10 CFR Appendix B to Subpart F of Part 431 - Appendix B to Subpart F of Part 431—Uniform Test Method For Measuring the Energy Consumption of Direct Expansion-Dedicated Outdoor Air Systems
Beginning July 24, 2023, representations with respect to energy use or efficiency of direct expansion-dedicated outdoor air systems must be based on testing conducted in accordance with this appendix. Manufacturers may elect to use this appendix early.
DOE incorporated by reference in § 431.95, the entire standard for AHRI 920-2020, AHRI 1060-2018; ANSI/ASHRAE 37-2009, ANSI/ASHRAE 41.1-2013, ANSI/ASHRAE 41.6-2014, and ANSI/ASHRAE 198-2013. However, only enumerated provisions of AHRI 920-2020, ANSI/ASHRAE 37-2009, ANSI/ASHRAE 41.6-2014, and ANSI/ASHRAE 198-2013, as listed in this section 1 are required. 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, as specified in section 2.2.1(a) of this appendix;
(b) Section 5—Test Requirements, as specified in section 2.2.1(b) of this appendix;
(c) Section 6—Rating Requirements, as specified in section 2.2.1(c) of this appendix, omitting section 6.1.2 (but retaining sections 6.1.2.1-6.1.2.8) and 6.6.1;
(d) Section 11—Symbols and Subscripts, as specified in section 2.2.1(d) of this appendix;
(e) Appendix A—References—Normative, as specified in section 2.2.1(e) of this appendix; and
(f) Appendix C—ANSI/ASHRAE Standard 198 and ANSI/ASHRAE Standard 37 Additions, Clarifications and Exceptions—Normative, as specified in section 2.2.1(f) of this appendix.
(a) Section 5.1—Temperature Measuring Instruments (excluding sections 5.1.1 and 5.1.2), as specified in sections 2.2.1(b) and (f) of this appendix;
(b) Section 5.2—Refrigerant, Liquid, and Barometric Pressure Measuring Instruments, as specified in section 2.2.1(b) of this appendix;
(c) Sections 5.3—Air Differential Pressure and Airflow Measurements, as specified in section 2.2.1(b) of this appendix;
(d) Sections 5.5(b)—Volatile Refrigerant Measurement, as specified in section 2.2.1(b) of this appendix;
(e) Section 6.1—Enthalpy Apparatus (excluding 6.1.1 and 6.1.3 through 6.1.6), as specified in section 2.2.1(b) of this appendix;
(f) Section 6.2—Nozzle Airflow Measuring Apparatus, as specified in section 2.2.1(b) of this appendix;
(g) Section 6.3—Nozzles, as specified in section 2.2.1(b) of this appendix;
(h) Section 6.4—External Static Pressure Measurements, as specified in section 2.2.1(b) of this appendix;
(i) Section 6.5—Recommended Practices for Static Pressure Measurements, as specified in section 2.2.1(f) of this appendix;
(j) Section 7.3—Indoor and Outdoor Air Enthalpy Methods, as specified in section 2.2.1(f) of this appendix;
(k) Section 7.4—Compressor Calibration Method, as specified in section 2.2.1(f) of this appendix;
(l) Section 7.5—Refrigerant Enthalpy Method, as specified in section 2.2.1(f) of this appendix;
(m) Section 7.6—Outdoor Liquid Coil Method, as specified in section 2.2.1(f) of this appendix;
(n) Section 7.7—Airflow Rate Measurement (excluding sections 7.7.1.2, 7.7.3, and 7.7.4), as specified in section 2.2.1(b) of this appendix;
(o) Table 1—Applicable Test Methods, as specified in section 2.2.1(f) of this appendix;
(p) Section 8.6—Additional Requirements for the Outdoor Air Enthalpy Method, as specified in section 2.2.1(f) of this appendix;
(q) Table 2b—Test Tolerances (I-P Units), as specified in sections 2.2.1(c) and 2.2(f) of this appendix; and
(r) Errata sheet issued on October 3, 2016, as specified in section 2.2.1(f) of this appendix.
(a) Section 4—Classifications, as specified in section 2.2.1(f) of this appendix;
(b) Section 5—Requirements, as specified in section 2.2.1(f) of this appendix;
(c) Section 6—Instruments and Calibration, as specified in section 2.2.1(f) of this appendix;
(d) Section 7.1—Standard Method Using the Cooled-Surface Condensation Hygrometer as specified in section 2.2.1(f) of this appendix; and
(e) Section 7.4—Electronic and Other Humidity Instruments. As specified in section 2.2.1(f) of this appendix.
(a) Section 4.4—Temperature Measuring Instrument, as specified in section 2.2.1(b) of this appendix;
(b) Section 4.5—Electrical Instruments, as specified in section 2.2.1(b) of this appendix;
(c) Section 4.6—Liquid Flow Measurement, as specified in section 2.2.1(b) of this appendix;
(d) Section 4.7—Time and Mass Measurements, as specified in section 2.2.1(b) of this appendix;
(e) Section 6.1—Test Room Requirements, as specified in section 2.2.1(b) of this appendix;
(f) Section 6.6—Unit Preparation, as specified in section 2.2.1(b) of this appendix;
(g) Section 7.1—Preparation of the Test Room(s), as specified in section 2.2.1(b) of this appendix;
(h) Section 7.2—Equipment Installation, as specified in section 2.2.1(b) of this appendix;
(i) Section 8.2—Equilibrium, as specified in section 2.2.1(b) of this appendix; and
(j) Section 8.4—Test Duration and Measurement Frequency, as specified in section 2.2.1(b) of this appendix.
Moisture removal capacity (in pounds per hour) and supply airflow rate (in standard cubic feet per minute) are determined according to AHRI 920-2020 as specified in section 2.2 of this appendix.
2.2.1. Determine the ISMRE2 for all DX-DOASes and the ISCOP2 for all heat pump DX-DOASes in accordance with the following sections of AHRI 920-2020 and the additional provisions described in this section.
(a) Section 3—Definitions, including the references to AHRI 1060-2018;
(i) Non-standard Low-static Fan Motor. A supply fan motor that cannot maintain external static pressure as high as specified in Table 7 of AHRI 920-2020 when operating at a manufacturer-specified airflow rate and that is distributed in commerce as part of an individual model within the same basic model of a DX-DOAS that is distributed in commerce with a different motor specified for testing that can maintain the required external static pressure.
(ii) Manufacturer-specified. Information provided by the manufacturer through manufacturer's installation instructions, as defined in Section 3.14 of AHRI 920-2020.
(iii) Reserved
(b) Section 5—Test Requirements, including the references to Sections 5.1, 5.2, 5.3, 5.5, 6.1, 6.2, 6.3, 6.4, and 7.7 (not including Sections 7.7.1.2, 7.7.3, and 7.7.4) of ANSI/ASHRAE 37-2009, and Sections 4.4, 4.5, 4.6, 4.7, 5.1, 6.1, 6.6, 7.1, 7.2, 8.2, and 8.4 of ANSI/ASHRAE 198-2013;
(i) All control settings are to remain unchanged for all Standard Rating Conditions once system set up has been completed, except as explicitly allowed or required by AHRI 920-2020 or as indicated in the supplementary test instructions (STI). Component operation shall be controlled by the unit under test once the provisions in section 2.2.1(c) of this appendix are met.
(ii) Break-in. The break-in conditions and duration specified in section 5.6 of AHRI 920-2020 shall be manufacturer-specified values.
(iii) Reserved
(c) Section 6—Rating Requirements (omitting sections 6.1.2 and 6.6.1), including the references to Table 2b of ANSI/ASHRAE 37-2009, and ANSI/ASHRAE 198-2013.
(i) For water-cooled DX-DOASes, the “Condenser Water Entering Temperature, Cooling Tower Water” conditions specified in Table 4 of AHRI 920-2020 shall be used. For water-source heat pump DX-DOASes, the “Water-Source Heat Pumps” conditions specified in Table 5 of AHRI 920-2020 shall be used.
(ii) For water-cooled or water-source DX- DOASes with integral pumps, set the external head pressure to 20 ft. of water column, with a −0/+1 ft. condition tolerance and a 1 ft. operating tolerance.
(iii) When using the degradation coefficient method as specified in Section 6.9.2 of AHRI 920-2020, Equation 20 applies to DX- DOAS without VERS, with deactivated VERS (see Section 5.4.3 of AHRI 920-2020), or sensible-only VERS tested under Standard Rating Conditions other than D.
(iv) Rounding requirements for representations are to be followed as stated in Sections 6.1.2.1 through 6.1.2.8 of AHRI 920-2020;
(d) Section 11—Symbols and Subscripts, including references to AHRI 1060-2018;
(e) Appendix A—References—Normative;
(f) Appendix C—ANSI/ASHRAE 198-2013 and ANSI/ASHRAE 37 Additions, Clarifications and Exceptions—Normative, including references to Sections 5.1, 6.5, 7.3, 7.4, 7.5, 7.6, 8.6, Table 1, Table 2b, and the errata sheet of ANSI/ASHRAE 37-2009, ANSI/ASHRAE 41.1-2013, Sections 4, 5, 6, 7.1, and 7.4 of ANSI/ASHRAE 41.6-2014, and AHRI 1060-2018;
(g) Appendix E—Typical Test Unit Installations—Informative, for information only.
2.2.2. Set-Up and Test Provisions for Specific Components. When testing a DX-DOAS that includes any of the features listed in Table 2.1 of this section, test in accordance with the set-up and test provisions specified in Table 2.1 of this section.
Table 2.1—Test Provisions for Specific Components
| Component | Description | Test provisions |
|---|---|---|
| Return and Exhaust Dampers | An automatic system that enables a DX-DOAS Unit to supply and use some return air (even if an optional VERS is not utilized) to reduce or eliminate the need for mechanical dehumidification or heating when ventilation air requirements are less than design | All dampers that allow return air to pass into the supply airstream shall be closed and sealed. Exhaust air dampers of DOAS units with VERS shall be open. Gravity dampers activated by exhaust fan discharge airflow shall be allowed to open by action of the exhaust airflow. |
| VERS Bypass Dampers | An automatic system that enables a DX-DOAS Unit to let outdoor ventilation air and return air bypass the VERS when preconditioning of outdoor ventilation is not beneficial | Test with the VERS bypass dampers installed, closed, and sealed. However, VERS bypass dampers may be opened if necessary for testing with deactivated VERS for Standard Rating Condition D. |
| Fire/Smoke/Isolation Dampers | A damper assembly including means to open and close the damper mounted at the supply or return duct opening of the equipment | The fire/smoke/isolation dampers shall be removed for testing. If it is not possible to remove such a damper, test with the damper fully open. For any fire/smoke/isolation dampers shipped with the unit but not factory-installed, do not install the dampers for testing. |
| Furnaces and Steam/Hydronic Heat Coils | Furnaces and steam/hydronic heat coils used to provide primary or supplementary heating | Test with the coils in place but providing no heat. |
| Power Correction Capacitors | A capacitor that increases the power factor measured at the line connection to the equipment. These devices are a requirement of the power distribution system supplying the unit | Remove power correction capacitors for testing. |
| Hail Guards | A grille or similar structure mounted to the outside of the unit covering the outdoor coil to protect the coil from hail, flying debris and damage from large objects | Remove hail guards for testing. |
| Ducted Condenser Fans | A condenser fan/motor assembly designed for optional external ducting of condenser air that provides greater pressure rise and has a higher rated motor horsepower than the condenser fan provided as a standard component with the equipment | Test with the ducted condenser fan installed and operating using zero external static pressure, unless the manufacturer specifies use of an external static pressure greater. than zero, in which case, use the manufacturer-specified external static pressure. |
| Sound Traps/Sound Attenuators | An assembly of structures through which the supply air passes before leaving the equipment or through which the return air from the building passes immediately after entering the equipment for which the sound insertion loss is at least 6 dB for the 125 Hz octave band frequency range | Removable sound traps/sound attenuators shall be removed for testing. Otherwise, test with sound traps/attenuators in place. |
| Humidifiers | A device placed in the supply air stream for moisture evaporation and distribution. The device may require building steam or water, hot water, electric or gas to operate | Remove humidifiers for testing. |
| UV Lights | A lighting fixture and lamp mounted so that it shines light on the conditioning coil, that emits ultraviolet light to inhibit growth of organisms on the conditioning coil surfaces, the condensate drip pan, and/other locations within the equipment | Remove UV lights for testing. |
| High-Effectiveness Indoor Air Filtration | Indoor air filters with greater air filtration effectiveness than MERV 8 or the lowest MERV filter distributed in commerce, whichever is greater | Test with a MERV 8 filter or the lowest MERV filter distributed in commerce, whichever is greater |
2.2.3. Optional Representations. Test provisions for the determination of the metrics indicated in paragraphs (a) through (d) of this section are optional and are determined according to the applicable provisions in section 2.2.1 of this appendix. The following metrics in AHRI 920-2020 are optional:
(a) ISMRE270;
(b) COPFull,x:
(c) COPDOAS,x: and
(d) ISMRE2 and ISCOP2 for water-cooled DX-DOASes using the “Condenser Water Entering Temperature, Chilled Water” conditions specified in Table 4 of AHRI 920-2020 and for water-source heat pump DX-DOASes using the “Water-Source Heat Pump, Ground-Source Closed Loop” conditions specified in Table 5 of AHRI 920-2020.
(a) Any references to energy recovery or energy recovery ventilator (ERV) in AHRI 920-2020 and ANSI/ASHRAE 198-2013 shall be considered synonymous with ventilation energy recovery system (VERS) as defined in § 431.92.
(b) Reserved