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Federal Register / Vol. 86, No. 134 / Friday, July 16, 2021 / Proposed Rules temperature freezer and mediumtemperature refrigeration operation.
See section II.C.2.a for more discussion on high-temperature freezers.

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3. Single-Package Refrigeration Systems Single-package refrigeration systems are considered a type of dedicated condensing refrigeration system. 81 FR
95758, 95763. Many single-package systems are constructed in such a way that the entire refrigeration system is located outside of the refrigerated space;
the package is typically mounted either on top of, or directly adjacent to the walk-in enclosure. Due to this construction, single-package systems may experience additional thermal losses not observed in split systems.
Specifically, single-package systems circulate air through a cold section evaporator, fans, and internal ducting that may have exterior surfaces exposed to the warm air outside of the walk-in enclosure and/or the warm condensing unit side of the refrigeration system.
This configuration can lead to conduction and/or infiltration thermal losses which represent a reduction in net capacity and efficiency.
As discussed in the June 2021 TP RFI, DOE is considering whether test procedure modifications are necessary to more appropriately address the conduction and/or infiltration thermal losses for single-package systems. 86 FR
32332, 3234332344. To the extent that these losses are accounted for in the test procedure, technology options that mitigate such losses would reduce energy consumption and increase AWEF. Given the differences in construction between single-package and split systems and the potential for differentiated design options, DOE
intends to separately evaluate singlepackage system representative units in its engineering and downstream analyses.
Issue 3: DOE requests data and information on the impact of singlepackage system design limitations on efficiency and how single-package systems differ from split systems. DOE
additionally requests information showing the trend of efficiency as a function of capacity for single-package refrigeration systems.
See section II.C.2.a for more discussion on single-package refrigeration systems.
4. Wine Cellar Refrigeration Systems As discussed in the June 2021 TP RFI, DOE has received requests for waiver and interim waiver from several manufacturers from the test procedure in Appendix C for walk-in wine cellar refrigeration systems. 86 FR 32332,
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3234432346. These systems are typically designed to provide a cold environment at a temperature range between 4565 F with 5070 percent relative humidity RH, and typically are kept at 55 F and 55 percent RH.
The wine cellar refrigeration systems addressed in waiver petitions are sold as single-package systems, matched-pair systems, and unit cooler-only systems.
The minimum capacity of available wine cellar refrigeration systems is lower than that of other walk-in cooler units e.g., capacity can be as low as 1,100 Btu/h 14 as compared with 4,200
Btu/h for the lowest-capacity mediumtemperature dedicated condensing unit currently listed in the DOE Compliance Certification Management System CCMS database.15 One manufacturer, Vinotheque, has noted that there are size constraints for wine cellar refrigeration systems. 86 FR
11961, 11972 March 1, 2021.
Additionally, certain wine cellar units can be ducted as an optioneither on the condensing unit side, the evaporator side, or bothfor greater installation flexibility. This factor increases fan energy use. Compressors that are typically available for use in lowercapacity wine cellar refrigeration systems are of a hermetic reciprocating design,16 which generally has a lower efficiency than the larger-capacity compressors used for lowand medium-temperature walk-in refrigeration systems. Finally, as discussed previously, single-package wine cellar systems are also subject to additional thermal losses. DOE intends to conduct a separate analysis for wine cellar refrigeration systems in its engineering and downstream analyses.
Issue 4: DOE seeks information on how trends in wine cellar installations e.g., commercial vs. residential, square footage, etc. are expected to impact the type of refrigeration system i.e., single14 Product literature for a wine cellar refrigeration system with a capacity of 1,130 Btu/h from one manufacturer can be found at www.regulations.gov Docket No. EERE2017BTSTD00090005.
15 U.S. Department of Energys Compliance Certification Database, www.regulations.doe.gov/
certification-data/CCMS-4-Walk-In_Coolers_and_
Freezers_-_Refrigeration_Systems.htmlq=Product_
Group_s%3A%22WalkIn%20Coolers%20and%20Freezers%20%20Refrigeration%20Systems%22, Last Accessed:
February 2, 2021.
16 In a hermetic compressor, the compressor and motor are both contained in a single outer welded steel shell. Reciprocating compressors have a piston that slides back and forth in a cylinder.
Refrigerant gas is drawn in through a suction valve as the piston moves away from the cylinder head, increasing the internal volume, and is compressed and discharged through a discharge valve as the piston returns. Hermetic reciprocating compressors are hermetically sealed with a reciprocating function.

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package, matched-pair, dedicated condensing unit, or unit cooler system used in wine cellars over the next 5 to 10 years. Additionally, DOE requests information and data on the extent to which capacity may impact the efficiency of wine cellar refrigeration systems.
B. Significant Savings of Energy As part of the rulemaking process, DOE conducts an energy use analysis to identify how a given equipment type is used, and thereby determine the energy savings potential of energy efficiency improvements.
The energy use analysis estimates the annual energy consumption of refrigeration systems dedicated condensing systems and unit coolers serving walk-ins, and the energy consumption, and losses, that can be directly ascribed to the selected components of the WICF envelopes doors and panels. These estimates are used in the subsequent consumer, and National Impacts Analysis.
The estimates for the annual energy consumption of each analyzed representative refrigeration system were derived assuming that 1 the refrigeration system is sized such that it follows a specific daily duty cycle for a given number of hours per day at fullrated capacity, and 2 the refrigeration system produces no additional refrigeration effect for the remaining period of the 24-hour cycle. These assumptions are consistent with the present industry practice for sizing refrigeration systems. This methodology assumes that the refrigeration system is correctly paired with an envelope e.g., panels, door, etc. that generates a load profile such that the rated hourly capacity of the paired refrigeration system, operated for the given number of run hours per day, produces sufficient refrigeration to meet the daily refrigeration load of the envelope with a safety margin to meet contingency situations. Thus, the annual energy consumption estimates for the refrigeration system depend on the methodology adopted for sizing, including implied assumptions and the extent of oversizing.
While DOE is particularly interested in comment, information, and data on the following issues, this request for information is not strictly limited to them.
1. Duty-Cycles and Typical Run Hours For both the June 2014 ECS final rule and July 2017 ECS final rule analyses, DOE used nominal daily run-times of 16
hours for coolers, and 18 hours for freezers to estimate the in-field energy
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