19/11/2017
How Air Conditioning Works
You might have pondered how your air conditioning actually works, or perhaps you have never given it a moment's thought. Just in case you are curious, let us explain it to you.
Air Conditioning How It Works
Air conditioning like it says 'conditions' the air. It not only cools it down, but also reduces the moisture content, or humidity. All air conditioners work the same way whether they are installed in a building, or in a car.
A number of people don't realise that turning on the air conditioning actually reduces the number of miles per gallon of your car. There is energy used in removing the heat and moisture from the air in the car, and this consumes petrol because of the extra engine load.
Hard tubing and flexible hoses connect all the actual components of the air conditioning in your car. Ev***ration and condensation, expansion and compression are the physics of why it works. There are five main components to the whole system, namely the Compressor, Condenser, Receiver-dryer, Expansion valve, and the Ev***rator.
Air Conditioning Cycle
The fluid that passes around the whole system is the refrigerant. The refrigerant can ev***rate at a low temperature, and then condense again at a higher pressure. In the bad old days, R-12 was the refrigerant used in almost all cars. It was widely available, however it was found to be a contributor to the hole in the earth's ozone layer as it was a chlorofluorocarbon (CFC). These refrigerants were discontinued, and all cars after 1996 use a non-CFC fluid called R-134A which is kinder to the environment.
So, here is how all the various parts of a car's air conditioning works:
Compressor: The compressor is the work horse of the air conditioning system, powered by a drive belt connected to the crankshaft of the engine. When the aircon system is turned on, the compressor pumps refrigerant vapour under high pressure to the condenser.
Condenser: The condenser is a device used to change the high-pressure refrigerant v***r to a liquid. It is mounted in front of the engine's radiator, and it looks very similar to a radiator. The vapour is condensed to a liquid because of the high pressure that is driving it in, and this generates a great deal of heat. The heat is then in turn removed from the condenser by air flowing through the condenser on the outside.
Receiver: The now liquid refrigerant moves to the receiver-dryer. This is a small reservoir vessel for the liquid refrigerant, and removes any moisture that may have leaked into the refrigerant. Moisture in the system causes havoc, with ice crystals causing blockages and mechanical damage.
Expansion Valve: The pressurised refrigerant flows from the receiver-drier to the expansion valve. The valve removes pressure from the liquid refrigerant so that it can expand and become refrigerant vapour in the ev***rator.Air Conditioning
Ev***rator: The ev***rator is another device that looks similar to a car radiator. It has tubes and fins and is usually mounted inside the passenger compartment behind the fascia above the footwell. As the cold low-pressure refrigerant is passed into the ev***rator, it v***rises and absorbs heat from the air in the passenger compartment. The blower fan inside the passenger compartment pushes air over the outside of the ev***rator, so cold air is circulated inside the car. On the 'air-side' of the ev***rator, the moisture in the air is reduced, and the 'condensate' is collected and drained away.
Compressor: The compressor then draws in the low-pressure refrigerant vapour to start another refrigeration cycle. The refrigeration cycle then runs continuously, and is regulated by the setting of the expansion valve.
The whole process is reasonably simple when explained like that. All air conditioning systems work on the same principle, even if the exact components used may vary slightly between car manufacturers.
We hope that explains a little as to how that little 'A/C' button works on your car, if you want it explained a little more in depth then if you roll up your sleeves we can show you the components in your car next time you call us for a check or service here at Cool Autos