Energy Conservation Program for Consumer Products: Test Procedure for Residential Central Air Conditioners and Heat Pumps, 41320-41344 [06-6320]

Agencies

• DEPARTMENT OF ENERGY
• Office of Energy Efficiency and Renewable Energy
• Energy Efficiency and Renewable Energy Office

[Federal Register Volume 71, Number 139 (Thursday, July 20, 2006)]
[Proposed Rules]
[Pages 41320-41344]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-6320]



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Part II





Department of Energy





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Office of Energy Efficiency and Renewable 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. 71, No. 139 / Thursday, July 20, 2006 / 
Proposed Rules

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DEPARTMENT OF ENERGY

Office of Energy Efficiency and Renewable Energy

10 CFR Part 430

[Docket No. EE-RM/TP-02-002]
RIN 1904-AB55


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 Department of Energy (DOE or the Department) is proposing 
to amend its test procedure for residential central air conditioners 
and heat pumps. The proposal implements test procedure changes for 
small-duct, high-velocity systems, multiple-split systems, two-capacity 
units, and updates references to the current American Society of 
Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) 
standards. The proposal also clarifies issues associated with sampling 
and rating both tested and untested systems. The Department will hold a 
public meeting to discuss and receive comments on the proposal.

DATES: The Department will hold a public meeting on Wednesday, August 
23, 2006, from 9 a.m. to 4 p.m., in Washington, DC. The Department must 
receive requests to speak at the public meeting before 4 p.m., 
Wednesday, August 9, 2006. The Department must receive a signed 
original and an electronic copy of statements to be given at the public 
meeting before 4 p.m., Wednesday, August 16, 2006.
    The Department will accept comments, data, and information 
regarding the notice of proposed rulemaking (NOPR) before and after the 
public meeting, but no later than September 18, 2006. See section IV, 
``Public Participation,'' of this NOPR for details.

ADDRESSES: You may submit comments, identified by docket number EE-RM/
TP-02-002 and/or RIN number 1904-AB55, by any of the following methods:
    1. Federal eRulemaking Portal: https://www.regulations.gov. Follow 
the instructions for submitting comments.
    2. E-mail: cactestprocedure2006@ee.doe.gov. Include docket number 
EE-RM/TP-02-002 and/or RIN number 1904-AB55 in the subject line of the 
message.
    3. Mail: Ms. Brenda Edwards-Jones, U.S. Department of Energy, 
Building Technologies Program, Mail-stop EE-2J, NOPR for Test Procedure 
for Residential Central Air Conditioners and Heat Pumps, docket number 
EE-RM/TP-02-002 and/or RIN number 1904-AB55, 1000 Independence Avenue, 
SW., Washington, DC 20585-0121. Please submit one signed original paper 
copy.
    4. Hand Delivery/Courier: Ms. Brenda Edwards-Jones, U.S. Department 
of Energy, Building Technologies Program, Room 1J-018, 1000 
Independence Avenue, SW., Washington, DC 20585-0121. Telephone: (202) 
586-2945. Please submit one signed original paper copy.
    Instructions: All submissions received must include the agency name 
and docket number or Regulatory Information Number (RIN) for this 
rulemaking. For detailed instructions on submitting comments and 
additional information on the rulemaking process, see section IV of 
this document (Public Participation).
    Docket: For access to the docket to read background documents or 
comments received, visit the U.S. Department of Energy, Forrestal 
Building, Room 1J-018 (Resource Room of the Building Technologies 
Program), 1000 Independence Avenue, SW., Washington, DC, 20585-0121, 
Telephone Number: (202) 586-2945, between 9 a.m. and 4 p.m., Monday 
through Friday, except Federal holidays. Please call Ms. Brenda 
Edwards-Jones at the above telephone number for additional information 
regarding visiting the Resource Room. Please note: The Department's 
Freedom of Information Reading Room (formerly Room 1E-190 at the 
Forrestal Building) is no longer housing rulemaking materials.

FOR FURTHER INFORMATION CONTACT: Michael Raymond, Project Manager, Test 
Procedures for Residential Central Air Conditioners and Heat Pumps, 
Docket No. EE-RM/TP-02-002, 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 
Number: (202) 586-9611, e-mail: Michael.raymond@ee.doe.gov;
    Francine Pinto, Esq., U.S. Department of Energy, Office of the 
General Counsel, GC-72, 1000 Independence Avenue, SW., Washington, DC 
20585-0121, (202) 586-9507, e-mail: Francine.Pinto@hq.doe.gov.

SUPPLEMENTARY INFORMATION:
I. Summary of the Proposed Rule
    A. Overview
    B. Authority
    C. Background
    D. Summary of the Test Procedure Revisions
II. Discussion
    A. Proposed substantive changes to the test procedure in 
Appendix M
    B. Proposed substantive changes to other parts of the CFR that 
affect the testing and rating of residential central air 
conditioners and heat pumps
    C. Proposed non-substantive changes to other parts of the CFR
    D. Effect of test procedure revisions on compliance with 
standards
III. Procedural Requirements
    A. Review Under Executive Order 12866
    B. Review Under the Regulatory Flexibility Act
    C. Review Under the Paperwork Reduction Act
    D. Review Under the National Environmental Policy Act
    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 of 1999
    I. Review Under Executive Order 12630
    J. Review Under the Treasury and General Government 
Appropriations Act of 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
(FEA) Act of 1974
IV. 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
V. Approval of the Office of the Secretary

I. Summary of the Proposed Rule

A. Overview

    DOE completed a multi-year rulemaking process to update the DOE 
test procedure for residential central air conditioners and heat pumps 
on October 11, 2005, when it published an amended test procedure in the 
Federal Register. (70 FR 59122) (Hereafter referred to as the October 
2005 final rule.) Today's notice initiates a new rulemaking that 
addresses several test procedure issues that were identified too late 
in the prior rulemaking to allow stakeholders an opportunity to comment 
on them. The October 2005 final rule was concerned almost exclusively 
with Appendix M to Subpart B (the test method proper), which was 
completely replaced. Today's revision has significant updates to 
Subpart B itself, in 10 CFR section 430.24 (units to be tested). These 
revisions concern topics such as the alternative rating method used to 
provide efficiency ratings for untested split system combinations, data 
submission requirements, and sampling requirements. There are also 
revisions to the test procedure proper in

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Appendix M. These revisions have no common theme. Most are concerned 
with improving the accuracy of the test procedure, and with extending 
coverage to new central air conditioner features.

B. Authority

    Part B of Title III of the Energy Policy and Conservation Act (EPCA 
or the Act) establishes the Energy Conservation Program for Consumer 
Products Other Than Automobiles (Program). (42 U.S.C. 6291 et seq.) The 
products currently subject to this Program (``covered products'') 
include residential central air conditioners and heat pumps, the 
subject of today's notice.
    Under the Act, the Program consists of three parts: testing, 
labeling, and the Federal energy conservation standards. The Federal 
Trade Commission (FTC) is responsible for labeling, and DOE implements 
the remainder of the program. The Department, in consultation with the 
National Institute of Standards and Technology (NIST), is authorized to 
establish or amend test procedures as appropriate for each of the 
covered products. (42 U.S.C. 6293) The purpose of the test procedures 
is to measure energy efficiency, energy use, or estimated annual 
operating cost of a covered product during a representative, average 
use cycle or period of use. The test procedure must not be unduly 
burdensome to conduct. (42 U.S.C. 6293(b)(3)) The central air 
conditioner and heat pump test procedures appear in title 10 of the 
Code of Federal Regulations (CFR), part 430, subpart B, Appendix M.
    If a test procedure is amended, DOE is required to determine to 
what extent, if any, the new test procedure amendments 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 DOE determines 
that an amended test procedure would alter the measured energy 
efficiency of a covered product, DOE is required to amend the 
applicable energy conservation standard with respect to such test 
procedure. In determining any such amended energy conservation 
standard, DOE is required to measure the energy efficiency or energy 
use of a representative sample of covered products that minimally 
comply with the existing standard. The average efficiency or energy use 
of these representative samples, tested using the amended test 
procedure, constitutes the amended standard. (42 U.S.C. 6293(e)(2))
    Beginning 180 days after a test procedure for a covered product is 
prescribed, no manufacturer, distributor, retailer, or private labeler 
may make representations with respect to the energy use, efficiency, or 
cost of energy consumed by such products, except as reflected in tests 
conducted according to the DOE procedure.

C. Background

    The latest revision of the DOE test procedure for central air 
conditioners and heat pumps--which covers units having rated cooling 
capacities of less than 65,000 Btu/h--was published as a final rule on 
October 11, 2005 (70 FR 59122), effective April 10, 2006.
    After the January 22, 2001, publication of the proposed rule for 
the above rulemaking, stakeholders urged additional test procedure 
revisions. On December 13, 2002, DOE received stakeholder views on 
these revisions during a public workshop. (Hereafter referred to as the 
December 2002 workshop.) Written comments were received from the 
American Council for an Energy-Efficient Economy (ACEEE), Unico, Inc., 
Carrier Corporation, Lennox International, York International, and the 
Air-Conditioning and Refrigeration Institute (ARI). In addition, five 
requests for test procedure waiver have been received from 
manufacturers of multi-split central air conditioners. These waivers 
are necessary because the current test procedure is inadequate for 
testing these products.
    This test procedure revision addresses changes requested by 
stakeholders, either directly or through test procedure waiver 
requests. A full list of the changes appears in the next section. The 
primary reasons for these changes are: (1) To implement test procedure 
revisions that are needed because of new energy efficiency standards 
for small-duct, high-velocity (SDHV) systems; (2) to better address 
multi-split units test procedure waivers; and (3) to address sampling 
and rating issues that have been raised since the new minimum energy 
efficiency standards became effective on January 23, 2006.

D. Summary of the Test Procedure Revisions

    Today's proposed rule includes twelve substantive changes to the 
test procedure in Appendix M. It includes eight substantive changes and 
four non-substantive changes to other parts of the CFR that concern 
rating of central air conditioners and heat pumps. The proposed test 
procedure changes are:
    Proposed substantive changes to Appendix M:
    1. Imposing higher minimum external-static-pressure requirements 
and adding test-setup modifications for testing small-duct, high-
velocity systems. (Sections 2.2, 2.4.1, 2.5.4.2, and 3.1.4.1.2)
    2. Reinstating the option of conducting a cyclic test at high 
capacity when testing a two-capacity unit. (Sections 3.2.3, 3.4, 3.5, 
3.5.3, 3.6.3, 3.8, 3.8.1, 4.1.3.3, and 4.2.3.3)
    3. Shortening the maximum duration of a Frost Accumulation Test on 
a two-capacity heat pump when it is operating at low capacity. (Section 
3.9)
    4. Using default equations to approximate the performance of a two-
capacity heat pump operating at low capacity, instead of conducting a 
Frost Accumulation Test. (Section 3.6.3)
    5. For modulating multi-split systems: Allowing indoor units to 
cycle off, allowing the manufacturer to specify the compressor speed 
used during certain tests, and introducing a new algorithm for 
estimating power consumption. (Sections 2.1, 2.2.3, 2.4.1, 3.2.4, 
3.6.4, 4.1.4.2, and 4.2.4.2)
    6. Extending the duct-loss correction to the indoor capacities used 
for calculating seasonal energy efficiency ratio (SEER) and heating 
seasonal performance factor (HSPF). (Sections 3.3, 3.4, 3.5, 3.7, 
3.9.1, and 3.11)
    7. Defining ``repeatable'' for cyclic tests. (Section 3.5)
    8. Articulating a definition of ``standard air.'' (Definition 1.37)
    9. Changing one of the cooling-mode outdoor test conditions for 
units having a two-capacity compressor. (Sections 3.2.3 and 4.1.3)
    10. Renaming ``Cooling and Heating Certified Air Volume Rates'' to 
``Full-load Air Volume Rates.'' (Definition 1.34)
    11. Modifying the criterion for using an air volume rate that is 
less than the manufacturer's specified value. (Sections 3.1.4.1.1 and 
3.1.4.4.3)
    12. Revising references to ASHRAE Standards (e.g., Standards 23, 37 
and 116) that have been reaffirmed (i.e., reviewed and approved by 
ASHRAE with no substantive changes) or revised too recently to have 
been included in the amended test procedure published on October 11, 
2005.
    Proposed substantive changes to other parts of the CFR that affect 
the testing and rating of residential central air conditioners and heat 
pumps:
    1. New data-submission-requirements when verifying an alternative 
rating method. 10 CFR 430.24(m)(6).
    2. Guidance on the inclusion of pre-production units in the sample 
population used to determine and validate the published ratings. 10 CFR 
430.24.
    3. Clarification of the sample population used to validate the 
rated

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SEER and the rated HSPF. 10 CFR 430.24(m).
    4. Clarification of the definition of a ``highest sales volume 
combination.'' 10 CFR 430.24(m)(2).
    5. Upper limit on the difference between calculated and tested SEER 
and HSPF values. 10 CFR 430.24(m), 10 CFR 430.2.
    6. Clarification of the published ratings for untested split-system 
combinations. 10 CFR 430.24.
    7. Adding requirement that ratings for an air conditioner or heat 
pump that is rated with a furnace include the model number of that 
furnace as part of the overall equipment model number. 10 CFR 
430.62(a)(4).
    8. For products such as multi-splits which have multiple indoor 
units, instituting a ``tested combination'' as an alternative to 
testing the combination with ``the largest volume of retail sales.'' 10 
CFR 430.24(m)(2), 10 CFR 430.2.
    Proposed non-substantive changes to related portions of the CFR:
    1. Clarification of a private labeler's (i.e., a third party) 
responsibility for ensuring that reported ratings are based on an 
approved alternative method for rating untested combinations or on 
laboratory test data. 10 CFR 430.24(m)(5).
    2. Revisions to the definition of ``coil family.'' 10 CFR 430.2.
    3. New definition for ``private labeler'' within Sec.  430.2.
    4. Definitions of terms: ``indoor unit,'' ``outdoor unit,'' ``ARM/
simulation adjustment factor,'' and ``tested combination.'' 10 CFR 
430.2.
    An expanded discussion of each proposed substantive change is 
provided in the next section. The complete test procedure is not 
printed as part of today's proposed rule. Instead, only the specific 
sections of the test procedure and related parts of the CFR where 
changes are proposed are printed. These specific, proposed changes are 
set forth at the end of this notice.

II. Discussion

A. Proposed Substantive Changes to the Test Procedure in Appendix M

    1. Imposing higher minimum external-static-pressure requirements 
and adding test-setup modifications for testing small-duct, high-
velocity systems. Based on consideration of comments received at the 
December 2002 workshop, DOE today proposes minimum external-static-
pressure levels for SDHV systems that are higher, by 1.0 inch of water, 
than the minimums that apply for all other units. For example, for 
equipment having rated cooling capacities from 29,000 to 42,500 Btu/h, 
the minimum external static pressures are 0.15 inches of water for 
conventional blower-coil systems and 1.15 inches of water for SDHV 
systems.
    Changes to the test procedure that complement the proposed testing 
of SDHV systems at the higher external static pressures are also 
proposed today. Changes are proposed that pertain to both the equipment 
setup and the test setup. For example, because the external-static-
pressure taps for the laboratory test setup are located downstream of 
the indoor unit, all balance dampers or restrictor devices on, or 
inside, the unit must be set fully open or on the lowest restriction 
setting. To avoid potential abuses of using static regain to meet the 
lab-measured, higher external-static requirements and to otherwise 
avoid attempts to qualify a conventional unit as a SDHV unit, limits 
are proposed to the size of the duct connected to the outlet of the 
indoor unit. For cases where a closed-loop, air-enthalpy test apparatus 
is used on the indoor side, DOE proposes to limit the airflow 
resistance on the inlet side of the indoor blower-coil to a maximum 
value of 0.1 inch of water. The balance of the airflow resistance shall 
be imposed on the supply side of the indoor blower. Such loading is 
consistent with a field application of a SDHV system and its smaller 
supply ducts and room diffusers. Finally, the test setup shall include 
an adjustable air damper that is positioned immediately upstream of the 
airflow measuring apparatus. This damper can minimize air leakage in 
the airflow measuring apparatus at points upstream of the flow nozzle 
by reducing the pressure difference between the duct and the 
surrounding ambient. A maximum differential of 0.5 inches of water is 
proposed. If practicable, the outlet air damper box used for cyclic 
tests can double as this adjustable air damper.
    Regarding the above-proposed new requirements for equipment and 
test setup, only one was discussed at the December 13, 2002 workshop. 
This requirement concerns the distribution of the external resistance 
between the supply and return sides when using a closed-loop test 
setup. No attendee opposed this addition, and no opposing views were 
voiced in the written comments that followed. The other proposed 
additions were raised in written comments from Unico, Inc. (Unico), a 
SDHV manufacturer. (Unico, No. 7) \1\
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    \1\ A notation in the form ``Unico, No. 7 at 4'' identifies a 
written comment DOE received in this rulemaking. This notation 
refers to a comment (1) by Unico, (2) in document number 7 in the 
docket in this matter, and (3) appearing at page 4 of document 
number 7. No page number may be cited if it is not needed because of 
the brevity of the comment, or, as here, the comment is in the form 
of a series of e-mails.
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    A definition for SDHV systems was developed by industry members 
during the previous test procedure rulemaking, and was adopted as 
Definition 1.35 (10 CFR 430.2) in the October 2005 final rule. The 
combination of this definition, the higher, lab-verified minimum 
external-static-pressure requirements, and limits on supply-duct sizes 
provides a safeguard against conventional systems being classified 
improperly as SDHV systems.
    Today's proposed rule does not include changes to the definition of 
``SDHV system.'' The requirement remains that all SDHV systems must be 
capable of operating at an external static pressure of 1.2 inches of 
water, or higher, at their Full-Load Air Volume Rate. During the brief 
discussion of this issue at the December 2002 workshop, there was 
support for making the definition congruent with the newly proposed 
testing requirements (Public Hearing Tr., pages 20, 69). However, DOE 
believes that the difference between the definition (fixed-minimum 
external static pressure of 1.2 inches of water) and the test procedure 
requirement (variable-minimum external static pressure of 1.1-1.2 
inches of water, depending on capacity) is acceptable. Any unit meeting 
the definition can be tested under the test procedure. The test 
procedure's variable-minimum, external-static-pressure requirements 
reflect similar variable static-pressure requirements for conventional 
systems. The only effects of changing the definition to incorporate a 
variable-minimum, external-static-pressure requirement would be to make 
the definition more complicated and somewhat less stringent. DOE has 
determined that it would not improve the current definition of ``SDHV 
system'' if DOE made it congruent with the newly proposed lab testing 
requirements.
    The DOE's Office of Hearings and Appeals (OHA) issued a decision 
and order on May 24, 2004, that requires SDHV systems manufactured on 
or after January 23, 2006, to achieve SEER and Heating Seasonal 
Performance Factor (HSPF) ratings that are not less than 11.0 and 6.8, 
respectively. While the changes proposed today would change the measure 
of energy efficiency for SDHV units, the amendments proposed were known 
by OHA and taken into consideration when OHA issued exceptions to the 
central air conditioner

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standards for SDHV units.\2\ DOE expects that the test procedure 
amendments, as proposed, will not cause any SDHV product to become 
noncompliant with the energy efficiency standards for SDHV units set by 
OHA. DOE requests comments on the proposed changes, whether they will 
change the measure of energy use and whether they will cause any SDHV 
model to be non-compliant with DOE's energy efficiency standards. In 
particular, DOE requests stakeholders to submit lab test results that 
show the impact of these changes on the measure of efficiency and on 
compliance with the standard.
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    \2\ SpacePak/Unico, 29 DOE ] 81,002 (2004).
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    The specific changes proposed within the DOE test procedure that 
pertain to the above discussion on SDHV systems appear in sections 2.2, 
2.4.1, 2.5.4.2, and 3.1.4.1.2 of the central air conditioner and heat 
pump test procedure.\3\
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    \3\ For the aid of the reader, the January 1, 2006, CFR includes 
both the central air conditioner test procedure as it existed prior 
to the October 2005 final rule (Appendix M to Subpart B of 10 CFR 
Part 430) and the test procedure as it exists as a result of the 
October 2005 final rule (Appendix M, Nt. to Subpart B of 10 CFR Part 
430). References to the central air conditioner and heat pump test 
procedures in today's proposed rule are to the test procedure as it 
exists as a result of the October 2005 final rule (Appendix M, Nt. 
to Subpart B of 10 CFR Part 430). It is referred to as either the 
central air conditioner and heat pump test procedure or the October 
2005 test procedure.
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    2. Reinstating the option of conducting a cyclic test at high 
capacity when testing a two-capacity unit. Beginning with the January 
17, 1980, effective date of the DOE test procedure for central air 
conditioners and heat pumps, the test procedure provided a rarely used 
option of conducting cyclic testing at high capacity on two-capacity 
units. The October 2005 final rule eliminated the option of testing to 
obtain a cyclic-degradation coefficient for high capacity, 
CD(k = 2) and instead assigned the coefficient the same 
value as the cyclic-degradation coefficient for low capacity, 
CD(k = 2) = CD(k = 1), in order to simplify the 
test procedure. The change, however, caused some two-capacity units 
(i.e., ones that lock out low capacity at certain outdoor temperatures) 
to lose a small SEER or HSPF rating boost, usually in the 0.1 range, 
that would have been gained by the optional test. There are cases where 
a 0.1 boost in SEER or HSPF would be of great value to a manufacturer. 
Thus, today's proposed rule includes the option of testing to determine 
the high-capacity CD. Assigning the value for the low-
capacity CD as the high-capacity CD now becomes 
the default option instead of testing at high capacity. Reinstating the 
option of testing to determine the high-capacity CD was 
supported at the December 2002 workshop (Public Hearing Tr., pages 67-
68).
    The specific changes proposed within the DOE test procedure that 
pertain to the reinstatement of the optional, high-capacity cyclic 
tests are shown in sections 3.2.3, 3.4, 3.5, 3.5.3, 3.6.3, 3.8, 3.8.1, 
4.1.3.3, and 4.2.3.3 of the central air conditioner and heat pump test 
procedure.
    3. Shortening the maximum duration of a Frost Accumulation Test on 
a two-capacity heat pump when it is operating at low capacity. A frost 
accumulation test at low capacity is required if the heat pump cycles 
between low and high heating capacities while matching the building 
load at temperatures of 37[deg]F and lower. Completing such a frost 
accumulation test, as presently specified, can be difficult, as 
discussed below. DOE is proposing changes that seek to reduce the test 
burden, while avoiding changing the measure of HSPF.
    During a frost accumulation test, the official test period lasts 
for one complete cycle, from defrost termination to defrost 
termination--or 12 hours, whichever occurs first. Most heat pumps 
conduct a complete cycle well in advance of the 12-hour time limit, at 
least with single-speed units or two-capacity heat pumps operating at 
high capacity. When running a frost accumulation test at low capacity, 
however, the outdoor coil builds frost more slowly or not at all. As a 
result, frost accumulation tests on two-capacity heat pumps having a 
demand defrost and running at low capacity take much longer to 
complete, potentially requiring the full 12 hours--that is, if the test 
condition tolerances can be maintained over the extended period.
    The frost accumulation test conditions are, in themselves, a 
challenge to maintain. The task is more difficult when testing a two-
capacity heat pump at low capacity. The test-room air reconditioning 
system has to be sized to accommodate high-capacity operation and so is 
more likely mismatched and oversized. The level of difficulty also 
increases because of having to maintain the test-room tolerances over a 
comparatively longer period. More opportunity exists for a perturbation 
in the operation of the heat pump or the test-room reconditioning 
system to shift the test conditions beyond the allowed tolerances.
    Three related modifications to the test procedure were discussed at 
the December 2002, workshop. The first option is to change the maximum 
test interval from 12 hours to either 3 or 6 hours. A second option is 
to state in the test procedure that the controls of the heat pump may 
be overridden during frost accumulation tests at low capacity in order 
to force a defrost cycle prior to 12 hours. In this case, the 
manufacturer would specify the time interval after which defrost would 
be manually initiated. The third option is to add a default equation 
that could be used instead of running the test.
    The rationale for the first option comes from draft revisions of 
International Standards Organization (ISO) standards that cover the 
testing and rating of residential heat pumps and air conditioners, ISO 
Standards 5151 and 13253. (ISO/DIS 5151R, Non-ducted Air Conditioners 
and Heat Pumps--Testing and Rating for Performance; ISO/DIS 13253R, 
Ducted Air Conditioners and Air-to-Air Heat Pumps--Testing and Rating 
for Performance) Currently, these draft revisions call for all heating-
capacity tests to last a maximum of three hours when using the air-
enthalpy test method. The second option would be an extension of the 
procedure that was instituted in the October 2005 test procedure to 
handle heat pumps that use history-dependent demand-defrost controls. 
The manually initiated option was invoked to avoid running an excessive 
number of cycles before repeatable defrost cycles occurred. The third 
option is consistent with the existing alternative allowed when testing 
variable-speed heat pumps. Instead of running frost accumulation tests 
at both the intermediate speed and at maximum speed, the manufacturer 
has the option of using a specified equation to approximate the 
maximum-speed heating capacity and average power at 35[deg]F outdoor 
temperature.
    At the December 2002 workshop, two manufacturers, Trane and 
Copeland, spoke in favor of the default equation (Public Hearing Tr., 
pages 62-63). Ducane spoke in favor of a shorter maximum test time, 6 
hours instead of 12 hours (Public Hearing Tr., page 62). ACEEE 
expressed a desire for making no change that ultimately discourages 
innovation (Public Hearing Tr., page 64). York favored letting the 
manufacturer specify the duration of the heating cycle (Public Hearing 
Tr., page 65). There was also a discussion of making the third option, 
which is a default equation, the default procedure. It was suggested 
that if a manufacturer wanted to test, it could use either the first or 
second option (Public Hearing Tr., page 66).
    After considering recommendations from NIST, based on its 
experience, and discussions with industry members familiar with running 
frost accumulation tests, DOE believes that if

[[Page 41324]]

a heat pump has not defrosted in six hours, it is either (1) not 
building frost or (2) is completely frosted and probably has been so 
for more than half of the interval. In both cases, the benefits from 
continuing to run the test past 6 hours are none to minimal. For the 
``not-building-frost'' case, extending the test is going to have 
virtually no impact on the average heating capacity and average power 
consumption. For the ``completely frosted'' alternative, the tested 
values of average performance might diminish, but at such a slow rate 
as to be insignificant.
    Any benefit from an extended frost accumulation test, in addition, 
is further reduced because of the comparatively smaller impact of a 
low-capacity frost accumulation test on HSPF. The results of the low-
capacity frost accumulation test affect low-capacity performance for 
the 22, 27, 32, and 37[deg]F temperature bins. For two-capacity heat 
pumps, operating time over this bin temperature range is typically 
split between low and high capacities rather than being exclusively at 
low capacity.
    DOE believes a reduction in the manufacturers' test burden is 
merited and that any change in the measure of HSPF will be negligible. 
Thus, DOE today proposes that the maximum duration of a frost 
accumulation test at low capacity be changed from 12 hours to 6 hours. 
This test procedure change is shown in section 3.9 of the central air 
conditioner and heat pump test procedure.
    4. Using default equations to approximate the performance of a two-
capacity heat pump operating at low capacity, instead of conducting a 
Frost Accumulation Test. This section builds on the discussion of the 
previous section. Although the proposed amendment discussed above will 
reduce the test burden, DOE believes the test burden remains 
considerable, especially if HSPF is relatively insensitive to the 
performance data derived from the test. One example would be a two-
capacity heat pump that locks out low-capacity operation at outdoor 
temperatures lower than 35 [deg]F. Such a lockout feature would result 
in the average capacity and power consumption from the low-capacity 
frost accumulation test being used only for 37 [deg]F-bin calculations.
    DOE is amenable to allowing an alternative to conducting a low-
capacity frost accumulation test as long as the alternative yields 
conservative estimates of average capacity and power consumption. DOE 
has not been able to obtain information on typical performance 
degradation at frosting conditions. Data is needed to quantify how much 
the heat pump's performance at low-capacity and 35 [deg]F outdoor 
temperature departs from the average capacity and power derived from 
linearly interpolating between the steady-state-heating-performance 
data at 47 and 17 [deg]F. Lacking such data, DOE is following the 
recommendation made at the December 2002, workshop and proposes using 
the same default equations that it permits for variable-speed heat 
pumps in lieu of running a frost accumulation test at maximum speed. 
These equations estimate that the average heating-capacity and power-
consumption values will be 90 percent, and 98.5 percent, respectively, 
of the interpolated, steady-state values. These percentages, when 
applied to low-capacity operation, provide conservative estimates of 
performance and are proposed in this rulemaking.
    DOE prefers to have current laboratory data on which to base the 
selected conservative defaults. Thus, DOE requests that the industry 
share its results from testing two-capacity heat pumps at low capacity 
for the 47, 35, and 17 [deg]F test conditions. The change, as proposed, 
is shown in section 3.6.3 of the central air conditioner and heat pump 
test procedure.
    5. For modulating multi-split systems: allowing indoor units to 
cycle off, allowing the manufacturer to specify the compressor speed 
used during certain tests, and introducing a new algorithm for 
estimating power consumption. Certain parts of the current test 
procedure are poorly suited for testing and rating modulating multi-
splits. In particular, three areas where shortcomings exist are (1) the 
requirement that all indoor coils operate during all tests, (2) the 
selection of the modulation levels for conducting tests on variable-
speed systems (maximum, minimum, and a specified intermediate speed), 
and (3) the calculation algorithm for estimating performance over the 
intermediate speed/capacity range. The first area of concern results 
from a requirement developed for mini-split systems and then wrongly 
extended to multi-split systems. The second and third shortcomings stem 
from test levels and a calculation algorithm that are reasonable for 
one-condenser-to-one-evaporator-coil, variable-speed units but less 
suited for multi-splits.
    In an effort to incrementally improve the test procedure's coverage 
of multi-splits, DOE proposes: (1) Allowing one or more indoor coils to 
cycle off during any test, if this occurs in normal operation, (2) 
allowing the manufacturer to specify the compressor speed used during 
the minimum-capacity and intermediate-speed tests, and (3) introducing 
a different algorithm for estimating power consumption in the 
intermediate-speed range. Another test procedure change is to remove 
the limitation on the use of only one indoor test room. Using two or 
more indoor test rooms may provide the flexibility needed to test 
certain multi-splits as complete systems. DOE recognizes that this 
change, however, will not be a solution to the prevailing problem where 
many multi-split systems cannot be lab tested, even in the most 
versatile test facility, due to the too-large number of indoor coils.
    The allowance for turning off one or more indoor coils during any 
lab test, if this occurs in normal operation, will more likely be 
relevant during the intermediate and minimum speed/capacity tests. 
However, one or more indoor coils may not operate during a maximum-
capacity test if the particular multi-split is configured using 
multiple indoor coils whose cumulative rated capacities exceed the 
rated capacity of the outdoor unit. During testing, DOE proposes that 
indoor coils that are cycled off be isolated in order to avoid any 
induced space conditioning, so that the aggregated, measured capacity 
includes no contribution from an inactive coil.
    At the December 2002 workshop, and in the comments following the 
workshop, stakeholders did not make any objection to testing multi-
splits in the lab in a manner more representative of field operation. 
(Public Hearing Tr., page 54) Allowing on/off control of indoor coils 
in the lab is consistent with this position.
    As for the two other amendments relating to multi-splits that are 
proposed in this notice, a brief review of background information is 
helpful. Within the DOE test procedure, variable-speed air conditioners 
and heat pumps were first covered as a result of amendments to the 
central air conditioner and heat pump test procedures published by DOE 
in 1988. (53 FR 8304, March 14, 1988) These amendments addressed the 
designs of variable-speed systems marketed at the time: split systems 
having a single indoor coil and a single outdoor coil (i.e., one-
condenser-to-one-evaporator-coil systems). These systems could 
typically modulate, such that minimum-speed operation corresponded to 
capacities in the range of 40 to 60 percent of the maximum-speed 
capacity. More importantly, for the operating region where the unit 
modulates to produce a capacity equal to the building load, these 
systems operate most efficiently at the minimum speed with efficiency 
monotonically decreasing as the system ramped to maximum speed.

[[Page 41325]]

Further, because EER and COP are more linear than power consumption, 
DOE used efficiency as the parameter for interpolating within the DOE 
test procedure.\4\
---------------------------------------------------------------------------

    \4\ Domanski, Piotr A., ``Recommended Procedure for Rating and 
Testing of Variable Speed Air Source Unitary Air Conditioners and 
Heat Pumps,'' NBSIR 88-3781, National Institute of Standards and 
Technology, May 1988.
---------------------------------------------------------------------------

    The range of modulation of multi-splits is greater than for any 
previously evaluated one-condenser-to-one-evaporator-coil, variable-
speed system. Most multi-splits can modulate their capacity to levels 
approaching 10 percent of rated capacity. Rated capacity, for some 
multi-splits, can be 5 to 10 percent lower than their maximum capacity, 
thus adding to the actual range of modulation. Multi-split 
manufacturers have informed DOE and NIST that both the minimum and 
maximum operating capacities correspond to points of declining 
efficiency with peak efficiency typically occurring in the 50-to-70 
percent speed/capacity range. Thus, for a fixed set of ambient 
conditions, the efficiency-versus-modulation curve is expected to be 
hump-shaped.
    The central air conditioner and heat pump test procedure's current 
algorithm calls for fitting a second-order polynomial (i.e., quadratic 
equation) to the efficiency values for the three available data points: 
the minimum-speed balance point, the intermediate-speed balance point, 
and the maximum-speed balance point. The curve fit is used to obtain an 
estimate of efficiency over the outdoor temperature range where the 
unit would modulate to provide a space conditioning capacity that 
equals the building load. Power consumption at any intermediate speed 
operating point is derived from the paired capacity and efficiency 
values (i.e., power = building load/EER) corresponding to the chosen 
outdoor (bin) temperature.
    The above algorithm is well suited for one-condenser-to-one-
evaporator-coil, variable-speed systems because the intermediate-speed, 
efficiency-versus-modulation data is monotonic and nearly linear. Due 
to insufficient data, DOE cannot quantify the value of using the 
algorithm with multi-split units. In the worst case, multi-split 
efficiency may deviate significantly from the balanced, parabolic shape 
that would be predicted by the second-order-polynomial fit. Another 
potential problem is that the efficiency at the intermediate-speed 
balance point will likely not be the peak efficiency point. As a 
result, the predicted peak efficiency is defined by the curve fit and 
not verified in the lab. The algorithm is not well suited for multi-
split units, because the predicted efficiency curve may overestimate 
the performance of one unit while underestimating the performance of 
another unit.
    DOE seeks data showing how the capacity and power consumption of 
multi-split units vary as a function of the modulation level and 
outdoor test conditions. Lacking such data, DOE proposes to calculate 
steady-state efficiency (EER and COP) over the intermediate-speed range 
using piece-wise linear fits: a line connecting the minimum- and 
intermediate-capacity balance points and a line connecting the 
intermediate- and maximum-capacity balance points. The linear fits 
should yield a conservative estimate of performance but are favored 
because of concern that the second-order fit may provide poor and most-
likely inflated estimates.
    Associated with the proposal to use a piece-wise linear fit of 
steady-state efficiency, DOE also proposes that the multi-split 
manufacturer shall specify the system capacity (i.e., compressor speed, 
indoor coil configurations, fan speeds, etc.) used for the cooling and 
heating intermediate speed/capacity tests. This change is being 
proposed so that the manufacturer has an opportunity to verify the 
peak-efficiency capabilities of the multi-split unit being tested. 
Defining two other capacities, maximum and minimum, are the last points 
specific to this multi-split discussion.
    DOE proposes that multi-splits be tested at their maximum capacity 
(maximum compressor speed), or full load, not their rated capacity. The 
tested compressor speed shall be the maximum for continuous duty 
operation as allowed by the unit's controls. For clarity, this tested 
capacity is not a ``turbo'' mode where a higher operating speed(s) is 
allowed but for only a limited time interval. This clearer definition 
of the maximum speed/capacity test applies to all variable-speed 
systems, not just multi-splits.
    DOE considered an alternative approach of allowing the manufacturer 
to specify the compressor capacity/speed used for maximum-capacity 
tests. However, in use, the variable-capacity system operates at 
capacities/speeds above this rated capacity. DOE's goal is to specify 
tests that yield a performance map that is as encompassing and 
representative as possible. Specifying the maximum-capacity tests as 
proposed in this notice is consistent with this goal. The approach is 
also consistent with the full-load testing approach taken in comparable 
ISO standards, 13253, 5151, and 15042. (ISO/DIS 15042P, Multi-split 
System Air-Conditioners and Air-to-Air Heat Pumps--Testing and Rating 
for Performance)
    DOE next considered the option of allowing an additional test at 
the manufacturer's rated cooling capacity, for the sole purpose of 
defining the building load line used for the SEER bin calculations. DOE 
decided not to introduce this option due to possible confusion from 
having two SEER's. There could be one SEER based on a building load 
line tied to the unit's performance at the A-Test condition at maximum 
capacity, and a second SEER based on the load line derived using the 
rated capacity at the A-Test conditions. Manufacturers of variable-
capacity systems, including multi-splits, can still show the impact of 
sizing the unit based on a rated capacity.
    From a testing standpoint, conducting tests at the true minimum 
capacity, possibly 10 percent of full load, is difficult. The test room 
reconditioning system has difficulty operating against such low loads 
and maintaining test conditions within tolerance. Thus, the multi-
split's performance at its true minimum capacity may have to be 
determined by extrapolation of test data collected at higher capacities 
where the tests are more easily conducted. In this case, some short 
test would be needed to verify the true minimum operating capacity of 
the multi-split. Alternatively, SEER and HSPF could be calculated based 
only on the operational range verified in the steady-state lab tests. 
For example, if a multi-split were tested at 30 percent of capacity 
even though it was reportedly able to ramp down to 10 percent of 
capacity, the SEER and HSPF calculations would be conducted assuming 
that the unit would cycle on and off at building loads that fell below 
the 30 percent capacity curve.
    DOE proposes that the minimum-capacity test be conducted at a 
capacity specified by the manufacturer. The operating level can be 
either the equipment's true minimum or a capacity that is greater than 
the true minimum but nonetheless chosen by the manufacturer as its 
designated minimum capacity. DOE prefers that multi-split manufacturers 
specify a tested minimum capacity for which test-room tolerances are 
readily maintainable. As with the maximum-capacity test, the tested 
capacity shall be one that the unit could maintain indefinitely, if 
needed. DOE further proposes that SEER and HSPF shall be calculated 
assuming that the tested minimum capacity corresponds to the actual 
minimum capacity. Extrapolation

[[Page 41326]]

of performance data will not be permitted for the case where the tested 
minimum is actually higher than the true minimum. DOE, however, is open 
to comments on how to verify the true minimum-capacity operation such 
that extrapolation of performance data could be incorporated.
    At the December 2002 workshop, Trane recommended that a multi-split 
manufacturer make a recommendation on the new test points, possibly 
through a waiver petition (Public Hearing Tr., pages 55-56). Copeland, 
and to a certain extent, ACEEE, expressed concern that multi-splits may 
be difficult to test with the DOE test procedure for central air 
conditioners and heat pumps (Public Hearing Tr., pages 58-61). Since 
the workshop, DOE has received four waiver petitions from manufacturers 
of residential multi-split systems. All four petitions take the 
approach of seeking waivers from the DOE test procedures due to 
shortcomings in the test procedure (e.g., no credit for a simultaneous 
heating and cooling mode), the lack of an alternative method for rating 
untested combinations, and the fact that many multi-split combinations 
simply cannot be lab tested because they have too many indoor coils. 
These limitations are among those multi-split issues that will be 
addressed in the future.
    The changes proposed in this notice are offered to address some of 
the test procedure shortcomings pertaining to residential multi-split 
units. At this time, DOE prefers to pursue covering multi-splits within 
the central air conditioner and heat pump test procedure rather than 
pursue development of a ``multi-split-only'' test procedure. DOE 
welcomes comments on the proposed test procedure changes. For those 
that feel multi-split systems are so different as to merit coverage in 
a separate test procedure, DOE asks that they provide suggestions on 
the possible structure of such a test procedure.
    The specific changes proposed within the DOE test procedure that 
pertain to the above discussion on multi-split systems are shown in 
sections 2.1, 2.2.3, 2.4.1, 3.2.4, 3.6.4, 4.1.4.2, and 4.2.4.2 of the 
central air conditioner and heat pump test procedure.
    6. Extending the duct-loss correction to the indoor capacities used 
for calculating SEER and HSPF. In the recently published test procedure 
final rule, a capacity correction for duct losses was added. This 
correction was added for compatibility with existing industry practice. 
Regrettably, the correction was applied too narrowly. As published, the 
correction was only used when evaluating whether the required 6-percent 
energy balance was achieved between the primary and secondary test 
methods for measuring capacity. The correction is also to be used to 
adjust the indoor capacities used in calculating SEER and HSPF. Today's 
proposed rule includes this corrective action, with one exception. The 
exception applies to the two indoor capacities used for calculating a 
cyclic-degradation coefficient, CD. The effort involved in accounting 
for the duct losses, especially during a cyclic test, is judged as 
overly burdensome, given the adjustment's small effect. Its impact is 
further reduced because the CD calculation only requires the ratio of 
the two indoor capacities. Duct losses are minimal because the test 
procedure requires that the supply ductwork be insulated to an R-19 
level.
    This topic spurred little discussion at the December 2002 workshop. 
In fact, the only related substantive discussion was whether the 
correction could be made within the then-pending final rulemaking. DOE 
spoke in favor of the issue being considered in a second, separate 
rulemaking, and so it is included here. The specific changes proposed 
within the DOE test procedure that pertain to the above discussion are 
shown in sections 3.3, 3.4, 3.5, 3.7, 3.9.1, and 3.11 in the central 
air conditioner and heat pump test procedure.
    7. Defining ``repeatable'' for cyclic tests. In the October 2005 
final rule, the following requirement is provided in section 3.5e 
regarding the duration of a cyclic test: ``After completing a minimum 
of two complete compressor OFF/ON cycles, determine the overall cooling 
delivered and total electrical energy consumption during any subsequent 
data collection interval where the test tolerances given in Table 8 are 
satisfied.'' (70 FR 59122) Many test laboratories, however, let the 
test continue until the results are repeatable. These laboratories take 
extra time to make sure that they have it right; they go further than 
the specified ``one good interval and done'' test procedure 
requirement.
    In today's proposed rule, DOE proposes to include the additional 
requirement that repeatable results be obtained before terminating a 
cyclic test. DOE plans to follow industry practice for what qualifies 
as ``repeatable.'' At the December 2002 workshop, two attendees spoke 
to this issue (Public Hearing Tr., pp. 42-43). After the workshop, NIST 
discussed the issue with these two attendees, Excel Comfort Systems 
(Excel) and Intertek Testing Services (ITS). Excel indicated that it 
typically runs 5 OFF/ON cycles and compares the [Ggr], the time-
integrated temperature difference on the indoor side, from each ``on'' 
cycle. The goal is to have the [Ggr] values vary by 0.04 
[deg]F[middot]hr or less. ITS looks at two parameters when making a 
judgment on repeatable cycles. On the capacity side, ITS seeks 
consecutive cycles in which the average indoor side air temperature 
difference changes by 0.3 [deg]F or less. On the input side, ITS seeks 
consecutive cycles where the average system power consumption for the 
complete OFF/ON interval changes by 5 watts or less. The ITS criterion 
for capacity is slightly less stringent than the Excel Comfort Systems 
criterion. The input side criterion imposed by ITS offsets this slight 
difference.
    DOE favors defining ``repeatable results'' in terms of both the 
unit's average capacity (i.e., using the integrated temperature 
difference) and its average power consumption. As compared to the above 
two industry members and their respective in-house criteria, DOE today 
proposes comparatively looser target levels. They are: [Ggr] values 
that vary by 0.05 [deg]F[middot]hr or less; and consecutive cycles 
where the average system power consumption changes by 10 watts or less. 
See section 3.5 of the test procedure for the specific changes proposed 
on implementing and defining repeatable results for a cyclic test.
    8. Articulating a definition of ``standard air.'' The October 2005 
final rule contains a definition for ``standard air'' (see Sec.  1.37, 
Appendix M, Nt. to Subpart B of 10 CFR part 430). This definition was, 
at the time, consistent with the definition contained in the public 
review draft of ASHRAE Standard 37-1988R (see 10 CFR 430.22(5)3). 
During the public review process, the definition in the ASHRAE Standard 
was modified to highlight that mass density is the key defining 
parameter, not the combination of the dry air's temperature and 
pressure. DOE proposes to amend its definition of ``standard air'' so 
that it matches the definition that appears in ASHRAE Standard 37-2005. 
This change is included among the list of substantive changes to 
emphasize that consistency with the revised ASHRAE standard language 
causes standard air volume rates to be expressed in terms of dry air, 
not moist air. The proposed update is shown in the definition of 
``standard air'' in section 1.37 of the central air conditioner and 
heat pump test procedure.
    9. Changing one of the cooling-mode outdoor test conditions for 
units having a two-capacity compressor. To minimize the testing burden, 
the

[[Page 41327]]

cooling-mode tests for air conditioners and heat pumps having a two-
capacity compressor are conducted only at 82 [deg]F and 95 [deg]F 
outdoor-dry-bulb temperatures. The 82 [deg]F and 95 [deg]F test 
conditions tend to bracket the key temperature bins in which maximum 
compressor capacity most affects the SEER bin calculation. By 
comparison, the 82 [deg]F and 95 [deg]F test conditions span a range 
that tends to be higher than the key temperature bins in which minimum 
compressor capacity most affects the SEER bin calculations. As a 
result, for the lowest outdoor temperature bins (i.e., 67 [deg]F, 72 
[deg]F, and 77 [deg]F), cooling capacity and electrical power 
consumption at low (stage) compressor capacity are derived from 
linearly extrapolating the 82[deg] and 95 [deg]F test results. These 
extrapolated capacities and powers are more susceptible to inaccuracies 
and, unfortunately, can potentially reward poor performance. In the 
latter case, for example, increased electrical power consumption during 
the A1 Test at 95 [deg]F and low compressor capacity could 
potentially result in a higher SEER. The higher power consumption for 
the A1 Test could cause the power consumption for the 
heavily weighted 67 [deg]F, 72 [deg]F, and 77 [deg]F bins to be 
underestimated to the point that they more than offset the higher power 
consumptions for 87 [deg]F and higher temperature bins.
    In today's proposed rule, DOE proposes to change the outdoor 
conditions used for certain tests on two-capacity air conditioners and 
heat pumps. The first change is the elimination of the steady-state 
A1 Test at 95 [deg]F outdoor temperature. Instead, two-
capacity units will now be tested at an outdoor-dry-bulb temperature of 
67 [deg]F, and in those few cases where it applies, at an outdoor-wet-
bulb temperature of 53.5 [deg]F. The results from this new steady-state 
test, designated the F1 Test, shall be used in conjunction 
with the results from the current low-capacity test at 82 [deg]F 
outdoor-dry-bulb temperature (i.e., the B1 Test) to 
determine the low-capacity cooling capacity and power consumption 
values used in SEER bin calculations. With this change, those outdoor 
temperature bins where low-capacity operation dominates will now be 
more accurately derived by interpolating, as opposed to extrapolating.
    The above change caused DOE to consider two additional changes. 
Currently, the two tests used to determine the low-capacity, cooling-
mode cyclic-degradation coefficient, C\c\D(k=1), are 
conducted at 82 [deg]F outdoor-dry-bulb temperature. Given the change 
to 67 [deg]F outdoor-dry-bulb temperature for one wet-coil steady-state 
test, DOE also proposes to conduct the two dry-coil tests at 67 [deg]F. 
These changes make the test conditions for two-capacity units 
consistent with the test conditions specified for variable-speed 
systems. These two additional 67 [deg]F tests are denoted by the same 
identifiers used for the comparable variable-speed tests: The optional 
dry-coil steady-state test is the G1 Test and the optional 
dry-coil cyclic test is the I1 test.
    The specific changes proposed within the DOE test procedure 
pertaining to new outdoor test conditions for one required, and two 
optional, cooling mode tests for two-capacity units are shown in 
sections 3.2.3 and 4.1.3 of the test procedure. These changes are 
combined with DOE's earlier proposal to reinstate the two optional dry-
coil tests at high capacity.
    10. Renaming ``Cooling and Heating Certified Air Volume Rates'' to 
``Full-load Air Volume Rates.'' The October 2005 final rule introduced 
proper names for the air volume rates associated with the many tests 
that are described in the test procedure. The name given to the air 
volume rate that is used during most tests was ``Certified Air Volume 
Rate,'' prefixed with the qualifier ``Cooling'' or ``Heating.'' 
Typically, the word ``certified'' is used within the industry to 
identify parameters that are subject to verification checks and, if 
appropriate, penalties for failure to comply with the rules for 
accurately reporting the certified parameter. Examples of such 
certified parameters are SEER, HSPF, and rated capacity. To avoid 
confusion on whether air volume rate is a ``certified parameter''--
which it is not--DOE proposes substituting the word ``Full-load'' for 
``Certified'' within the proper name of the particular air volume rate. 
DOE considered other substitutes, including ``Nominal,'' ``Rated,'' 
``Tested,'' and ``Target.'' DOE welcomes comments on alternative 
substitutes. In addition, DOE seeks comments on instituting this change 
within the definition for small-duct, high-velocity systems in section 
1.35 of the central air conditioner and heat pump test procedure.
    11. Modifying the criterion for using an air volume rate that is 
less than the manufacturer's specified value. The October 2005 final 
rule rigidly specified the air volume rate to use during each test. In 
particular, DOE definitively stated in section 3.1.4.1.1 of the central 
air conditioner and heat pump test procedure that there are only two 
circumstances in which the test lab could use an air volume rate that 
is less than the manufacturer's specified value. The criterion for 
these circumstances, which applies to ducted blower-coil systems having 
a fixed-speed, multi-speed, or variable-speed, variable-air-volume-rate 
indoor fan, is reexamined in this rulemaking.
    The first lab test is the A or A2 Test (except for 
heating-only heat pumps). For this test, the unit must generate an 
external static pressure that is equal to or greater than the 
applicable value listed in the test procedure: 0.10, 0.15, or 0.20 
inches of water, the value being assigned based on the unit's 
(expected) rated cooling capacity. When running the A or A2 
Test, the test lab will either achieve the manufacturer's specified air 
volume rate and observe the corresponding external static pressure, or 
it will achieve the specified minimum external static pressure and 
observe the air volume rate. If this check indicates that the indoor 
unit, as configured, cannot provide the manufacturer's specified air 
volume rate and meet the minimum external-static requirement, the 
central air conditioner and heat pump test procedure (section 
3.1.4.4.3a) says to ``incrementally change the setup of the indoor fan 
(e.g., fan motor pin settings, fan motor speed) until the Table 2 
[minimum static] requirement is met while maintaining the same [target] 
air volume rate.'' The central air conditioner and heat pump test 
procedure continues, in the section cited above: ``If the indoor fan 
setup changes cannot provide the minimum external static, then reduce 
the air volume rate until the correct Table 2 minimum is equaled.'' 
This last case covers one of two cases where the test lab can use an 
air volume rate that is less than the value specified by the 
manufacturer. The second case is the more global stipulation to set the 
air volume rate to 37.5 scfm per 1000 Btu/h if the manufacturer's 
specified air volume rate yields a higher ratio.
    Since the publication of the final rule, DOE now understands that 
this approach is too rigid and is inconsistent with industry practice. 
Specifically, although the test requirement to achieve the minimum 
external static pressure has been universally upheld, the requirement 
that this be done by first changing the motor's speed has not been 
universally employed. In particular, for cases in which the specified 
minimum external static pressure is achieved at an air volume rate that 
is slightly less than the value specified by the manufacturer, the 
testing customarily proceeds using this slightly lower air volume rate 
rather than increasing the speed setting of the fan motor.

[[Page 41328]]

    The desired approach should account for normal equipment tolerances 
and variability, and should be compatible with allowing the 
manufacturer to specify an air volume rate representative of the 
average indoor unit, for each indoor unit model. The current, more 
rigid, approach causes manufacturers to specify an air volume rate at 
the low end of the range for a typical model.
    Because the current algorithm does not account for the inherent 
variability in fan motors, housings, and wheels, DOE proposes to add an 
overall tolerance when assigning the indoor-air volume rate used for 
testing. This change will result in more representative testing, 
because of the use of an average air volume rate, rather than a rate on 
the low end of the range. DOE proposes to assign a tolerance of -5 
percent on the air volume rate specified by the manufacturer. Thus, if 
the indoor unit can attain the minimum external static pressure while 
operating at an indoor air volume rate that is between 0 and -5 percent 
of the manufacturer-specified value, then this lab air volume rate 
shall be used. The tolerance of -5 percent is recommended because it is 
representative of indoor blower variations and also because a maximum 
tolerance of -5 percent in air volume rate typically causes a change in 
total capacity that is within the uncertainty of the measurement.
    Proposed language for effecting the above change is provided in the 
last section of this notice as part of the revised section 3.1.4.1.1 of 
the central air conditioner and heat pump test procedure and, for 
ducted, heating-only heat pumps, section 3.1.4.4.3. DOE requests 
comments on the approach of including the tolerance within the setup 
algorithm, and assigning it as a one-sided tolerance. DOE also requests 
data concerning the selection of -5 percent as the tolerance.
    12. Revising references to ASHRAE Standards (e.g., Standards 23, 
37, 116) that have been reaffirmed (i.e., reviewed and approved by 
ASHRAE with no substantive changes) or revised too recently to have 
been included in the amended test procedure published on October 11, 
2005. ASHRAE Standard 23, ``Methods of Testing for Rating Positive 
Displacement Refrigerant Compressors and Condensing Units,'' and 
Standard 37 ``Methods of Testing for Rating Unitary Air-Conditioning 
and Heat Pump Equipment'' completed the revision, public review, and 
publication process in 2005. ASHRAE Standard 116, ``Methods of Testing 
for Rating for Seasonal Efficiency of Unitary Air Conditioners and Heat 
Pumps,'' completed the reaffirmation, public rev