| 摘要 |
PROBLEM TO BE SOLVED: To control the amount of refrigerant circulation properly with a cooling-heating load, without lowering the work efficiency of a compressor. SOLUTION: A heat pump repeats a heat pumping cycle, where the refrigerant is compressed by the compressor 1, condensed in an outdoor heat exchanger 2, subjected to pressure reduction by an expansion valve 3 and evaporated in an indoor heat exchanger 4. The compressor 1 includes an inlet 1b, letting in a low-pressure refrigerant and a discharge port 1a discharge a high-pressure refrigerant. It includes a bypass 13, which returns part of the refrigerant compressed thereby to the inlet 1b before the refrigerant is discharged from the discharge port 1a and a refrigerant opening-closing valve 14 which adjusts a flow rate of the refrigerant in the bypass 13. A controller 17 adjusts the time ratio of the opening of the refrigerant opening-closing valve 14 which is opened and closed periodically, on the basis of the cooling-heating load detected by pressure sensors 15A and 15B, so as to control the flow rate of the refrigerant in the bypass, and thereby controls the amount of circulation of the refrigerant of the heat pump.
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