[Federal Register Volume 79, Number 90 (Friday, May 9, 2014)]
[Proposed Rules]
[Pages 26639-26650]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-10692]


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DEPARTMENT OF ENERGY

10 CFR Part 430

[Docket No. EERE-2014-BT-TP-0014]
RIN 1904-AD22


Energy Conservation Program for Consumer Products: Test Procedure 
for Portable Air Conditioners

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

ACTION: Notice of data availability; request for comment.

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SUMMARY: In a notice of proposed determination (NOPD) published on July 
5, 2013, the U.S. Department of Energy (DOE) tentatively determined 
that portable air conditioners (ACs) qualify as a covered product under 
Part B of Title III of the Energy Policy and Conservation Act (EPCA), 
as amended. To assist in a final determination and to consider 
approaches for a future DOE test procedure for these products, should 
DOE determine that portable ACs are covered products, DOE conducted 
investigative testing to evaluate industry test procedures that could 
be used to measure cooling capacity and energy use for portable ACs. In 
today's notice, DOE discusses various industry test procedures and 
presents results from its investigative testing that evaluated existing 
methodologies and alternate approaches adapted from these methodologies 
for portable ACs. DOE requests comment and additional information 
regarding the testing and results presented in this NODA. DOE also 
encourages interested parties to provide comment on any alternate 
approaches for testing portable ACs and information that may improve 
the analysis.

DATES: DOE will accept comments, data, and information regarding this 
notice of data availability (NODA) submitted no later than June 9, 
2014.

ADDRESSES: Any comments submitted must identify the Notice of Data 
Availability for Portable Air Conditioners, and provide docket number 
EERE-2014-BT-TP-0014 and/or RIN 1904-AD22. Comments may be submitted 
using any of the following methods:
    1. Federal eRulemaking Portal: www.regulations.gov. Follow the 
instructions for submitting comments.
    2. Email: [email protected]. Include docket EERE-
2014-BT-TP-0014 and/or RIN 1904-AD22 in the subject line of the 
message.
    3. Mail: Ms. Brenda Edwards, U.S. Department of Energy, Building 
Technologies Program, Mailstop EE-5B, 1000 Independence Avenue SW., 
Washington, DC 20585-0121. If possible, please submit all items on a 
compact disc (CD), in which case it is not necessary to include printed 
copies.
    4. 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. If possible, 
please submit all items on a CD, in which case it is not necessary to 
include printed copies.
    Docket: The docket is available for review at www.regulations.gov, 
including Federal Register notices, public meeting attendee lists and 
transcripts, comments, and other supporting documents/materials. All 
documents in the docket are listed in the www.regulations.gov index. 
However, not all documents listed in the index may be publicly 
available, such as information that is exempt from public disclosure.
    A link to the docket Web page can be found at: http://www.regulations.gov/#!docketDetail;D=EERE-2014-BT-TP-0014. This Web 
page contains a link to the docket for this notice on the 
www.regulations.gov site. The www.regulations.gov Web page contains 
simple instructions on how to access all documents, including public 
comments, in the docket.
    For further information on how to submit a comment or review other 
public comments and the docket, contact Ms. Brenda Edwards at (202) 
586-2945 or email: [email protected].

FOR FURTHER INFORMATION CONTACT: 
Mr. Bryan Berringer, U.S. Department of Energy, Office of Building 
Technology Office, EE-5B, 950 L'Enfant Plaza SW., Room 603, Washington, 
DC 20585-0121. Telephone: 202-586-0371. Email: 
[email protected].
Ms. Sarah Butler, U.S. Department of Energy, Office of the General 
Counsel, Mailstop GC-71, 1000 Independence Ave. SW., Washington, DC 
20585-0121. Telephone: 202-586-2902; Email: [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Authority and Background
II. Discussion
    A. Test Units
    B. Baseline Testing
    C. Investigative Testing
    1. Calorimeter Approach
    2. Duct Heat Loss and Leakage
    3. Infiltration Air
    a. Infiltration Air Flowrate
    b. Effect of Infiltration Air Temperature
    4. Mixing Between the Condenser Inlet and Exhaust for Dual-Duct 
Portable Air Conditioners
    D. Alternate Testing Approach
    E. Additional Issues on Which DOE Seeks Comment
III. Public Participation

I. Authority and Background

    Title III, Part B \1\ of the Energy Policy and Conservation Act of 
1975 (EPCA), Public Law 94-163, (42 U.S.C. 6291-6309, as codified), 
sets forth a variety of provisions designed to improve energy 
efficiency and established the Energy Conservation Program for Consumer 
Products Other Than Automobiles, a program covering most major 
household appliances (hereinafter referred to as ``covered 
products'').\2\ In addition to specifying a list of covered products, 
EPCA contains provisions that enable the Secretary of Energy to 
classify additional types of consumer products as covered products. For 
a given product to be classified as a covered product, the Secretary 
must determine that:
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    \1\ For editorial reasons, upon codification in the U.S. Code, 
Part B was re-designated Part A.
    \2\ All references to EPCA in this document refer to the statute 
as amended through the American Manufacturing Technical Corrections 
Act (AEMTCA), Public Law 112-210 (Dec. 18, 2012).
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    (1) Classifying the product as a covered product is necessary for 
the purposes of EPCA; and
    (2) The average annual per-household energy use by products of such 
type is likely to exceed 100 kilowatt-hours (kWh) per year. (42 U.S.C. 
6292(b)(1)).
    In order to prescribe an energy conservation standard pursuant to 
42 U.S.C. 6295(o) and (p) for covered products added pursuant to 42 
U.S.C. 6292(b)(1), the Secretary must also determine that:
    (1) The average household energy use of the products has exceeded 
150 kWh per household for any 12-month period ending before such 
determination;
    (2) The aggregate household energy use of the products has exceeded 
4.2 terawatt-hours (TWh) for any such 12-month period;
    (3) Substantial improvement in energy efficiency is technologically 
feasible; and

[[Page 26640]]

    (4) Application of a labeling rule under 42 U.S.C. 6294 is not 
likely to be sufficient to induce manufacturers to produce, and 
consumers and other persons to purchase, covered products of such type 
(or class) that achieve the maximum energy efficiency that is 
technologically feasible and economically justified. (42 U.S.C. 
6295(l)(1)).
    On July 5, 2013, DOE issued a notice of proposed determination 
(NOPD) of coverage (hereinafter referred to as the ``July 2013 NOPD''), 
in which DOE announced that it tentatively determined that portable ACs 
meet the criteria for covered products. In reaching this tentative 
determination, DOE found that classifying products of such type as 
covered products is necessary or appropriate to carry out the purposes 
of EPCA, and the average U.S. household energy use for portable ACs is 
likely to exceed 100 kWh per year. 78 FR 40403-07.
    In response to the July 2013 NOPD, DOE received comments from 
interested parties on several topics, including appropriate test 
procedures for portable ACs that DOE should consider if it issues a 
final determination that classifies portable ACs as covered products. 
Consumer Reports recommended that portable ACs be tested similar to, 
and performance compared with, room ACs because they are seen by 
consumers as comparable products that perform nearly identical 
functions. (Consumer Reports, No. 2 at p. 2).\3\ In addition, the 
Appliance Standards Awareness Project (ASAP), American Council for an 
Energy-Efficient Economy (ACEEE), Consumers Union (CU), Natural 
Resources Defense Council (NRDC), and Northwest Energy Efficiency 
Alliance (NEEA), (hereinafter referred to as the ``Joint Commenters''), 
commented that any portable AC test procedure must facilitate a 
realistic comparison with room ACs, and that a portable AC test 
procedure must reflect actual installation and operation to determine a 
meaningful and applicable cooling capacity and Energy Efficiency Ratio 
(EER). (Joint Commenters, No. 4 at p. 2).
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    \3\ A notation in the form ``Consumer Reports, No. 2 at p. 2'' 
identifies a written comment: (1) Made by Consumer Reports; (2) 
recorded in document number 2 that is filed in the docket of the 
portable AC determination of coverage rulemaking (Docket No. EERE-
2013-BT-STD-0033) and available for review at www.regulations.gov; 
and (3) which appears on page 2 of document number 2.
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    The Pacific Gas and Electric Company (PG&E), Southern California 
Gas Company (SCGC), San Diego Gas and Electric (SDG&E), and Southern 
California Edison (SCE), (hereinafter referred to as the ``California 
IOUs''), commented that based on Consumer Reports' testing, the 
published ratings for portable ACs may underestimate actual performance 
in the field by approximately 50 percent. The California IOUs 
recommended establishing a standardized test procedure to ensure that 
representations of portable AC energy use would better reflect actual 
usage and be more meaningful for consumers making purchasing decisions. 
(California IOUs, No. 5 at p. 3)
    The Association of Home Appliance Manufacturers (AHAM) commented 
that a DOE test procedure would ensure that all manufacturers test and 
rate their products according to the same test procedure. AHAM also 
suggested that DOE incorporate current test procedures by reference, 
particularly the version of AHAM's portable AC test procedure which is 
currently under development to harmonize with the Canadian Standards 
Association (CSA) test procedure. AHAM commented that DOE should work 
with Natural Resources Canada (NRCan) and CSA to harmonize the U.S. and 
Canadian test procedures for portable ACs. (AHAM, No. 6 at pp. 2-4)
    DOE agrees that a DOE test procedure for portable ACs would provide 
consistency and clarity for representations of energy use of these 
products. DOE is evaluating available industry test procedures to 
determine whether their methodologies are suitable for incorporation in 
a future DOE test procedure, should DOE determine that portable ACs are 
a covered product.

II. Discussion

    In the July 2013 NOPD, DOE proposed defining a portable AC as ``a 
consumer product, other than a `packaged terminal air conditioner,' 
which is powered by a single-phase electric current and which is an 
encased assembly designed as a portable unit that may rest on the floor 
or other elevated surface for the purpose of providing delivery of 
conditioned air to an enclosed space. It includes a prime source of 
refrigeration and may include a means for ventilating and heating.'' 78 
FR 40403, 40404 (Jul. 5, 2013). The most common type of portable AC 
configuration in the United States utilizes a single condenser air 
exhaust duct that removes heat to the unconditioned space. Other 
configurations include dual-duct, which intakes and exhausts 
unconditioned air to cool the condenser and remove moisture, and spot 
coolers, which have no ducting on the condenser side and may utilize 
small directional ducts on the evaporator exhaust.
    In response to comments from interested parties, DOE conducted 
testing to determine typical portable AC cooling capacities and energy 
efficiencies based on the existing industry test methods and to 
investigate their applicability to a possible DOE test procedure for 
portable ACs. DOE is aware of three test procedures that measure 
portable AC performance and that are applicable to products sold in 
North America.
    (1) American National Standards Institute (ANSI)/AHAM PAC-1-2009 
``Portable Air Conditioners'' \4\ (ANSI/AHAM PAC-1-2009) specifies 
cooling mode testing conducted in accordance with ANSI/American Society 
of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) 
Standard 37-2005 ``Methods of Testing for Rating Electrically Driven 
Unitary Air-Conditioning and Heat Pump Equipment'' (ANSI/ASHRAE 
Standard 37-2005).\5\ The metrics incorporated in ANSI/AHAM PAC-1-2009 
include cooling capacity and EER for the following configurations: 
Single-Duct, Dual-Duct, Spot Cooling, and Water Cooled Condenser.
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    \4\ ANSI/AHAM test procedures are available for purchase online 
at: www.aham.org.
    \5\ ANSI/ASHRAE Standard 37 was updated in 2009. DOE reviewed 
the 2005 and 2009 versions and concluded there would be no 
measurable difference in portable AC results obtained from each. 
Therefore, DOE utilized ANSI/ASHRAE Standard 37-2009 when testing 
according to ANSI/AHAM PAC-1-2009. ANSI/ASHRAE test procedures are 
available for purchase online at: www.techstreet.com.
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    (2) CSA C370-2013 ``Cooling Performance of Portable Air 
Conditioners'' \6\ (CSA C370) is harmonized with ANSI/AHAM PAC-1-2009, 
and thus also incorporates testing provisions from ANSI/ASHRAE Standard 
37, although it specifies the later 2009 version.
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    \6\ CSA test procedures are available for purchase online at: 
www.csagroup.org.
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    (3) ANSI/ASHRAE Standard 128-2011 ``Method of Rating Unitary Spot 
Air Conditioners'' (ANSI/ASHRAE Standard 128-2011) is adapted from the 
previous 2009 version of CSA C370. It too references ANSI/ASHRAE 
Standard 37-2009. The previous version of ANSI/ASHRAE Standard 128, 
published in 2001, is required by California regulations to be used to 
certify spot cooler performance for such products sold in that State. A 
key difference between ANSI/ASHRAE Standard 128-2011 and ANSI/ASHRAE 
Standard 128-2001 is that the older version specifies a higher indoor 
ambient testing

[[Page 26641]]

temperature, which increases measured cooling capacity and EER.
    DOE found no significant differences that would provide varying 
results among the AHAM, CSA, and ASHRAE test procedures. In reviewing 
the current versions of these test procedures, DOE observed that each 
measures cooling capacity and EER based on an air enthalpy approach 
that measures the airflow rate, dry-bulb temperature, and water vapor 
content of air at the inlet and outlet of the indoor (evaporator) side. 
In addition, for air-cooled portable ACs with cooling capacities less 
than 135,000 British thermal units per hour (Btu/h), which include the 
products that are the subject of today's notice, the indoor air 
enthalpy results must be validated by additionally measuring cooling 
capacity by either an outdoor air enthalpy method or a compressor 
calibration method. In its testing, DOE selected the outdoor air 
enthalpy method to minimize its test burden because that approach only 
requires additional metering components, similar to those used for the 
indoor air enthalpy method. The compressor calibration method requires 
monitoring refrigerant conditions with additional equipment that was 
not available at the time in the test laboratory. DOE expects that 
using either approach would produce equivalent results because the 
compressor calibration approach measures the heat transferred to the 
refrigerant from the evaporator side and the outdoor air enthalpy 
approach measures that same heat when it is transferred from the 
refrigerant and rejected at the condenser side.
    DOE conducted initial testing according to ANSI/AHAM PAC-1-2009 to 
establish baseline cooling capacities and efficiencies of the test 
units according to the existing industry test procedures. As noted 
previously, although ANSI/AHAM PAC-1-2009 references ANSI/ASHRAE 
Standard 37-2005, DOE determined there were no differences in the 
relevant provisions between this version and the current version, ANSI/
ASHRAE Standard 37-2009.\7\ DOE, therefore, used ANSI/ASHRAE Standard 
37-2009 for all testing according to ANSI/AHAM PAC-1-2009.
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    \7\ Both versions of ANSI/ASHRAE Standard 37 are available for 
purchase online at: www.techstreet.com.
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    In addition, DOE reviewed information suggesting that certain 
operational factors not addressed in existing test procedures could 
have a significant effect on portable AC performance. For example, a 
Consumer Reports buying guide indicates that units tested as part of a 
field study delivered only half of the rated cooling capacity.\8\ DOE 
observed that when condenser air is drawn from the conditioned space 
and exhausted to the unconditioned space, a pressure gradient is 
created that results in replacement air infiltrating into the 
conditioned space. If this infiltration air is drawn from unconditioned 
locations, including possibly directly from outdoors through leaky 
windows or mounting brackets, the net cooling capacity and EER of the 
portable AC would be reduced. DOE notes that this air infiltration 
likely has the largest effect on the performance of single-duct units 
because these units intake all condenser air from the conditioned 
space. Dual-duct units may intake a portion of condenser air from the 
conditioned space; the remainder, which may be all of the condenser 
air, is drawn from outdoors through the condenser inlet duct. If air 
infiltration is not accounted for, testing may suggest that a single-
duct unit would perform better than a dual-duct unit with comparable 
components. Single-duct units utilize lower-temperature air from the 
conditioned space to cool the condenser and it would appear that these 
units are able to operate more efficiently than equivalent dual-duct 
units.
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    \8\ Consumer Reports, Buying Advice: Portable Air Conditioners, 
June 20, 2008. Available online at: www.consumerreports.org/cro/news/2008/06/buying-advice-portable-air-conditioners/index.htm.
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    Portable AC performance may also be reduced due to the heat 
transfer to the room through leaks in the product case and 
manufacturer-provided ducting that is not addressed in current test 
procedures. The portable AC and all associated equipment are located in 
the conditioned space and the ducting is typically flexible plastic 
with no additional insulation. Further, the connection between the duct 
and the case and the connection between the duct and the manufacturer-
supplied window fixture may not be tightly sealed, allowing some 
condenser-side air to leak into the room. Finally, DOE observed that 
mixing may occur between the condenser air exhaust and intake for dual-
duct units because the window fixtures typically locate the air intake 
and exhaust connections adjacent to one another, allowing some of the 
hotter exhaust air to potentially short-circuit and enter the intake 
duct.
    To investigate the contribution of these operational factors on the 
apparent reduction in cooling capacity observed for units in the field, 
DOE compared the results of ANSI/AHAM PAC-1-2009 testing with the 
results of additional testing using a test room calorimeter approach 
based on ANSI/ASHRAE Standard 16-1983 (RA 99), ``Method of Testing for 
Rating Room Air Conditioners and Packaged Terminal Air Conditioners'' 
(ANSI/ASHRAE Standard 16-1983), with certain modifications as explained 
below to allow testing of portable ACs. The room calorimeter approach 
would allow DOE to determine the cooling capacity and associated EER of 
a portable AC that accounts for any air infiltration effects and heat 
transfer to the conditioned space through gaps in the product case and 
seams in the duct connections. Values of these performance metrics 
measured accordingly may more accurately reflect real-world portable AC 
operation. In this test series, DOE also investigated cooling capacity 
and EER as a function of the infiltration air temperature for single-
duct and dual-duct units, and the effect of condenser exhaust air 
entrainment at the intake for dual-duct portable ACs.
    The following sections detail the units in DOE's test sample, the 
baseline test results obtained using ANSI/AHAM PAC-1-2009, and the 
results from the investigative tests using the modified ANSI/ASHRAE 
Standard 16-1983 to estimate the effects of infiltration air, case and 
duct heat transfer, and condenser duct air mixing.

A. Test Units

    For its portable AC testing, DOE selected a sample of units that 
are representative of products and configurations currently available 
on the U.S. market. The test sample included four single-duct, two 
dual-duct, and two spot-cooling portable ACs, covering a range of rated 
cooling capacities (8,000-13,500 Btu/h) and EERs (7.0-11.2 Btu per 
watt-hour (Btu/Wh)). Because DOE does not currently require 
manufacturers to certify portable ACs to any energy conservation 
standards, manufacturers may advertise or market their products using 
any available test procedure. For models that are included in the 
California Energy Commission (CEC) product database and that are sold 
in California, however, manufacturers must report cooling capacity and 
EER according to ANSI/ASHRAE Standard 128-2001. DOE notes that the 
cooling capacities and EERs obtained from using ANSI/ASHRAE Standard 
128-2001 are higher than those obtained using the current ANSI/ASHRAE 
Standard 128-

[[Page 26642]]

2011, primarily due to higher temperature evaporator inlet air.\9\
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    \9\ ANSI/ASHRAE Standard 128-2011 specifies 80.6 degrees 
Fahrenheit ([deg]F) dry-bulb temperature and 66.2 [deg]F wet-bulb 
temperature for the standard rating conditions for the evaporator 
inlet of dual-duct portable ACs and both the evaporator and 
condenser inlets of single-duct units. It also specifies standard 
rating conditions of 95 [deg]F dry-bulb temperature and 75.2 [deg]F 
wet-bulb temperature for the condenser inlet side of dual-duct 
portable ACs and both the evaporator and condenser inlets of spot 
coolers. ANSI/ASHRAE Standard 128-2001 specified 95 [deg]F dry-bulb 
temperature and 83 [deg]F wet-bulb temperature for the standard 
rating conditions for both the evaporator and condenser inlets of 
all portable ACs, including spot coolers.
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    Due to the consistent method of reporting, DOE selected units for 
its test sample largely from cooling capacities and EERs listed in the 
CEC product database. Where values were not available in the CEC 
product database, DOE utilized information from manufacturer literature 
to inform its selection. However, due to the difference in testing 
temperature, DOE expected that these values would differ from the 
cooling capacities and EERs that would be obtained using any one of the 
three industry test methods. The eight test units and their key 
features are presented in Table II.1, with cooling capacity expressed 
in Btu/h and EER expressed in Btu/Wh. DOE included two spot coolers in 
the test sample that, unlike the majority of spot coolers which are 
designed for commercial applications, have supply power requirements 
that would allow them to be used in residential applications.

                          Table II.1--Portable Air Conditioner Test Units and Features
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                                                                                Rated cooling    Rated EER (Btu/
                  Test unit                              Duct type            capacity (Btu/h)         Wh)
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SD1.........................................  Single........................             8,000               7.0
SD2.........................................  Single........................             9,500               9.6
SD3.........................................  Single........................            12,000               8.7
SD4.........................................  Single........................            13,000               9.7
DD1.........................................  Dual..........................             9,500               9.4
DD2.........................................  Dual..........................            13,000               8.9
SC1.........................................  Spot Cooler...................            10,000              10.1
SC2.........................................  Spot Cooler...................            13,500              11.2
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B. Baseline Testing

    DOE performed testing according to ANSI/AHAM PAC-1-2009 to 
determine baseline performance when using the industry standards. ANSI/
AHAM PAC-1-2009 requires two-chamber air enthalpy testing for single-
duct and dual-duct units, and a single-chamber setup for spot coolers. 
For each ducted configuration, the portable AC and any associated 
ducting is located entirely within a chamber held at ``indoor'' 
standard rating conditions at the evaporator inlet of 80 degrees 
Fahrenheit ([deg]F) dry-bulb temperature and 67 [deg]F wet-bulb 
temperature, which correspond to 51-percent relative humidity. For the 
condenser side exhaust on single-duct and dual-duct units, the 
manufacturer-supplied or manufacturer-specified flexible ducting 
connects the unit under test to a separate test chamber maintained at 
``outdoor'' standard rating conditions. The outdoor conditions specify 
95 [deg]F dry-bulb temperature \10\ and 75 [deg]F wet-bulb temperature 
(40-percent relative humidity) at the condenser inlet for dual-duct 
units. The outdoor conditions for single-duct units, however, are not 
explicitly specified. ANSI/AHAM PAC-1-2009 only requires that the 
condenser inlet conditions, which would be set by air intake from the 
indoor side chamber, be maintained at 80 [deg]F dry-bulb temperature 
and 67 [deg]F wet-bulb temperature. Because the single-duct condenser 
air is discharged to the outdoor side with no intake air from that 
location, DOE does not believe that the results obtained using ANSI/
AHAM PAC-1-2009 would be measurably affected by the conditions in the 
outdoor side chamber. Nonetheless, for consistency with the testing of 
dual-duct units, DOE chose to maintain the outdoor side conditions, 
measured near to the condenser exhaust but not close enough to be 
affected by that airflow, at 95 [deg]F dry-bulb temperature and 75 
[deg]F wet-bulb temperature. For spot coolers, ANSI/AHAM PAC-1-2009 
specifies testing the unit in a chamber maintained at the outdoor 
standard rating conditions of 95 [deg]F dry-bulb temperature and 75 
[deg]F wet-bulb temperature.
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    \10\ Table 3 of ANSI/AHAM PAC-1-2009, which specifies standard 
rating conditions, lists a dry-bulb temperature of 94 [deg]F and a 
wet-bulb temperature of 75[emsp14][deg]F for single-duct and dual-
duct portable ACs. DOE expects this to be a typographical error, and 
that the correct dry-bulb temperature is 95 [deg]F.
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    Section 6.1 of ANSI/AHAM PAC-1-2009, ``Method of Test,'' instructs 
that the details of testing are as specified in ANSI/ASHRAE Standard 
37-2005, with references in Section 8.5.1 of ANSI/ASHRAE Standard 37-
2005 to the indoor side (the cooling, or evaporator, side) of the 
portable AC under test and references to the outdoor side (the heat 
rejection, or condenser, side). No additional instructions regarding 
the specific provisions to use in ANSI/ASHRAE Standard 37-2005 are 
included. As discussed previously, DOE utilized the latest version of 
ANSI/ASHRAE Standard 37, published in 2009. The following paragraphs 
describe the clauses from ANSI/ASHRAE Standard 37-2009 that DOE decided 
were appropriate for conducting its baseline tests.
    The test apparatus (i.e., ducts, air flow-measurement nozzle, and 
additional instrumentation) were adjusted according to Section 8.6, 
``Additional Requirements for the Outdoor Air Enthalpy Method,'' of 
ANSI/ASHRAE Standard 37-2009, which ensures that air flow rate and 
static pressure in the condenser exhaust air stream, and condenser 
inlet air stream for dual-duct units, are representative of actual 
installations. The test room conditioning apparatus and the units under 
test were then operated until steady-state performance was achieved 
according to the specified test tolerances in Section 8.7, ``Test 
Procedure for Cooling Capacity Tests,'' of ANSI/ASHRAE Standard 37-
2009. Airflow rate, dry-bulb temperature, and water vapor content were 
recorded to evaluate cooling capacity at equal intervals that spanned 
five minutes or less until readings over one-half hour were within the 
same tolerances, as required by that section.
    These collected data were then used to calculate total, sensible, 
and latent indoor cooling capacity based on the equations in Section 
7.3.3, ``Cooling

[[Page 26643]]

Calculations,'' of ANSI/ASHRAE Standard 37-2009. This section provides 
calculations to determine indoor cooling capacity based on both the 
indoor and outdoor air enthalpy methods. As described in Section 
7.3.3.3 of ANSI/ASHRAE Standard 37-2009, the indoor air enthalpy 
cooling capacity calculation was adjusted for heat transferred from the 
surface of the duct(s) to the conditioned space. DOE estimated a 
convective heat transfer coefficient of 4 Btu/h per square foot per 
[deg]F, based on a midpoint of values for forced convection and free 
convection as recommended by the test laboratory for this specific test 
and setup. Four thermocouples were placed in a grid on the surface of 
the condenser duct(s). The heat transfer was determined by multiplying 
the estimated heat transfer coefficient by the surface area of each 
component and by the average temperature difference between the duct 
surface and test chamber air.
    Although ANSI/AHAM PAC-1-2009 specifies that the evaporator 
circulating fan heat shall be included in the total cooling capacity, 
DOE did not meter the fan power for testing. Rather, for ducted units, 
DOE estimated the heat transferred to the conditioned space based on 
the temperature differential between the case surfaces and the indoor 
room, with measurements and calculations similar to those used for the 
ducts. This estimate was made by placing four thermocouples on each 
surface of the case and measuring the surface area to determine the 
heat transfer. This approach directly estimates the heating 
contribution of all internal components within the case to the cooling 
capacity, while making no assumption regarding whether the heat from 
individual components is transferred to the cooling or heat rejection 
side. Although ANSI/AHAM PAC-1-2009 requires the evaporator circulating 
fan heat be addressed in the cooling capacity for all portable ACs 
including spot coolers, DOE decided not to include case heat transfer 
for spot coolers because these units reject all heat directly to the 
space where the unit sits. That rejected heat does not impact the 
cooling provided by the unit to the specific conditioned spot.
    Section 10.1.2 of ANSI/ASHRAE Standard 37-2009 requires that the 
calculated indoor cooling capacities from each method shall agree 
within 6.0 percent for a valid test. From the calculated cooling 
capacity, DOE determined the associated EER consistent with the 
definitions in Sections 3.8 to 3.10 and ratings requirements in 
Sections 5.3 to 5.5 of ANSI/AHAM PAC-1-2009. Table II.2 shows the 
results of the baseline testing for all test units according to ANSI/
AHAM PAC-1-2009.

                                                            Table II.2--Baseline Test Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Cooling capacity (Btu/h)                                    EER (Btu/Wh)
                 Test unit                  ------------------------------------------------------------------------------------------------------------
                                                   Rated           Baseline        Reduction (%)          Rated           Baseline        Reduction (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
SD1........................................             8,000           5,842.7              27.0                7.0              6.84               2.3
SD2........................................             9,500           6,599.8              30.5                9.6              7.41              22.8
SD3........................................            12,000          10,947.6               8.8                8.7              7.47              14.1
SD4........................................            13,000           9,505.6              26.9                9.7              6.59              32.0
DD1........................................             9,500           8,597.2               9.5                9.4              7.41              21.2
DD2........................................            13,000           7,211.2              44.5                8.9              5.50              38.2
SC1........................................            10,000          10,225.7              -2.3               10.1              9.62               4.7
SC2........................................            13,500          10,774.7              20.19              11.2              6.72              39.9
--------------------------------------------------------------------------------------------------------------------------------------------------------

    For all units, the tested cooling capacity and EER were on average 
19 percent and 21 percent lower, respectively, when compared with the 
rated values. However, the difference between tested and rated cooling 
capacity ranged from an increase of 2.3 percent to a decrease of over 
44 percent, while the tested EERs showed a reduction from 2.3 to 40 
percent compared to the rated values. DOE notes that cooling capacity 
and EER for single-duct units were lower on average than the rated 
values by 23 and 18 percent, respectively; the cooling capacity and EER 
for dual-duct units were lower on average by 27 and 30 percent, 
respectively; and the cooling capacity and EER for spot coolers were 
lower on average by 9 and 22 percent, respectively. Although the 
results were generally consistent for the different product types, DOE 
notes that these data are based on a small sample of test units, and a 
larger sample may provide more representative trends for each 
configuration.
    Due to lack of information available regarding typical spot cooler 
operating locations and conditions, DOE also tested the two spot 
coolers at reduced ambient conditions consistent with the ``indoor'' 
conditions for single-duct and dual-duct units, at 80 [deg]F dry-bulb 
temperature and 67 [deg]F wet-bulb temperature. The test results at 
both conditions and percent reductions in cooling capacity and EER at 
the indoor conditions are shown in Table II.3.

                                           Table II.3--Baseline Spot Cooler Performance at Reduced Conditions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Cooling capacity (Btu/h)                                    EER (Btu/Wh)
                                             -----------------------------------------------------------------------------------------------------------
                  Test unit                    Baseline 95/75     Indoor 80/67                       Baseline 95/75     Indoor 80/67
                                                   [deg]F            [deg]F         Reduction (%)        [deg]F            [deg]F         Reduction (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
SC1.........................................          10,225.7          10,061.9              1.60              9.62             10.80            -12.28
SC2.........................................          10,774.7           9,557.5             11.30              6.72              6.68              0.64
--------------------------------------------------------------------------------------------------------------------------------------------------------

    DOE notes that the SC1 test unit tested within 3 percent of its 
rated cooling capacity and within 7 percent of its rated EER for both 
tests. The tested cooling capacity and EER for the SC2 test unit were 
within 12 percent of the

[[Page 26644]]

tested values at the baseline test conditions, but still roughly 30 
percent and 40 percent, respectively, below the rated values.
    Issue 1. DOE seeks comment on the suitability of current industry 
standards for a potential DOE portable AC test procedure; specifically:
    (1) ANSI/AHAM PAC-1-2009;
    (2) ANSI/ASHRAE Standard 128-2001, which although not current is 
required for reporting in California;
    (3) ANSI/ASHRAE Standard 128-2011; and
    (4) CSA C370-13.
    Issue 2. DOE seeks comment on whether the metrics for cooling 
capacity and EER as determined in these industry test procedures 
measure representative performance of the different portable AC product 
types (i.e., single-duct, dual-duct, and spot cooler).
    Issue 3. DOE seeks comment on the approach used to estimate case 
and duct heat transfer to the conditioned space.

C. Investigative Testing

1. Calorimeter Approach
    In response to the comments mentioned previously, suggesting a 
testing approach for portable ACs comparable to that for room ACs, and 
to further investigate heat transfer effects not currently captured in 
available portable AC test procedures, DOE conducted testing according 
to a room calorimeter approach adapted from ANSI/ASHRAE Standard 16-
1983. DOE tested all of the single-duct and dual-duct units in its test 
sample by this approach, which used two test chambers, one maintained 
at the indoor conditions and the other adjusted to maintain the outdoor 
conditions as specified below. Rather than installing the test unit in 
the wall between the indoor and outdoor test rooms, as for a room AC, 
the portable AC under test was located within the indoor test room with 
the condenser duct(s) interfacing with the outdoor test room by means 
of the manufacturer-supplied or manufacturer-recommended mounting 
fixture. Unless otherwise noted, no sealing other than that recommended 
in manufacturer instructions was made at the duct connections or around 
the mounting fixture during the tests.
    DOE used a pressure-equalizing device placed between the indoor 
chamber and outdoor chamber to maintain a static pressure differential 
of less than 0.005 inches of water between the chambers throughout 
testing, as specified in Section 4.2.3 of ANSI/ASHRAE Standard 16-1983. 
Consistent with the ambient conditions required by ANSI/AHAM PAC-1-
2009, DOE maintained the indoor conditions at 80 [deg]F dry-bulb and 67 
[deg]F wet-bulb (51-percent relative humidity) and the outdoor 
conditions at 95 [deg]F dry-bulb and 75 [deg]F wet-bulb (40-percent 
relative humidity). For some units, significant infiltration air flow 
from the outdoor chamber to the indoor chamber was required to maintain 
the required static pressure differential between the two test 
chambers. The calorimeter approach consisted of monitoring all energy 
consumed by the indoor chamber components to maintain the required 
ambient conditions while the portable AC under test operated 
continuously at its maximum fan speed. Following a period of no less 
than 1 hour with stabilized conditions under continuous portable AC 
operation, the data of a subsequent 1-hour stable period were analyzed 
to sum all heating and cooling contributions to the indoor chamber, 
including: Chamber cooling, heat transferred through the chamber wall, 
air circulation fans, dehumidifiers, humidifiers, and scales. These 
instruments, conditioning equipment, and heat transfer components were 
all necessary to maintain the indoor chamber conditions throughout 
testing. The net indoor chamber cooling was recorded as the portable 
AC's cooling capacity. This approach encompasses all cooling and 
heating effects generated by the portable AC, including air 
infiltration effects that are not captured or estimated by the air 
enthalpy approach.
    For the first set of calorimeter tests, the test units were 
installed with the manufacturer-provided ducting, duct attachment 
collar, and mounting fixture. This was done in order to include the 
impacts of heat transfer from the ducts and air leaks in the duct 
connections and mounting fixture, in addition to heat leakage through 
the case and infiltration air. Table II.4 shows the measured net 
cooling capacities and EERs for single-duct and dual-duct units tested 
according to the calorimeter approach when the infiltration air dry-
bulb temperature was 95 [deg]F. The results are compared to rated 
values.

                                                        Table II.4--Calorimeter Approach Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Cooling capacity (Btu/h)                                    EER (Btu/Wh)
                  Test unit                  -----------------------------------------------------------------------------------------------------------
                                                    Rated          Calorimeter      Reduction (%)         Rated          Calorimeter      Reduction (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
SD1.........................................             8,000            -470.8             105.9               7.0             -0.54             107.7
SD2.........................................             9,500            -641.4             106.8               9.6             -0.70             107.3
SD3.........................................            12,000            3475.5              71.0               8.7              2.30              73.5
SD4.........................................            13,000            1841.4              85.8               9.7              1.34              86.2
DD1.........................................             9,500            3379.9              64.4               9.4              2.89              69.2
DD2.........................................            13,000            3442.4              73.5               8.9              2.60              70.8
--------------------------------------------------------------------------------------------------------------------------------------------------------

    DOE notes the significant difference between the rated cooling 
capacity and the results measured according to the calorimeter approach 
for both single-duct and dual-duct units. As expected, due to the 
larger effect of air infiltration, the difference was greater for 
single-duct units than for dual-duct ones. On average for single-duct 
units, cooling capacity was reduced by 92.4 percent and EER was reduced 
by 93.7 percent. For single-duct units SD1 and SD2, however, the net 
effects captured by the calorimeter approach resulted in negative 
cooling capacities; that is, there was overall heating in the indoor-
side chamber. For dual-duct units, the average reductions in cooling 
capacity and EER were 69 percent and 70 percent, respectively.
    As discussed previously, the calorimeter approach requires 
monitoring the energy consumption of all heating and cooling components 
required to maintain stable chamber conditions, while accounting for 
the heat transferred between the indoor and outdoor chambers. To 
quantify the combined impact of the heat transfer from leaks in the 
case and ducts and the enthalpy added from the infiltration air, DOE 
compared these calorimeter test results with the baseline results, as 
shown in Table II.5.

[[Page 26645]]



                                       Table II.5--Comparison of Baseline Results and Calorimeter Approach Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Cooling Capacity (Btu/h)                                    EER (Btu/Wh)
                  Test unit                  -----------------------------------------------------------------------------------------------------------
                                                  Baseline         Calorimeter      Reduction (%)       Baseline         Calorimeter      Reduction (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
SD1.........................................           5,842.7            -470.8             108.1              6.84             -0.54             107.9
SD2.........................................           6,599.8            -641.4             109.7              7.41             -0.70             109.4
SD3.........................................          10,947.6            3475.5              68.3              7.47              2.30              69.2
SD4.........................................           9,505.6            1841.4              80.6              6.59              1.34              79.7
DD1.........................................           8,597.2            3379.9              60.7              7.41              2.89              60.9
DD2.........................................           7,211.2            3442.4              52.3              5.50              2.60              52.7
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The percent reduction from baseline results to those measured using 
the calorimeter approach range from 52 percent to over 100 percent for 
both cooling capacity and EER.
    Issue 4. DOE requests feedback on the applicability of the 
calorimeter approach for measuring the performance of portable ACs, and 
the associated testing burden.
    Issue 5. DOE seeks comment on other possible testing methods or 
alternate approaches to measure representative portable AC performance.
    DOE performed additional investigative testing to quantify the 
individual impacts on performance due to each of the factors discussed 
previously in this section of today's notice. The test setup, approach, 
and data collected for each of these investigations is presented below.
2. Duct Heat Loss and Leakage
    To quantify the heat transfer to the conditioned space through the 
minimally insulated condenser duct(s) and from any leaks at the duct 
connections or mounting fixture, DOE repeated the calorimeter testing 
with insulation surrounding the condenser ducts to benchmark results 
without this heat transfer. DOE used insulation having a nominal R 
value of 6 (in units of hours-[deg]F-square feet per Btu), with seams 
around the duct, adapter, and mounting bracket sealed with tape to 
minimize air leakage. To determine duct losses and air leakage effects, 
DOE compared results from these tests to the results from the initial 
calorimeter approach tests with no insulation, as shown in Table II.6.

                                                      Table II.6--Duct Loss and Air Leakage Effects
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Cooling capacity (Btu/h)                                    EER (Btu/Wh)
                  Test unit                  -----------------------------------------------------------------------------------------------------------
                                                 Uninsulated        Insulated          Change*         Uninsulated        Insulated          Change*
--------------------------------------------------------------------------------------------------------------------------------------------------------
SD1.........................................            -470.8              -5.0             465.8             -0.54            -0.006              0.54
SD2.........................................            -641.4             -32.3             609.0             -0.70            -0.035              0.66
SD3.........................................            3475.5           4,091.8             616.3              2.30             2.723              0.42
SD4.........................................            1841.4           3,024.8           1,183.4              1.34              2.17              0.83
DD1.........................................            3379.9           4,682.0           1,302.1              2.89              3.94              1.04
DD2.........................................            3442.4           4,209.4             767.0              2.60              3.14              0.53
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Change in performance in the table above may not align with the performance values listed due to rounding considerations.

    For all units in the test sample, insulating the ducts and sealing 
any potential leak locations improved the measured cooling capacity and 
EER results; however, the magnitude of the change varied from unit to 
unit.
    Issue 6. DOE requests feedback on the potential performance impacts 
related to all components of duct heat losses, and whether and how a 
test procedure should account for them.
3. Infiltration Air
    DOE investigated the impacts of air infiltration from outside the 
conditioned space in which the portable AC is located due to the 
negative pressure induced as condenser air is exhausted to the outdoor 
space. Although this effect is most pronounced for single-duct units, 
which draw all of their condenser air from within the conditioned 
space, dual-duct units may also draw a portion of their condenser air 
from the conditioned space.
a. Infiltration Air Flowrate
    DOE estimated the infiltration air flow rate as equal to the 
condenser exhaust flow rate to the outdoor chamber minus any condenser 
intake flow rate from the outdoor chamber. DOE concluded, based on 
review of the test chamber configurations, that air leakage from the 
outdoor chamber to locations other than the indoor chamber was 
negligible. The net flow rate into the outdoor chamber was thus 
estimated to entirely be transferred into the indoor chamber through 
the pressure regulating apparatus during calorimeter testing. For 
accurate measurement of condenser air flow rates, the inlet and outlet 
air flow rates were measured during baseline testing using the duct 
instrumentation necessary for the air enthalpy method.
    For a single-duct unit, the air balance equation results in the 
infiltration air flow rate being equal to the condenser exhaust air 
flow rate. For dual-duct units, the condenser exhaust duct flow rate 
may be higher than the inlet duct flow rate. This is due to some intake 
air being drawn from the indoor chamber via louvers or leakage through 
the case, duct connections, or between the evaporator and condenser 
sections. The estimated infiltration air flow rate for all single-duct 
and dual-duct units in DOE's test sample are presented in Table II.7.

[[Page 26646]]



                                     Table II.7--Infiltration Air Flow Rate
----------------------------------------------------------------------------------------------------------------
                                                       Condenser outlet     Condenser inlet    Net Infiltration
                      Test unit                          air flow rate       air flow rate       air flow rate
                                                             (CFM)              (CFM) *              (CFM)
----------------------------------------------------------------------------------------------------------------
SD1.................................................               268.0                 N/A               268.0
SD2.................................................               262.6                 N/A               262.6
SD3.................................................               285.5                 N/A               285.5
SD4.................................................               254.3                 N/A               254.3
DD1.................................................               271.9               170.8               101.1
DD2.................................................               214.8               128.1                86.8
----------------------------------------------------------------------------------------------------------------
* Condenser inlet air flow rate is only applicable for dual-duct units.

b. Effect of Infiltration Air Temperature
    In its initial calorimeter test, DOE maintained the outdoor test 
chamber conditions at 95 [deg]F dry-bulb temperature and 75 [deg]F wet-
bulb temperature. Infiltration air was provided by means of a pressure-
regulated connection between the outdoor and indoor test chambers, 
thereby resulting in infiltration air at those temperatures. Such 
conditions would be representative of outdoor air being drawn directly 
into the conditioned space to replace any condenser inlet air from that 
same conditioned space. However, it is possible that some or all of the 
replacement air is drawn from a location other than the outdoors 
directly, such as a basement, attic, garage, or a space that is 
conditioned by other equipment. Because varying infiltration air 
temperature would have a significant impact on cooling capacity and EER 
when using the calorimeter test method, and because DOE was unable to 
identify information on a representative infiltration air temperature 
and relative humidity, DOE performed calorimeter testing over a range 
of dry-bulb temperatures for the infiltration air that spanned 78 
[deg]F to 95 [deg]F, all at the 40-percent relative humidity specified 
at the 95 [deg]F condition. DOE selected conditions at 87 [deg]F and 82 
[deg]F dry-bulb temperature based on outdoor test conditions among 
those specified for cooling mode tests in the ANSI/Air-Conditioning, 
Heating, and Refrigeration Institute (AHRI) Standard 210/240-2008, 
``Performance Rating of Unitary Air-Conditioning & Air-Source Heat Pump 
Equipment.'' The 78 [deg]F test condition was selected based on the 
lowest temperature maintainable by the third-party test laboratory 
conducting testing.\11\ Dual-duct units were not tested at this lowest-
temperature test condition because DOE estimated that infiltration 
effects are not as significant for dual-duct units as they are for 
single-duct units and therefore did not warrant additional testing.
---------------------------------------------------------------------------

    \11\ The lowest maintainable temperature varied depending upon 
the test unit's capacity and air flow configuration. The 78 [deg]F 
dry-bulb test condition was selected as the lowest maintainable 
condition for all units in the test sample.
---------------------------------------------------------------------------

    DOE tested two single-duct and two dual-duct units at the 
infiltration air conditions shown in Table II.8.

                              Table II.8--Infiltration Air Temperature Test Series
----------------------------------------------------------------------------------------------------------------
                                           Infiltration air
     Infiltration air test series        temperature (dry/wet         Single-duct               Dual-duct
                                                bulb)
----------------------------------------------------------------------------------------------------------------
Test 1...............................  95 [deg]F/75 [deg]F....  SD2, SD4...............  DD1, DD2
Test 2...............................  87 [deg]F/69 [deg]F....  SD2, SD4...............  DD1, DD2
Test 3...............................  82 [deg]F/65 [deg]F....  SD2, SD4...............  DD1, DD2
Test 4...............................  78 [deg]F/62 [deg]F....  SD2, SD4...............  N/A
----------------------------------------------------------------------------------------------------------------

    Infiltration air conditions at the lower end of the tested 
temperature range were similar to the ambient conditions being 
maintained in the indoor test chamber, and therefore would result in 
the smallest air infiltration effect on the measurement of cooling 
capacity and EER. Test results obtained under those conditions could 
potentially be similar to those obtained by the use of the current 
industry test procedures, after accounting for case and duct heat 
losses.
    Table II.9 shows the cooling capacity and EER results for single-
duct and dual-duct units at the various infiltration temperatures.

                                      Table II.9--Cooling Capacity and EER at Varying Infiltration Air Temperature
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Cooling capacity (Btu/h)                                      EER (Btu/Wh)
                                         ---------------------------------------------------------------------------------------------------------------
                Test unit                  Test 1 (95/   Test 2 (87/   Test 3 (82/   Test 4 (78/   Test 1 (95/   Test 2 (87/   Test 3 (82/   Test 4 (78/
                                           75 [deg]F)    69 [deg]F)    65 [deg]F)    62 [deg]F)    75 [deg]F)    69 [deg]F)    65 [deg]F)    62 [deg]F)
--------------------------------------------------------------------------------------------------------------------------------------------------------
SD2.....................................        -614.4       4,048.3       7,039.5       9,584.0         -0.70          4.51          7.88         10.66
SD4.....................................       1,841.4       7,808.2      10,468.9      12,247.4          1.34          5.47          7.51          9.00
DD1.....................................       3,379.9       6,268.8       7,801.0           N/A          2.89          5.53          7.07           N/A
DD2.....................................       3,442.4       6,396.1       8,147.3           N/A          2.60          4.99          6.40           N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------

    These results confirm that single-duct unit performance as 
determined using the calorimeter approach is highly dependent on 
infiltration air temperature. The dual-duct units tested also showed 
significant variation of

[[Page 26647]]

performance with infiltration air temperature because of the portion of 
condenser air that is drawn from the indoor chamber. Table II.10 lists 
the calorimeter test results at each infiltration air temperature as a 
percentage of the results obtained during baseline testing. At 
temperatures representative of many likely real-world infiltration air 
temperatures, it can be seen that the actual performance of portable 
ACs may be substantially lower than values obtained using the air 
enthalpy method would suggest.

                                Table II.10--Comparison of Baseline and Calorimeter Testing for Varying Infiltration Air
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Calorimeter cooling capacity as a percentage of      Calorimeter EER as a percentage of baseline EER  (%)
                                                          baseline  capacity (%)                 -------------------------------------------------------
                Test unit                --------------------------------------------------------
                                           Test 1 (95/   Test 2 (87/   Test 3 (82/   Test 4 (78/   Test 1 (95/   Test 2 (87/   Test 3 (82/   Test 4 (78/
                                           75 [deg]F)    69 [deg]F)    65 [deg]F)    62 [deg]F)    75 [deg]F)    69 [deg]F)    65 [deg]F)    62 [deg]F)
--------------------------------------------------------------------------------------------------------------------------------------------------------
SD2.....................................          -9.7         61.30         106.7         145.2          -9.4          60.9         106.3         143.8
SD4.....................................          19.4          82.1         110.1         128.8          20.3          83.0         113.9         136.5
DD1.....................................          39.3          72.9          90.7           N/A          39.1          74.7          95.4           N/A
DD2.....................................          47.7          88.7         113.0           N/A          47.3          90.6         116.2           N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------

    DOE notes that the test results with infiltration air at 82 [deg]F 
dry-bulb temperature and 65 [deg]F wet-bulb temperature were most 
similar to the baseline tests conducted according to the air enthalpy 
method.
    DOE next quantified the total heat added to the room by the 
infiltration air at each reduced temperature test. DOE used the 
following equation to calculate the sensible heat contribution of the 
infiltration air as:
[GRAPHIC] [TIFF OMITTED] TP09MY14.000

Where:

Qs is the sensible heat added to the room by infiltration 
air, in Btu/h,
V is the volumetric flow rate of infiltration air, in cubic feet per 
minute (cfm),
[delta] is the density of the air mixture, in pounds mass per cubic 
feet (lbm/ft\3\),
cp--da is the specific heat of dry air, in Btu/
lbm-[deg]F,
[omega] is the humidity ratio, in pounds mass of water vapor per 
pounds of dry air,
cp--wv is the specific heat of water vapor, in Btu/
lbm-[deg]F,
60 is the conversion factor from minutes to hours, and
[Delta]T is the difference between the infiltration air and indoor 
chamber dry-bulb temperatures, in [deg]F.

    DOE used the following equation for the latent heat contribution of 
the infiltration air:
[GRAPHIC] [TIFF OMITTED] TP09MY14.001

Where:

Ql is the latent heat added to the room by infiltration 
air, in Btu/h,
V is the volumetric flow rate of infiltration air, in cfm,
[delta] is the density of the air mixture, in lbm/ft\3\,
[omega] is the humidity ratio, in pounds mass of water vapor per 
pounds of dry air,
60 is the conversion factor from minutes to hours, and
hfg is the latent heat of vaporization for water vapor, 
in Btu/lbm.

    The total heat contribution of the infiltration air is the sum of 
the sensible and latent heat. Table II.11 presents results for the 
total heat input from the infiltration air at various temperatures for 
each test unit, along with a comparison to the baseline cooling 
capacity.

                                                      Table II.11--Heat Input From Infiltration Air
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Total heat transferred (Btu/h)           Heat transferred as a percentage of baseline
                                                         ------------------------------------------------              cooling capacity (%)
                        Test unit                                                                        -----------------------------------------------
                                                           Test 1 (95/75   Test 2 (87/69  Test 3* (82/65   Test 1 (95/75   Test 2 (87/69   Test 3 (82/65
                                                              [deg]F)         [deg]F)         [deg]F)         [deg]F)         [deg]F)         [deg]F)
--------------------------------------------------------------------------------------------------------------------------------------------------------
SD2.....................................................         6,391.6           885.7        -2,294.0            96.8            13.4           -34.8
SD4.....................................................         5,523.5           587.0        -2,263.9            58.1             6.2           -23.8
DD1.....................................................         2,070.5           327.0          -679.9            24.1             3.8            -7.9
DD2.....................................................         1,707.4           259.5          -576.8            23.7             3.6            -8.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
*DOE notes that at an infiltration air dry-bulb temperature slightly higher than the indoor 80 [deg]F dry-bulb standard test condition, a net cooling
  effect is achieved because the latent heat of the infiltration air is less than the latent heat of the indoor test condition.

    Table II.11 shows that infiltration air heat input is significant, 
almost 97 percent for one single-duct unit, when compared with the 
overall cooling capacity measured with current industry test procedures 
that do not address this heating effect. As expected, infiltration air 
at higher temperatures has a larger impact on performance than at lower 
temperatures, and is therefore a larger percentage of the baseline 
cooling capacity.
    Issue 7. DOE seeks comment on whether infiltration air should be 
accounted for as part of a future DOE test procedure for portable ACs, 
should DOE determine to include portable ACs as a covered product, and 
if so, what test method would be appropriate to account for the 
infiltration air.

[[Page 26648]]

    Issue 8. DOE seeks comment and information on whether the current 
industry standard outdoor air conditions of 95 [deg]F dry-bulb 
temperature and 75 [deg]F wet-bulb temperature are representative for 
real-world infiltration air, and if not, on what would be 
representative infiltration air temperatures.
    Issue 9. DOE requests feedback on the effects of heat input from 
infiltration air and the performance differences that are observed 
between the results of testing according to the air enthalpy approach 
and the calorimeter approach.
4. Mixing Between the Condenser Inlet and Exhaust for Dual-Duct 
Portable Air Conditioners
    The current industry test procedures specify the condenser inlet 
conditions for single-duct and dual-duct portable ACs, but do not 
address potential air mixing between the condenser inlet and exhaust 
air streams for the dual-duct configuration. Manufacturers typically 
provide a single mounting fixture for both the condenser inlet and 
exhaust ducts to minimize installation time and optimize the use of 
window space. However, this approach typically positions the condenser 
inlet and exhaust directly adjacent to one another. During operation 
when installed in the field, short-circuiting may occur between some of 
the condenser exhaust air (typically above 110 [deg]F) and the outdoor 
ambient air (95 [deg]F according to current industry test procedures). 
Elevated condenser inlet air temperature reduces the efficiency of the 
refrigeration system because it limits the ability of the condenser to 
reject heat from the conditioned space.
    To investigate the effects of potential condenser inlet and exhaust 
mixing, DOE tested both dual-duct units according to two different 
approaches for maintaining the outdoor room conditions. The first 
approach was to maintain the overall outdoor chamber conditions at 95 
[deg]F dry-bulb temperature and 75 [deg]F wet-bulb temperature as 
measured at the infiltration air inlet, allowing for mixing of 
condenser inlet and outlet air and thereby possibly increasing the 
condenser inlet temperature. Additionally, DOE notes that test chamber 
dimensions resulted in the duct fixture being located approximately 
four feet from the opposite wall of the outdoor chamber, which would 
likely be a worst-case configuration in terms of condenser air mixing 
for real-world installations.
    The second approach was to monitor the condenser inlet dry-bulb and 
wet-bulb temperatures and adjust the chamber conditions to maintain the 
95 [deg]F/75 [deg]F conditions at that location. Condenser exhaust and 
inlet air mixing would result in a lower temperature being maintained 
in the outdoor chamber.
    Table II.12 shows the condenser inlet air and infiltration air dry-
bulb temperatures when testing the two dual-duct units according to 
both test approaches. DOE tested each unit in two different 
configurations, once with manufacturer provided ducting and the second 
time with sealed and insulated ducts as described in section II.C.2 of 
today's notice.

                         Table II.12--Condenser Mixing Effects on Air Flow Temperatures
----------------------------------------------------------------------------------------------------------------
                                       Infiltration air at 95 [deg]F         Condenser inlet air at 95 [deg]F
                                 -------------------------------------------------------------------------------
           Test units               Condenser inlet    Infiltration air     Condenser inlet    Infiltration air
                                       ([deg]F)            ([deg]F)            ([deg]F)            ([deg]F)
----------------------------------------------------------------------------------------------------------------
DD1 Uninsulated.................                95.5                95.1                94.8                94.3
DD1 Insulated...................                95.9                95.0                95.0                94.1
DD2 Uninsulated.................                95.1                95.1                95.0                95.0
DD2 Insulated...................                95.0                94.6                95.3                95.0
----------------------------------------------------------------------------------------------------------------

    As shown in Table II.12 the difference between the condenser inlet 
air temperature and infiltration air temperature for both test 
approaches is at most 0.9 [deg]F, regardless of duct heat losses. These 
results indicated that there was minimal mixing between the condenser 
exhaust and inlet air flows. Further confirming this observation were 
data for cooling capacity and EER shown in Table II.13, also showing 
that the difference between the two test approaches was minimal.

                                                  Table II.13--Condenser Mixing Effects on Performance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Infiltration air at 95 [deg]F     Condenser inlet air at 95            Percent change
                                                         --------------------------------             [deg]F             -------------------------------
                                                                                         --------------------------------
                       Test units                             Cooling                         Cooling                         Cooling
                                                          capacity (Btu/   EER (Btu/Wh)   capacity (Btu/   EER (Btu/Wh)    capacity (%)       EER (%)
                                                                h)                              h)
--------------------------------------------------------------------------------------------------------------------------------------------------------
DD1 Uninsulated.........................................         3,379.9            2.89         3,447.7            2.96            2.01            2.18
DD1 Insulated...........................................         4,682.0            3.94         4,640.1            3.93           -0.90           -0.23
DD2 Uninsulated.........................................         3,442.4            2.60         3,413.8            2.58           -0.83           -1.02
DD2 Insulated...........................................         4,209.4            3.14         4,242.5            3.16            0.79            0.90
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Percent reduction in the table above may not align with the performance values listed due to rounding considerations.

    Issue 10. DOE requests feedback regarding measures that should be 
considered in a portable AC test procedure to address any condenser 
exhaust air and inlet air mixing in dual-duct units.

D. Alternate Testing Approach

    Based on the investigative testing, DOE considered whether another 
approach that utilizes the existing test procedures with numerical 
adjustments for infiltration air would accurately reflect portable AC 
performance. As described above in section II.C.3.b of this notice, DOE 
calculated the infiltration heat effects from the air flow rate and 
humidity ratio of the infiltration air. Subtracting the

[[Page 26649]]

infiltration air heat from the cooling capacity as determined by the 
baseline test could be close enough to results obtained from the 
calorimeter method to provide a representative measure of portable AC 
performance. Table II.14 displays the cooling capacity as determined by 
combining the estimated infiltration air heat transfer with the 
baseline results, and the cooling capacity as determined by the 
calorimeter method.

                                                   Table II.14--Alternate Testing Approach Performance
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Cooling capacity  (Btu/h)                             EER (Btu/Wh)
                                                         -----------------------------------------------------------------------------------------------
                        Test Unit                                           Baseline--                                      Baseline--
                                                            Calorimeter    infiltration    Increase  (%)    Calorimeter    infiltration    Increase  (%)
                                                                                air                                             air
--------------------------------------------------------------------------------------------------------------------------------------------------------
SD1.....................................................          -470.8          -878.4           -86.6           -0.54           -1.03           -90.0
SD2.....................................................          -641.4           208.2           132.5           -0.70            0.23           133.5
SD3.....................................................          3475.5         4,032.9            16.0            2.30            2.75            19.5
SD4.....................................................          1841.4         3,982.1           116.3            1.34            2.76           106.1
DD1.....................................................          3379.9         6,526.7            93.1            2.89            5.62            94.3
DD2.....................................................          3442.4         5,503.8            59.9            2.60            4.20            61.5
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The data in Table II.14 indicate that there is no consistent 
difference between the two test approaches. The increase in cooling 
capacity from the calorimeter approach to the alternate approach for 
single-duct units ranged between negative 87 percent and over 133 
percent, while the two dual-duct units in the test sample had a smaller 
range in cooling capacity change, from 60 to 93 percent. A larger 
sample size may further show the trends for difference unit 
configurations.
    Issue 11. DOE welcomes comment on this alternate testing approach, 
and in particular on the testing burden associated with it.

E. Additional Issues On Which DOE Seeks Comment

    Should DOE issue a final determination that portable ACs are a 
covered product, DOE may prescribe test procedures and energy 
conservation standards for portable ACs. As part of that effort, DOE 
may propose a new portable AC test procedure. In addition to the 
specific issues discussed above for which DOE is seeking comment, DOE 
welcomes comment on any aspect of this NODA and is also interested in 
receiving comments and views from interested parties on the following 
issues:
    Issue 12. DOE welcomes general comments about the various 
investigative test approaches DOE conducted as discussed and presented 
above in this notice, including whether any of these approaches are 
currently utilized by manufacturers and test facilities. DOE also 
welcomes comment on any testing methodologies appropriate for 
consideration as an alternative to the industry accepted methodologies 
and those performed by DOE.
    Issue 13. DOE requests data on the repeatability and 
reproducibility of such testing methods. DOE also welcomes additional 
data on the repeatability and reproducibility of testing results using 
the test methods presented in this notice.
    The purpose of this NODA is to solicit feedback from industry, 
manufacturers, academia, consumer groups, efficiency advocates, 
government agencies, and other interested parties on issues related to 
a potential DOE portable AC test procedure. DOE is specifically 
interested in information and additional data on the current industry 
test procedures for portable ACs and alternate test approaches 
discussed in today's notice. Respondents are advised that DOE is under 
no obligation to acknowledge receipt of the information received or 
provide feedback to respondents with respect to any information 
submitted under this NODA. Responses to this NODA do not bind DOE to 
any further actions related to this topic.

III. Public Participation

    DOE is interested in receiving comments on all aspects of the data 
and analysis presented in the NODA and supporting documentation that 
can be found at: http://www1.eere.energy.gov/buildings/appliance_standards/product.aspx/productid/79.

Submission of Comments

    DOE will accept comments, data, and information regarding this 
notice no later than the date provided in the DATES section at the 
beginning of this notice. Interested parties may submit comments, data, 
and other information using any of the methods described in the 
ADDRESSES section at the beginning of this notice.
    Submitting comments via www.regulations.gov. The 
www.regulations.gov Web page will require you to provide your name and 
contact information. Your contact information will be viewable to DOE 
Building Technologies staff only. Your contact information will not be 
publicly viewable except for your first and last names, organization 
name (if any), and submitter representative name (if any). If your 
comment is not processed properly because of technical difficulties, 
DOE will use this information to contact you. If DOE cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, DOE may not be able to consider your comment.
    However, your contact information will be publicly viewable if you 
include it in the comment itself or in any documents attached to your 
comment. Any information that you do not want to be publicly viewable 
should not be included in your comment, nor in any document attached to 
your comment. Otherwise, persons viewing comments will see only first 
and last names, organization names, correspondence containing comments, 
and any documents submitted with the comments.
    Do not submit to www.regulations.gov information for which 
disclosure is restricted by statute, such as trade secrets and 
commercial or financial information (hereinafter referred to as 
Confidential Business Information (CBI)). Comments submitted through 
www.regulations.gov cannot be claimed as CBI. Comments received through 
the Web site will waive any CBI claims for the information submitted. 
For information on submitting CBI, see the Confidential Business 
Information section below.

[[Page 26650]]

    DOE processes submissions made through www.regulations.gov before 
posting. Normally, comments will be posted within a few days of being 
submitted. However, if large volumes of comments are being processed 
simultaneously, your comment may not be viewable for up to several 
weeks. Please keep the comment tracking number that www.regulations.gov 
provides after you have successfully uploaded your comment.
    Submitting comments via email, hand delivery/courier, or mail. 
Comments and documents submitted via email, hand delivery, or mail also 
will be posted to www.regulations.gov. If you do not want your personal 
contact information to be publicly viewable, do not include it in your 
comment or any accompanying documents. Instead, provide your contact 
information in a cover letter. Include your first and last names, email 
address, telephone number, and optional mailing address. The cover 
letter will not be publicly viewable as long as it does not include any 
comments.
    Include contact information each time you submit comments, data, 
documents, and other information to DOE. If you submit via mail or hand 
delivery/courier, please provide all items on a CD, if feasible, in 
which case it is not necessary to submit printed copies. No facsimiles 
(faxes) will be accepted.
    Comments, data, and other information submitted to DOE 
electronically should be provided in PDF (preferred), Microsoft Word or 
Excel, WordPerfect, or text (ASCII) file format. Provide documents that 
are not secured, that are written in English, and that are free of any 
defects or viruses. Documents should not contain special characters or 
any form of encryption and, if possible, they should carry the 
electronic signature of the author.
    Campaign form letters. Please submit campaign form letters by the 
originating organization in batches of between 50 to 500 form letters 
per PDF or as one form letter with a list of supporters' names compiled 
into one or more PDFs. This reduces comment processing and posting 
time.
    Confidential Business Information. Pursuant to 10 CFR 1004.11, any 
person submitting information that he or she believes to be 
confidential and exempt by law from public disclosure should submit two 
well-marked copies: One copy of the document marked ``confidential'' 
including all the information believed to be confidential, and one copy 
of the document marked ``non-confidential'' with the information 
believed to be confidential deleted. DOE will make its own 
determination about the confidential status of the information and 
treat it according to its determination.
    Factors of interest to DOE when evaluating requests to treat 
submitted information as confidential include: (1) A description of the 
items; (2) whether and why such items are customarily treated as 
confidential within the industry; (3) whether the information is 
generally known by or available from other sources; (4) whether the 
information has previously been made available to others without 
obligation concerning its confidentiality; (5) an explanation of the 
competitive injury to the submitting person which would result from 
public disclosure; (6) when such information might lose its 
confidential character due to the passage of time; and (7) why 
disclosure of the information would be contrary to the public interest.
    It is DOE's policy that all comments may be included in the public 
docket, without change and as received, including any personal 
information provided in the comments (except information deemed to be 
exempt from public disclosure).

    Issued in Washington, DC on May 5, 2014.
Kathleen B. Hogan,
Deputy Assistant Secretary for Energy Efficiency, Energy Efficiency and 
Renewable Energy.
[FR Doc. 2014-10692 Filed 5-8-14; 8:45 am]
BILLING CODE 6450-01-P