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 Code of Federal Regulations (Last Updated: November 8, 2024)
 Title 10 - Energy
 Chapter II - Department of Energy
 SubChapter D - Energy Conservation
 Part 431 - Energy Efficiency Program for Certain Commercial and Industrial Equipment
 Subpart G - Commercial Water Heaters, Hot Water Supply Boilers and Unfired Hot Water Storage Tanks

  Appendix E to Subpart G of Part 431 - Uniform Test Method for the Measurement of Energy Efficiency of Commercial Heat Pump Water Heaters

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  • Appendix E to Subpart G of Part 431 - Uniform Test Method for the Measurement of Energy Efficiency of Commercial Heat Pump Water Heaters

    Note: On and after November 6, 2017, manufacturers must make any representations with respect to energy use or efficiency of commercial heat pump water heaters in accordance with the results of testing pursuant to this appendix.

    1. General. Determine the COPh for commercial heat pump water heaters (CHPWHs) using the test procedure set forth below. Certain sections below reference ANSI/ASHRAE 118.1-2012 (incorporated by reference; see § 431.105). Where the instructions contained below differ from those contained in ANSI/ASHRAE 118.1-2012, the sections in this appendix control.

    2. Definitions and Symbols. The definitions and symbols are as listed in section 3 of ANSI/ASHRAE 118.1-2012.

    3. Instrumentation. The instruments required for the test are as described in section 6 of ANSI/ASHRAE 118.1-2012 (except sections 6.3, 6.4, and 6.6).

    4. Test Set-Up. Follow the provisions described in this section to install the CHPWH for testing. Use the test set-up and installation instructions set forth for Type IV and Type V equipment (as applicable), defined in sections 4.4 and 4.5 of ANSI/ASHRAE 118.1-2012 and in accordance with the sections below:

    4.

    1. Test set-up and installation instructions.

    4.1.1. For air-source CHPWHs, set up the unit for testing as per section 7.1 and Figure 5a of ANSI/ASHRAE 118.1-2012 for CHPWHs without an integral storage tank, and as per Figure 6 in section 7.7.1 of ANSI/ASHRAE 118.1-2012 for CHPWHs with an integral storage tank.

    4. 1.2. For direct geo-exchange CHPWHs, set up the unit for testing as per section 7.1 and Figure 5b of ASNI/ASHRAE 118.1-2012 for CHPWHs without an integral storage tank, and as per Figure 7 in section 7.7.2 of ANSI/ASHRAE 118.1-2012 for CHPWHs with an integral storage tank.

    4. 1.3. For indoor water-source, ground-source closed-loop, and ground water-source CHPWHs, set up the unit for testing as per section 7.1 and Figure 5c of ANSI/ASHRAE 118.1-2012 for CHPWHs without an integral storage tank, and as per Figure 8 in section 7.7.3 of ANSI/ASHRAE 118.1-2012 for CHPWHs with an integral storage tank.

    4. 2. Use the water piping instructions described in section 7.2 of ANSI/ASHRAE 118.1-2012 and the special instructions described in section 7.7.6 of ANSI/ASHRAE 118.1-2012. Insulate all the pipes used for connections with material having a thermal resistance of not less than 4 h· °F·ft2/Btu for a total piping length of not less than 4 feet from the water heater connection ports.

    4.3. Install the thermocouples, including the room thermocouples, as per the instructions in sections 7.3.1, 7.3.2, and 7.3.3 (as applicable) of ANSI/ASHRAE 118.1-2012.

    4.4. Section 7.6 of ANSI/ASHRAE 118.1-2012 must be used if the manufacturer neither submits nor specifies a water pump applicable for the unit for laboratory testing.

    4.5. Install the temperature sensors at the locations specified in Figure 5a, 5b, 5c, 6, 7, or 8 of ANSI/ASHRAE 118.1-2012, as applicable as per section 4.1 of this appendix. The sensor shall be installed in such a manner that the sensing portion of the device is positioned within the water flow and as close as possible to the center line of the pipe. Follow the instructions provided in sections 7.7.7.1 and 7.7.7.2 of ANSI/ASHRAE 118.1-2012 to install the temperature and flow-sensing instruments.

    4.6. Use the following evaporator side rating conditions as applicable for each category of CHPWHs. These conditions are also mentioned in Table 5.1 of this appendix:

    4.6.1. For air-source CHPWHs, maintain the evaporator air entering dry-bulb temperature at 80.6 °F ± 1 °F and wet-bulb temperature at 71.2 °F ± 1 °F throughout the conduct of the test.

    4.6.2. For direct geo-exchange CHPWHs, maintain the evaporator refrigerant temperature at 32 °F ± 1 °F.

    4.6.3. For indoor water-source CHPWHs, maintain the evaporator entering water temperature at 68 °F ± 1 °F.

    4.6.4. For ground water-source CHPWHs, maintain the evaporator entering water temperature at 50 °F ± 1 °F.

    4.6.5. For ground-source closed-loop CHPWHs, maintain the evaporator entering water temperature at 32 °F ± 1 °F.

    4.6.5.1. For ground-source closed-loop CHPWHs, the evaporator water must be mixed with 15-percent methanol by-weight to allow the solution to achieve the rating conditions required in section 4.6.5.

    4.7. The CHPWH being tested must be installed as per the instructions specified in sections 4.1 to 4.6 (as applicable) of this appendix. For all other installation requirements, use section 7.7.4 of ANSI/ASHRAE 118.1-2012 to resolve any issues related to installation (other than what is specified in this test procedure) of the equipment for testing. Do not make any alterations to the equipment except as specified in this appendix for installation, testing, and the attachment of required test apparatus and instruments.

    4. 8. Use Table 3 of ANSI/ASHRAE 118.1-2012 for measurement tolerances of various parameters.

    4.9. If the CHPWH is equipped with a thermostat that is used to control the throttling valve of the equipment, then use the provisions in section 7.7.7.3 of ANSI/ASHRAE 118.1-2012 to set up the thermostat.

    4.10. For CHPWHs equipped with an integral storage tank, supplemental heat inputs such as electric resistance elements must be disabled as per section 7.7.8 of ANSI/ASHRAE 118.1-2012.

    4.11. Install instruments to measure the electricity supply to the equipment as specified in section 7.5 of ANSI/ASHRAE 118.1-2012.

    5. Test Procedure

    Test all CHPWHs that are not equipped with an integral storage tank as per the provisions described in ANSI/ASHRAE 118.1-2012 for “Type IV” equipment as defined in section 4.4 of ANSI/ASHRAE 118.1-2012. Test all CHPWHs that are equipped with an integral storage tank as per the provisions described in ANSI/ASHRAE 118.1-2012 for “Type V” equipment as defined in section 4.5 of ANSI/ASHRAE 118.1-2012. Tests for all CHPWHs must follow the steps described below.

    5.1. Supply the CHPWH unit with electricity at the voltage specified by the manufacturer. Follow the provisions in section 8.2.1 of ANSI/ASHRAE 118.1-2012 to maintain the electricity supply at the required level.

    5.1.1. For models with multiple voltages specified by the manufacturer, use the minimum voltage specified by the manufacturer to conduct the test. Maintain the voltage as per the limits specified in section 8.2.1 of ANSI/ASHRAE 118.1-2012. The test may be repeated at other voltages at the manufacturer's discretion.

    5.2. Set the condenser supply water temperature and outlet water temperature per the following provisions and as set forth in Table 5.1 of this section:

    Table 5.1 - Evaporator and Condenser Side Rating Conditions

    Category of CHPWH Evaporator side rating conditions Condenser side rating conditions
    Air-source commercial heat pump water heater Evaporator entering air conditions:
    Dry bulb: 80.6 °F ± 1 °F
    Wet bulb: 71.2 °F ± 1 °F    		 Entering water temperature: 70 °F ± 1 °F. Vary water flow rate (if needed) to achieve the outlet water temperature as specified in section 8.7.2 of ANSI/ASHRAE 118.1-2012.
    If the required outlet water temperature as specified in section 8.7.2 of ANSI/ASHRAE 118.1-2012 is not met even after varying the flow rate, then change the condenser entering water temperature to 110 °F ± 1 °F. Vary flow rate to achieve the conditions in section 8.7.2 of ANSI/ASHRAE 118.1-2012.
    Direct geo-exchange commercial heat pump water heater Evaporator refrigerant temperature: 32 °F ± 1 °F Entering water temperature: 110 °F ± 1 °F.
    Indoor water-source commercial heat pump water heater Evaporator entering water temperature: 68 °F ± 1 °F Entering water temperature: 110 °F ± 1 °F.
    Ground water-source commercial heat pump water heater Evaporator entering water temperature: 50 °F ± 1 °F Entering water temperature: 110 °F ± 1 °F.
    Ground-source closed-loop commercial heat pump water heater Evaporator entering water temperature: 32 °F ± 1 °F Entering water temperature: 110 °F ± 1 °F.

    5.2.1. For air-source CHPWHs:

    5.2.1.1. Set the supply water temperature to 70 °F ± 1 °F. The water pressure must not exceed the maximum working pressure rating for the equipment under test.

    5.2.1.2. Use the provisions in section 8.7.1 of ANSI/ASHRAE 118.1-2012 to set the tank thermostat for CHPWHs equipped with an integral storage tank.

    5.2.1.3. Initiate operation at the rated pump flow rate and measure the outlet water temperature. If the outlet water temperature is maintained at 120 °F ± 5 °F with no variation in excess of 2 °F over a three-minute period, as required by section 8.7.2 of ANSI/ASHRAE 118.1-2012, skip to section 5.3 of this appendix.

    5.2.1.4. If the outlet water temperature condition as specified in section 8.7.2 of ANSI/ASHRAE 118.1-2012 is not achieved, adjust the water flow rate over the range of the pump's capacity. If, after varying the water flow rate, the outlet water temperature is maintained at 120 °F ± 5 °F with no variation in excess of 2 °F over a three-minute period, as required by section 8.7.2 of ANSI/ASHRAE 118.1-2012, skip to section 5.3 of this appendix.

    5.2.1.5. If, after adjusting the water flow rate within the range that is achievable by the pump, the outlet water temperature condition as specified in section 8.7.2 of ANSI/ASHRAE 118.1-2012 is still not achieved, then change the supply water temperature to 110 °F ± 1 °F and repeat the instructions from sections 5.2.1.2 and 5.2.1.4 of this appendix.

    5.2.1. 6. If the outlet water temperature condition cannot be met, then a test procedure waiver is necessary to specify an alternative set of test conditions.

    5.2.2. For direct geo-exchange, indoor water-source, ground-source closed-loop, and ground water-source CHPWHs use the following steps:

    5.2.2.1. Set the condenser supply water temperature to 110 °F ± 1 °F. The water pressure must not exceed the maximum working pressure rating for the equipment under test.

    5.2.2.2. Use the provisions in section 8.7.1 of ANSI/ASHRAE 118.1-2012 to set the tank thermostat for CHPWHs equipped with an integral storage tank.

    5.2.2.3. Follow the steps specified in section 8.7.2 of ANSI/ASHRAE 118.1-2012 to obtain an outlet water temperature of 120 °F ± 5 °F with no variation in excess of 2 °F over a three-minute period.

    5.3. Conduct the test as per section 9.1.1, “Full Input Rating,” of ANSI/ASHRAE 118.1-2012. The flow rate, “FR,” referred to in section 9.1.1 of ANSI/ASHRAE 118.1-2012 is the flow rate of water through the CHPWH expressed in gallons per minute obtained after following the steps in section 5.2 of this appendix. Use the evaporator side rating conditions specified in section 4.6 of this appendix to conduct the test as per section 9.1.1 of ANSI/ASHRAE 118.1-2012.

    5.4. Calculate the COPh of the CHPWH according to section 10.3.1 of the ANSI/ASHRAE 118.1-2012 for the “Full Capacity Test Method.” For all calculations, time differences must be expressed in minutes.

    [81 FR 79346, Nov. 10, 2016]