High-efficiency screw-type auto-cascading refrigeration system

Abstract

The invention discloses a high-efficiency screw-type auto-cascading refrigeration system which comprises a screw-type refrigeration compressor for the cycle operation of a binary mixed refrigerant, a condenser, a gas-liquid separator, a first throttle element, a condensing evaporator, a second throttle element and an evaporator. The high-efficiency screw-type auto-cascading refrigeration system is characterized in that an economizer gas-supplementing hole is arranged on the screw-type refrigeration compressor; and an economizer component is arranged between the liquid outlet of the gas-liquid separator and the first throttle element or / and between the high-pressure liquid outlet of the condensing evaporator and the second throttle element, mainly comprises an auxiliary throttle element and an economizer and utilizes the economizer gas-supplementing hole of the screw-type refrigeration compressor to recycle a small part of gas evaporated by solely throttling the recycled refrigerant in the economizer. The liquid temperature of the refrigerant with a low boiling point is directly or indirectly reduced to remarkably improve the refrigeration amount and the refrigeration coefficient of the whole refrigeration system under a low-temperature condition. The invention is extremely suitable for the low-cost upgrading and regenerating modification of the traditional screw-type auto-cascading refrigeration system.

Description

technical field [0001] The invention relates to a refrigeration system with ultra-low temperature and large refrigeration capacity, in particular to a high-efficiency screw type self-cascading refrigeration system. Background technique [0002] In industrial or commercial fields such as petroleum, chemical industry, pharmaceuticals, military industry, electronics and food, in order to meet the cryogenic and low temperature requirements of production technology and scientific research, screw cascade refrigeration systems are generally used to obtain large cooling capacity and relatively low temperature. Low evaporation temperature is generally used to obtain low temperature from -60°C to -125°C. The traditional screw cascade refrigeration system usually consists of two parts: a high-temperature refrigeration system and a low-temperature refrigeration system. The high-temperature refrigeration system uses a medium-temperature refrigerant, and the low-temperature refrigeration ...

AI Technical Summary

Problems solved by technology

However, as the evaporating temperature of conventional screw refrigeration compressors decreases gradually with the operation, especially when the evaporating temperature reaches -40°C, the ratio of the discharge pressure to the suction pressure will reach about 20, resulting in a biased volumetric efficiency. Low cooling capacity and cooling performance coefficient, poor economy, and thus limit the promotion and use of screw self-cascading refrigeration systems in the field of industrial and commercial low-temperature refrigeration

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