Discribes the theory of air refrigerator and its application to train air-condi- tioning,freezing and cold storage,aircraft air-conditioning and large low temperature en- vironmental laboratory.

Considering the problem of the long maintaining cycle and the difficult judgment of the relay protection status,a convenient method to store and collect data of AUFA(Air-condition Unit For Aircraft) by adopting the embedded USB host technology is proposed,which provides an objective and adequate data basis for developing and perfecting the control strategy of the control system.

Discussion on design of VRF air conditioning systems;