The car's air conditioning system basically conditions the air, which means whilst cooling the air in the car down, it also helps to ensure there isn't too much moisture in the car, so it stops the air getting too humid. The car's air conditioning unit also cleans the air in the car by filtering the dust and other particles from the air inside the car.
The aircon condenser, usually made out of aluminum, is situated in front of the engine's radiator. It looks a lot like a radiator, is usually about the same size or a bit smaller than a radiator and a bit thinner, and is sometimes referred to as the aircon radiator.
Hot gas or vapour is pumped from the aircon compressor into the aircon condenser where it is cooled and turned back into a really cold liquid which is pumped into the aircon evaporator and flows into the car as cold air. This whole process is then repeated over and again.
If the air conditioning system is losing refrigerant vapour, it could be a sign that the aircon condenser has a leak. If there is insufficient cold air it could be a clogged aircon condenser. Situated in front of your car's water radiator, the aircon condenser is an easy target for corrosion and dirt which can cause problems with this part. Have a chat with your mechanic, and once you have established this part needs replacing, buying a new aircon condenser will ensure you get the perfect for the make and model of your vehicle.