Determination of coil-defrosting loads. Part 4: Refrigeration/defrost cycle dynamics
- Kuwait Univ., Safat (Kuwait). Dept. of Mechanical Engineering
- Univ. of Florida, Gainesville, FL (United States). Dept. of Mechanical Engineering
This is the fourth part of a paper intended to quantify heat loads due to coil defrosting using the hot-gas refrigerant method. Experience with defrosting industrial freezer coils suggests that the defrost heat input is partially removed with the melt, partially warms the coil and refrigerant, and partially escapes to the refrigerated space as sensible heat by convection and radiation or as latent heat by evaporation and sublimation. The evaporated and sublimated portions return again, both as a refrigeration load and as part of another defrosting cycle. The purpose of this part of the paper is to provide a time-dependent history of the variations of key variables during the complete refrigeration/defrost (R/D) cycle. In order to simulate the actual performance of freezer coils during the R/D cycle, three complete consecutive cycles are considered at several FCU-T entering air dry-bulb temperatures (EAT). The variables measured during the R/D cycles are described in detail in Part 2. Some of these variables were measured and plotted as a function of time for all cases tested. While the experimental program on which this paper partly reports examined FCU-T entering air dry-bulb temperatures of 0 F, {minus}8 F, and {minus}13 F, only the last two cases will be included in this paper.
- Sponsoring Organization:
- American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA (United States); Florida Univ., Gainesville, FL (United States)
- OSTI ID:
- 653203
- Report Number(s):
- CONF-980123--
- Country of Publication:
- United States
- Language:
- English
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