Three-level stepped cooling ultra-low temperature cold storage

Abstract

The invention discloses a three-stage stepped cooling ultra-low temperature cold storage, which realizes the stepped cooling of the cold storage, saves operating costs, reduces energy consumption, and operates more stably. Includes cold storage enclosure and tertiary refrigeration system. The three-stage refrigeration system includes a high-temperature refrigeration system, a medium-temperature refrigeration system and a low-temperature refrigeration system; the high-temperature refrigeration system includes a high-temperature refrigeration unit, a first high-temperature solenoid valve, a second high-temperature solenoid valve and a high-temperature air-cooled device. The medium-temperature refrigeration system includes a medium-temperature refrigeration unit, the first medium-temperature solenoid valve, the second medium-temperature solenoid valve, and a medium-temperature air-cooled evaporator; the low-temperature refrigeration system includes a low-temperature refrigeration unit, a low-temperature solenoid valve, and a low-temperature air Cold evaporator. Above -30°C, only the high-temperature refrigeration system is operated, above -75°C, the high-temperature refrigeration system and the medium-temperature refrigeration system are operated, and below -75°C, the three-stage refrigeration system is operated, and step-wise cooling is adopted to save operating costs and reduce energy consumption.

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.

Images