Low energy consumption and low pressure drop can minimize the operation cost and save energy. The gas and gas heat exchanger (precooling / reheater) removes half of the heat load in the input air, so as to minimize the refrigeration system and power consumption and ensure sufficient cooling and no condensation in the downstream pipeline. The effective evaporation of gas and refrigerant can make the compressed air cool evenly to the dew point temperature. The refrigerant multi-channel design scheme can maximize the refrigeration capacity and ensure that the evaporator is frost free.