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Federal Register / Vol. 86, No. 58 / Monday, March 29, 2021 / Rules and Regulations theoretical comparable single-speed room AC.
To measure this improved performance, in the June 2020 NOPR, DOE proposed a test procedure for variable-speed room ACs that adds three test conditions 92 F, 87 F, and 82 F
dry-bulb outdoor temperatures and 72.5 F, 69 F, and 65 F wet-bulb outdoor temperatures, respectively to the existing 95 F test condition, consistent with the test conditions in the waivers. 85 FR 35700, 35709 Jun.
11, 2020. These temperatures represent potential outdoor temperature conditions between the existing 95 F
test condition and the indoor setpoint of 80 F. These additional test conditions are also consistent with the representative temperatures for bin numbers 6, 5, and 4 in Table 19 of DOEs test procedure for central air conditioners at appendix M. See id.
Rice expressed concern that the temperature range of the proposed test points in the NOPR is too narrow, as they are based on only four of the eight cooling-mode outdoor-temperature bins of the 2017 version of Air-Conditioning, Heating and Refrigeration Institute AHRI Standard 210/240, AHRI
Standard 210/240, Performance Rating of Unitary Air-conditioning &
Air-source Heat Pump Equipment, and a wider temperature range for testing is needed. Rice commented that the binned loads in AHRI Standard 210/240
were determined for more typical indoor dry-bulb settings, but the analysis in AHRI Standard 210/240 uses 80 F dry-bulb and 67 F wet-bulb indoor ratings data. Rice recommended that a more complete range of temperature bins and their associated cooling load hours from AHRI Standard 210/240 should be considered for the CEER analysis. Rice, No. 17 at pp. 1
2; see also Rice, Preliminary Analysis,25
No. 25 at p. 2 Rice recommended accounting for the fractional loads and hours of outdoor-temperature bins 67, 72, and 77 F with a lower temperature test condition with an outdoor dry-bulb temperature of 75 F be used in place of the 92 F dry-bulb temperature test condition. Rice asserted that there was not sufficient justification to test at full speed test at 92 F, as it is close to a full speed test at the 95 F dry-bulb temperature test condition. Rice recommended that the fractional bin hours of the 92, 97, and 102 F outdoortemperature bins should be applied to 25 The notation Preliminary Analysis indicates that the comment is filed in the docket of the Energy Conservation Standards for Room Air Conditioners Preliminary Analysis rulemaking EERE2014BTSTD0059 and available for review at http www.regulations.gov.

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the 95 F dry-bulb temperature test condition, which is actually the midpoint temperature of the lower two bins. Rice, No. 17 at pp. 12; see also Rice, Preliminary Analysis, No. 25 at p.
2 DOE recognizes that the test conditions proposed in the June 2020
NOPR do not encompass the full range of bin temperature in Table 16 of ANSI/
AHRI Standard 210/240. The temperature bins in Table 16 of ANSI/
AHRI Standard 201/240 apply to central air conditioners, which are fixed appliances, installed year-round, built into homes, and operate based on a central thermostat to maintain a relatively constant temperature throughout the conditioned space.
Room ACs are instead, often seasonally, installed in a single room; operate based on an internal thermostat when turned on, typically only during the cooling season; and may be readily turned off when the room is not occupied.
Consumers are more acutely aware of a room ACs operation than that of a central air conditioner; as they are used to cool a single room, often only when that room is occupied; make more noise;
and are visible in the room. For these reasons, consumers are more likely to rely on a room AC at the higher temperatures in the range of bin temperatures in Table 16 of ANSI/AHRI
Standard 210/240, as compared to at the lower temperatures in the bin. At the lower temperatures, consumers using room ACs are more likely than consumers with central air conditioners to open a window or operate the unit with only the fan on to circulate indoor air when cooler outdoor air is available to draw in through a fresh air vent, making the lower temperature bins less representative of room AC operation in cooling mode. DOE also notes that the temperature conditions proposed in the June 2020 NOPR are consistent with the industry-accepted test procedure, AHAM RAC12020.
For the reasons discussed in this section, DOE is adopting the four temperature conditions for variablespeed room ACs proposed in the June 2020 NOPR.
3. Variable-Speed Compressor Operation The DOE test procedure maintains fixed temperature and humidity conditions in the indoor chamber and requires configuring the test unit settings i.e., setpoint and fan speed, to achieve maximum cooling capacity. See Section 3.1 of appendix F, as amended, and Section 6.1.1.4 of ANSI/ASHRAE
Standard 162016. Under these conditions, units under test may operate
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continuously at their full cooling capacity, even at the reduced outdoor temperature test conditions described in section III.C.2 of this document, without the compressor cycling for single-speed units or compressor speed reduction for variable-speed units that would be expected under real-world operation.
Therefore, in this final rule, DOE
establishes additional test procedure adjustments, beyond reduced outdoor temperature test conditions, to fully capture the energy efficiency of variable variable-speed room ACs at reduced cooling loads.
As described previously, in a typical consumer installation, reduced outdoor temperatures would result in reduced indoor cooling loads. A test that would provide constant reduced cooling loads could be considered, but as discussed below in section III.E.1.e of this document, DOE concludes such a test would not be feasible at this time.
Instead, in the June 2020 NOPR, DOE
proposed adopting a test that requires fixing the variable-speed room AC
compressor at particular compressor speeds that would reflect the expected load under each of the four test conditions, as described further in the following sections. 85 FR 35700, 35709
Jun. 11, 2020.
a. Compressor Speeds In the June 2020 NOPR, to ensure the compressor speeds are representative of actual speeds at the expected cooling loads at each of the outdoor test conditions, DOE proposed requiring that the compressor speed of a variablespeed room AC be set to full speed at the two highest outdoor temperature test conditions based on test AFull at 95 F
and test BFull at 92 F from Table 8 of AHRI Standard 210/240, at intermediate compressor speed at the 87 F test condition based on test EInt, and at low compressor speed at the 82 F test condition based on test DLow, consistent with the tests and requirements in Table 8 of AHRI
Standard 210/240, which specifies representative test conditions and the associated compressor speeds for variable-speed unitary air conditioners.
85 FR 35700, 35709 Jun. 11, 2020.
The California IOUs questioned the representativeness of testing variablespeed room ACs using fixed-speed testing and referenced statements from the 2019 Appliance Standards and Rulemaking Federal Advisory Committees Variable Refrigerant Flow Working Group that such testing was not representative of field performance, largely because the control settings used during testing did not match the operational behavior of units outside of
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