Cascade heat pump system with variable flow single working medium and shared heat exchanger

Abstract

The invention discloses a cascaded heat pump system with variable flow and single working fluid sharing heat exchangers. Each group of compressor units in the present invention includes a compressor, a four-way reversing valve, a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve, and the exhaust end of the compressor is connected to the first interface of the four-way reversing valve , the suction end of the compressor is connected to the third port of the four-way reversing valve, one end of the first solenoid valve is connected in parallel with one end of the second solenoid valve and then connected to the second port of the four-way reversing valve, and the other end of the first solenoid valve is connected in parallel and then passed through The first heat exchanger, the first throttle valve are connected to the second port of the condensing evaporator, the other end of the second solenoid valve is connected in parallel to the third port of the condensing evaporator, and the third solenoid valve is connected to the fourth solenoid valve in parallel. It is connected to the fourth port of the four-way reversing valve, the other end of the third solenoid valve is connected in parallel to the first port of the condensing evaporator, and the other end of the fourth solenoid valve is connected in parallel to pass through the second heat exchanger, the second throttle valve and the condensation The fourth port of the evaporator is connected. The cascaded heat pump system of the present invention is composed of a single working medium without expansion vessels and other devices, and the system structure is simple.

Description

technical field [0001] The invention relates to a heat pump unit, more specifically, to a multi-head cascade heat pump cycle system, which is used to improve the efficiency of the cascade heat pump system and to regulate the flow rate of the heat pump system. Background technique [0002] The single-stage compression heat pump system is not suitable for heat pump systems with a compression ratio (ratio of exhaust pressure to suction pressure) greater than 12 due to the limitation of the suction and discharge compression ratio of the compressor. In the prior art, when the compression ratio is greater than 12, a two-stage compression heat pump system is usually used. The two-stage compression heat pump unit can be driven by a motor, or it can be realized by combining multiple heads. However, the high and low pressure of these two methods are interoperable, and the oil return problem of the compressor is not easy to solve. [0003] Cascade heat pump systems are also a good so...

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