Environmental concerns about HFCs, global warming and the resulting increasingly stringent legislation have revived interest in alternatives to existing refrigeration technologies.

The circulation system in air cycle technology is mainly composed of compressor, expander, end cooler and recuperative heat exchanger. The base of technology is that air is heated during the compression phase and cooled during expansion. The repetition of the compression and expansion cycles makes it possible to achieve and maintain ultra-low temperatures down to - 160 °C.

According to the principle of operation, air-cycle refrigeration systems are classified into the following categories: < ...