Car air-conditioning is no longer the privilege of the rich, with 99 per cent of all new vehicles being fitted with AC as standard to keep drivers and passengers comfortable in all seasons. Learning how your car air-conditioning system works will make it easier to identify the source of problems if something goes wrong.

Early air conditioners

Air-conditioning was fitted to luxury cars as early as 1939, though it took several decades before the systems became affordable for everyday vehicles. These early air conditioners used the refrigerant R-12, commonly known as Freon, which was banned from use in the 1990s due to its damaging effects on the ozone layer. Modern air conditioners use the greener refrigerant R-134a.


Automotive air-conditioning works on the same principles as cooling systems in buildings, removing heat and humidity from the air using a compressor, condenser and evaporator. Every step in the sequence is essential for delivering cooling power to the cabin and keeping the system working as normal. To better understand this process, here’s a breakdown of all major operating components:

Compressor This pump is powered by the engine and pressurises the gas refrigerant to force it through the system.

Condenser The pressurised refrigerant flows through the condenser where it loses heat and changes state to a pressurised liquid.

Receiver-drier This reservoir contains desiccants that attract and remove any remaining liquid water that could cause damage to the system.

Thermal expansion valve The refrigerant is permitted to expand and loses pressure. The low-pressure liquid is released at the desired rate through the valve and into the evaporator.

Evaporator As low-pressure liquid is passed into the evaporator the fins are chilled and the heat is removed from the air passing through the unit. As the heat transfers out of the air and into the low-pressure liquid it changes state into a low-pressure vapour and returns back to the compressor to start the cycle again.

It’s important to remember that your air conditioning compressor relies on the correct gas charge in the system to keep cool and prevent expensive damage. Ensure you regularly have your air conditioning serviced at a qualified and registered service centre to prolong the life of your AC system.

Car air conditioning in Brisbane

Contact Mr Cool on 07 3188 4348 to talk to our technicians about any air-conditioning issues. Our friendly and experienced mechanics offer a same-day service on all air-conditioning repairs.