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Federal Register / Vol. 86, No. 58 / Monday, March 29, 2021 / Rules and Regulations
confusing to consumers who are trying to compare single-speed room ACs with metrics that are not directly comparable.
Additionally, because single-speed units cannot cycle on and off during a reduced outdoor temperature test i.e., because the chamber conditions are held constant throughout the test, the reduced outdoor temperature test alone would not be representative of the single-speed room ACs real world operation, and cycling would need to additionally be considered. Aligning the room AC test procedure with the appendix M1 test procedure would greatly increase the test burden on manufacturers for typically inexpensive and seasonal units. Therefore, in this final rule, DOE is not establishing multiple test conditions for single-speed room ACs or adopting provisions to align the room AC test procedure with the central air conditioner test procedure at appendix M1.
Cooling Test Alternatives DOE is aware of two approaches to measure part-load performance of a room AC, dynamic-cooling-load testing and constant-cooling-load testing. In both a dynamic-cooling-load test and a constant-cooling-load test, the chamber indoor cooling load was provided at a specified rate or value throughout testing instead of maintaining specific temperature conditions within the test chamber. In the June 2020 NOPR, DOE
explored a constant-cooling-load test and concluded that increased test burden, reduced repeatability and reproducibility, and a current lack of industry consensus on a constantcooling-load or dynamic-cooling-load test procedure outweighed potential benefits. 85 FR 35700, 35723 Jun. 11, 2020. Thus, in the June 2020 NOPR, DOE did not propose a constant-coolingload or dynamic-cooling-load test for room ACs. Id.
AHAM agreed with DOEs initial conclusion that the potential benefits of constant-cooling-load or dynamiccooling-load tests do not justify the increase in test burden or the negative impact on repeatability and reproducibility. According to AHAM, DOEs testing demonstrated that conducting a constant-cooling-load test in a calorimeter test chamber would impact the repeatability and reproducibilityat cooling loads less than 75 percent of the tested unit cooling capacity, the indoor wet-bulb temperature variation in DOEs test sample sometimes exceeded 0.3 F.
AHAM cited that DOE also observed challenges with the test chamberthe chamber controls were not capable of automatically achieving a specific
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cooling load condition. Additionally, AHAM commented that this type of testing would significantly increase test burden. AHAM, No. 13 p. 6
ASAP, Joint Commenters, NEAA, and the California IOUs disagreed with DOEs initial conclusion and proposal in the June 2020 NOPR and urged DOE
to use a load-based test to better represent real-world efficiency of both single-speed and variable-speed units.
ASAP, Public Meeting Transcript, No.
12 at p. 1; Joint Commenters, No. 15 at pp. 34; NEAA, No. 16 at pp. 45
ASAP commented that using a loadbased test procedure for all room ACs would provide the most representative efficiency ratings and accurate information for customers. ASAP, Public Meeting Transcript, No. 12 at p.
1 The Joint Commenters noted that, for single-speed units, a load-based test would capture the impact of cycling losses. The Joint Commenters further noted that, for variable-speed units, load-based testing would capture the impact of control strategies that determine compressor and fan speed operation and would ensure that the test procedure reflects the real-world operation of these units. Joint Commenters, No. 15 at pp. 35 NEAA
commented that its initial load-based testing of ductless heat pumps indicated that controls can dramatically affect performance and suggested the same effects could be found with room ACs.
NEAA, No. 16 at pp. 45
DOE acknowledges that a constantcooling-load or dynamic-cooling-load test for all room ACs has the potential to be more representative of real-world operation. However, a load-based test would reduce repeatability and reproducibility due to limitations in current test chamber capabilities, as discussed in the June 2020 NOPR, which would negatively impact the representativeness of the results and potentially be unduly burdensome. 85
FR 35700, 3572335726 Jun. 11, 2020.
Therefore, based on DOEs investigative testing and to maintain test procedure alignment with AHAM RAC12020, in this final rule DOE maintains its proposal not to include a constantcooling-load or dynamic-cooling-load test for room ACs in appendix F.
e. Power Factor In the June 2020 NOPR, DOE did not propose requirements for measuring and reporting the power factor 37 for room 37 The power factor of an alternating current electrical power system is defined as the ratio of the real power flowing to the load to the apparent power in the circuit. A load with a low power factor draws more electrical current than a load with a high power factor for the same amount of useful
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ACs. 85 FR 35700, 35726 Jun. 11, 2020. Based on investigative testing DOE found that there was no significant difference between the actual power drawn by a room AC and the apparent power supplied to the unit, meaning the additional burden of measuring and reporting the power factor would outweigh any benefits this information would provide. Id. The California IOUs agreed that the resultsan average power factor of 0.97 on 23 unitsdo not provide evidence that warrants the inclusion of power factor in the test procedure. However, the California IOUs commented that variable-speed motor controllers often have lower power factors compared to direct-online motors used in single-speed room ACs 38 and requested that DOE indicate whether the room ACs tested included representative variable-speed compressor room ACs. If not, the California IOUs requested that DOE
consider conducting power factor testing of variable-speed room ACs and reporting the results. California IOUs, No. 14 at p. 5
None of the 23 units DOE tested during the power factor investigation for the June 2020 NOPR were variablespeed units. To date, DOE has been unable to gather power factor data for variable-speed room ACs due to instrumentation limitations. In the absence of data that suggest that variable-speed power factors are significantly different than single-speed power factors, DOE is not adopting a power factor measurement or reporting requirements for room ACs at appendix F in this final rule.
2. Heating Mode When a reverse cycle room AC is in heating mode, the indoor evaporator coil switches roles and becomes the condenser coil, providing heat to the indoor room. The outdoor condenser unit also switches roles to serve as the evaporator and discharges cold air to the outdoors. Appendix F does not include a method for measuring room AC energy consumption in heating mode.
In the June 2020 NOPR, DOE did not propose a heating mode test procedure for room ACs based on the lack of data of room AC used for heating and given the potential concerns raised by stakeholders that combining cooling mode and heating mode performance power transferred. The higher currents associated with low power factor increase the amount of energy lost in the electricity distribution system.
38 Greenberg, S. 1988. Technology Assessment:
Adjustable-Speed Motors and Motor Drives.
Lawrence Berkeley National Laboratory. LBNL
Report : LBL25080. Retrieved from https
escholarship.org/uc/item/41z9k3q3.

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