Carrier Corporation

Hongmei Liang

Larry J Burkhart

Don Alan Schuster

Raymond A Rust, Jr

Timothy J Perry

Louis J Sullivan

Nathan D Wright

Frederick J Keller, Jr

Gary D Wedlake

A method and apparatus for controlling supplemental heat added to the air stream passing from an indoor coil to an air supply duct of a heat pump system, the heat pump system being of the type that includes an indoor thermostat having a first set point for initiating heat supplied by the indoor coil and a second set point for initiating additional heat supplied by supplemental heating means. The supplemental heating elements include an adjustable output heating element for heating air passing from the indoor coil to the air supply duct. The coil discharge temperature of the air stream heated by the indoor coil is determined at a position between the indoor coil and the supplemental heating means. The adjustable output heating element is selectively energized in response to the coil discharge temperature, independent of the second set point of the indoor thermostat.

Method and apparatus for controlling supplemental heat in a heat pump

A method is described of selectively varying the speed of the indoor blower of a heat pump for heating a building or other indoor area when ambient temperature drops below a predetermined level, in order to reduce the cold blow effect of air entering the building. The operating run time fraction of a heating cycle is determined, and the speed of the indoor blower is adjusted when the run time fraction crosses a predetermined threshold value, except that the speed of the indoor blower is maintained when the run time fraction is sufficiently changed compared with a previous run time fraction.

Run time criteria to control indoor blower speed

A method of controlling a current defrost cycle for an outdoor coil of a heat pump system, the heat pump system having a plurality of supplemental heating elements for heating an air stream passing from an indoor coil to an air supply duct during defrost operation, wherein an initial quantity of supplemental heating elements energized is a function of a most recent previous defrost cycle. The initial quantity of supplemental heating elements is energized upon initiation of a defrost cycle. Whether the initial quantity of supplemental heating elements provided is insufficient or excessive is determined. At least one of the supplemental heating elements is deactivated if the initial quantity of supplemental heating elements being provided is excessive. At least one of the supplemental heating elements is activated if the initial quantity of supplemental heating elements being provided is if the initial quantity of supplemental heating elements being provided is insufficient, and at least one additional supplemental heating element is available. Information as to an initial quantity of supplemental heating elements to be activated for a following defrost cycle is retained. The initial quantity of supplemental heating elements to be activated for a following defrost cycle is equal to a number of supplemental heating elements activated upon termination of the current defrost cycle. The heat pump is kept on to complete the defrost cycle during an overshoot condition.

Managing supplementary heat during defrost on heat pumps

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Indianapolis, IN, United States of America

Hongmei Liang