HEAT PUMP SYSTEM AND HEAT PUMP TYPE WATER HEATER

摘要

PROBLEM TO BE SOLVED: To provide a two-stage compression type heat pump system that can easily maintain amounts of refrigerating machine oil in two compressors equally.SOLUTION: A heat pump system 1 includes: a compression mechanism that has a low stage side compressor 10a and a high stage side compressor 10b for compressing and discharging a refrigerant; a water-refrigerant heat exchanger 11 for exchanging heat between the refrigerant compressed by the compression mechanism and a heat exchange target; an expansion valve 12 for decompressing and expanding the refrigerant flowing out from the water-refrigerant heat exchanger 11; a heat source side air heat exchanger 13 for exchanging heat between the refrigerant decompressed and expanded by the expansion valve 12 and the heat exchange target; and an oil storage tank 21 that is connected to the low stage side compressor 10a via first oil equalizing piping 23 with a first oil equalizing valve 24 and is connected to the high stage side compressor 10b via second oil equalizing piping 25 with a second oil equalizing valve 26.