The automatic air conditioner uses the sensors to detect the ambient air temperature, cabin air temperature, water temperature and quantity of solar radiation, and uses the microcomputer to determine the required blow-out air temperature, thereby controlling the refrigeration cycle system.

During the refrigeration cycle, interior heat absorbed by the evaporator is sent through the compressor to the condenser, then released outside the vehicle. The coolant inside the condenser is liquefied by the ambient air, and sent through the expansion valve to the evaporator, where it is vaporized to cool the cabin air.