Three-stage step cooling super-low temperature cold store

Abstract

The invention discloses a three-stage step cooling super-low temperature cold store. Step cooling of the cold store is realized, running cost is lowered, energy consumption is reduced, and the cold store can run more stably. The cold store comprises a cold store enclosure structure and a three-stage cooling system, wherein the three-stage cooling system comprises a high-temperature-stage cooling system, a medium-temperature-stage cooling system and a low-temperature-stage cooling system; the high-temperature-stage cooling system comprises a high-temperature-stage cooling unit, a first high-temperature-stage electromagnetic valve, a second high-temperature-stage electromagnetic valve and a high-temperature-stage air-cooled evaporator; the medium-temperature-stage cooling system comprises a medium-temperature-stage unit, a first medium-temperature-stage electromagnetic valve, a second medium-temperature-stage electromagnetic valve and a medium-temperature-stage air-cooled evaporator; the low-temperature-stage cooling system comprises a low-temperature-stage cooling unit, a low-temperature-stage electromagnetic valve and a low-temperature-stage air-cooled evaporator. According to the cold store, only the high-temperature-stage cooling system runs at temperature of higher than minus 30 DEG C, the high-temperature-stage cooling system and the medium-temperature-stage cooling system run at temperature of higher than minus 75 DEG C, and the three stages of cooling system run at temperature of lower than minus 75 DEG C; a step cooling manner is adopted, so that the running cost is lowered, and the energy consumption is reduced.

Description

technical field [0001] The invention relates to an ultra-low temperature cold storage, and more specifically, relates to a three-stage stepped cooling ultra-low temperature cold storage. Background technique [0002] At present, ultra-low temperature cold storage is mostly used in special occasions such as low-temperature medical treatment, low-temperature storage and providing low-temperature test environment. There are few ultra-low temperature cold storage in China, and the refrigeration system mostly adopts cascade refrigeration system. [0003] When traditional three-stage cascade refrigeration is used, the high-temperature stage, medium-temperature stage and low-temperature stage refrigeration system are started in sequence, and finally the low-temperature stage refrigerant is evaporated and refrigerated in the air-cooled evaporator. Considering that this refrigeration method has restrictions on the pressure ratio of each stage, when the pressure ratios of the three st...

AI Technical Summary

Problems solved by technology

Considering that this refrigeration method has restrictions on the pressure ratio of each stage, when the pressure ratios of the three stages are roughly equal, the medium-temperature refrigerant will generate negative pressure when the medium-temperature refrigeration system is running, and the low-temperature refrigerant will generate negative pressure in the low-temperature stage. The refrigeration system is close to negative pressure when it is running, which will cause the entire refrigeration system to run unstable, and the medium-temperature and low-temperature refrigeration compressors will stop, and the three-stage operation will cause very low efficiency in the initial stage of cold storage cooling.

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