In a hot weather, car air conditioning is a critical element. And the truth is that it serves not only to cool the air in the passenger compartment, but also to eliminate unpleasant odors, to reduce the humidity inside the car and to purify this air. So yes, it's a lot more important than it might seem, but how does car air conditioning work?

It consists of a number of components: a compressor, a condenser, a temperature sensor -or several, or none in some cars-, a fan, refrigerant gas and an evaporator. At least, this is the basic scheme of most air conditioning systems of our vehicles, although there may be small differences between one and another.

How a car's air conditioning system works

The air conditioning system of a car, and its operation, is based on the compression and decompression of the refrigerant gas. When it is compressed and becomes a liquid, it heats up, while its decompression, being previously filtered, is what cools the passenger compartment.

person driving car

Basically, it is a process that removes thermal energy from the indoor air and redirects it to the outside, thus heating the outside to cool the inside by means of a refrigerant that changes its state to absorb and release energy. The coolant flows inside a tube and contacts the air inside the vehicle, absorbs the thermal energy of the air and cools it and then sends it to the passenger compartment.



The compressor's function is to compress the refrigerant by raising the pressure so that it flows through the pipes.


It is located in front of the radiator and its function is to cool the refrigerant heated by compression. The hot gas passes through the condenser and dissipates the heat to the outside through pipes, the refrigerant goes from gaseous to liquid.

Dehydrating or accumulator filters

Their function is to remove impurities such as particles of burnt oil or pieces of metal, in addition to the humidity of the coolant, which enters the filter through a drying and hygroscopic agent.


They are intended to ventilate the vehicle so that the windows do not fog up and the passenger compartment is pleasantly air-conditioned. In addition to cooling, the air conditioner also dehumidifies the air, with the advantage that it can be used, for example, to remove mist from panoramic glass. The disadvantage is that it can dry out the mucous membranes if used for a long time. 

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