Defrost control for variable speed heat pumps

Patent · Tue Jun 21 04:00:00 EDT 1988

OSTI ID:6828416

Voohis, R; Palmer, J M; Erbs, D G

An improved method of determining the time between defrosts in a heat pump system of the type having outdoor and indoor coils and a compressor is described comprising the steps: sensing when the ambient temperature reaches a predetermined level where frost will form on the outdoor coil; after a predetermined time to defrost, sensing the pre-defrost saturated outdoor coil temperature and initiating a defrost cycle; sensing when the temperature of the liquid refrigerant at the outdoor coil reaches a predetermined level to indicate that defrost is complete; sensing the after-defrost saturated outdoor coil temperature; determining the actual temperature difference that occurs during the defrost cycle between the pre-defrost and after-defrost saturated coil temperatures; and determining a new time-to-defrost on the basis of the actual temperature difference.

• Assignee: Carrier Corp., Syracuse, NY
• Patent Number(s): US 4751825
• OSTI ID: 6828416
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320106* -- Energy Conservation
Consumption
& Utilization-- Building Equipment-- (1987-)
COMPRESSORS
CONTROL
DEFROSTING
FLUIDS
GROUND SOURCE HEAT PUMPS
HEAT EXCHANGERS
HEAT PUMPS
MONITORING
OPERATION
REFRIGERANTS
TEMPERATURE CONTROL
TEMPERATURE MONITORING
TIMING PROPERTIES
WORKING FLUIDS