The compressor is the propelling element for the refrigerant in the A/C system. A compressor circulates the refrigerant in the system and it acts as the heart of A/C. It also raises the pressure and then the temperature of the gaseous refrigerant, coming from the evaporator at low pressure and temperature. The compressor moves the refrigerant from evaporator, through the condenser via a receiver and expansion valve, right back to the evaporator.

Compressors used in the automotive A/C systems must be compact in dimension and lightweight in order to permit easy installation when the available space is limited and so as to overload the relative vehicle's suspension.