Voglio sapere a riguardo di…

jbell on DSKJLSW7X2PROD with PROPOSALS

37698

Federal Register / Vol. 86, No. 134 / Friday, July 16, 2021 / Proposed Rules
Thermostatically-controlled crankcase heaters adjust whether the heater is on or off based on a temperature sensor that measures outdoor ambient air. When the outside ambient temperature is high enough the heater turns off, thus reducing energy use. Id.. Selfregulating crankcase heaters have control systems that vary the resistivity as a function of temperature, thus providing internal thermostatic control to reduce energy use. Id. In its testing, DOE has observed that some walk-in refrigeration systems have the crankcase heater energized 100 percent of the time including when the compressor is operating, without demand-based controls. DOE is considering whether crankcase heater control technology might be applied to WICF refrigeration systems to improve efficiency.
Issue 25: DOE seeks comment on the prevalence of the use of crankcase heater controls for walk-in refrigeration systems. Additionally, DOE requests information on what type of crankcase heater controls are considered viable, and what application circumstances would make certain control approaches inappropriate e.g., by unacceptably increasing the chance of compressor failure.
As discussed in section II.A.3 of this document, single-package refrigeration systems are susceptible to thermal losses associated with the structural design. Table II.13 lists thermal insulation as a potential technology option for these systems. Improved thermal insulation may reduce conduction losses, and better sealing of cabinet air leaks may reduce infiltration of warm outdoor air.
Issue 26: DOE seeks information on the potential for improved thermal insulation and sealing of air leaks to improve the efficiency of single-package refrigeration systems. Specifically, DOE
is interested in data on the range of typical insulation thickness used in single-package systems to insulate the indoor portion, in addition to the insulation materials that are typically used. Additionally, DOE requests information on the processes and materials that manufacturers utilize to ensure airtight enclosures. DOE is also interested in understanding the quality control processes manufacturers have in place to ensure that airtight units are released to the market.
Evaluation of outdoor dedicated condensing units in DOEs CCMS

VerDate Sep<11>2014

16:52 Jul 15, 2021

Jkt 253001

database 33 indicate that 86 percent of medium-temperature and 91 percent of low-temperature models are offered with R404A, R407A, R448A/R
449A, or R507A. R448A/R449A has low Global Warming Potential GWP
compared to R407A, which in turn has lower GWP than R404A and R507A.
The remaining mediumand lowtemperature condensing unit models are offered with R407C, R407F, and R52A. Additionally, DOE is aware that wine cellar walk-in refrigeration systems are currently offered with R134A.
In past rulemakings, DOE has conducted its walk-in refrigeration system engineering analysis using a single refrigerantusing R404A for the June 2014 ECS final rule and using R407A for the July 2017 ECS final rule.
79 FR 32050, 3207332074 and 82 FR
31808, 3183531836. However, for basic models certified with an AWEF value higher than the minimum standard in DOEs CCMS database, DOE observes that some refrigerants provide efficiency advantages over others for products with similar rated capacities. For instance, between certified capacities of 13,500 Btu/h and 16,500 Btu/h, one low-temperature condensing unit basic model was certified with a reported AWEF range from 3.5 to 3.87 and from 3.49 to 4.43 with R407A and R448A/
R449A, respectively.
Issue 27: DOE requests comment and data to support whether it should include refrigerant as a design option in its engineering analysis for walk-in refrigeration systems. DOE also requests information on the availability and relative utility of R452A, R407C, and R407F compared to R407A and R448A/R449A for use in walk-in dedicated condensing units and singlepackage systems. Additionally, DOE is interested in understanding the availability and relative utility of R450A, R513A/R513B, and R515A
compared to R134A for wine cellar walk-in refrigeration systems. DOE is also interested in understanding what domestic and international activities may be driving trends in the market adoption of low GWP refrigerants.
In addition to evaluating low GWP
refrigerants, DOE is investigating the potential use of non-traditional refrigerants, such as hydrocarbon refrigerants.
Issue 28: DOE requests information on the availability of specific non-

PO 00000

33 Please
see footnote 15.

Frm 00012

Fmt 4702

Sfmt 4702

traditional e.g. hydrocarbon refrigerants for use in dedicated condensing unit, unit cooler, singlepackage, and wine cellar walk-in refrigeration systems. DOE is interested in understanding what domestic and international activities may be driving trends in market adoption of nontraditional e.g. hydrocarbon refrigerants. DOE also seeks comment on whether and how the availability of higher-efficiency compressors might be impacted by the use of non-traditional e.g. hydrocarbon refrigerants. DOE
requests information on whether charge limits or safety standards e.g., standards issued by Underwriters Laboratory would restrict the use of non-traditional e.g. hydrocarbon refrigerants in walk-in refrigeration systems. Finally, DOE requests comment on any additional design changes or safety measures that may be necessary for WICFs to incorporate nontraditional e.g. hydrocarbon refrigerants.
In its supporting analysis to the June 2014 ECS final rule, DOE evaluated evaporator coils with either 4 or 6 fins per inch for both lowand mediumtemperature unit coolers.34 For the July 2017 ECS final rule, DOEs engineering analysis included evaporator coils with 4 fins per inch for low-temperature and 6 fins per inch for medium-temperature unit coolers.35 An evaluation of DOEs CCMS database 36 indicates a minimum of 4 fins per inch and a maximum of 8
fins per inch for both low-temperature and medium-temperature units, with higher certified AWEF values for models with a higher number of fins per inch. Roughly 65 percent of lowtemperature models have more than 4
fins per inch, while about 10 percent of medium-temperature models have more than 6 fins per inch.
Issue 29: DOE seeks comment on if 4
fins per inch and 6 fins per inch for lowand medium-temperature unit coolers, respectively, are still appropriate to use in its engineering analysis given the number of certified models at each operating temperature that do not meet these specificationsand if not, which fin configurations should DOE use for its analysis?
34 See Table 5.3.5 of the TSD for the June 2014
ECS final rule. Docket EERE2008BTSTD0015
0131.
35 See Table 5.3.2 of the TSD for the July 2017
ECS final rule. Docket EERE2015BTSTD0016
0099.
36 Please see footnote 15.

E:FRFM16JYP1.SGM

16JYP1