Abstract: A refrigeration system and refrigeration method thereof utilizing the principle of thermodynamics comprises a compressor, an air cooler connected to the compressor, an expander having a first end connected to the air cooler, a second end connected to the compressor, and a third end as an outlet wherein air pressure and air temperature are increased by the compressor, the pressurized high temperature air is fed to the air cooler, the pressurized low temperature air is fed to the expander for converting enthalpy of air into work to activate the compressor, energy contained in the air at the outlet of the expander is decreased, and temperature at the outlet of the expander is decreased. According to the present invention power is recycled in the process of conversion.