CO2 trans-critical refrigerating system capable of overcooling through non-azeotropic working medium super-charging machinery

Abstract

The invention discloses a CO2 trans-critical refrigerating system capable of overcooling through non-azeotropic working medium super-charging machinery. The CO2 trans-critical refrigerating system comprises a gas cooler, a medium-temperature-stage cooling evaporator, a low-temperature-stage cooling evaporator, a throttle valve, an evaporator and a compressor; an overcooling circulating system of the non-azeotropic working medium super-charging machinery comprises a medium-temperature-stage compressor, a condenser, a high-temperature-stage throttle valve, a liquid accumulator, a medium-temperature-stage throttle valve, a bypass valve, a low-temperature-stage throttle valve and a low-temperature-stage compressor. Overcooling cycle is assisted through the non-azeotropic working medium super-charging machinery, so that heat exchange forms better temperature matching, heat transfer temperature difference is reduced, and the irreversible loss of a heat exchange process is reduced, and therefore, irreversible loss of heat transfer of the condenser and the evaporator is reduced, and efficiency of the refrigerating cycle is improved.

Description

technical field [0001] The invention relates to the technical field of refrigeration, in particular to a non-azeotropic working medium supercooled CO 2 Transcritical refrigeration systems. Background technique [0002] With the increasingly serious environmental problems such as global warming and the destruction of the ozone layer, the most important research topic for the air-conditioning and refrigeration industries is to find new environmentally friendly natural refrigerants that can replace the ozone layer and produce greenhouse effects. CFCs, HCFCs and other working fluids. CO 2 As a refrigerant, it has attracted more and more attention due to its advantages such as non-toxicity, abundant sources, compatibility with ordinary lubricating oil, and large cooling capacity per unit volume. [0003] But due to CO 2 Lower critical temperature and higher critical pressure, resulting in lower refrigeration efficiency, especially when the ambient temperature is high, CO 2 T...

AI Technical Summary

Problems solved by technology

The condensing side of the mechanical subcooling refrigeration cycle exchanges heat with the air, and the evaporating side exchanges heat with the CO 2 The fluid performs heat exchange, and the temperature rise on the air side generally does not exceed 8°C, while CO 2 The temperature drop of the non-azeotropic refrigerant is about 20°C, and the glide temperature of the non-azeotropic refrigerant evaporation and condensation processes is not much different. If the single-stage subcooling of the conventional non-azeotropic refrigerant refrigeration cycle is used, it cannot satisfy both the air side and the CO 2 Temperature matching on the fluid side, which in turn causes large irreversible losses

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