10 C.F.R. § R app A to Subpart R of Part 431
Note: Prior to October 31, 2023, representations with respect to the energy use of envelope components of walk-in coolers and walk-in freezers, including compliance certifications, must be based on testing conducted in accordance with the applicable provisions of 10 CFR part 431, subpart R, appendix A, revised as of January 1, 2022. Beginning October 31, 2023, representations with respect to energy use of envelope components of walk-in coolers and walk-in freezers, including compliance certifications, must be based on testing conducted in accordance with this appendix.
0. Incorporation by Reference
DOE incorporated by reference in § 431.303 the entire standard for ASTM C1199-14 and NFRC 102-2020. However, certain enumerated provisions of these standards, as set forth in sections 0.1 and 0.2 of this appendix are inapplicable. To the extent that there is a conflict between the terms or provisions of a referenced industry standard and the CFR, the CFR provisions control.
0.1 ASTM C1199-14
(a) Section 1 Scope, is inapplicable,
(b) Section 4 Significance and Use is inapplicable,
(c) Section 7.3 Test Conditions, is inapplicable,
(d) Section 10 Report, is inapplicable, and
(e) Section 11 Precision and Bias, is inapplicable.
0.2 NFRC 102-2020
(a) Section 1 Scope, is inapplicable,
(b) Section 4 Significance and Use, is inapplicable,
(c) Section 7.3 Test Conditions, is inapplicable,
(d) Section 10 Report, is inapplicable,
(e) Section 11 Precision and Bias, is inapplicable,
(f) Annex A3 Standard Test Method for Determining the Thermal Transmittance of Tubular Daylighting Devices, is inapplicable, and
(g) Annex A5 Tables and Figures, is inapplicable.
1. General. The following sections of this appendix provide additional instructions for testing. In cases where there is a conflict, the language of this appendix takes highest precedence, followed by NFRC 102-2020, followed by ASTM C1199-14. Any subsequent amendment to a referenced document by the standard-setting organization will not affect the test procedure in this appendix, unless and until the test procedure is amended by DOE. Material is incorporated as it exists on the date of the approval, and a notification of any change in the incorporation will be published in the FEDERAL REGISTER.
2. Scope
This appendix covers the test requirements used to measure the energy consumption of the components that make up the envelope of a walk-in cooler or walk-in freezer.
3. Definitions
The definitions contained in § 431.302 are applicable to this appendix.
4. Additional Definitions
4.1 Automatic door opener/closer means a device or control system that "automatically" opens and closes doors without direct user contact, such as a motion sensor that senses when a forklift is approaching the entrance to a door and opens it, and then closes the door after the forklift has passed.
4.2 Percent time off (PTO) means the percent of time that an electrical device is assumed to be off.
4.3 Rated power means the input power of an electricity-consuming device as specified on the device's nameplate. If the device does not have a nameplate or such nameplate does not list the device's input power, then the rated power must be determined from the device's product data sheet, literature, or installation instructions that come with the device or are available online.
4.4 Rating conditions means, unless explicitly stated otherwise, all conditions shown in table A.1 of this appendix.
Table A.1-Temperature Conditions
| Internal Temperatures (cooled space within the envelope) | |
| Cooler Dry-Bulb Temperature | 35 °F |
| Freezer Dry-Bulb Temperature | -10 °F |
| External Temperatures (space external to the envelope) | |
| Freezer and Cooler Dry-Bulb Temperatures | 75 °F |
5. Test Methods and Measurements
5.1 U-Factor Test of Doors and Display Panels
Determine the U-factor of the entire door or display panel, including the frame, in accordance with the specified sections of NFRC 102-2020 and ASTM C1199-14 at the temperature conditions listed in table A.1 of this appendix.
5.2 Required Test Measurements
5.2.1 For display doors and display panels, thermal transmittance, Udd or Udp, respectively, shall be the standardized thermal transmittance, UST, determined per section 5.1 of this appendix.
5.2.2 For non-display doors, thermal transmittance, Und, shall be the standardized thermal transmittance, UST, determined per section 5.1 of this appendix.
5.2.3 Projected area of the test specimen, As, in ft2, as referenced in ASTM C1199-14.
6. Calculations
6.1 Display Panels
6.1.1 Determine the U-factor of the display panel in accordance with section 5.1 of this appendix, in units of Btu/(h-ft2- °F).
6.1.2 Calculate the temperature differential, [DELTA]Tdp, °F, for the display panel, as follows:
Where:
TDB,ext,dp = dry-bulb air external temperature, °F, as prescribed in table A.1 of this appendix; and
TDB,int,dp = dry-bulb air temperature internal to the cooler or freezer, °F, as prescribed in table A.1 of this appendix.
6.1.3 Calculate the conduction load through the display panel, Qcond-dp, Btu/h, as follows:
Where:
As = projected area of the test specimen (same as the test specimen aperture in the surround panel) or the area used to determine the U-factor in section 5.1 of this appendix, ft2;
[DELTA]Tdp = temperature differential between refrigerated and adjacent zones, °F; and
Udp = thermal transmittance, U-factor, of the display panel in accordance with section 5.1 of this appendix, Btu/(h-ft2- °F).
6.1.4 Calculate the total daily energy consumption, Edp, kWh/day, as follows:
Where:
Qcond,dp = the conduction load through the display panel, Btu/h; and
EER = Energy Efficiency Ratio of walk-in (cooler or freezer), Btu/W-h. For coolers, use EER = 12.4 Btu/W-h. For freezers, use EER = 6.3 Btu/W-h.
6.2 Display Doors
6.2.1 Conduction Through Display Doors
6.2.1.1 Determine the U-factor of the display door in accordance with section 5.1 of this appendix, in units of Btu/(h-ft2- °F).
6.2.1.2 Calculate the temperature differential, [DELTA]Tdd, °F, for the display door as follows:
Where:
TDB,ext,dd = dry-bulb air temperature external to the display door, °F, as prescribed in table A.1 of this appendix; and
TDB,int,dd = dry-bulb air temperature internal to the display door, °F, as prescribed in table A.1 of this appendix.
6.2.1.3 Calculate the conduction load through the display doors, Qcond,dd, Btu/h, as follows:
Where:
As = projected area of the test specimen (same as the test specimen aperture in the surround panel) or the area used to determine the U-factor in section 5.1 of this appendix, ft2;
[DELTA]Tdd = temperature differential between refrigerated and adjacent zones, °F; and
Udd = thermal transmittance, U-factor of the door, in accordance with section 5.1 of this appendix, Btu/(h-ft2- °F).
6.2.1.4 Calculate the total daily energy consumption due to conduction thermal load, Edd,thermal, kWh/day, as follows:
Where:
Qcond,dd = the conduction load through the display door, Btu/h; and
EER = EER of walk-in (cooler or freezer), Btu/W-h. For coolers, use EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).
6.2.2 Direct Energy Consumption of Electrical Component(s) of Display Doors
Electrical components associated with display doors could include but are not limited to: heater wire (for anti-sweat or anti-freeze application); lights; door motors; control system units; and sensors.
6.2.2.1 Select the required value for percent time off (PTO) for each type of electricity-consuming device per table A.2 of this appendix, PTOt (%).
Table A.2-Percent Time Off Values
| Device | Temperature condition | Controls, timer, or other auto-shut-off system | Percent time off value (%) |
| Lights | All | Without With | 25 50 |
| Anti-sweat heaters | All Coolers Freezers | Without With With | 0 75 50 |
| Door motors | All | 97 | |
| All other electricity-consuming devices | All | Without With | 0 25 |
6.2.2.2 Calculate the power usage for each type of electricity-consuming device, Pdd,comp,u,t, kWh/day, as follows:
Where:
u = the index for each of type of electricity-consuming device located on either (1) the interior facing side of the display door or within the inside portion of the display door, (2) the exterior facing side of the display door, or (3) any combination of (1) and (2). For purposes of this calculation, the interior index is represented by u = int and the exterior index is represented by u = ext. If the electrical component is both on the interior and exterior side of the display door then use u = int. For anti-sweat heaters sited anywhere in the display door, 75 percent of the total power is be attributed to u = int and 25 percent of the total power is attributed to u = ext;
t = index for each type of electricity-consuming device with identical rated power;
Prated,u,t = rated input power of each component, of type t, kW;
PTOu,t = percent time off, for device of type t, %; and
nu,t = number of devices at the rated input power of type t, unitless.
6.2.2.3 Calculate the total electrical energy consumption for interior and exterior power, Pdd,tot,int (kWh/day) and Pdd,tot,ext (kWh/day), respectively, as follows:
Where:
t = index for each type of electricity-consuming device with identical rated input power;
Pdd,comp,int,t = the energy usage for an electricity-consuming device sited on the interior facing side of or in the display door, of type t, kWh/day; and
Pdd,comp,ext,t = the energy usage for an electricity-consuming device sited on the external facing side of the display door, of type t, kWh/day.
6.2.2.4 Calculate the total electrical energy consumption, Pdd,tot, (kWh/day), as follows:
Where:
Pdd,tot,int = the total interior electrical energy usage for the display door, kWh/day; and
Pdd,tot,ext = the total exterior electrical energy usage for the display door, kWh/day.
6.2.3 Total Indirect Electricity Consumption Due to Electrical Devices
Calculate the additional refrigeration energy consumption due to thermal output from electrical components sited inside the display door, Cdd,load, kWh/day, as follows:
Where:
Pdd,tot,int = The total internal electrical energy consumption due for the display door, kWh/day; and
EER = EER of walk-in cooler or walk-in freezer, Btu/W-h. For coolers, use EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).
6.2.4 Total Display Door Energy Consumption
Calculate the total energy, Edd,tot, kWh/day,
Where:
Edd,thermal = the total daily energy consumption due to thermal load for the display door, kWh/day;
Pdd,tot = the total electrical load, kWh/day; and
Cdd,load = additional refrigeration load due to thermal output from electrical components contained within the display door, kWh/day.
6.3 Non-Display Doors
6.3.1 Conduction Through Non-Display Doors
6.3.1.1 Determine the U-factor of the non-display door in accordance with section 5.1 of this appendix, in units of Btu/(h-ft2- °F).
6.3.1.2 Calculate the temperature differential of the non-display door, [DELTA]Tnd, °F, as follows:
Where:
TDB,ext,nd = dry-bulb air external temperature, °F, as prescribed by table A.1 of this appendix; and
TDB,int,nd = dry-bulb air internal temperature, °F, as prescribed by table A.1 of this appendix. If the component spans both cooler and freezer spaces, the freezer temperature must be used.
6.3.1.3 Calculate the conduction load through the non-display door: Qcond,nd, Btu/h,
Where:
As = projected area of the test specimen (same as the test specimen aperture in the surround panel) or the area used to determine the U-factor in section 5.1 of this appendix, ft2;
[DELTA]Tnd = temperature differential across the non-display door, °F; and
Und = thermal transmittance, U-factor of the door, in accordance with section 5.1 of this appendix, Btu/(h-ft2- °F).
6.3.1.4 Calculate the total daily energy consumption due to thermal load, End,thermal, kWh/day, as follows:
Where:
Qcond,nd = the conduction load through the non-display door, Btu/h; and
EER = EER of walk-in (cooler or freezer), Btu/W-h. For coolers, use EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).
6.3.2 Direct Energy Consumption of Electrical Components of Non-Display Doors
Electrical components associated with non-display doors comprise could include, but are not limited to: heater wire (for anti-sweat or anti-freeze application), lights, door motors, control system units, and sensors.
6.3.2.1 Select the required value for percent time off for each type of electricity-consuming device per table A.2 of this appendix, PTOt (%).
6.3.2.2 Calculate the power usage for each type of electricity-consuming device, Pnd,comp,u,t, kWh/day, as follows:
Where:
u = the index for each of type of electricity-consuming device located on either (1) the interior facing side of the non-display door or within the inside portion of the non-display door, (2) the exterior facing side of the non-display door, or (3) any combination of (1) and (2). For purposes of this calculation, the interior index is represented by u = int and the exterior index is represented by u = ext. If the electrical component is both on the interior and exterior side of the non-display door then use u = int. For anti-sweat heaters sited anywhere in the non-display door, 75 percent of the total power is be attributed to u = int and 25 percent of the total power is attributed to u = ext;
t = index for each type of electricity-consuming device with identical rated input power;
Prated,u,t = rated input power of each component, of type t, kW;
PTOu,t = percent time off, for device of type t, %; and
nu,t = number of devices at the rated input power of type t, unitless.
6.3.2.3 Calculate the total electrical energy consumption for interior and exterior power, Pnd,tot,int, kWh/day, and Pnd,tot,ext, kWh/day, respectively, as follows:
Where:
t = index for each type of electricity-consuming device with identical rated input power;
Pnd,comp,int,t = the energy usage for an electricity-consuming device sited on the internal facing side or internal to the non-display door, of type t, kWh/day; and
Pnd,comp,ext,t = the energy usage for an electricity-consuming device sited on the external facing side of the non-display door, of type t, kWh/day. For anti-sweat heaters,
6.3.2.4 Calculate the total electrical energy consumption, Pnd,tot, kWh/day, as follows:
Where:
Pnd,tot,int = the total interior electrical energy usage for the non-display door, of type t, kWh/day; and
Pnd,tot,ext = the total exterior electrical energy usage for the non-display door, of type t, kWh/day.
6.3.3 Total Indirect Electricity Consumption Due to Electrical Devices
Calculate the additional refrigeration energy consumption due to thermal output from electrical components associated with the non-display door, Cnd,load, kWh/day, as follows:
Where:
Pnd,tot,int = the total interior electrical energy consumption for the non-display door, kWh/day; and
EER = EER of walk-in cooler or freezer, Btu/W-h. For coolers, use EER = 12.4 Btu/(W-h). For freezers, use EER = 6.3 Btu/(W-h).
6.3.4 Total Non-Display Door Energy Consumption
Calculate the total energy, End,tot, kWh/day, as follows:
Where:
End,thermal = the total daily energy consumption due to thermal load for the non-display door, kWh/day;
Pnd,tot = the total electrical energy consumption, kWh/day; and
Cnd,load = additional refrigeration load due to thermal output from electrical components contained on the inside face of the non-display door, kWh/day.
10 C.F.R. § R app A to Subpart R of Part 431