The car's air conditioning system 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 rads, also referred to as a aircon condenser or aircon radiator, is fixed in front of the engine's radiator, looking a lot like a smaller version of the radiator.
Hot gas or vapour is pumped from the aircon compressor into the aircon rads 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.
Situated in front of the engine's radiator, the aircon rads are an easy target for corrosion. A common reason for loss of refrigerant gas in your air conditioning system is the failure of the air conditioning radiator. If there is insufficient cold air, it could be clogged aircon rads. This may mean you need to get a new/replacement part and should seek advice from your mechanic.