energy conservation standards is also
required (after the date of a final rule amending the test procedure
for consumer water heaters and residential-duty commercial water
heaters). Therefore, DOE has tentatively determined that this proposed
amendment, if adopted, would not impose additional costs for
manufacturers until such time as potential amended standards would be
required. DOE will consider these impacts in a separate rulemaking as
part of its ongoing review of potential amended energy conservation
standards.
Lastly, there is currently no method to determine ratings for water
heaters which have rated storage volumes of 2 gallons or more but
cannot have the internal storage tank temperature directly measured by
means of the instrumentation required in the appendix E test procedure.
The use of standard instrumentation is limited by the geometries of
these products. Examples of such cases include products which have
built-in mixing valves at the water outlet, products which do not use a
sacrificial anode rod (and therefore do not have the associated opening
for the anode rod), or products with complex heat exchanger geometries.
DOE previously proposed to rely on inlet and outlet water temperatures
to approximate the internal storage tank temperatures for these water
heaters. 87 FR 1554, 1586 (Jan. 11, 2022). However, in this SNOPR, DOE
is revising its proposed methodology for determining the internal tank
temperatures of such products to improve the accuracy as compared to
the method originally proposed in the January 2022 NOPR.
The method proposed in this SNOPR relies on drawing out water from
the tank at the beginning and end of the 24-hour simulated use test and
monitoring the temperature of the water as it is drawn out to estimate
the internal tank temperature of the stored water prior to being drawn
out of the water heater. This method may result in overall testing
costs of $4,000 to $6,000 per basic model of water heater which cannot
be directly measured. This is comparable to the average cost of $3,000
to $4,500 per basic model of water heater which can be directly
measured. DOE is currently not aware of any small businesses which
produce water heaters which will have to be tested in this manner, and,
thus, DOE has tentatively concluded that this amendment, if finalized,
would not impact small manufacturers.
DOE requests comment on its understanding of the cost impacts of
the proposed amendments in this notice on small, domestic
manufacturers.
5. Duplication, Overlap, and Conflict With Other Rules and Regulations
DOE is not aware of any rules or regulations that duplicate,
overlap, or conflict with the rule being considered today.
6. Significant Alternatives to the Rule
The discussion in the previous section analyzes impacts on small
businesses that would result from DOE's proposed test procedure, if
finalized. In reviewing alternatives to the proposed test procedure,
DOE examined not establishing a performance-based test procedure for
consumer and residential-duty commercial water heaters or establishing
prescriptive-based test procedures. While not establishing performance-
based test procedures or establishing prescriptive-based test
procedures for consumer and residential-duty commercial water heaters
would reduce the burden on small businesses, DOE must use test
procedures to determine whether the products comply with relevant
standards promulgated under EPCA. (42 U.S.C. 6295(s)) Because
establishing performance-based test procedures for consumer and
residential-duty commercial water heaters is necessary prior to
establishing performance-based energy conservation standards, DOE
tentatively concludes that establishing performance-based test
procedures, as proposed in this SNOPR, supports DOE's authority to
achieve the maximum improvement in energy efficiency that is
technologically feasible and economically justified. (42 U.S.C.
6295(o)(2)(A); 42 U.S.C. 6313(a)(6)(A)(ii)(II))
The Department has tentatively determined that there are no better
alternatives than the test procedures amendments proposed in this
SNOPR, in terms of both meeting the agency's objectives and reducing
burden. Additionally, manufacturers subject to DOE's test procedures
may apply to DOE's Office of Hearings and Appeals for exception relief
under certain circumstances. Manufacturers should refer to 10 CFR part
430, subpart E, and 10 CFR part 1003 for additional details.
C. Review Under the Paperwork Reduction Act of 1995
Manufacturers of consumer and residential-duty commercial water
heaters must certify to DOE that their products comply with any
applicable energy conservation standards. To certify compliance,
manufacturers must first obtain test data for their products according
to the DOE test procedures, including any amendments adopted for those
test procedures. DOE has established regulations for the certification
and recordkeeping requirements for all covered consumer products and
commercial equipment, including consumer and residential-duty
commercial water heaters. (See generally 10 CFR part 429.) The
collection-of-information requirement for certification and
recordkeeping is subject to review and approval by OMB under the
Paperwork Reduction Act (``PRA''). This requirement has been approved
by OMB under OMB control number 1910-1400. Public reporting burden for
the certification is estimated to average 35 hours per response,
[[Page 42288]]
including the time for reviewing instructions, searching existing data
sources, gathering and maintaining the data needed, and completing and
reviewing the collection of information.
DOE is not proposing to amend the certification or reporting
requirements for consumer and residential-duty commercial water heaters
in this SNOPR. Instead, DOE may consider proposals to amend the
certification requirements and reporting for these products under a
separate rulemaking regarding appliance and equipment certification.
DOE will address changes to OMB Control Number 1910-1400 at that time,
as necessary.
Notwithstanding any other provision of the law, no person is
required to respond to, nor shall any person be subject to a penalty
for failure to comply with, a collection of information subject to the
requirements of the PRA, unless that collection of information displays
a currently valid OMB Control Number.
D. Review Under the National Environmental Policy Act of 1969
In this SNOPR, DOE proposes test procedure amendments that it
expects will be used to develop and implement future energy
conservation standards for consumer and residential-duty commercial
water heaters. DOE has determined that this rule falls into a class of
actions that are categorically excluded from review under the National
Environmental Policy Act of 1969 (42 U.S.C. 4321 et seq.) and DOE's
implementing regulations at 10 CFR part 1021. Specifically, DOE has
determined that adopting test procedures for measuring energy
efficiency of consumer products and industrial equipment is consistent
with activities identified in 10 CFR part 1021, appendix A to subpart
D, A5 and A6. Accordingly, neither an environmental assessment nor an
environmental impact statement is required.
E. Review Under Executive Order 13132
Executive Order 13132, ``Federalism,'' 64 FR 43255 (August 4,
1999), imposes certain requirements on agencies formulating and
implementing policies or regulations that preempt State law or that
have federalism implications. The Executive order requires agencies to
examine the constitutional and statutory authority supporting any
action that would limit the policymaking discretion of the States and
to carefully assess the necessity for such actions. The Executive order
also requires agencies to have an accountable process to ensure
meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.
On March 14, 2000, DOE published a statement of policy describing the
intergovernmental consultation process it will follow in the
development of such regulations. 65 FR 13735. DOE has examined this
proposed rule and has determined that it would not have a substantial
direct effect on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government. EPCA governs
and prescribes Federal preemption of State regulations as to energy
conservation for the products that are the subject of this proposed
rule. States can petition DOE for exemption from such preemption to the
extent, and based on criteria, set forth in EPCA. (42 U.S.C. 6297(d))
No further action is required by Executive Order 13132.
F. Review Under Executive Order 12988
Regarding the review of existing regulations and the promulgation
of new regulations, section 3(a) of Executive Order 12988, ``Civil
Justice Reform,'' 61 FR 4729 (Feb. 7, 1996), imposes on Federal
agencies the general duty to adhere to the following requirements: (1)
eliminate drafting errors and ambiguity; (2) write regulations to
minimize litigation; (3) provide a clear legal standard for affected
conduct rather than a general standard, and (4) promote simplification
and burden reduction. Section 3(b) of Executive Order 12988
specifically requires that Executive agencies make every reasonable
effort to ensure that the regulation: (1) clearly specifies the
preemptive effect, if any; (2) clearly specifies any effect on existing
Federal law or regulation; (3) provides a clear legal standard for
affected conduct while promoting simplification and burden reduction;
(4) specifies the retroactive effect, if any; (5) adequately defines
key terms, and (6) addresses other important issues affecting clarity
and general draftsmanship under any guidelines issued by the Attorney
General. Section 3(c) of Executive Order 12988 requires Executive
agencies to review regulations in light of applicable standards in
sections 3(a) and 3(b) to determine whether they are met or it is
unreasonable to meet one or more of them. DOE has completed the
required review and determined that, to the extent permitted by law,
the proposed rule meets the relevant standards of Executive Order
12988.
G. Review Under the Unfunded Mandates Reform Act of 1995
Title II of the Unfunded Mandates Reform Act of 1995 (``UMRA'')
requires each Federal agency to assess the effects of Federal
regulatory actions on State, local, and Tribal governments and the
private sector. Public Law 104-4, sec. 201 (codified at 2 U.S.C. 1531).
For a proposed regulatory action likely to result in a rule that may
cause the expenditure by State, local, and Tribal governments, in the
aggregate, or by the private sector of $100 million or more in any one
year (adjusted annually for inflation), section 202 of UMRA requires a
Federal agency to publish a written statement that estimates the
resulting costs, benefits, and other effects on the national economy.
(2 U.S.C. 1532(a), (b)) The UMRA also requires a Federal agency to
develop an effective process to permit timely input by elected officers
of State, local, and Tribal governments on a proposed ``significant
intergovernmental mandate,'' and requires an agency plan for giving
notice and opportunity for timely input to potentially affected small
governments before establishing any requirements that might
significantly or uniquely affect small governments. On March 18, 1997,
DOE published a statement of policy on its process for
intergovernmental consultation under UMRA. 62 FR 12820; also available
at www.energy.gov/gc/office-general-counsel. DOE examined this proposed
rule according to UMRA and its statement of policy and determined that
the rule contains neither an intergovernmental mandate, nor a mandate
that may result in the expenditure of $100 million or more in any year,
so these requirements do not apply.
H. Review Under the Treasury and General Government Appropriations Act,
1999
Section 654 of the Treasury and General Government Appropriations
Act, 1999 (Pub. L. 105-277) requires Federal agencies to issue a Family
Policymaking Assessment for any rule that may affect family well-being.
This proposed rule would not have any impact on the autonomy or
integrity of the family as an institution. Accordingly, DOE has
concluded that it is not necessary to prepare a Family Policymaking
Assessment.
I. Review Under Executive Order 12630
DOE has determined, under Executive Order 12630, ``Governmental
Actions and Interference with Constitutionally Protected Property
Rights,'' 53 FR 8859 (March 18, 1988), that this proposed regulation
would not result in any takings that might require compensation under
the Fifth Amendment to the U.S. Constitution.
[[Page 42289]]
J. Review Under the Treasury and General Government Appropriations Act,
2001
Section 515 of the Treasury and General Government Appropriations
Act, 2001 (44 U.S.C. 3516 note) provides for agencies to review most
disseminations of information to the public under guidelines
established by each agency pursuant to general guidelines issued by
OMB. OMB's guidelines were published at 67 FR 8452 (Feb. 22, 2002), and
DOE's guidelines were published at 67 FR 62446 (Oct. 7, 2002). Pursuant
to OMB Memorandum M-19-15, Improving Implementation of the Information
Quality Act (April 24, 2019), DOE published updated guidelines which
are available at www.energy.gov/sites/prod/files/2019/12/f70/DOE%20Final%20Updated%20IQA%20Guidelines%20Dec%202019.pdf. DOE has
reviewed this proposed rule under the OMB and DOE guidelines and has
concluded that it is consistent with applicable policies in those
guidelines.
K. Review Under Executive Order 13211
Executive Order 13211, ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use,'' 66 FR 28355
(May 22, 2001), requires Federal agencies to prepare and submit to OMB,
a Statement of Energy Effects for any proposed significant energy
action. A ``significant energy action'' is defined as any action by an
agency that promulgated or is expected to lead to promulgation of a
final rule, and that: (1) is a significant regulatory action under
Executive Order 12866, or any successor order; and (2) is likely to
have a significant adverse effect on the supply, distribution, or use
of energy; or (3) is designated by the Administrator of OIRA as a
significant energy action. For any proposed significant energy action,
the agency must give a detailed statement of any adverse effects on
energy supply, distribution, or use should the proposal be implemented,
and of reasonable alternatives to the action and their expected
benefits on energy supply, distribution, and use.
The proposed regulatory action to amend the test procedure for
measuring the energy efficiency of consumer and residential-duty
commercial water heaters is not a significant regulatory action under
Executive Order 12866. Moreover, it would not have a significant
adverse effect on the supply, distribution, or use of energy, nor has
it been designated as a significant energy action by the Administrator
of OIRA. Therefore, it is not a significant energy action, and,
accordingly, DOE has not prepared a Statement of Energy Effects.
L. Review Under Section 32 of the Federal Energy Administration Act of
1974
Under section 301 of the Department of Energy Organization Act
(Pub. L. 95-91; 42 U.S.C. 7101), DOE must comply with section 32 of the
Federal Energy Administration Act of 1974, as amended by the Federal
Energy Administration Authorization Act of 1977. (15 U.S.C. 788;
``FEAA'') Section 32 essentially provides in relevant part that, where
a proposed rule authorizes or requires use of commercial standards, the
notice of proposed rulemaking must inform the public of the use and
background of such standards. In addition, section 32(c) requires DOE
to consult with the Attorney General and the Chairman of the Federal
Trade Commission (``FTC'') concerning the impact of the commercial or
industry standards on competition.
As discussed in the January 11, 2022 NOPR, the proposed
modifications to the test procedure for consumer and residential-duty
commercial water heaters would incorporate testing methods contained in
certain sections of the following commercial standards: ASHRAE 41.1-
2020, ASTM D2156-09 (RA 2018), and a finalized version of ASHRAE 118.2.
DOE has evaluated these standards and is unable to conclude whether
they fully comply with the requirements of section 32(b) of the FEAA
(i.e., whether they were developed in a manner that fully provides for
public participation, comment, and review). DOE will consult with both
the Attorney General and the Chairman of the FTC concerning the impact
of these test procedures on competition, prior to prescribing a final
rule.
V. Public Participation
DOE will accept comments, data, and information regarding this
supplemental proposed rule no later than the date provided in the DATES
section at the beginning of this SNOPR. 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. Comments and documents submitted via
email 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. With this instruction followed, the cover letter will not be
publicly viewable as long as it does not include any comments.
Include contact information each time you submit comments, data,
documents, and other information to DOE. No telefacsimiles (faxes) will
be accepted.
[[Page 42290]]
Comments, data, and other information submitted to DOE
electronically should be provided in PDF (preferred), Microsoft Word or
Excel, WordPerfect, or text (ASCII) file format. Provide documents that
are not secured, written in English, and free of any defects or
viruses. Documents should not contain special characters or any form of
encryption, and, if possible, they should carry the electronic
signature of the author.
Campaign form letters. Please submit campaign form letters by the
originating organization in batches of between 50 to 500 form letters
per PDF or as one form letter with a list of supporters' names compiled
into one or more PDFs. This reduces comment processing and posting
time.
Confidential Business Information. Pursuant to 10 CFR 1004.11, any
person submitting information that he or she believes to be
confidential and exempt by law from public disclosure should submit via
email two well-marked copies: one copy of the document marked
``confidential'' including all the information believed to be
confidential, and one copy of the document marked ``non-confidential''
with the information believed to be confidential deleted. 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).
VI. Approval of the Office of the Secretary
The Secretary of Energy has approved publication of this
supplemental notice of proposed rulemaking and request for comment.
List of Subjects in 10 CFR Part 430
Administrative practice and procedure, Confidential business
information, Energy conservation, Household appliances, Imports,
Intergovernmental relations, Reporting and recordkeeping requirements,
Small businesses.
Signing Authority
This document of the Department of Energy was signed on July 1,
2022, by Kelly J. Speakes-Backman, 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 July 6, 2022.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.
For the reasons stated in the preamble, DOE is proposing to amend
part 430 of Chapter II of Title 10, Code of Federal Regulations, as set
forth below:
PART 430--ENERGY CONSERVATION PROGRAM FOR CONSUMER PRODUCTS
0
1. The authority citation for part 430 continues to read as follows:
Authority: 42 U.S.C. 6291-6309; 28 U.S.C. 2461 note.
0
2. Appendix E to subpart B of part 430 is amended by:
0
a. Revising the note at the beginning of the appendix;
0
b. Revising section 1;
0
c. Adding new sections 2.8, 4.10;
0
d. Revising sections 5.1, 5.4.2;
0
e. Adding sections 5.6, 6.3.1.1;
0
f. Revising section 6.3.9; and
0
g. Adding new section 6.5;
The revisions and additions read as follows:
Appendix E to Subpart B of Part 430--Uniform Test Method for Measuring
the Energy Consumption of Water Heaters
Note: Prior to [date 180 days after date of publication of the
final rule in the Federal Register], representations with respect to
the energy use or efficiency of consumer water heaters and
residential-duty commercial water heaters covered by this test
method, including compliance certifications, must be based on
testing conducted in accordance with either this appendix as it now
appears or appendix E as it appeared at 10 CFR part 430, subpart B
revised as of January 1, 2021.
On and after [date 180 days after date of publication of the
final rule in the Federal Register], representations with respect to
energy use or efficiency of consumer water heaters and residential-
duty commercial water heaters covered by this test method, including
compliance certifications, must be based on testing conducted in
accordance with this appendix.
In addition, water heaters subject to section 5.1.2 of this
appendix may optionally apply the requirements in section 5.1.1 of
this appendix in lieu of the requirements in section 5.1.2 of this
appendix until the compliance date of a final rule reviewing
potential amended energy conservation standards for these products
published after [date of publication of the final rule in the
Federal Register].
1. Definitions.
1.1. Cut-in means the time when or water temperature at which a
water heater control or thermostat acts to increase the energy or
fuel input to the heating elements, compressor, or burner.
1.2. Cut-out means the time when or water temperature at which a
water heater control or thermostat acts to reduce to a minimum the
energy or fuel input to the heating elements, compressor, or burner.
1.3. Demand-response water heater means a storage-type water
heater that--
(1) Has integrated communications hardware and additional
hardware and software required to enable connected functionality
with a utility or third party, which dispatches signals with demand
response instructions and/or price signals to the product and
receives messages from the demand-response water heater;
(2) Meets the communication and equipment standards for Consumer
Technology Association Standard 2045-B (CTA-2045-B);
(3) Automatically heats the stored water above the delivery
temperature setpoint only in response to instructions received from
a utility or third party.
1.4. Design Power Rating means the power rating or input rate
that a water heater manufacturer assigns to a particular design of
water heater and that is included on the nameplate of the water
heater, expressed in kilowatts or Btu (kJ) per hour as appropriate.
For modulating water heaters, the design power rating is the maximum
power rating or input rate that is specified by the manufacturer on
the nameplate of the water heater.
1.5. Draw Cluster means a collection of water draws initiated
during the 24-hour simulated-use test during which no successive
draws are separated by more than 2 hours.
1.6. First-Hour Rating means an estimate of the maximum volume
of ``hot'' water that a non-flow activated water heater can supply
within an hour that begins with the water heater fully heated (i.e.,
with all thermostats satisfied).
1.7. Flow-Activated describes an operational scheme in which a
water heater initiates and terminates heating based on sensing flow.
1.8. Heat Trap means a device that can be integrally connected
or independently attached to the hot and/or cold water pipe
connections of a water heater such that the device will develop a
thermal or mechanical seal to minimize the recirculation of water
due to thermal convection between the water heater tank and its
connecting pipes.
1.9. Maximum GPM (L/min) Rating means the maximum gallons per
minute (liters per minute) of hot water that can be supplied by
flow-activated water heater when tested in accordance with section
5.3.2 of this appendix.
[[Page 42291]]
1.10. Modulating Water Heater means a water heater that can
automatically vary its power or input rate from the minimum to the
maximum power or input rate specified on the nameplate of the water
heater by the manufacturer.
1.11. Rated Storage Volume means the water storage capacity of a
water heater, in gallons (liters), as certified by the manufacturer
pursuant to 10 CFR part 429.
1.12. Recovery Efficiency means the ratio of energy delivered to
the water to the energy content of the fuel consumed by the water
heater.
1.13. Recovery Period means the time when the main burner of a
water heater with a rated storage volume greater than or equal to 2
gallons is raising the temperature of the stored water.
1.14. Split-system heat pump water heater means a heat pump-type
water heater with an indoor storage tank and outdoor heat pump
component.
1.15. Standby means the time, in hours, during which water is
not being withdrawn from the water heater.
1.16. Symbol Usage. The following identity relationships are
provided to help clarify the symbology used throughout this
procedure:
Cp--specific heat of water
Eannual--annual energy consumption of a water heater
Eannual,e--annual electrical energy consumption of a water heater
Eannual,f --annual fossil-fuel energy consumption of a water heater
EX--energy efficiency of a heat pump-type water heater when the 24-
hour simulated use test is optionally conducted at any of the
additional air temperature conditions as specified in section 2.8 of
this appendix, where the subscript ``X'' corresponds to the dry-bulb
temperature at which the test is conducted.
Fhr--first-hour rating of a non-flow activated water heater
Fmax--maximum GPM (L/min) rating of a flow-activated water heater
i--a subscript to indicate the draw number during a test
kV--storage tank volume scaling ratio for water heaters with a rated
storage volume greater than or equal to 2 gallons
Mdel,i--mass of water removed during the ith draw of the 24-hour
simulated-use test
Min,i--mass of water entering the water heater during the ith draw
of the 24-hour simulated-use test
M*del,i--for non-flow activated water heaters, mass of water removed
during the ith draw during the first-hour rating test
M *in,i--for non-flow activated water heaters, mass of water
entering the water heater during the ith draw during the first-hour
rating test
Mdel,10m--for flow-activated water heaters, mass of water removed
continuously during the maximum GPM (L/min) rating test
Min,10m--for flow-activated water heaters, mass of water entering
the water heater continuously during the maximum GPM (L/min) rating
test
n--for non-flow activated water heaters, total number of draws
during the first-hour rating test
N--total number of draws during the 24-hour simulated-use test
Nr--number of draws from the start of the 24-hour simulated-use test
to the end to the first recovery period as described in section
5.4.2 of this appendix
Q--total fossil fuel and/or electric energy consumed during the
entire 24-hour simulated-use test
Qd--daily water heating energy consumption adjusted for net change
in internal energy
Qda--Qd with adjustment for variation of tank to ambient
air temperature difference from nominal value
Qdm--overall adjusted daily water heating energy consumption
including Qda and QHWD
Qe--total electrical energy used during the 24-hour simulated-use
test
Qf--total fossil fuel energy used by the water heater during the 24-
hour simulated-use test
Qhr--hourly standby losses of a water heater with a rated storage
volume greater than or equal to 2 gallons
QHW--daily energy consumption to heat water at the measured average
temperature rise across the water heater
QHW,67 [deg]F--daily energy consumption to heat quantity of water
removed during test over a temperature rise of 67 [deg]F (37.3
[deg]C)
QHWD--adjustment to daily energy consumption, QHW, due to
variation of the temperature rise across the water heater not equal
to the nominal value of 67 [deg]F (37.3 [deg]C)
Qr--energy consumption of water heater from the beginning of the
test to the end of the first recovery period
Qstby--total energy consumed during the standby time interval
[tau]stby,1, as determined in section 5.4.2 of this
appendix
Qsu,0--cumulative energy consumption, including all fossil fuel and
electrical energy use, of the water heater from the start of the 24-
hour simulated-use test to the start of the standby period as
determined in section 5.4.2 of this appendix
Qsu,f--cumulative energy consumption, including all fossil fuel and
electrical energy use, of the water heater from the start of the 24-
hour simulated-use test to the end of the standby period as
determined in section 5.4.2 of this appendix
T0--mean tank temperature at the beginning of the 24-hour simulated-
use test as determined in section 5.4.2 of this appendix
T24--mean tank temperature at the end of the 24-hour simulated-use
test as determined in section 5.4.2 of this appendix
Ta,stby--average ambient air temperature during all standby periods
of the 24-hour simulated-use test as determined in section 5.4.2 of
this appendix
Ta,stby,1--overall average ambient temperature between the start and
end of the standby period as determined in section 5.4.2 of this
appendix
Tt,stby1--overall average mean tank temperature between the start
and end of the standby period as determined in section 5.4.2 of this
appendix
Tdel--for flow-activated water heaters, average outlet water
temperature during the maximum GPM (L/min) rating test
Tdel,i--average outlet water temperature during the ith draw of the
24-hour simulated-use test
Tin--for flow-activated water heaters, average inlet water
temperature during the maximum GPM (L/min) rating test
Tst--for water heaters which cannot have internal tank temperature
directly measured, estimated average internal storage tank
temperature
Tp--for water heaters which cannot have internal tank temperature
directly measured, average of the inlet and the outlet water
temperatures at the end of the period defined by [tau]p
Tin,p--for water heaters which cannot have internal tank temperature
directly measured, average of the inlet water temperatures
Tout,p--for water heaters which cannot have internal tank
temperature directly measured, average of the outlet water
temperatures
Tin,i--average inlet water temperature during the ith draw of the
24-hour simulated-use test
Tmax,1--maximum measured mean tank temperature after the first
recovery period of the 24-hour simulated-use test as determined in
section 5.4.2 of this appendix
Tsu,0--maximum measured mean tank temperature at the beginning of
the standby period as determined in section 5.4.2 of this appendix
Tsu,f--measured mean tank temperature at the end of the standby
period as determined in section 5.4.2 of this appendix
T*del,i--for non-flow activated water heaters, average outlet water
temperature during the ith draw (i = 1 to n) of the first-hour
rating test
T*max,i--for non-flow activated water heaters, maximum outlet water
temperature observed during the ith draw (i = 1 to n) of the first-
hour rating test
T*min,i--for non-flow activated water heaters, minimum outlet water
temperature to terminate the ith draw (i = 1 to n) of the first-hour
rating test
UA--standby loss coefficient of a water heater with a rated storage
volume greater than or equal to 2 gallons
UEF--uniform energy factor of a water heater
V--the volume of hot water drawn during the applicable draw pattern
Vdel,i--volume of water removed during the ith draw (i = 1 to N) of
the 24-hour simulated-use test
Vin,i--volume of water entering the water heater during the ith draw
(i = 1 to N) of the 24-hour simulated-use test
V*del,i--for non-flow activated water heaters, volume of water
removed during the ith draw (i = 1 to n) of the first-hour rating
test
V*in,i--for non-flow activated water heaters, volume of water
entering the water heater during the ith draw (i = 1 to n) of the
first-hour rating test
Vdel,10m--for flow-activated water heaters, volume of water removed
during the maximum GPM (L/min) rating test
[[Page 42292]]
Vin,10m--for flow-activated water heaters, volume of water entering
the water heater during the maximum GPM (L/min) rating test
Vst--measured storage volume of the storage tank for water heaters
with a rated storage volume greater than or equal to 2 gallons
Veff--effective storage volume of water heaters with a rated storage
volume greater than or equal to 2 gallons
vout,p--for water heaters which cannot have internal tank
temperature directly measured, average flow rate
Wf --weight of storage tank when completely filled with water for
water heaters with a rated storage volume greater than or equal to 2
gallons
Wt--tare weight of storage tank when completely empty of water for
water heaters with a rated storage volume greater than or equal to 2
gallons
[eta]r--recovery efficiency
[rho]--density of water
[tau]p--for water heaters which cannot have internal tank
temperature directly measured, duration of the temperature
measurement period, determined by the length of time taken for the
outlet water temperature to be within 2 [deg]F of the inlet water
temperature for 15 consecutive seconds (including the 15-second
stabilization period)
[tau]stby,1--elapsed time between the start and end of the standby
period as determined in section 5.4.2 of this appendix
[tau]stby,2--overall time of standby periods when no water is
withdrawn during the 24-hour simulated-use test as determined in
section 5.4.2 of this appendix
1.17. Temperature Controller means a device that is available to
the user to adjust the temperature of the water inside a water
heater that stores heated water or the outlet water temperature.
1.18. Uniform Energy Factor means the measure of water heater
overall efficiency.
1.19. Water Heater Requiring a Storage Tank means a water heater
without a storage tank specified or supplied by the manufacturer
that cannot meet the requirements of sections 2 and 5 of this
appendix without the use of a storage water heater or unfired hot
water storage tank.
2. * * *
2.8 Optional Test Conditions (Heat Pump-Type Water Heaters).
The following test conditions may be used for optional
representations of EX for heat pump-type water heaters.
When conducting a 24-hour simulated use test to determine
EX, the test conditions in section 2.1 and sections 2.4
through 2.7 apply. The ambient air temperature and humidity
conditions in section 2.2 and the supply water temperature in
section 2.3 are replaced with the air temperature, humidity, and
supply water temperature conditions as shown in the following table.
Testing may optionally be performed at any or all of the conditions
in the table.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Outdoor air conditions Indoor air conditions
---------------------------------------------------------------- Supply water
Heat pump type Metric Dry-bulb Relative Dry-bulb Relative temperature
temperature humidity (%) temperature humidity (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Split-System............................................ E5 5.0 [deg]F 30 67.5 [deg]F 50 42.0 [deg]F
E34 34.0 [deg]F 72 47.0 [deg]F
E95 95.0 [deg]F 25 67.0 [deg]F
Integrated or Heat Pump-Only............................ E50 N/A N/A 50.0 [deg]F 58 50.0 [deg]F
E95 N/A N/A 95.0 [deg]F 40 67.0 [deg]F
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * *
4. * * *
4.10 Storage Tank Requirement for Circulating Water Heaters.
When testing a gas-fired, oil-fired, or electric resistance
circulating water heater (i.e., any circulating water heater that
does not use a heat pump), the tank to be used for testing shall be
an unfired hot water storage tank having a certified volume between
80 and 120 gallons (364-546 liters) that meets but does not exceed
the minimum energy conservation standards required according to 10
CFR 431.110. When testing a heat pump circulating water heater, the
tank to be used for testing shall be an electric storage water
heater that uses only electric resistance elements for heating, has
a measured volume of 40 gallons ( 4 gallons), has a
First-Hour Rating greater than or equal to 51 gallons and less than
75 gallons resulting in classification under the medium draw
pattern, and has a rated UEF equal to the minimum UEF standard
specified at Sec. 430.32(d), rounded to the nearest 0.01. In
addition, the water heater used for testing shall not be capable of
``over-heating'' the stored water, as determined by
Tmax,1 (maximum measured mean tank temperature after the
first recovery period of the 24-hour simulated-use test) being less
than or equal to Tdel,2 (average outlet water temperature
during the 2nd draw of the 24-hour simulated-use test).
5. * * *
5.1 Operational Mode Selection. For water heaters that allow for
multiple user-selected operational modes, all procedures specified
in this appendix shall be carried out with the water heater in the
same operational mode (i.e., only one mode). Water heaters subject
to section 5.1.2 of this appendix may optionally apply the
requirements in section 5.1.1 in lieu of the requirements in section
5.1.2 of this appendix until the compliance date of a final rule
reviewing potential amended energy conservation standards for these
products published after [date of publication of the test procedure
final rule in the Federal Register]
5.1.1 Water Heaters Without Storage Tank Over-heating
Capability. If a non-flow-activated water heater does not have any
user-selectable operational modes where the mean temperature of the
storage tank can be maintained at a temperature higher than the
delivery setpoint temperature (e.g., by use of a mixing valve), the
instructions in this section apply. The operational mode shall be
the default mode (or similarly named, suggested mode for normal
operation) as defined by the manufacturer in the I&O manual for
giving selection guidance to the consumer. For heat pump water
heaters, if a default mode is not defined in the product literature,
each test shall be conducted under an operational mode in which both
the heat pump and any electric resistance backup heating element(s)
are activated by the unit's control scheme, and which can achieve
the internal storage tank temperature specified in this test
procedure; if multiple operational modes meet these criteria, the
water heater shall be tested under the most energy-intensive mode.
If no default mode is specified and the unit does not offer an
operational mode that utilizes both the heat pump and the electric
resistance backup heating element(s), the first-hour rating test and
the 24-hour simulated-use test shall be tested in heat-pump-only
mode. For other types of water heaters where a default mode is not
specified, test the unit in all modes and rate the unit using the
results of the most energy-intensive mode.
5.1.2 Water Heaters With Storage Tank Over-heating Capability.
If a non-flow-activated water heater that is not a demand-response
water heater (as defined in section 1.3 of this appendix) has a
user-selectable operational mode where the mean temperature of the
storage tank can be maintained at a temperature higher than the
delivery setpoint temperature (e.g., by use of a mixing valve), set
the unit to maintain the highest mean tank temperature possible
while delivering water at 125 [deg]F 5 [deg]F. Maintain
this setting throughout the entirety of the test.
* * * * *
5.4 * * *
5.4.2 Test Sequence for Water Heater With Rated Storage Volume
Greater Than or Equal to 2 Gallons.
If the water heater is turned off, fill the water heater with
supply water at the temperature specified in section 2.3 of this
appendix and maintain supply water pressure as described in section
2.6 of this appendix. Turn on the water heater and associated heat
pump unit, if present. If turned on in this fashion, the soak-in
period described in section 5.2.4 of this appendix shall be
implemented. If the water heater has
[[Page 42293]]
undergone a first-hour rating test prior to conduct of the 24-hour
simulated-use test, allow the water heater to fully recover after
completion of that test such that the main burner, heating elements,
or heat pump compressor of the water heater are no longer raising
the temperature of the stored water. In all cases, the water heater
shall sit idle for 1 hour prior to the start of the 24-hour test;
during which time no water is drawn from the unit, and there is no
energy input to the main heating elements, heat pump compressor,
and/or burners.
For water heaters that can have their internal storage tank
temperature measured directly, perform testing in accordance with
the instructions in section 5.4.2.1 of this appendix. For water
heaters that cannot have their internal tank temperatures measured,
perform testing in accordance with the instructions in section
5.4.2.2. of this appendix.
5.4.2.1 Water Heaters which Can Have Internal Storage Tank
Temperature Measured Directly.
After the 1-hour period specified in section 5.4.2 of this
appendix, the 24-hour simulated-use test will begin. One minute
prior to the start of the 24-hour test simulated-use test, record
the mean tank temperature (T0).
At the start of the 24-hour simulated-use test, record the
electrical and/or fuel measurement readings, as appropriate. Begin
the 24-hour simulated-use test by withdrawing the volume specified
in the appropriate table in section 5.5 of this appendix (i.e.,
Table III.1, Table III.2, Table III.3, or Table III.4, depending on
the first-hour rating or maximum GPM rating) for the first draw at
the flow rate specified in the applicable table. Record the time
when this first draw is initiated and assign it as the test elapsed
time ([tau]) of zero (0). Record the average storage tank and
ambient temperature every minute throughout the 24-hour simulated-
use test. At the elapsed times specified in the applicable draw
pattern table in section 5.5 of this appendix for a particular draw
pattern, initiate additional draws pursuant to the draw pattern,
removing the volume of hot water at the prescribed flow rate
specified by the table. The maximum allowable deviation from the
specified volume of water removed for any single draw taken at a
nominal flow rate of 1.0 GPM or 1.7 GPM is 0.1 gallons
( 0.4 liters). The maximum allowable deviation from the
specified volume of water removed for any single draw taken at a
nominal flow rate of 3.0 GPM is 0.25 gallons (0.9
liters). The quantity of water withdrawn during the last draw shall
be increased or decreased as necessary such that the total volume of
water withdrawn equals the prescribed daily amount for that draw
pattern 1.0 gallon (3.8 liters). If this
adjustment to the volume drawn during the last draw results in no
draw taking place, the test is considered invalid.
All draws during the 24-hour simulated-use test shall be made at
the flow rates specified in the applicable draw pattern table in
section 5.5 of this appendix, within a tolerance of 0.25
gallons per minute (0.9 liters per minute). Measurements
of the inlet and outlet temperatures shall be made 15 seconds after
the draw is initiated and at every subsequent 3-second interval
throughout the duration of each draw. Calculate and record the mean
of the hot water discharge temperature and the cold water inlet
temperature for each draw Tdel,i and Tin,i).
Determine and record the net mass or volume removed (Mi
or Vi), as appropriate, after each draw.
The first recovery period is the time from the start of the 24-
hour simulated-use test and continues during the temperature rise of
the stored water until the first cut-out; if the cut-out occurs
during a subsequent draw, the first recovery period includes the
time until the draw of water from the tank stops. If, after the
first cut-out occurs but during a subsequent draw, a subsequent cut-
in occurs prior to the draw completion, the first recovery period
includes the time until the subsequent cut-out occurs, prior to
another draw. The first recovery period may continue until a cut-out
occurs when water is not being removed from the water heater or a
cut-out occurs during a draw and the water heater does not cut-in
prior to the end of the draw.
At the end of the first recovery period, record the maximum mean
tank temperature observed after cut-out (Tmax,1). At the
end of the first recovery period, record the total energy consumed
by the water heater from the beginning of the test (Qr),
including all fossil fuel and/or electrical energy use, from the
main heat source and auxiliary equipment including, but not limited
to, burner(s), resistive elements(s), compressor, fan, controls,
pump, etc., as applicable.
The start of the portion of the test during which the standby
loss coefficient is determined depends upon whether the unit has
fully recovered from the first draw cluster. If a recovery is
occurring at or within five minutes after the end of the final draw
in the first draw cluster, as identified in the applicable draw
pattern table in section 5.5 of this appendix, then the standby
period starts when a maximum mean tank temperature is observed
starting five minutes after the end of the recovery period that
follows that draw. If a recovery does not occur at or within five
minutes after the end of the final draw in the first draw cluster,
as identified in the applicable draw pattern table in section 5.5 of
this appendix, then the standby period starts five minutes after the
end of that draw. Determine and record the total electrical energy
and/or fossil fuel consumed from the beginning of the test to the
start of the standby period (Qsu,0).
In preparation for determining the energy consumed during
standby, record the reading given on the electrical energy (watt-
hour) meter, the gas meter, and/or the scale used to determine oil
consumption, as appropriate. Record the mean tank temperature at the
start of the standby period (Tsu,0). At 1-minute
intervals, record ambient temperature, the electric and/or fuel
instrument readings and the mean tank temperature until the next
draw is initiated. The end of the standby period is when the final
mean tank temperature is recorded, as described. Just prior to
initiation of the next draw, record the mean tank temperature
(Tsu,f). If the water heater is undergoing recovery when
the next draw is initiated, record the mean tank temperature
(Tsu,f) at the minute prior to the start of the recovery.
Determine the total electrical energy and/or fossil fuel energy
consumption from the beginning of the test to the end of the standby
period (Qsu,f). Record the time interval between the
start of the standby period and the end of the standby period
([tau]stby,1).
Following the final draw of the prescribed draw pattern and
subsequent recovery, allow the water heater to remain in the standby
mode until exactly 24 hours have elapsed since the start of the 24-
hour simulated-use test (i.e., since [tau] = 0). During the last
hour of the 24-hour simulated-use test (i.e., hour 23 of the 24-hour
simulated-use test), power to the main burner, heating element, or
compressor shall be disabled. At 24 hours, record the reading given
by the gas meter, oil meter, and/or the electrical energy meter as
appropriate. Determine the fossil fuel and/or electrical energy
consumed during the entire 24-hour simulated-use test and designate
the quantity as Q.
In the event that the recovery period continues from the end of
the last draw of the first draw cluster until the subsequent draw,
the standby period will start after the end of the first recovery
period after the last draw of the 24-hour simulated-use test, when
the temperature reaches the maximum mean tank temperature, though no
sooner than five minutes after the end of this recovery period. The
standby period shall last eight hours, so testing may extend beyond
the 24-hour duration of the 24-hour simulated-use test. Determine
and record the total electrical energy and/or fossil fuel consumed
from the beginning of the 24-hour simulated-use test to the start of
the 8-hour standby period (Qsu,0). In preparation for
determining the energy consumed during standby, record the
reading(s) given on the electrical energy (watt-hour) meter, the gas
meter, and/or the scale used to determine oil consumption, as
appropriate. Record the mean tank temperature at the start of the
standby period (Tsu,0). Record the mean tank temperature,
the ambient temperature, and the electric and/or fuel instrument
readings at 1-minute intervals until the end of the 8-hour period.
Record the mean tank temperature at the end of the 8-hour standby
period (Tsu,f). If the water heater is undergoing
recovery at the end of the standby period, record the mean tank
temperature (Tsu,f) at the minute prior to the start of
the recovery, which will mark the end of the standby period.
Determine the total electrical energy and/or fossil fuel energy
consumption from the beginning of the test to the end of the standby
period (Qsu,f). Record the time interval between the
start of the standby period and the end of the standby period as
[tau]stby,1. Record the average ambient temperature from
the start of the standby period to the end of the standby period
(Ta,stby,1). Record the average mean tank temperature
from the start of the standby period to the end of the standby
period (Tt,stby,1).
If the standby period occurred at the end of the first recovery
period after the last draw of the 24-hour simulated-use test, allow
the water heater to remain in the standby mode
[[Page 42294]]
until exactly 24 hours have elapsed since the start of the 24-hour
simulated-use test (i.e., since [tau] = 0) or the end of the standby
period, whichever is longer. At 24 hours, record the mean tank
temperature (T24) and the reading given by the gas meter,
oil meter, and/or the electrical energy meter as appropriate. If the
water heater is undergoing a recovery at 24 hours, record the
reading given by the gas meter, oil meter, and/or electrical energy
meter, as appropriate, and the mean tank temperature
(T24) at the minute prior to the start of the recovery.
Determine the fossil fuel and/or electrical energy consumed during
the 24 hours and designate the quantity as Q.
Record the time during which water is not being withdrawn from
the water heater during the entire 24-hour period
([tau]stby,2). When the standby period occurs after the
last draw of the 24-hour simulated-use test, the test may extend
past hour 24. When this occurs, the measurements taken after hour 24
apply only to the calculations of the standby loss coefficient. All
other measurements during the time between hour 23 and hour 24
remain the same.
5.4.2.2 Water Heaters which Cannot Have Internal Storage Tank
Temperature Measured Directly.
After the water heater has undergone a 1-hour idle period (as
described in section 5.4.2 of this appendix), deactivate the burner,
compressor, or heating element(s).
Remove the water from the storage tank by performing a
continuous draw at a flow rate of 3.0 GPM (11.4 L/min)
0.25 GPM (0.9 L/min) until the outlet water temperature is within
2 [deg]F (1.1 [deg]C) of the inlet water
temperature for 15 consecutive seconds. While removing the hot
water, measure the inlet and outlet temperature beginning 15 seconds
after initiating the draw and at 3-second intervals thereafter until
the outlet condition has stabilized. Determine the mean tank
temperature using section 6.3.9 of this appendix and assign this
value of Tst for T0, Tmax,1, and
Tsu,0.
After completing the draw, reactivate the burner, compressor, or
heating elements(s) and allow the unit to fully recover such that
the main burner, heating elements, or heat pump compressor is no
longer raising the temperature of the stored water. Let the water
heater sit idle again for 1 hour prior to beginning the 24-hour
test, during which time no water shall be drawn from the unit, and
there shall be no energy input to the main heating elements. After
the 1-hour period, the 24-hour simulated-use test will begin.
At the start of the 24-hour simulated-use test, record the
electrical and/or fuel measurement readings, as appropriate. Begin
the 24-hour simulated-use test by withdrawing the volume specified
in the appropriate table in section 5.5 of this appendix (i.e.,
Table III.1, Table III.2, Table III.3, or Table III.4, depending on
the first-hour rating or maximum GPM rating) for the first draw at
the flow rate specified in the applicable table. Record the time
when this first draw is initiated and assign it as the test elapsed
time ([tau]) of zero (0). Record the average ambient temperature
every minute throughout the 24-hour simulated-use test. At the
elapsed times specified in the applicable draw pattern table in
section 5.5 of this appendix for a particular draw pattern, initiate
additional draws pursuant to the draw pattern, removing the volume
of hot water at the prescribed flow rate specified by the table. The
maximum allowable deviation from the specified volume of water
removed for any single draw taken at a nominal flow rate of 1.0 GPM
or 1.7 GPM is 0.1 gallons ( 0.4 liters).
The maximum allowable deviation from the specified volume of water
removed for any single draw taken at a nominal flow rate of 3.0 GPM
is 0.25 gallons (0.9 liters). The quantity of water
withdrawn during the last draw shall be increased or decreased as
necessary such that the total volume of water withdrawn equals the
prescribed daily amount for that draw pattern 1.0
gallon ( 3.8 liters). If this adjustment to the volume
drawn during the last draw results in no draw taking place, the test
is considered invalid.
All draws during the 24-hour simulated-use test shall be made at
the flow rates specified in the applicable draw pattern table in
section 5.5 of this appendix, within a tolerance of 0.25
gallons per minute (0.9 liters per minute). Measurements
of the inlet and outlet temperatures shall be made 15 seconds after
the draw is initiated and at every subsequent 3-second interval
throughout the duration of each draw. Calculate and record the mean
of the hot water discharge temperature and the cold water inlet
temperature for each draw Tdel,i and Tin,i).
Determine and record the net mass or volume removed (Mi
or Vi), as appropriate, after each draw.
The first recovery period is the time from the start of the 24-
hour simulated-use test and continues until the first cut-out; if
the cut-out occurs during a subsequent draw, the first recovery
period includes the time until the draw of water from the tank
stops. If, after the first cut-out occurs but during a subsequent
draw, a subsequent cut-in occurs prior to the draw completion, the
first recovery period includes the time until the subsequent cut-out
occurs, prior to another draw. The first recovery period may
continue until a cut-out occurs when water is not being removed from
the water heater or a cut-out occurs during a draw and the water
heater does not cut-in prior to the end of the draw.
At the end of the first recovery period, record the total energy
consumed by the water heater from the beginning of the test
(Qr), including all fossil fuel and/or electrical energy
use, from the main heat source and auxiliary equipment including,
but not limited to, burner(s), resistive elements(s), compressor,
fan, controls, pump, etc., as applicable.
The standby period begins at five minutes after the first time a
recovery ends following last draw of the simulated-use test and
shall continue for 8 hours. At the end of the 8-hour standby period,
record the total amount of time elapsed since the start of the 24-
hour simulated-use test (i.e., since [tau] = 0).
Determine and record the total electrical energy and/or fossil
fuel consumed from the beginning of the 24-hour simulated-use test
to the start of the 8-hour standby period (Qsu,0). In
preparation for determining the energy consumed during standby,
record the reading(s) given on the electrical energy (watt-hour)
meter, the gas meter, and/or the scale used to determine oil
consumption, as appropriate. Record the ambient temperature and the
electric and/or fuel instrument readings at 1-minute intervals until
the end of the 8-hour period. At the 8-hour mark, deactivate the
water heater and before drawing water from the tank. Remove water
from the storage tank by performing a continuous draw at a flow rate
of 3.0 GPM (11.4 L/min) 0.25 GPM (0.9 L/min) until the
outlet water temperature is within 2 [deg]F (1.1 [deg]C) of the inlet water temperature for 15 consecutive
seconds. While removing the hot water, measure the inlet and outlet
temperature beginning 15 seconds after initiating the draw and at 3-
second intervals thereafter until the outlet condition has
stabilized. Determine the mean tank temperature using section 6.3.9
of this appendix and assign this value of Tst for
Tsu,f and T24.
Determine the total electrical energy and/or fossil fuel energy
consumption from the beginning of the test to the end of the standby
period (Qsu,f). Record the time interval between the
start of the standby period and the end of the standby period as
[tau]stby,1. Record the average ambient temperature from
the start of the standby period to the end of the standby period
(Ta,stby,1). The average mean tank temperature from the
start of the standby period to the end of the standby period
(Tt,stby,1) shall be the average of Tsu,0 and
Tsu,f.
5.4.3 Test Sequence for Water Heaters with Rated Storage Volume
Less Than 2 Gallons.
Establish normal operation with the discharge water temperature
at 125 [deg]F 5 [deg]F (51.7 [deg]C 2.8
[deg]C) and set the flow rate as determined in section 5.2 of this
appendix. Prior to commencement of the 24-hour simulated-use test,
the unit shall remain in an idle state in which controls are active
but no water is drawn through the unit for a period of one hour.
With no draw occurring, record the reading given by the gas meter
and/or the electrical energy meter as appropriate. Begin the 24-hour
simulated-use test by withdrawing the volume specified in Tables
III.1 through III.4 of section 5.5 of this appendix for the first
draw at the flow rate specified. Record the time when this first
draw is initiated and designate it as an elapsed time, [tau], of 0.
At the elapsed times specified in Tables III.1 through III.4 for a
particular draw pattern, initiate additional draws, removing the
volume of hot water at the prescribed flow rate specified in Tables
III.1 through III.4. The maximum allowable deviation from the
specified volume of water removed for any single draw taken at a
nominal flow rate less than or equal to 1.7 GPM (6.4 L/min) is
0.1 gallons (0.4 liters). The maximum
allowable deviation from the specified volume of water removed for
any single draw taken at a nominal flow rate of 3.0 GPM (11.4 L/min)
is 0.25 gallons (0.9 liters). The quantity of water
drawn during the final draw shall be increased or decreased as
necessary such that the total volume of water withdrawn equals the
prescribed daily amount for that draw pattern 1.0 gallon
[[Page 42295]]
(3.8 liters). If this adjustment to the volume drawn in
the last draw results in no draw taking place, the test is
considered invalid.
All draws during the 24-hour simulated-use test shall be made at
the flow rates specified in the applicable draw pattern table in
section 5.5 of this appendix within a tolerance of 0.25
gallons per minute (0.9 liters per minute) unless the
unit being tested has a rated Max GPM of less than 1 gallon per
minute, in which case the tolerance shall be 25% of the
rated Max GPM. Measurements of the inlet and outlet water
temperatures shall be made 15 seconds after the draw is initiated
and at every 3-second interval thereafter throughout the duration of
the draw. Calculate the mean of the hot water discharge temperature
and the cold water inlet temperature for each draw. Record the mass
of the withdrawn water or the water meter reading, as appropriate,
after each draw. At the end of the first recovery period following
the first draw, determine and record the fossil fuel and/or
electrical energy consumed, Qr. Following the final draw
and subsequent recovery, allow the water heater to remain in the
standby mode until exactly 24 hours have elapsed since the start of
the test (i.e., since [tau] = 0). At 24 hours, record the reading
given by the gas meter, oil meter, and/or the electrical energy
meter, as appropriate. Determine the fossil fuel and/or electrical
energy consumed during the entire 24-hour simulated-use test and
designate the quantity as Q.
* * * * *
5.6 Optional Tests (Heat Pump-Type Water Heaters).
Optional testing may be conducted on heat pump-type water
heaters to determine EX. If optional testing is
performed, conduct the additional 24-hour simulated use test(s) at
one or multiple of the test conditions specified in section 2.8 of
this appendix. Prior to conducting a 24-hour simulated use test at
an optional condition, confirm the air and water conditions
specified in section 2.8 are met and re-set the outlet discharge
temperature in accordance with section 5.2.2 of this appendix.
Perform the optional 24-hour simulated use test(s) in accordance
with section 5.4 of this appendix using the same draw pattern used
for the determination of UEF.
* * * * *
6.3 * * *
6.3.1.1 Effective Storage Volume. The effective storage tank
capacity, Veff, is computed as follows:
Veff = kvVst
where:
Vst = as defined in section 6.3.1 and
kV = a dimensionless volume scaling factor determined as
follows:
[GRAPHIC] [TIFF OMITTED] TP14JY22.002
where:
Tmax,1 = the maximum measured mean tank temperature after
cut-out following the first draw of the 24-hour simulated-use test,
[deg]F([deg]C).
Tdel,2= the average outlet water temperature during the
second draw of the 24-hour simulated-use test, [deg]F([deg]C).
[rho](Tmax,1) = the density of the stored hot water
evaluated at the maximum measured mean tank temperature after cut-
out following the first draw of the 24-hour simulated-use test
(Tmax,1), lb/gal (kg/L).
Cp(Tmax,1) = the specific heat of the stored
hot water, evaluated at Tmax,1, Btu/(lb[middot][deg]F)
(kJ/(kg[middot][deg]C)).
[rho](125 [deg]F) = the density of the stored hot water at 125
[deg]F, lb/gal (kg/L).
Cp(125 [deg]F) = the specific heat of the stored hot
water at 125 [deg]F, Btu/(lb[middot][deg]F) (kJ/(kg[middot][deg]C)).
125 [deg]F (51.7 [deg]C) = the nominal maximum mean tank temperature
for a storage tank that does not utilize a mixing valve to achieve a
125 [deg]F delivery temperature.
67.5 [deg]F (19.7 [deg]C) = the nominal average ambient air
temperature.
* * * * *
6.3.9 Estimated Mean Tank Temperature for Water Heaters with
Rated Storage Volumes Greater Than or Equal to 2 Gallons. If testing
is conducted in accordance with section 5.4.2.2 of this appendix,
calculate the mean tank temperature immediately prior to the
internal tank temperature determination draw using the following
equation:
[GRAPHIC] [TIFF OMITTED] TP14JY22.003
Where:
Tst = the estimated average internal storage tank
temperature, [deg]F ([deg]C)
Tp = the average of the inlet and the outlet water
temperatures at the end of the period defined by [tau]p,
[deg]F ([deg]C).
vout,p = the average flow rate during the period, gal/min
(L/min).
Vst = the rated storage volume of the water heater, gal
(L).
[tau]p = the number of minutes in the duration of the
period, determined by the length of time taken for the outlet water
temperature to be within 2 [deg]F of the inlet water temperature for
15 consecutive seconds and including the 15-second stabilization
period.
Tin,p = the average of the inlet water temperatures
during the period, [deg]F ([deg]C).
Tout,p = the average of the outlet water temperatures
during the period, [deg]F ([deg]C).
* * * * *
6.5 Energy Efficiency at Optional Test Conditions. If testing is
conducted at optional test conditions in accordance with section 5.6
of this appendix, calculate the energy efficiency at the test
condition, EX, using the formulas section 6.3 or 6.4 of
this appendix (as applicable), except substituting the applicable
ambient temperature and supply water temperature used for testing
(as specified in section 2.8 of this appendix) for the nominal
ambient temperature and supply water temperature conditions used in
the equations for determining UEF (i.e., 67.5 [deg]F and 58 [deg]F).
[FR Doc. 2022-14687 Filed 7-13-22; 8:45 am]
BILLING CODE 6450-01-P