Method and apparatus for enhancement of heat pump defrost
AssigneeCarrier Corporation
InventorsDerrick A. Marris, Ross K. Burnside
Life of this patent
Estimating the term…
Abstract
A heat pump is provided with a reversible fan motor in its outdoor coil and, after a delay period following initiation of the defrost cycle, the fan is caused to operate in a reverse direction to thereby cause the surrounding air to flow through the outdoor coil in a direction opposite to that in which it flows during the heating mode operation. During this time, the fan is operated at a relative slow speed to thereby prevent the convective flow of heat upwardly, while at the same time causing little, if any, flow of ambient air downwardly into the coil.
Claims10
An improved heat pump system of the type having outdoor and indoor heat exchange coils with associated fans, a compressor, an expansion device, and means for reversing the flow of refrigerant for purposes of selecting between heating, cooling, and defrost modes of operation, wherein the improvement comprises;
- reversible drive means for driving the outdoor fan;
- and
- control means for selectively reversing said reversible drive means during periods in which the system is operating in the defrost mode, such the heated air from the outdoor coil defrost is confined to the interior of the heat pump, thereby raising the ambient temperature surrounding the outdoor coil.
An improved method of operating a heat pump system of the type having an outdoor coil with a fan for causing ambient air to flow therethrough, and means for reversing the flow of refrigerant in the system to change from a heating mode to a defrost mode of operation, comprising the steps of:
- determining when the system is operating in the defrost mode;
- and responsively causing the outdoor coil fan to rotate in the direction opposite to that in which it operates during the heating mode to thereby prevent the convective flow of heat upwardly, while at the same time causing little, if any, flow of ambient air downwardly into the outdoor coil.
Dependencies are inferred from the claim text.