Heat pump device, two-stage compressor, and operation method of heat pump device

摘要

In a heat pump device using a two-stage compressor and a two-stage compressor, an object is to improve the efficiency when the load is small. The heat pump device includes a main refrigerant circuit in which a two-stage compressor 100, a first heat exchanger, a first expansion mechanism, and a second heat exchanger are sequentially connected by piping. When the load is higher than a predetermined load, the two-stage compressor 100 discharges the refrigerant that has been two-stage compressed by the low-stage compressor 10 and the high-stage compressor 30 to the refrigerant circuit. On the other hand, when the load is lower than the predetermined load, the two-stage compressor 100 bypasses the refrigerant compressed by the low-stage compressor 10 without being compressed by the high-stage compressor 30 and discharges it to the main refrigerant circuit. .