Prevention of compressor unpowered reverse rotation in heat pump units
AssigneeCarrier Corporation
InventorsAlexander Lifson, Michael F. Taras
Life of this patent
Estimating the term…
Abstract
A heat pump is provided with a method and control for eliminating compressor un-powered reverse rotation at shutdown. In particular, the position of the four-way reversing valve is changed and the heat pump is moved to the opposite mode of operation as compared to the one it had been operated before shutdown. The compressed refrigerant, that might otherwise re-expand through the compressor and cause the compressor to run in reverse, is now communicated to the suction line of the compressor, while the discharge port of the compressor communicates with a refrigerant at suction pressure. Thus the unpowered reverse rotation of the compressor is no longer possible.
Claims23
A heat pump comprising:
- a compressor, said compressor delivering refrigerant to a discharge line, and receiving refrigerant from a suction line, said discharge line and said suction line communicating with a reversing valve, said reversing valve being movable between a heating position and a cooling position, said reversing valve directing refrigerant between an indoor heat exchanger and an outdoor heat exchanger in opposite flow directions in said heating position and in said cooling position, and a control for said reversing valve, said control being programmed to move said reversing valve to the opposite position relative to a current position at shutdown, said movement of said reversing valve to the opposite position occurring within one minute prior to shutdown.
A heat pump comprising:
- a compressor, said compressor delivering refrigerant to a discharge line, and receiving refrigerant from a suction line, said discharge line and said suction line communicating with a reversing valve, said reversing valve being movable between a heating position and a cooling position, said reversing valve directing refrigerant between an indoor heat exchanger and an outdoor heat exchanger in opposite flow directions in said heating position and in said cooling position, and a control for said reversing valve, said control being programmed to move said reversing valve to the opposite position relative to a current position at shutdown;
- and
- said movement of said reversing valve to the opposite position occurring no later than two second after shutdown.
A method of operating a heat pump comprising the steps of:
- (1) operating said heat pump in one of a cooling and heating mode;
- (2) deciding to shut down said heat pump;
- (3) moving said heat pump to operate in the other of said cooling and heating modes;
- (4) shutting down a compressor associated with the heat pump either shortly before or after, or at the same time as step 3;
- and
- (5) moving said heat pump to operate in the other of said cooling and heating modes within one minute prior to shutdown.
A method of operating a heat pump comprising the steps of:
- (1) operating said heat pump in one of a cooling and heating mode;
- (2) deciding to shut down said heat pump;
- (3) moving said heat pump to operate in the other of said cooling and heating modes;
- (4) shutting down a compressor associated with the heat pump either shortly before or after, or at the same time as step 3;
- (5) moving said reversing valve to the opposite position no later than two second after shutdown.
Dependencies are inferred from the claim text.