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U.S. Department of Energy
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Heat pump on-off capacity control and defrost performance tests using demand and time-temperature defrost controls

Technical Report ·
OSTI ID:6163969
Two heat pumps were tested at several on-off cycles to determine performance at part load conditions. Also, the heat pumps were tested at full capacity under frost buildup conditions with both time-temperature and demand deforst controls. The objectives were to develop correlations for use in seasonal performance models. For on-off cycling, it was found that COP as a fraction of steady state COP could be predicted with power law relationships involving capacity as a fraction of steady state capacity. Frost buildup occurred in a two step process, with initial gradual frost buildup to a transition point followed by rapid frost buildup until a defrost cycle was initiated. Heat capacities under frost buildup conditions were predicted as a function of outdoor air temperature and difference between specific humidity of the outtdoor air and specific humidity of saturated air at outdoor coil temperatures.
Research Organization:
Science Applications, Inc., La Jolla, CA (USA)
DOE Contract Number:
AC01-79CS10757
OSTI ID:
6163969
Report Number(s):
SAI-444-80-278-LJ/Rev.
Country of Publication:
United States
Language:
English