Method and mechanism for expanding heat producing capacity of heat pump under low temperature environment

Abstract

The present invention is method and mechanism for expanding heat producing capacity of heat pump under low temperature environment. The air source heat pump system includes low temperature part, high temperature part and the connecting heat exchanger in between. The system may run in conventional circulating mode or in superposed circulating mode. When used for cooling in summer or for producing heat in winter while outdoor temperature is relatively higher, the system runs in conventional circulating mode; and with the lowering outdoor temperature in winter, the system converts automatically into superposed circulating mode by means of its intermediate heat exchanger to reduce the compression ratio of the compressor, strengthen the heating capacity in low temperature environment and expand the applying outdoor temperature range.

Description

technical field [0001] The invention relates to a method and device for expanding the heating capacity of a heat pump in a low-temperature environment, so as to expand the ambient temperature range of the system and improve the seasonal use efficiency. Improve the heating capacity of the system and the service life of the compressor. Background technique [0002] Heat pump systems are usually bi-directional, meaning they are capable of either heating or cooling, or sometimes both at the same time. Since the heat pump can realize the function of transferring heat energy from a low temperature to a high temperature, it can use a large amount of heat in natural resources and waste heat resources, effectively reducing the input energy, so it can save heating, air conditioning, hot water supply and industrial heating. energy. Many countries promote the application of heat pumps as a way to reduce CO 2 a means of emission. [0003] At present, the air source heat pump system h...

AI Technical Summary

Problems solved by technology

Mainly, at lower ambient temperatures, the compressor pressure ratio is very high, and the air transmission coefficient of the compressor is reduced. Especially for heat pumps using piston compressors, when the pressure ratio reaches 20, the air transmission coefficient is close to 0, and the compressor The gas cannot be sucked in; the volume of the suction ratio becomes larger and the mass flow rate of the refrigeration system becomes smaller, resulting in a sharp decrease in heat supply; the larger the pressure ratio, the greater the deviation between the actual compression process and the theoretical isentropic compression process, and the refrigeration / supply The thermal coefficient decreases, even if the heat pump uses the screw or scroll compressor, which basically has no clearance volume and has much less influence on the pressure ratio, the internal volume ratio factor determines that the thermal insulation efficiency is very low in a low temperature environment; The high pressure ratio also leads to the high exhaust temperature of the heat pump compressor using the conventional process, the thinning of the lubricating oil, the deterioration of the lubrication conditions, and even the carbonization of the lubricating oil, resulting in cylinder scuffing and carbon formation, shortening the use of the compressor life

[0004] Excessive compression ratio makes the heat pump unable to operate normally in the coldest time in the north, thus hindering the promotion of energy-saving heat pump products in the northern region, and even if it is applied, its utilization rate in the heating season is low

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