Two-stage compression heat pump system

The invention discloses a two-stage compression heat pump system, aiming at providing the two-stage compression heat pump system easy for energy adjustment. The two-stage compression heat pump system can realize the mutual conversion between a high-pressure state compressor and a low-pressure stage compressor and improve the efficiency of a heat pump system. Meanwhile, all compressors can be put into use to improve the refrigerating capacity in summer when the heat pump system is used as an air conditioner in summer. The two-stage compression heat pump system comprises multiple groups of compressor units, a first heat exchanger, a second heat exchanger and an intermediate cooler, wherein each group of compressor unit comprises a compressor, a four-way reverse valve, a first solenoid valve, a second solenoid valve, a third solenoid valve and a fourth solenoid valve; the exhaust ends of the compressors are respectively connected with the first solenoid valve and the second solenoid valve; the air sucking ends of the compressors are respectively connected with the third solenoid valve and the fourth solenoid valve; and the interchange between the high-pressure stage and the low-pressure stage can be realized by opening or closing the solenoid valves connected to various compressors. The efficiency of the system can be improved by adjusting the flow of a refrigerator during two-stage compressor refrigeration circulation and two-stage compression heat pump circulation.