Generally, cold storage is cooled by refrigerator, using the liquid with low gasification temperature as refrigerant, making it evaporate under the condition of low pressure and mechanical control and absorb the heat in the cold storage, finally to achieve the purpose of cooling.
The most commonly used is the compressor refrigerator, mainly made up of compressor, condenser, throttle valve and evaporator, and so on.
It can be divided into direct cooling and indirect cooling according to the way of evaporation tube device. The direct cooling installs the evaporator in the cold storage, whereas indirect cooling uses blower to suck the air in the cold storage into the air cooling device. The advantage of the air cooling is cooling rapidly, uniform temperature etc.