Twin-stage compression heat pump system with hot gas bypass defrosting device

Abstract

The invention provides a twin-stage compression heat pump system with a hot gas bypass defrosting device. The low-pressure compressor of the twin-stage compression heat pump system is communicated with a high-pressure compressor via a mixing chamber; the high-pressure compressor is communicated with a refrigerating fluid / water heat exchanger by an oil separator and a four-way reversing valve; the refrigerating fluid / water heat exchanger is communicated with the port of an intermediate cooler by an electronic expansion valve; the port b of the intermediate cooler is communicated with the mixing chamber by a shut-off valve; another port of the intermediate cooler is communicated with the refrigerating fluid / water heat exchanger by an electronic expansion valve and a gas and liquid mixing head; the refrigerating fluid / water heat exchanger is communicated with the low-pressure compressor by the four-way reversing valve and a gas and liquid separator to form a circulation; and the outlet end of the high-pressure compressor is communicated with the gas and liquid mixing head by a solenoid valve. The twin-stage compression heat pump system can be stably operated in the low-temperature environment for a long time, has the advantages of enough heat generation amount, higher performance coefficient and high thermal efficiency and is favorable for popularizing the heat pump in northern areas, frost is removed with a hot gas bypass method, halting conversion is not required when the frost is removed, heat supply and frost removal can be performed at the same time, and the energy consumption is lowered.

Description

technical field [0001] The invention relates to a two-stage compression heat pump system, in particular to a two-stage compression heat pump system using a hot gas bypass method for defrosting, and belongs to the technical field of air-conditioning heat pumps. Background technique [0002] With the rapid development of economic construction, heat pumps for air conditioning have been widely used in countries all over the world. It can meet the heating requirements in winter with low energy consumption. It is widely used in non-heating areas. [0003] In recent years, with the country's increasing attention to energy conservation and environmental protection, heat pumps, as a clean and efficient heating device, have become more and more important to promote to the north. However, many problems occurred in the process of promotion to the north. Due to the low temperature in the northern region, the common air source heat pump system will find that the exhaust temperature of th...

AI Technical Summary

Problems solved by technology

However, many problems occurred in the process of promotion to the north. Due to the low temperature in the northern region, the common air source heat pump system will find that the exhaust temperature of the compressor is too high, the gas transmission coefficient drops sharply, and the compressor pressure ratio is too large. , its heating capacity and performance coefficient are greatly reduced, the system starts and stops frequently, and cannot work normally

Especially when the outdoor temperature is low and the humidity is high, the evaporator of the heat pump will often frost during the heating cycle, which will have a negative impact on the heat-absorbing phase transition of the refrigerant in the air-side heat exchanger. It will also damage the copper tube of the heat exchanger

However, the previous method of reverse cycle defrosting through the four-way valve to change the heating cycle of the unit into a refrigeration cycle also has disadvantages: it takes up a lot of heating time, which not only has low thermal efficiency and wastes electric energy, but also makes the indoor The temperature drop will affect the comfort of the air, and even cause compressor failure, so it needs to be improved

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