Refrigerant
The liquid/gas used as the ‘active’ ingredient in the A/C system. It is used to absorb heat from surrounding air and changes in composition from gas to liquid at various points in the process.
Compressor
The compressor is at the heart of the A/C system. It is the ‘pump’ that pressurises and circulates the refrigerant through the system. The compressor is powered by a drive belt that is connected to the engine crankshaft. A clutch system is used to engage and disengage the compressor (so the A/C can be turned on and off) when the engine is running.
Condenser
The condenser converts the high-pressure gas refrigerant into a liquid. It is similar to a radiator and cool air flows around it removing heat from the refrigerant inside. Removing heat from the gas changes its state from vapour to liquid.
Receiver
The liquid refrigerant flows to the receiver, a component that removes moisture from the refrigerant.
Expansion valve
The expansion valve is the point at which the high-pressure system becomes a low-pressure system. The valve allows the pressurized refrigerant to expand, at which point it converts back to a gaseous state. At this point, the refrigerant is extremely cold.
Evaporator
The evaporator resembles a small radiator and is located behind the dash near the cabin. Cold, low-pressure refrigerant flows through the evaporator and a blower fan pushes air across it. The refrigerant in the evaporator works to absorb the heat and remove moisture from this air and the result is a cold, dry breeze flowing into the cabin. The refrigerant is then moved back to the compressor at which point the process starts again.