Energy Conservation Program for Consumer Products: Test Procedure for Residential Central Air Conditioners and Heat Pumps, 31224-31271 [2010-12271]

Agencies

• DEPARTMENT OF ENERGY

[Federal Register Volume 75, Number 105 (Wednesday, June 2, 2010)]
[Proposed Rules]
[Pages 31224-31271]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-12271]



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Part III





Department of Energy





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10 CFR Part 430



Energy Conservation Program for Consumer Products: Test Procedure for 
Residential Central Air Conditioners and Heat Pumps; Proposed Rule

Federal Register / Vol. 75, No. 105 / Wednesday, June 2, 2010 / 
Proposed Rules

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DEPARTMENT OF ENERGY

10 CFR Part 430

[Docket No. EERE-2009-BT-TP-0004]
RIN 1904-AB94


Energy Conservation Program for Consumer Products: Test Procedure 
for Residential Central Air Conditioners and Heat Pumps

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

ACTION: Notice of proposed rulemaking and public meeting.

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SUMMARY: The U.S. Department of Energy (DOE) proposes amendments to its 
test procedure for residential central air conditioners and heat pumps. 
The proposed amendments would add requirements for the calculation of 
sensible heat ratio, incorporate a method to evaluate off mode power 
consumption, and add parameters for establishing regional measures of 
energy efficiency. DOE will hold a public meeting to receive and 
discuss comments on the proposal.

DATES: DOE will hold a public meeting in Washington, DC on Friday, June 
11, 2010 from 9 a.m. to 4 p.m. The purpose of the meeting is to receive 
comments and to help DOE understand potential issues associated with 
this proposed rulemaking. DOE must receive requests to speak at the 
meeting before 4 p.m. Friday, June 4, 2010. DOE must receive a signed 
original and an electronic copy of statements to be given at the public 
meeting before 4 p.m. Friday, June 4, 2010.
    DOE will accept comments, data, and other information regarding 
this notice of proposed rulemaking (NOPR) before or after the public 
meeting, but no later than August 16, 2010. See section V., ``Public 
Participation,'' of this NOPR for details.

ADDRESSES: The public meeting will be held at the U.S. Department of 
Energy, Forrestal Building, Room 8E-089. You may submit comments, 
identified by docket number EERE-2009-BT-TP-0004 and/or Regulation 
Identifier Number (RIN) 1904-AB94, by any of the following methods:
     Federal eRulemaking Portal https://www.regulations.gov.: 
Follow the instructions for submitting comments.
     E-mail: RCAC-HP-2009-TP-0004@ee.doe.gov. Include the 
docket number EERE-2009-BT-TP-0004 and/or RIN number 1904-AB94 in the 
subject line of the message.
     Postal Mail: Ms. Brenda Edwards, U.S. Department of 
Energy, Building Technologies Program, Mailstop EE-2J, 1000 
Independence Avenue, SW., Washington, DC 20585-0121. Please submit one 
signed paper original.
     Hand Delivery/Courier: Ms. Brenda Edwards, U.S. Department 
of Energy, Building Technologies Program, 6th Floor, 950 L'Enfant 
Plaza, SW., Washington, DC 20024. Telephone: (202) 586-2945. Please 
submit one signed paper original.
    Instructions: All submissions must include the agency name and 
docket number or RIN for this rulemaking. For detailed instructions on 
submitting comments and additional information on the rulemaking 
process, see section V., ``Public Participation,'' of this document.
    Docket: For access to the docket to read background documents or 
comments received, visit the U.S. Department of Energy, 6th Floor, 950 
L'Enfant Plaza, SW., Washington, DC 20024, (202) 586-2945, between 9 
a.m. and 4 p.m., Monday through Friday, except Federal holidays. Please 
call Ms. Brenda Edwards at (202) 586-2945 for additional information 
regarding visiting the Resource Room. Please note: DOE's Freedom of 
Information Reading Room (Forrestal Building, Room 1E-190) no longer 
houses rulemaking materials.

FOR FURTHER INFORMATION CONTACT: Mr. Wes Anderson, U.S. Department of 
Energy, Office of Energy Efficiency and Renewable Energy, Building 
Technologies Program, EE-2J, 1000 Independence Avenue, SW., Washington, 
DC 20585-0121. Telephone: (202) 586-7335. E-mail: 
Wes.Anderson@ee.doe.gov.
    Ms. Francine Pinto, U.S. Department of Energy, Office of the 
General Counsel, GC-71, 1000 Independence Avenue, SW., Washington, DC 
20585. Telephone: (202) 586-7432. E-mail: Francine.Pinto@hq.doe.gov.

SUPPLEMENTARY INFORMATION: 
I. Authority and Background
    A. Authority
    B. Background
II. Summary of the Proposed Rule
III. Discussion
    A. Framework Comment Summary and DOE Responses
    1. Test Procedure Schedule
    2. Bench Testing of Third-Party Coils
    3. Defaults for Fan Power
    4. Changes to External Static Pressure Values
    5. Fan Time Delay Relays
    6. Inverter-Driven Compressors
    7. Addition of Calculation for Sensible Heat Ratio
    8. Regional Rating Procedure
    9. Address Testing Inconsistencies for Ductless Mini- and Multi-
Splits
    10. Standby Power Consumption and Measurement
    B. Summary of the Test Procedure Revisions
    1. Modify the Definition of ``Tested Combination'' for 
Residential Multi-Split Systems
    2. Add Alternative Minimum External Static Pressure Requirements 
for Testing Ducted Multi-Split Systems
    3. Clarify That Optional Tests May Be Conducted Without 
Forfeiting Use of the Default Value(s)
    4. Allow a Wider Tolerance on Air Volume Rate To Yield More 
Repeatable Laboratory Setups
    5. Change the Magnitude of the Test Operating Tolerance 
Specified for the External Resistance to Airflow and the Nozzle 
Pressure Drop
    6. Modify Third-Party Testing Requirements When Charging the 
Test Unit
    7. Clarify Unit Testing Installation Instruction and Address 
Manufacturer and Third-Party Testing Laboratory Interactions
    8. When Determining the Cyclic Degradation Coefficient 
CD, Correct the Indoor-Side Temperature Sensors Used 
During the Cyclic Test To Align With the Temperature Sensors Used 
During the Companion Steady-State Test, If Applicable
    9. Clarify Inputs for the Demand Defrost Credit Equation
    10. Add Calculations for Sensible Heat Ratio
    11. Incorporate Changes To Cover Testing and Rating of Ducted 
Systems Having More Than One Indoor Blower
    12. Add Changes To Cover Triple-Capacity, Northern Heat Pumps
    13. Specify Requirements for the Low-Voltage Transformer Used 
When Testing Only Air Conditioners and Heat Pumps and Require 
Metering of All Sources of Energy Consumption During All Tests
    14. Add Testing Procedures and Calculations for Off Mode Energy 
Consumption
    15. Add Parameters for Establishing Regional Standards
    a. Use a Bin Method for Single-Speed SEER Calculations for the 
Hot-Dry Region and National Rating
    b. Add New Hot-Dry Region Bin Data
    c. Add Optional Testing at the A and B Test Conditions With the 
Unit in a Hot-Dry Region Setup
    d. Add a New Equation for Building Load Line in the Hot-Dry 
Region
    16. Add References to ASHRAE 116-1995 (RA 2005) for Equations 
That Calculate SEER and HSPF for Variable Speed Systems
    17. Update Test Procedure References to the Current Standards of 
AHRI and ASHRAE
IV. Regulatory Review
    A. Review Under Executive Order 12866
    B. Review Under the National Environmental Policy Act
    C. Review Under the Regulatory Flexibility Act
    D. Review Under the Paperwork Reduction Act

[[Page 31225]]

    E. Review Under the Unfunded Mandates Reform Act of 1995
    F. Review Under the Treasury and General Government 
Appropriations Act, 1999
    G. Review Under Executive Order 13132
    H. Review Under Executive Order 12988
    I. Review Under the Treasury and General Government 
Appropriations Act, 2001
    J. Review Under Executive Order 13211
    K. Review Under Executive Order 12630
    L. Review Under Section 32 of the Federal Energy Administration 
(FEA) Act of 1974
V. Public Participation
    A. Attendance at Public Meeting
    B. Procedure for Submitting Requests To Speak
    C. Conduct of Public Meeting
    D. Submission of Comments
    E. Issues on Which DOE Seeks Comment
VI. Approval of the Office of the Secretary

I. Authority and Background

A. Authority

    Title III of the Energy Policy and Conservation Act (42 U.S.C. 6291 
et seq.; EPCA or the Act) sets forth a variety of provisions designed 
to improve energy efficiency. Part A of Title III (42 U.S.C. 6291-6309) 
establishes the ``Energy Conservation Program for Consumer Products 
Other Than Automobiles.'' (This part was originally titled Part B; 
however, it was redesignated Part A in the United States Code for 
editorial reasons.) The program covers consumer products and certain 
commercial products (collectively ``covered products''), including 
residential central air conditioners and heat pumps having rated 
cooling capacities less than 65,000 British thermal units/hour (Btu/h). 
(42 U.S.C. 6291(1)-(2), (21) and 6292(a)(3))
    Under the Act, the overall program consists of testing, labeling, 
and Federal energy conservation standards. Manufacturers of covered 
products must use the test procedures prescribed under EPCA to measure 
energy efficiency, to certify to DOE that products comply with EPCA's 
energy conservation standards, and for representing the energy 
efficiency of their products. Similarly, DOE must use these test 
procedures when determining whether the equipment complies with energy 
conservation standards adopted pursuant to EPCA.
    Section 323 of EPCA (42 U.S.C. 6293) sets forth generally 
applicable criteria and procedures for DOE's adoption and amendment of 
such test procedures. For example, the Act states that ``[a]ny test 
procedures prescribed or amended under this section 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, as 
determined by the Secretary [of Energy], and shall not be unduly 
burdensome to conduct.'' (42 U.S.C. 6293(b)(3)) DOE's existing test 
procedures for central air conditioners and heat pumps adopted pursuant 
to these provisions appear under Title 10 of the Code of Federal 
Regulations (CFR) part 430, subpart B, appendix M (``Uniform Test 
Method for Measuring the Energy Consumption of Central Air Conditioners 
and Heat Pumps'').
    Further, if any rulemaking amends a test procedure, DOE must 
determine ``to what extent, if any, the proposed test procedure would 
alter the measured energy efficiency * * * of any covered product as 
determined under the existing test procedure.'' (42 U.S.C. 6293(e)(1)) 
If it determines that the amended test procedure would alter the 
measured efficiency of a covered product, DOE must amend the applicable 
energy conservation standard accordingly. (42 U.S.C. 6293(e)(2)) The 
amendments proposed in today's rulemaking will not alter the measured 
efficiency, as represented in the regulating metrics of SEER and HSPF. 
Thus, today's proposed test procedure changes can be adopted without 
amending the standards for SEER and HSPF.
    On December 19, 2007, the President signed the Energy Independence 
and Security Act of 2007 (EISA 2007; Pub. L. 110-140), which contains 
numerous amendments to EPCA. Section 310 of EISA 2007 established that 
the Department's test procedures for all covered products must account 
for standby and off mode energy consumption. (42 U.S.C. 6295(gg)(2)(A)) 
DOE must modify the test procedures to integrate such energy 
consumption into the energy descriptor(s) for each product, unless the 
Secretary determines that ``(i) the current test procedures for a 
covered product already fully account for and incorporate the standby 
mode and off mode energy consumption of the covered product; or (ii) 
such an integrated test procedure is technically infeasible * * * in 
which case the Secretary shall prescribe a separate standby mode and 
off mode energy use test for the covered product, if technically 
feasible. (42 U.S.C. 6295 (gg)(2)(A)) In addition, section 306(a) of 
EISA 2007 amended EPCA section 325(o)(6) to consider one or two 
regional standards for central air conditioners and heat pumps (among 
other products) in addition to a base national standard. (42 U.S.C. 
6295(o)(6)(B)) EPCA 325(o)(6)(C)(i) requires that DOE consider only 
regions made up of contiguous States. (42 U.S.C. 6295(o)(6)(C)(i)) 
Accordingly, today's proposed test procedure rulemaking includes 
additions that specifically address sections 306 and 310 of EISA 2007.

B. Background

    Most portions of the existing test procedure for central air 
conditioners and heat pumps were originally published as a final rule 
in the Federal Register on December 27, 1979. 44 FR 76700. DOE modified 
the test procedure on March 14, 1988, to expand coverage to variable-
speed central air conditioners and heat pumps, to address testing of 
split non-ducted units, and to change the method for crediting heat 
pumps that provide a demand defrost capability. 53 FR 8304.
    The next revision of the central air conditioners and heat pumps 
test procedure was published as a final rule on October 11, 2005, and 
became effective on April 10, 2006. 70 FR 59122. The October 2005 final 
rule provided a much needed updating to reference current standards, 
adopted improved measurement capabilities, and presented more detail on 
how to conduct the laboratory testing. The 2005 final rule also 
expanded coverage for equipment features previously not covered (e.g., 
two-capacity northern heat pumps, heat comfort controllers, triple-
split systems, etc.). During this revision process, the test procedure 
was significantly reorganized in an effort to improve its readability.
    On July 20, 2006, DOE published a proposed rule to consider 
additional changes to the test procedure in response to issues 
interested parties submitted before the October 2005 publication of the 
final rule. 71 FR 41320. DOE determined that it was appropriate to 
consider additional modifications to the test procedure for the 
following reasons: (1) To implement test procedure revisions for new 
energy conservation standards for small-duct, high-velocity (SDHV) 
systems; (2) to address test procedure waivers for multi-split systems; 
and (3) to address interested parties' concerns about sampling and 
rating after new energy conservation standards became effective on 
January 23, 2006. (10 CFR 432.32(c)(2)) DOE issued a final rule 
adopting relevant amendments to the central air conditioner and heat 
pump test procedures on October 22, 2007, which became effective on 
April 21, 2008. 72 FR 59906. This latter final rule was published 
before EISA's implementation on December 19, 2007; therefore, the test 
procedures did not incorporate the requirements in sections 306 and 310 
of EISA 2007.

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    While making changes necessary to comply with the amendments in 
EISA 2007, DOE is considering additional changes to the test procedure 
that were identified after finalizing the prior rulemaking.

II. Summary of the Proposed Rule

    DOE proposes amendments to its test procedure for residential 
central air conditioners and heat pumps. The amendments would add 
calculations for determination of sensible heat ratio (SHR), would 
incorporate a method to evaluate off mode power consumption, and would 
add parameters for establishing regional measures of energy efficiency.
    In addition to statutory requirements for amended test procedures, 
EISA 2007 has three separate provisions regarding the inclusion of 
standby mode and off mode energy use in any energy conservation 
standard that have bearing on the current test procedure rulemaking. 
First, test procedure amendments to include standby mode and off mode 
energy consumption shall not be used to determine compliance with 
standards established prior to the adoption of such test procedure 
amendments. (42 U.S.C. 6295(gg)(2)(C)) Second, standby mode and off 
mode energy use must be included into a single amended or new standard 
for a covered product adopted in a final rule after July 1, 2010. 
Finally, a separate standard for standby mode and off mode energy 
consumption is required if a single amended or new standard is not 
feasible. (42 U.S.C. 6295(gg)(3)(B))
    In order to accommodate the above-mentioned first provision, DOE 
clarifies that today's proposed amended test procedure would not alter 
the measure of energy efficiency used in existing energy conservation 
standards; therefore, this proposal would neither affect a 
manufacturer's ability to demonstrate compliance with previously 
established standards nor require retesting and rerating of existing 
units that are already certified. These amended test procedures would 
become effective, in terms of adoption into the CFR, 30 days after the 
date of publication in the Federal Register of the final rule in this 
test procedure rulemaking. However, DOE is proposing added language to 
the regulations codified in the CFR that would state that any added 
procedures and calculations for determining off mode energy consumption 
and regional cooling mode performance being proposed in order to 
satisfy the relevant provisions of EISA 2007 need not be performed at 
this time to determine compliance with the current energy conservation 
standards. Subsequently, and consistent with the second provision 
above, manufacturers would be required to use the amended test 
procedures' off mode and regional cooling mode provisions to 
demonstrate compliance with DOE's energy conservation standards on the 
effective date of a final rule establishing amended energy conservation 
standards for these products that address off mode energy consumption 
and/or regional cooling mode performance, at which time the limiting 
statement in the DOE test procedure would be revised or removed. 
Further clarification would also be provided that as of 180 days after 
publication of a test procedure final rule, any representations as to 
the off mode energy consumption and regional cooling mode performance 
of the products that are the subject of this rulemaking would need to 
be based upon results generated under the applicable provisions of this 
test procedure. (42 U.S.C. 6293(c)(2)) A separate standard for off-mode 
energy consumption is required if a single amended or new standard is 
not feasible. (42 U.S.C. 6295(gg)(3)(B))

III. Discussion

    The current standards rulemaking preliminary analysis for 
residential central air conditioners and heat pumps is ready for 
stakeholder review and comment. This preliminary analysis follows the 
first step in the standards rulemaking process, the release of the 
framework document (https://www1.eere.energy.gov/buildings/appliance_standards/residential/pdfs/cac_framework.pdf) and the subsequent June 
12, 2008 public meeting. At and following this latter meeting, 
stakeholder comments were received, some of which apply to today's 
proposed test procedure.
    In formulating today's notice of proposed rulemaking (NOPR), DOE 
considered these test procedure related comments and, where 
appropriate, proposed changes to the test procedure. Moreover, DOE 
responses to stakeholder comments are provided in the following subject 
areas:
    1. Test Procedure Schedule
    2. Bench Testing of Third Party coils
    3. Defaults for Fan Power
    4. Changes to External Static Pressure Values
    5. Fan Time Delay Relays
    6. Inverter-Driven Compressors
    7. Addition of Calculation for Sensible Heat Ratio
    8. Regional Rating Procedure
    9. Address Testing Inconsistencies for Ductless Mini- and Multi-
Splits
    10. Standby Power Consumption and Measurement
    Section III. A. provides a more in-depth discussion on those 
comments that questioned or disagreed with DOE's positions in the 
framework document.
    Section III. B. provides a summary of the proposed changes to the 
test procedure, including
    1. Modify the definition of ``tested combination'' for residential 
multi-split systems
    2. Add Alternative Minimum External Static Pressure Requirements 
for Testing Ducted Multi-Split Systems
    3. Clarify that Optional Tests May Be Conducted Without Forfeiting 
Use of the Default Value(s)
    4. Allow a Wider Tolerance on Air Volume Rate to Yield More 
Repeatable Laboratory Setups
    5. Change the Magnitude of the Test Operating Tolerance Specified 
for the External Resistance to Airflow and the Nozzle Pressure Drop
    6. Modify Third-Party Testing Requirements when Charging the Test 
Unit
    7. Clarify Unit Testing Installation Instruction and Address 
Manufacturer and Third-Party Testing Laboratory Interactions
    8. When Determining the Cyclic Degradation Coefficient 
CD, Correct the Indoor-Side Temperature Sensors Used During 
the Cyclic Test to Align with the Temperature Sensors Used During the 
Companion Steady-State Test, If Applicable
    9. Clarify Inputs for the Demand Defrost Credit Equation
    10. Add Calculations for Sensible Heat Ratio
    11. Incorporate Changes to Cover Testing and Rating of Ducted 
Systems Having More than One Indoor Blower
    12. Add Changes To Cover Triple-Capacity, Northern Heat Pumps.
    13. Specify Requirements for the Low-Voltage Transformer Used when 
Testing Coil-Only Air Conditioners and Heat Pumps and Require Metering 
of All Sources of Energy Consumption During All Tests
    14. Add Testing Procedures and Calculations for Off Mode Energy 
Consumption
    15. Add Parameters for Establishing Regional Standards
    As part of today's rulemaking, DOE provides the specific proposed 
changes to 10 CFR part 430, subpart B, appendix M, ``Uniform Test 
Method for Measuring the Energy Consumption of Central Air Conditioners 
and Heat Pumps.''

A. Framework Comment Summary and DOE Responses

    A notation in the form ``Southern Company Systems (SCS), No. 13 at 
p. 105'' identifies a written comment DOE

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has received and has included in the docket of this rulemaking. This 
particular notation refers to a comment (1) by the Southern Company 
Systems (SCS); (2) in document number 13 in the docket of this 
rulemaking; and (3) appearing on page 105 of document number 13.
1. Test Procedure Schedule
    Several interested parties commented that DOE should consider the 
timeline necessary when modifying this test procedure, and how the 
publication of the test procedure coincides with publication of the 
revised standard. (Southern Company Systems (SCS), No. 13 at p. 105; 
Air-Conditioning, Heating and Refrigeration Institute (AHRI), No. 13 at 
p. 116; the American Council for an Energy Efficient Economy (ACEEE), 
No. 13 at p. 117; Trane, No. 13 at p. 123)
    DOE is coordinating the publication timelines of both the test 
procedure and the amended standard. The test procedure NOPR will be 
open for public comments. DOE will then address those comments and 
publish a final test procedure rule. The associated standard will 
proceed concurrently with the test procedure rulemaking to maximize the 
time interval between the test procedure final rule and the revised 
energy standards final rule.
2. Bench Testing of Third-Party Coils
    The Northeast Energy Efficiency Partnerships (NEEP) comment stated 
that test procedures should require laboratory/bench testing for 
independent coil manufacturers' (ICM) indoor units. (NEEP, No. 37 at p. 
3) NEEP includes representatives from the Connecticut Office of Policy 
and Management, New Hampshire Office of Energy and Planning, Efficiency 
Maine, and Department of Energy Resources for the Commonwealth of 
Massachusetts.
    As amended, EPCA makes all residential central air conditioners and 
heat pumps sold in the United States subject to specific testing, 
rating, minimum efficiency, and labeling requirements. These 
requirements apply to complete systems, including those split systems 
where the outdoor components are provided by one manufacturer, while 
the indoor components are provided by a separate manufacturer. The 
typical two-manufacturer split system is where the indoor unit is 
provided by an ICM and the outdoor unit is provided by an original 
equipment manufacturer (OEM). Because the ICM wants to advertise the 
performance of its indoor coils with various OEM outdoor units, the ICM 
is responsible for obtaining the system seasonal energy efficiency 
ratio (SEER) and heating seasonal performance factor (HSPF) ratings 
according to DOE requirements. In obtaining these ratings, the ICM can 
either test complete systems or use a DOE-approved alternative rating 
method (ARM) to calculate the rating. Approval of the ARM requires 
laboratory test results for complete systems, but inputs to the ARM may 
or may not require testing of just the indoor unit. (10 CFR 430.24)
    Although DOE does not have the authority to regulate a component of 
an air conditioner or heat pump system, it does regulate the complete 
systems. The system ratings published by ICMs must be obtained in 
accordance with DOE requirements summarized above.
3. Defaults for Fan Power
    A Joint Comment stated that the present rating method does not 
credit advanced air handler designs adequately because the default 
value is much lower than the average air handler energy use observed in 
the field. (Joint Comment, No. 25 at pp. 4, 6-7) According to the Joint 
Comment, a low default value for fan power reduces the incentive to 
improve fan efficiency. The Joint Comment includes representatives from 
ACEEE, Appliance Standards Awareness Project (ASAP), the California 
Energy Commission (CEC), the Northwest Power and Conservation Council 
(NPCC), and the Western Cooling Efficiency Center (WCEC).
    Proctor Engineering Group (Proctor) stated that the inside coil fan 
energy needs to represent the median values from actual installations, 
and also provided input on the methodology for evaluating fan power 
based on air volume rate and equipment tonnage. (Proctor, No. 38 at p. 
1)
    NEEP stated that testing should be required for motors in actual 
operation and that the procedure should include provisions for testing 
while air handler fans are running. (NEEP, No. 37 at p. 3)
    Split-system ducted air conditioners and heat pumps are primarily 
designed for two different applications. These applications depend on 
whether the air conditioner or heat pump is installed with a hot-air 
furnace and share a common duct system. Air conditioners and heat pumps 
not designed for installation with a hot-air furnace must contain a 
blower to circulate air through the indoor coil and ductwork. Systems 
that include the integral or modular indoor blower are typically 
referred to as blower-coil units. Coil-only units--air conditioners and 
heat pumps designed for installation with a hot-air furnace--rely on 
the furnace blower to circulate air through the indoor coil, ductwork, 
and the furnace section when the compressor and outdoor fan are 
operating.
    The Joint Comment pertains to coil-only units, so discussion in the 
following paragraphs is limited to those products. This comment does 
not apply to blower-coil units within the test procedure because there 
is no required default assumption for the average air handler. With 
regard to the NEEP comment, the ratings for blower coil units already 
reflect the performance of the system's particular indoor blower. When 
blower coils are tested, the indoor blower operates, and its 
performance is accounted for in the measured system capacity and power 
consumption values and ultimately in SEER and HSPF.
    A coil-only air conditioner or heat pump can be installed with a 
multitude of new and existing furnaces. The key considerations for 
matching a coil-only unit with a furnace are (1) the furnace blower's 
ability to provide the necessary air volume rate for the system; and 
(2) whether the outlet flange dimensions of the furnace are compatible 
with the inlet flanges on the indoor coil-only section of the air 
conditioner or heat pump. Another factor for field application is 
whether the overall height (length) of the furnace and coil-only indoor 
section will fit into the available building space.
    The SEER and HSPF ratings represent the seasonal efficiencies of a 
complete, functioning air conditioner or heat pump system. However, 
coil-only split systems in laboratory testing are incomplete because a 
hot-air furnace is not part of the setup. Instead of the furnace 
blower, the exhaust fan in the test facility pulls air through the 
indoor unit of the coil-only system. The exhaust fan is located 
downstream of the test unit's indoor section, outlet instrumentation, 
and air volume measurement station. When the hot-air furnace and blower 
are removed from testing, the associated power consumption and measured 
cooling or heating capacity are adjusted to account for the 
hypothetical hot-air furnace blower. The Joint Comment asserted that 
the test procedure default value is too low and should require 
additional real-time blower testing. Proctor Engineering Group agreed 
and offered an alternative default equation based on data collected 
from actual installations.
    Given the variety of furnaces within which a coil-only unit may be 
installed, the range of blower sizes and associated efficiency of a 
complete installed system are unknown. As a result, there are several 
options for calculating the assumed power and heat contributions for 
the hypothetical hot-air furnace

[[Page 31228]]

blower. To obtain a SEER (and for heat pumps, an HSPF) rating for each 
coil-only split system, the hot-air furnace blower receives a default 
value. According to the DOE test procedure, the hypothetical hot-air 
furnace blower contribution is expressed in terms of power (watts) and 
heat (Btu/h) per unit of air volume rate (in this case, 1,000 standard 
cubic feet per minute [scfm]).
    Since it was issued in 1979, the DOE test procedure for central air 
conditioners and heat pumps has used the same default fan power and 
heat for rating coil-only air conditioners and heat pumps: 365 watts 
per 1,000 scfm and 1,250 Btu/h per 1,000 scfm. These default values 
result in the adjustment range from approximately 220 watts (750 Btu/h) 
for a 1.5-ton unit to approximately 730 watts (2,500 Btu/h) for a 5-ton 
unit.
    The default value does not indicate the efficiency of blowers in 
furnaces; it simply provides a means of comparing products on a 
complete system basis. The long-standing default values represent a 
typical furnace blower while not being overly conservative. Changing 
the default values would shift the SEER and HSPF ratings, but the 
ranking among most comparably sized equipment would change minimally, 
if at all. DOE evaluated the worst-case scenario: multiple units with 
the same SEER calculated using the existing fan power and heat 
defaults, but with degradation coefficients (CD) varying from 0.01 and 
0.25, and capacities differing up to 10 percent. If the SEER 
calculation uses a higher default like 500 watts per 1,000 scfm (1,700 
Btu/h per 1,000 scfm), the new SEER ratings would all decrease but lie 
within a range that spans less than 0.20 points (on the SEER rating 
scale). The minimal impact on the ranking lessens the need for better 
defaults. To determine whether higher default values better represent 
actual installations, DOE must address three questions:
     What data can accurately represent the typical 
installation?
     What coordination will ensure that blower coils and coil-
only units are evaluated on a common basis?
     Should poor duct systems affect equipment ratings?
    DOE expects that addressing these questions will require additional 
data collection, analysis, and input from interested parties. With 
minimal impact on altering the relative ranking among competing 
products combined with the need to answer the above questions, DOE 
chose not to propose alternative default values for the power and heat 
contribution of the hypothetical furnace blower used when calculating 
the SEER and HSPF for coil-only air conditioners and heat pumps.
4. Changes to External Static Pressure Values
    A Joint Comment stated that the current assumed inches of water 
column (in wc) values are lower than those typically found in the field 
and unrealistically deemphasize the importance of fan efficiency as a 
part of overall system effectiveness. (Joint Comment, No. 25 at pp. 4, 
6) The discrepancy often leads to less airflow in a field application, 
which generally improves latent (at the expense of sensible) capacity.
    The Joint Utility Comment suggested that new test conditions for 
external static pressure and default fan power should be consistent 
with current field research findings. (Joint Utility Comment, No. 30 at 
pp. 1, 21) The Joint Utility Comment includes representatives from 
Pacific Gas and Electric Company (PG&E), Southern California Edison, 
Sempra Energy Utilities (Southern California Gas Company and San Diego 
Gas and Electric Company; hereafter ``Sempra''), Sacramento Municipal 
Utility District, the Nevada Power Company, and Sierra Pacific Power.
    DOE received a number of comments requesting that the minimum 
external static pressure levels be increased. (Florida Solar Energy 
Center (FSEC), No. 31 at p. 4; Sempra, No. 13 at p. 121; SCS, No. 39 at 
p. 2) Additionally, Proctor Engineering Group (Proctor) provided a 
formula for estimating the static pressure based on the rated cfm/ton 
(Proctor, No. 38 at p. 2).
    Some split system and all single-package system air conditioners 
and heat pumps are sold with integral indoor blowers. Split systems 
with integral indoor blowers (i.e., blower-coil units) may be designed 
for ducted or non-ducted installation. The integral indoor blower may 
be located either upstream (push-through configuration) or downstream 
(draw-through configuration) of the indoor refrigerant-to-air heat 
coil.
    To mimic a field installation, single-package and blower-coil split 
air conditioners and heat pumps are laboratory tested with installed 
components to include the most restrictive filter(s), supplementary 
heating coils, and other equipment specified as part of the unit. The 
DOE test procedure allows testing of a ducted unit without an indoor 
air filter but requires a compensatory increase of 0.08 in wc for the 
minimum external static pressure requirement. Otherwise, the test 
procedure requires that the unit be installed and configured in 
accordance with the manufacturer's instructions.
    The DOE test procedure requires that a minimum external static 
pressure be equaled or exceeded during the wet-coil cooling mode test. 
If this requirement is not met initially, the configuration of the 
indoor unit is incrementally changed (e.g., switched to the next 
highest speed tap), and the wet-coil test is repeated until the 
measured external static pressure meets or surpasses the applicable DOE 
test procedure minimum value.
    Since its issuance in 1980, the DOE test procedure for central air 
conditioners and heat pumps has used the same set of minimum external 
static pressure values (except for SDHV systems): 0.10 in wc for 
systems with a rated cooling capacity less than or equal to 28,800 Btu/
h, 0.15 in wc for 29,000 to 42,500 Btu/h, and 0.20 in wc for 43,000 to 
64,500 Btu/h. The laboratory static pressure measurement tries to 
account for the supply and return home or building duct system unit 
flow resistance.
    Limited field testing reports and the general decline in the 
quality of installed duct systems (in part from the proliferation of 
the flexible duct) would support an increase in the minimum external 
static pressure. Efforts by building trades and code compliance 
communities to improve the quality of installed duct systems would 
support smaller increases in the minimum statics prescribed in the DOE 
test procedure. More field data would be helpful but would likely never 
be acquired to the level needed to provide a definitive basis for 
selecting new minimums. The greater impact of higher minimum external 
static pressures will be on lowering the SEER and HSPF of all units 
equally. Lacking a basis to propose new values or reference a consensus 
standard where alternatives to the current minimums are established, 
DOE chose not to propose an alternative to the existing minimum values 
as part of today's NOPR.
5. Fan Time Delay Relays
    FSEC and SCS commented that the fan time delay relays should be 
disabled for the SEER test procedure. (FSEC, No. 31 at p. 3; SCS, No. 
39 at p. 2)
    Many air conditioners and heat pumps employ a fan-off delay feature 
on the indoor blower. This delay, which is usually active for both the 
cooling and heating modes, is used to extract stored energy from the 
indoor coil immediately after the compressor has cycled off. The indoor 
blower typically continues to operate for 45 to 90 seconds after the 
compressor cycles off.

[[Page 31229]]

    The DOE test procedure seeks to evaluate the performance of central 
air conditioners and heat pumps without making the process overly 
burdensome or expensive. The test procedure includes optional cyclic 
tests used to quantify the degradation in performance from the system 
cycling (predominantly in field installation) compared with operating 
continuously (as in most laboratory tests). During these cyclic tests, 
the fan-off delay feature is not disabled. The evaluation thus accounts 
for an incremental increase in total delivered capacity at the expense 
of increased electrical energy consumption in extending the indoor 
blower operation.
    Disabling the fan time delay from central air conditioners and heat 
pumps during the cooling season will prevent re-evaporation of moisture 
on the indoor coil and in the condensation pan. Substantial re-
evaporation can occur if the indoor blower continues for an extended 
period after compressor shutoff. Because of this evaporative mechanism, 
continuous fan operation is discouraged during the cooling season. 
However, DOE is not aware of definitive data that show significant re-
evaporation during short fan-off delays. Part of the data void is due 
to the challenge of measuring rapidly changing values (humidity and 
temperature) during the relatively short fan-off delay period. Because 
of this difficulty, the cyclic cooling mode test, used in establishing 
the SEER, is conducted at an indoor wet bulb (wb) temperature that 
results in a dry coil. This also explains why this test cannot be used 
to address the concern about re-evaporation.
    In a related comment, Proctor recommended conducting the cooling 
mode cyclic tests with the indoor conditions set to the same values 
used for the steady-state tests, 80 degrees Fahrenheit ([deg]F) dry 
bulb (db)/67 [deg]F wb (Proctor, No. 38 at p. 2). Proctor stated that 
such a change to wet-coil cooling mode cyclic tests is well within the 
reach of today's measurement technologies.
    DOE needs additional information to quantify the potential benefits 
of converting from dry-coil to wet-coil cyclic testing. DOE must 
evaluate any potential benefits relative to any laboratory upgrades 
that would be needed to achieve acceptably accurate and repeatable 
results across the industry, and the impact of changing the time 
required to run a cyclic test. DOE seeks data and information that 
would aid efforts to quantify the relative performance impact and 
associated expense of laboratory upgrades in combination with 
achievable measurement uncertainty. Until more is known about the 
impact of changing from the long-standing dry-coil tests to a wet-coil 
cyclic test, DOE has tentatively decided not to modify this test 
procedure to convert to wet-coil cyclic testing.
6. Inverter-Driven Compressors
    Mitsubishi Electric and Electronics USA, Inc. (MEUS) commented that 
new systems incorporating inverter-driven compressor technology require 
a modification to the test procedure. (MEUS, No. 13 at p. 19)
    Since 1988, the DOE test procedure has covered air conditioners and 
heat pumps with variable-speed compressors, single indoor units, and 
single outdoor units. The October 2007 final rule extended coverage to 
variable-speed multi-split systems. 72 FR 59906. Before DOE can offer a 
more substantive evaluation of the comment, DOE will need specific 
examples, including laboratory data, of how the test procedure fails to 
capture the performance characteristics of an air conditioner or heat 
pump that uses ``new inverter-driven compressor technology.''
7. Addition of Calculation for Sensible Heat Ratio
    The Joint Comment contended that the latent heat removal capability 
of CAC equipment should be measured under typical operating conditions, 
as opposed to high temperature conditions, and should be certified for 
all models sold in hot and humid climates. (Joint Comment, No. 25 at p. 
4) FSEC expressed similar views and suggested that the latent heat 
ratio should be measured under different test conditions for single 
speed and multi-speed equipment. (FSEC, No. 31 at p. 2) Ice Energy 
suggested that the dehumidification capability of CAC equipment under 
hot and humid conditions be included in the standard, and any regional 
standard for the Southeast region should address this issue. (Ice 
Energy, No. 33 at p. 3) On the other hand, the Edison Electric 
Institute (EEI) wants dehumidification capability to be included in the 
standards for all regions. (EEI, No. 20 at p. 4) SCS stated that for 
hot and humid climates, a higher dehumidification capacity should be 
incorporated in the standard. (SCS, No. 13 at p. 42) SCS also stated 
that any regional air conditioning standard should provide for minimum 
dehumidification performance that should be measured at normal 
operating conditions and not at a higher temperature like 95 [deg]F. 
(SCS, No. 39 at p. 1) The Joint Utilities Comment stated that DOE 
should require that all units be certified and rated for SHR at 82 
[deg]F ambient db temperature. (Joint Comment, No. 30 at pp. 1, 21) 
Proctor stated that the rating for humid climates should include 
information about what portion of the capacity is latent. (Proctor, No. 
38 at p. 2)
    DOE proposes including the calculation for the SHR within the 
revised DOE test procedure. (10 CFR part 430, subpart B, appendix M, 
revised section 3.3c and proposed section 4.5) The Federal Trade 
Commission (FTC) could then consider incorporating this information in 
labels for these products.
8. Regional Rating Procedure
    DOE received some comments that were supportive and others that 
were neutral on the development of regional ratings. The Joint Comment 
noted that DOE already applies regional rating methods in the current 
test procedure for residential central air conditioners and heat pumps. 
(Joint Comment, No. 25 at pp. 3-4) It further noted that adoption of 
regional rating methods might allow DOE to set standards of comparable 
stringency, but using different rating conditions. (Joint Comment, No. 
25 at p. 8) Ice Energy stated that the test protocol should be 
comprehensive and should span outdoor ambient conditions over the 
complete range of expected operating conditions. (Ice Energy, No. 33 at 
p. 3) FSEC stated that DOE should develop new cooling season bin 
temperature profiles using 2008 typical meteorological year (TMY) data 
from the National Renewable Energy Laboratory (NREL). (FSEC, No. 31 at 
pp. 3-4) The National Rural Electric Cooperative Association (NRECA) 
commented that DOE should evaluate whether its test procedures account 
for the vast differences in ambient humidity levels in different 
regions. The air conditioner and heat pump standards should also take 
into account the effects of humidity on different regional standards. 
(NRECA, No. 35 at p. 1)
    A second Joint Comment (Joint Comment 2) from the National 
Resources Defense Council, National Consumer Law Center, Inc., and 
Enterprise stated that DOE should strengthen the SEER test procedure to 
provide a more robust measure of actual performance in varying 
conditions in different regions. (Joint Comment 2, No. 36 at p. 2) PG&E 
noted that DOE needs to reevaluate test procedures to determine the 
performance of this equipment in the various climate zones. (PG&E, No. 
13 at p. 116) EEI suggested

[[Page 31230]]

that the test procedure be updated to account for ambient conditions in 
hot-dry and hot-humid climates. (EEI, No. 20 at p. 3) Proctor commented 
that the temperature bins used for the rating calculation are not 
representative of the hotter portions of the United States and provided 
data representative of specific hot climates. Proctor also commented 
that the ratings for dry climates should be based only on the sensible 
capacities measured in the test, and suggested that the sensible 
capacities and latent capacities, as well as the appropriate watt 
draws, be measured in the existing 115 [deg]F test. Further, the 
results of that test should be used in conjunction with any 
intermediate tests to establish the relationship between the energy 
efficiency ratio (EER) and outdoor temperature. Proctor also suggested 
that in defining regions, DOE start with examination of the existing 
DOE climate map (currently used in the DOE Building Energy Codes 
Program), which defines dry and humid regions of the United States. 
(Proctor, No. 38 at pp. 1, 2) SCS also commented that measuring 
performance at 115 [deg]F would allow the design of temperature bin 
profiles that better reflect the actual climate of the desert 
Southwest. SCS supports the concept of a regional rating that reflects 
actual weather conditions, stating that for a ``hot-dry'' regional 
standard, setting the performance rating at 115 [deg]F would be of 
great value to consumers and would not put an unreasonable burden on 
manufacturers. (SCS, No. 39 at p. 2) SCS stated, however, that it is 
neutral at this time on whether a hot-humid regional standard should be 
established, due to uncertainties about changes in test procedures, 
future design options manufacturers could use to reach higher 
efficiency, of the ability of local jurisdictions to limit use of 
equipment with poor dehumidification performance, and changes in 
consumer repair versus replacement or substitute behavior due to higher 
standards. (SCS, No. 39 at pp. 2, 3, 4)
    Regarding the comments that favor region-specific cooling mode 
performance evaluations, DOE proposes changes that will allow the 
calculation of a region-specific SEER. (10 CFR 430, subpart B, appendix 
M, proposed section 2.2e and revised sections 3.2.1, 3.2.2.1, 3.2.3, 
and 3.2.4) The calculation parameters that permit this proposed region-
specific SEER are the fractional bin hour distribution and the outdoor 
design temperature. DOE proposes modifying the indoor wet bulb 
temperature as part of additional required and optional testing. (10 
CFR part 430, subpart B, appendix M, revised sections 3.2.1 (table 3A), 
3.2.2.1 (table 4A), and 3.2.2 (table 5A)) These test procedure proposed 
changes will complement efforts to evaluate the merit of a regional 
standard for a cooling-dominated region with dry climate. DOE believes 
that similar changes are not needed for cooling-dominated States with 
humid climates. The current indoor side entering wet-bulb test 
condition of 67 [deg]F, fractional bin-hour distribution, and outdoor 
design temperature sufficiently represent the conditions for a humid 
climate. Calculation of the SHR from such existing tests, however, is 
proposed in today's NOPR to quantify the product's dehumidification 
capabilities.
    Section 306(a) of EISA amended section 325(o) of EPCA to require 
that regions defined for the purposes of regional standards are 
required to be composed of contiguous States. (42 U.S.C. 
6295(o)(6)(C)(i)) In addition, individual States shall be placed only 
into a single region. (42 U.S.C. 6295(o)(6)(C)(iii)) DOE is proposing 
an alternative regional efficiency metric, a region-specific SEER 
(SEER-HD) for a four-State region consisting of Arizona, California, 
Nevada, and New Mexico. The proposed SEER-HD reflects equipment 
performance in this region.
    DOE does not endorse the recommendation to add testing at 115 
[deg]F outdoor temperature. A linear fit of data collected from the 
cooling mode tests at 82 [deg]F and 95 [deg]F can sufficiently estimate 
capacity and power consumption at 105 [deg]F, 110 [deg]F, and even 115 
[deg]F. Interested parties have not provided, and DOE has not 
identified, examples where a SEER rating or the proposed region-
specific SEER was statistically different as a result of being 
evaluated based on laboratory data at 115 [deg]F as opposed to 95 
[deg]F.
    In other related comments, ACEEE asked how DOE would capture and 
evaluate the efficiency of continuous ventilation for regional 
standards, as it is provided and used in a reasonable fraction of 
houses. (ACEEE, No. 13 at p. 138) Sempra indicated that the test 
protocols should be able to accommodate technologies other than air-
cooled expansion unitary equipment. Sempra also commented that DOE 
should consider using the time value of energy in the new test 
procedures. (Sempra, No. 13 at p. 121) WCEC contended that certain 
changes in the test procedures could result in energy savings: (1) A 
24-hour test protocol that can measure and characterize the energy and 
peak demand implications of control and thermal storage technologies; 
(2) a test protocol that provides different types of evaporative-cooled 
equipment with directly comparable SEER ratings; and (3) a test 
protocol that seriously addresses installation and performance-
longevity issues. (WCEC, No. 41 at p. 2) ACEEE stated that DOE could 
use an alternative rating route to deal with enhanced dehumidification 
products. (ACEEE, No. 13 at p. 154)
    Regarding installation and performance longevity issues, DOE does 
not have the authority to implement new performance metrics for 
characterizing such features at this time. Presently, the only metrics 
available for representing performance are SEER and HSPF. These are 
seasonal performance metrics and are not useful for characterizing 
installation issues, performance longevity, or quantifying performance 
at peak demand.
    DOE notes that while there may be value in defining a test 
procedure that can provide consistent, comparable rating of alternative 
cooling systems, including evaporative cooling technologies and 
technologies incorporating thermal storage, such expansion of the test 
procedure is beyond the scope of this rulemaking. This rulemaking seeks 
to address changes mandated in EISA and otherwise improve upon coverage 
of comparatively conventional air conditioners and heat pumps. 
Determining additions and changes needed to allow testing and rating of 
thermal storage technologies, for example, is a formidable task, one 
that requires significant investigation. Such an investigation is 
difficult to pursue until such equipment is readily available as a 
commercial product.
9. Address Testing Inconsistencies for Ductless Mini- and Multi-Splits
    Two interested parties commented that there are inconsistencies 
within the central air conditioning test procedure for mini- and multi-
split systems. (MEUS, No. 13 at p. 21 and 22; Daikin, No. 28 at p. 6)
    The proposed changes to items 1 through 3 of Appendix M, cover test 
procedure changes addressing inconsistencies for ductless mini- and 
multi-splits. In response to the comments, DOE proposes three changes 
to the test procedure to address these inconsistencies: (1) Modify the 
definition of tested combination for multi-split systems. DOE proposes 
to use the term ``nominal cooling capacity'' within the definition of 
``tested combination'' (proposed change to 10 CFR 430, subpart A, 
section 430.2, Definitions, Tested Combination) and to simplify the 
requirements for multi-split systems with cooling capacities of

[[Page 31231]]

24,000 Btu/h or lower; (2) add an alternative minimum static pressure 
requirement for use when testing ducted multi-split systems (10 CFR 
430, subpart B, appendix M, proposed table 2); (3) clarify within the 
test procedure that optional testing may be conducted without 
forfeiting the use of default values (10 CFR 430, subpart B, appendix 
M, proposed section 3.6.4d).
10. Standby Power Consumption and Measurement
    Interested parties submitted comments refuting the need to revise 
the test procedure to consider standby power consumption when EISA does 
not explicitly call for its revision, and noting that standby power 
consumption is already addressed in the standard. (AHRI, No. 13 at p. 
105; Sempra, No. 13 at p. 133; Energy Solutions, No. 13 at p. 108; 
Emerson, No. 13 at p. 111) Some contended that the test procedure's 
accounting of standby power consumption is adequate and does not 
require modification. (Trane, No. 16 at p. 3; Carrier Corporation 
(Carrier), No. 18 at p. 1; ASAP, No. 13 at p. 114; MEUS, No. 19 at p. 
1; AHRI, No. 24 at p. 2). Trane and Carrier representatives both stated 
that the standby power consumption calculation is already captured in 
the degradation coefficient, CD calculation. (Trane, No. 16 
at p. 3; Carrier, No. 18 at p. 1)
    SEER reflects all modes of climate control energy consumption that 
occur during the cooling season, as HSPF does for the heating season. 
SEER does not capture the time that an air conditioner could be 
energized but idle during the non-cooling season. Similarly, the 
current test procedure does not capture energy consumed by a heat pump 
during the non-cooling and non-heating seasons. These are the shoulder 
seasons that occur between the cooling and heating seasons and can be 
quantified by converting the cooling and heating load hours for any 
location into actual hours. In each case, the actual site or region-
specific cooling and heating season hours always sum to less than 
8,760. To calculate annual energy consumption or annual operating cost, 
all 8,760 hours of the year must be accounted for. Until now, these 
annual quantities have been based on energy consumption of fewer than 
8,760 hours. The DOE test procedure must account for the idle mode 
energy consumption of the air conditioner and heat pump during the 
shoulder seasons and the idle mode energy consumption of an air 
conditioner during the heating season.
    Several interested parties commented that although the current 
standard does address standby power consumption, standby and off mode 
power need to be better defined. (Joint Comment, No. 25 at p. 6; CFM 
Equipment Distributors, No. 13 at p. 129; Lennox, No. 13 at pp. 113, 
134; Carrier, No. 13 at p. 113; the Unico System, No. 13 at p. 129; 
Trane, No. 13 at pp. 130, 131, 136; PG&E, No. 13 at pp. 132, 137; 
General Electric, No. 13 at p. 135; EEI, No. 20 at p. 5; ASAP, No. 13 
at p. 132)
    DOE concurs with the commenters. The definitions of standby and off 
mode as provided in EPCA section 325(gg) were amended by section 310 of 
EISA and are purposely generic so that they can apply to all covered 
products. (42 U.S.C. 6295(gg)(1)(A)(iii), (42 U.S.C. 
6295(gg)(1)(A)(ii), respectively) EPCA section 325 allows DOE to 
redefine these definitions, including off mode, as part of this 
rulemaking. (42 U.S.C. 6295(gg)(1)(B)) The proposed definition is as 
follows:

    The term ``off mode'' means:
    (1) For air conditioners, all times during the non-cooling 
season of an air conditioner. This mode includes the ``shoulder 
seasons'' between the cooling and heating seasons when the unit 
provides no cooling to the building and the entire heating season, 
when the unit is idle. The air conditioner is assumed to be 
connected to its main power source at all times during the off mode; 
and
    (2) For heat pumps, all times during the non-cooling and non-
heating seasons of a heat pump. This mode includes the ``shoulder 
seasons'' between the cooling and heating seasons when the unit 
provides neither heating nor cooling to the building. The heat pump 
is assumed to be connected to its main power source at all times 
during the off mode.
    DOE requests comments on this proposed definition (10 CFR, 
subpart B, appendix M, proposed section 1.48).

B. Summary of the Test Procedure Revisions

    Today's proposed rule contains the following proposed changes to 
the test procedure in 10 CFR part 430, subpart B, appendix M.
1. Modify the Definition of ``Tested Combination'' for Residential 
Multi-Split Systems
    DOE procedures require testing a complete system, not just its 
components. For multi-split systems, each model of outdoor unit may be 
installed with numerous indoor unit combinations. Systems may differ in 
the number of connected indoor units, their physical type (e.g., wall-
mounted versus ceiling cassette, ducted versus non-ducted), and 
individual capacities.
    As part of the October 2007 final rule, multi-split units with 
rated cooling capacities less than 65,000 Btu/h were newly covered in 
the DOE central air conditioner and heat pump test procedure. As part 
of this coverage, manufacturers are required to test each model of a 
multi-split outdoor unit with at least one set of non-ducted (and at 
least one set of ducted, if applicable) indoor units. DOE placed limits 
on the set of indoor units selected to meet this testing requirement 
for each multi-split outdoor unit. These limits are prescribed in 10 
CFR 430.2 definition for ``tested combination.'' During the previous 
test procedure rulemaking, DOE refined the ``tested combination'' 
definition from the version published in the July 20, 2006 NOPR to the 
version published in the October 2007 final rule. After implementing 
the new test procedures, manufacturers of multi-split systems requested 
additional changes.
    In its May 27, 2008 letter to DOE, the Air-Conditioning, Heating, 
and Refrigeration Institute (AHRI) recommended three changes to the 
``tested combination'' definition. First, AHRI supported changing 
specific references to ``capacity'' and ``nominal capacity'' to 
``nominal cooling capacity.'' AHRI argued that ``this correction is 
necessary to clarify that the test procedures are based on the cooling 
(rather than heating) capacity of the equipment and to recognize that 
the nominal means the cooling capacity of the system at 95 [deg]F 
ambient, 80/67 [deg]F indoor conditions.''
    Second, AHRI requested that the requirement preventing the use of 
an indoor unit having a nominal cooling capacity that exceeds 50 
percent of the nominal cooling capacity of the outdoor unit be waived 
for outdoor units with a nominal cooling capacity of 24,000 Btu/h or 
lower. AHRI noted that it is not always possible to meet this 
requirement, especially because of the additional DOE requirement that 
the nominal cooling capacities of the indoor units, when summed, must 
fall between 95 and 105 percent of the outdoor unit's nominal capacity. 
AHRI gave the example of an outdoor unit rated for 20,000 Btu/h that is 
designed to be used with indoor units having nominal capacities of 
9,000 and 12,000 Btu/h. In this case, the only combination that meets 
the 95 to 105 percent indoor-outdoor capacity criteria is where two 
indoor units are used, one having a capacity of 12,000 Btu/h and one 
having a capacity of 9,000 Btu/h. The current definition for tested 
combination, however, does not allow this combination because the 
12,000 Btu/h indoor unit exceeds the 50 percent limit on the capacity 
of the indoor unit to the capacity of the outdoor unit.
    AHRI's final suggested change pertains to multi-split systems with 
nominal capacities greater than 150,000

[[Page 31232]]

Btu/h. The current limit of five indoor units to complete the system is 
often insufficient for the required 95 to 105 percent match with the 
outdoor unit. As AHRI stated in its letter, AHRI recognizes that ``this 
capacity is beyond the cooling capacity limit of 65,000 Btu/h * * * but 
many manufacturers have been granted waivers in which this tested 
combination definition applies.''
    DOE concurs with two of the three changes AHRI requested. DOE 
proposes to adopt the wording ``nominal cooling capacity'' within the 
definition of ``tested combination.'' (10 CFR 430.2) DOE will also 
waive the restriction that no indoor unit shall have a nominal cooling 
capacity exceeding 50 percent of the outdoor unit's nominal cooling 
capacity for multi-split systems having a nominal cooling capacity of 
24,000 Btu/h or less. (10 CFR 430.2(2)(iii)) Additionally, DOE proposes 
to modify the definition for ``tested combination'' to indicate that 
the allowed range for the indoor to outdoor capacity percentages is 95 
to 105 percent, inclusive. (10 CFR 430.2(2)(ii) The current wording 
calls for the match to be ``between'' (i.e., not ``including'') these 
bounds. Especially with the above switch to using ``nominal cooling 
capacity,'' specifying a set of indoor units that yields an indoor to 
outdoor capacity percentage of either 95 or 105 percent increases 
should be allowed.
    With regard to the third change requested by AHRI, DOE will not 
establish a different limit on the number of indoor units used when 
testing multi-split systems with nominal capacities greater than 
150,000 Btu/h because these systems are outside the scope of this 
residential test procedure rulemaking.
2. Add Alternative Minimum External Static Pressure Requirements for 
Testing Ducted Multi-Split Systems
    Since the inception of DOE central air conditioner and heat pump 
test procedures, the majority of covered products have used a single 
indoor unit designed to work with a multi-branch duct system to 
distribute air within a building. This system imposes an additional 
load (quantified as external static pressure (ESP)) on the indoor 
blower as it distributes and returns air to and from the conditioned 
space.
    When a system is laboratory tested according to the DOE test 
procedure, airflow resistance imposed on the blower by external 
attachments is measured when the indoor blower and the laboratory's 
airflow measurement apparatus maintain the manufacturer-specified air 
volume rate. To constitute a valid setup for ducted indoor units, this 
external resistance measurement must equal or exceed a value--the 
minimum ESP expressed in wc--specified in the DOE test procedure. The 
minimum ESP value depends on one of three minimum rated cooling 
capacities of the tested system: 0.1 in wc for units up to 28,800 Btu/
h, 0.15 in wc for units between 29,000 and 42,500 Btu/h, and 0.2 in wc 
for units 43,000 Btu/h and above. These minimums were adopted from 
industry standards that were in place when the test procedure was 
developed and that have remained unchanged.
    The majority of multi-split systems use non-ducted indoor units. In 
laboratory testing following the DOE test procedure, these free 
discharge units are tested with an ESP of 0 in wc. Multi-splits are 
also offered where one or more of the indoor units is ducted. Compared 
with conventional ducted units, indoor unit ducting for multi-splits is 
shorter and used on the return or supply, or both.
    In its May 27, 2008 letter, AHRI stated that ``many ductless 
manufacturers have `ducted' indoor units that are intended for a 
minimum (less than a few feet) or no duct runs and as a result have a 
rated external static pressure capability of less than 0.1 ESP and 
usually around 0.02 ESP.'' AHRI recommended a mechanism and language 
for addressing this issue in the DOE test procedure. Specifically, AHRI 
suggested that DOE amend its test procedure by adding the following 
footnote to Table 2 of Appendix M (shown as Table III.1 below): ``If 
the manufacturer's rated external static pressure is less than 0.10 in 
wc (25 Pascals (Pa)), then the indoor unit should be tested at that 
rated external static pressure.''

     Table III.1--Minimum External Static Pressure for Ducted Systems Tested With an Indoor Fan Installed *
----------------------------------------------------------------------------------------------------------------
                                                                   Minimum External Resistance [dagger] in wc
                                                               -------------------------------------------------
          Rated cooling or heating capacity ** Btu/h