Method and apparatus for controlling supplemental electric heat during heat pump defrost
AssigneeCarrier Corporation
InventorDerrick A. Marris
Life of this patent
Estimating the term…
Abstract
In a heat pump system having supplemental heat for application to the supply air during periods of defrost operation, a "cold blow" condition is avoided by turning on a supplemental heater and by sensing the temperature of the supply air and responsively turning on additional heat in stages when necessary to maintain the temperature level of the supply air at a comfortable level.
Claims14
An improved method of defrosting an outdoor coil of a heat pump system having a supplemental heater for heating the air stream passing from an indoor coil to an air supply duct during defrost operation, comprising the steps of:
- providing at least one additional heater for heating air passing from the indoor coil to the air supply duct during defrost operation;
- sensing when the temperature of the air being delivered to the air supply duct decreases to a predetermined level;
- and
- responsively turning on said at least one additional heater when said predetermined level is so sensed.
An improved heat pump system of the type having outdoor and indoor heat exchange coils with associated fans, a compressor, an expansion device, means for reversing the flow of refrigerant for purposes of selecting between heating, cooling, and defrost modes of operation and a supplemental heater for heating an air stream passing from the indoor coil to an air supply duct during defrost operation, wherein the improvement comprises:
- at least one additional heater for heating air passing from the indoor coil to the air supply duct during defrost operation;
- sensing means for sensing when the temperature of the air being delivered to the air supply duct decreases to a predetermined level;
- and control means for responsively turning on said at least one additional heater when said predetermined level is so sensed.
Dependencies are inferred from the claim text.