PURPOSE: To suppress the high pressure in a coolant circuit so as to keep it from rising over a certain pressure by providing means which lowers the capability of a compressor when the temperature sensed by a temperature sensor installed on a heat exchanger on the side of a user during room heating operation is higher than a second set temperature which is higher than a first set temperature.
CONSTITUTION: A refrigerating machine is provided with a heat pump type coolant circuit 8 comprising a compressor 1 the capability of which is variable, four-way valve 2, heat exchanger 3 on the side of a heat source, pressure regulator 5, and heat exchanger 6 on the side of the user with those devices connected successively in this order; high pressure switches 25, 26 which are actuated to stop the operation when the high pressure goes over a certain value; and temperature sensor 24 installed on the heat exchanger 6 on the side of the user. And, a microcomputer 20 changes during the room heating operation the capability of the compressor 1 according to the difference of the temperature of the load and a set temperature when a temperature detected by the temperature sensor 24 is lower than a first set temperature. Further, a temperature detected by the temperature sensor 24 is between the first set temperature and a second set temperature which is higher than the first set temperature, the capability of the compressor 1 is held and when the detected temperature by the temperature sensor is higher than the second set temperature, the capability of the compressor 1 is lowered.
| JPH09210519 | CONTROL DEVICE FOR AIR-CONDITIONER |
| JP2008045814 | GAS ENGINE HEAT PUMP AND ITS CONTROL METHOD |
KISHIMOTO TETSUO
OKUBO ICHIRO
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