Appendix D1 to Subpart F of Part 431—Uniform Test Method for Measuring the Energy Consumption of Variable Refrigerant Flow Multi-Split Air Conditioners and Heat Pumps (Other Than Air-Cooled With Rated Cooling Capacity Less Than 65,000 Btu/h)

Manufacturers must use the results of testing under this appendix to determine compliance with any amended standards for variable refrigerant flow multi-split air conditioners and heat pumps provided in § 431.97 that are published after January 1, 2022, and that rely on integrated energy efficiency ratio (IEER). Representations related to energy consumption must be made in accordance with the appropriate appendix that applies (i.e., appendix D or appendix D1) when determining compliance with the relevant standard. DOE incorporated by reference in § 431.95, the entire standard for AHRI 1230-2021 and ANSI/ASHRAE 37-2009, as corrected by the Errata sheet for ANSI/ASHRAE 37-2009 issued on March 27, 2019 (“ANSI/ASHRAE 37-2009 (as corrected)”). However, only enumerated provisions of AHRI 1230-2021 and ANSI/ASHRAE 37-2009 are required or excluded, as listed in this section 1. To the extent there is a conflict between the terms or provisions of a referenced industry standard and the CFR, the CFR provisions control. (a) Section 3—Definitions, except section 3.11, as specified in section 2 of this appendix, (b) Section 5—Test Requirements, except section 5.1.2, as specified in sections 2 and 5.1 of this appendix, (c) Section 6—Rating Requirements, except sections 6.3.3 and 6.5, as specified in sections 2, 4.1, 4.1.1, 4.2, 4.2.1, and 5.1 of this appendix, (d) Section 11—Calculations is applicable as specified in sections 2, 5.2.1.2, and 5.2.2 of this appendix, (e) Section 12—Symbols, Subscripts, and Superscripts as specified in section 2 of this appendix, (f) Appendix E—ANSI/ASHRAE Standard 37-2009 Clarifications/Exceptions—Normative as specified in section 2 of this appendix. (a) Section 1—Purpose, (b) Section 2—Scope, and (c) Section 4—Classification. 2. General. Determine IEER and coefficient of performance (COP) (as applicable) in accordance with AHRI 1230-2021 and ANSI/ASHRAE 37-2009 (as corrected). Sections 3 through 5 of this appendix provide additional instructions for determining IEER and COP. In cases where there is a conflict, the language of this appendix takes highest precedence, followed by AHRI 1230-2021, followed by ANSI/ASHRAE 37-2009 (as corrected). The controls verification procedure specified in Appendix C of AHRI 1230-2021 is referenced as part of DOE's certification provisions at § 429.43(b) and product-specific enforcement provisions located at § 429.134(v)(3). 3.1. Critical Parameter(s) are the following settings of modulating components of variable refrigerant flow multi-split air conditioners and heat pumps: compressor speed(s), outdoor fan speed(s), and outdoor variable valve position(s). 4.1 Test Conditions for Air-Cooled VRF Multi-split Systems with Rated Cooling Capacity Greater Than 65,000 Btu/h. When testing to certify to the energy conservation standards in § 431.97, test using the “Standard Rating Conditions, Cooling” and “Standard Rating Part-Load Conditions (IEER)” conditions for cooling mode tests and “Standard Rating Conditions (High Temperature Steady-state Test for Heating)” conditions for heat pump heating mode tests, as specified in Table 9 in Section 6 of AHRI 1230-2021. 4.1.1 Representations of COP for air-cooled VRF multi-split systems with rated cooling capacity greater than 65,000 Btu/h made using the “Low Temperature Operation, Heating” condition specified in Table 9 in Section 6 of AHRI 1230-2021 are optional. 4.2 Test Conditions for Water-source VRF Multi-split Systems. When testing to certify to the energy conservation standards in § 431.97, test using the “Part-load Conditions (IEER)” conditions specified for “Water Loop Heat Pumps” in Table 10 of AHRI 1230-2021 for cooling mode tests and the “Standard Rating Test” conditions specified for “Water Loop Heat Pumps” in Table 11 in Section 6 of AHRI 1230-2021 for heat pump heating mode tests. 4.2.1 For water-source VRF multi-split systems, representations of EER made using the “Standard Rating Test” conditions specified for “Ground-loop Heat pumps” in Table 10 of Section 6 of AHRI 1230-2021 and representations of COP made using the “Standard Rating Test” conditions specified for “Ground-loop Heat Pumps” in Table 11 of Section 6 of AHRI 1230-2021 are optional. 5.1 Control Settings. Control settings must be set in accordance with Sections 5.1.3, 5.1.4, 5.1.5, and 5.2 of AHRI 1230-2021. For systems equipped with head pressure controls, the head pressure controls must be set per manufacturer installation instructions or per factory settings if no instructions are provided. Indoor airflow-control settings must be set in accordance with Section 6.3.1 of AHRI 1230-2021. At each load point, critical parameters must be set to the values certified in the supplemental testing instructions (STI) provided by the manufacturer pursuant to § 429.43(b)(4) of this chapter. In cases in which a certified critical parameter value is not in the STI, the system must operate per commands from the system controls for that parameter. Once set, control settings must remain unchanged for the remainder of the test (except for allowable adjustment of critical parameters as described in section 5.2 of this appendix). 5.2 Allowable Critical Parameter Adjustments for IEER Cooling Tests. The following sections describe allowable adjustments to critical parameters after the initial system set-up (during which all control settings, including certified critical parameters, are set). Adjust critical parameters in order to achieve full- and part-load cooling capacity targets and sensible heat ratio (SHR) limits. 5.2.1 Critical Parameter Adjustments for Meeting Cooling Capacity Targets. Once critical parameters have been set to the values certified in the STI, if the unit cannot operate within 3% of the target cooling capacity (i.e., within 3% of the load fraction for a given part-load cooling test (75%, 50%, or 25% load) or within 3% of the certified cooling capacity for a 100% full-load cooling test), manually-controlled critical parameters must be adjusted according to the following provisions: 5.2.1.1. Cooling Capacity is Below Lower Tolerance. If, for any test, the cooling capacity operates below the lower tolerance for the target cooling capacity, increase the compressor speed(s) beyond the STI-certified value(s) until the cooling capacity operates within 3% of the target cooling capacity. If multiple compressors are present in the system, increase compressor speed by the same absolute increment in RPM or Hz for each compressor for which the following conditions apply: (a) The STI specifies a non-zero compressor speed for the compressor for that test and (b) The compressor has not yet reached its maximum capable operating speed. The compressor speed(s) must not be less than the STI-certified value(s) at any point during the test. Upward adjustments to compressor speed are not constrained by a budget on RSS Points Total (See section 5.2.1.2.1 of this appendix). 5.2.1.2 Cooling Capacity is Above Upper Tolerance. If, for any test, the cooling capacity operates above the upper tolerance for the target cooling capacity, adjust any manually-controlled critical parameters per the STI. If the STI does not include a hierarchy of instructions for adjustment of critical parameters to reduce cooling capacity during IEER cooling tests, then reduce only the compressor speed(s) to reduce cooling capacity. If multiple compressors are present in the system, decrease compressor speed by the same absolute increment for each compressor for which the following conditions apply: (a) The STI specifies a non-zero compressor speed for the compressor for that test and (b) The compressor has not yet reached minimum speed. Continue reducing cooling capacity in this manner until one of the following occurs: (1) The unit operates within 3% of the target cooling capacity; or (2) The RSS point total reaches a budget of 70 points (see section 5.2.1.2.1 of this appendix). For the 75%, 50%, and 25% part-load cooling test points, if the RSS point total reaches 70 during critical parameter adjustments before the capacity operates within 3% of the target cooling capacity, stop adjustment and follow cyclic degradation procedures in accordance with Section 11.2.2.1 of AHRI 1230-2021. 5.2.1.2.1 Measuring Critical Parameter Variation During Adjustment Period. When adjusting critical parameters to reduce cooling capacity, critical parameter variation must be calculated each time the critical parameters are adjusted, using the following equations: (a) First, use equation 5.2-1 to calculate the absolute parameter percent difference () between each adjusted critical parameter and the value for that parameter certified in the STI. (b) Next, use equation 5.2-2 to this section to determine the accrued points for each critical parameter: Table 5.1—Critical Parameter Nominal Point Values (c) Finally, use equation 5.2-3 to this section to calculate the root-sum-squared (RSS) Points Total across all critical parameters. 5.2.2 Critical Parameter Adjustments for Meeting SHR Limits. The SHR for the 100% load test point and the 75% part-load test point must not be higher than 0.82 and 0.85, respectively (measured to the nearest hundredth). If the SHR is above the allowable limit, increase the compressor speed(s) until either the SHR is less than or equal to the allowable limit or the cooling capacity reaches 3% greater than the target cooling capacity for that test, whichever happens first. If multiple compressors are present in the system, increase compressor speed by the same absolute increment for each compressor for which the following conditions apply: (a) The STI specifies a non-zero compressor speed for the compressor for that test and (b) The compressor has not yet reached maximum speed. Upwards adjustments to compressor speed are not constrained by a budget on RSS Points Total. Should the SHR remain above the maximum limit when the cooling capacity reaches its upper 3% tolerance, no further compressor adjustments shall be made, and the calculation procedures specified in Section 11.2.2.2 of AHRI 1230-2021 must be applied using the adjusted SHR value obtained after increasing the compressor speed(s). 6. Set-Up and Test Provisions for Specific Components. When testing a VRF multi-split system that includes any of the specific components listed in table 6.1 to this appendix, test in accordance with the set-up and test provisions specified in table 6.1. Table 6.1—Test Provisions for Specific Components