Basic Car A/C Parts

How Auto A/C Works

It's nice to know the basics of your car's important systems, especially when it's time for repair or service. That way, you know what is going on with your vehicle. Austin's Automotive Specialists in Lakeway, Texas, is always happy to explain things on the spot, or you can keep reading to learn more about your car's A/C system!


Refrigerant, also commonly known as Freon, fills the A/C system. It changes physical properties from gas to liquid as it moves through the different parts of the A/C system — the compressor and condenser. As it changes temperature and state, it absorbs the heat, which makes the air left behind cooler. Car AC doesn't work by creating cool air. Instead, it removes heat and moisture to make the cabin feel more comfortable.


The compressor is powered by the car's serpentine belt. It places the refrigerant under extremely high pressure, causing it to liquefy and warm up. Once it's hot, the refrigerant moves from the compressor through high-pressure lines to the condenser.


The condenser works similarly to a small radiator and brings fresh air from outside the vehicle into contact with the hot liquid refrigerant from the compressor. Shaped with a series of coils, the condenser removes heat from the liquid as it flows through each coil. Once the air and refrigerant meet, the air absorbs the heat from the liquid. The cooled refrigerant then flows into an expansion valve or orifice tube, where it is restricted and turned into a gas.


In expansion valve and receiver-drier systems, the refrigerant flows into an accumulator that contains a desiccant bag. It removes and collects impurities and unwanted moisture, effectively cleaning the refrigerant in its gaseous state.


Clean gaseous refrigerant travels from the receiver-drier to the evaporator. In the gaseous state, freon absorbs heat from air passing through the evaporator fins and leaves behind cool, dry air. That cool, dry air is blown into the car's cabin while the refrigerant is cycled back into the compressor to begin the process again.

Still have questions about your car's AC system or its major parts? Austin's Automotive Specialists in Lakeway, Texas, is happy to explain!