Air conditioning system for automobiles is a system that controls the temperature, moisture content, and flow of air inside the cabin so that the driver and passengers feel comfortable, and combines the function of a heater and the function of a cooler. The temperature and the direction and amount of airflow inside the cabin are controlled using an automatic or manual controller, and air conditioning is realized by an HVAC Unit mounted inside the cabin. For cooling, refrigerant should undergo the cycle: COMPRESSION CONDENSATION EXPANSION EVAPORATION, sequentially performed by COMPRESSOR CONDENSER EXPANSION VALVE EVAPORATOR.