The Air Conditioning System Tasks
The air conditioning system has two main tasks:
- to lower the air temperature in the passenger compartment to a comfortable level.
- to dehumidify the air (reduce the humidity) that enters the passenger compartment.
Note that the air conditioning expels heat but does NOT create coolness.
The air conditioning is a contained system filled with refrigerant and in principle its function is the same as a normal refrigerator:
- an evaporator which takes the heat from the air and dehumidifies the air.
- a condenser in which the removed heat is transferred to the air.
- in addition there is a compressor and a number of other components in the system.
Lowered passenger compartment temperature - increased traffic safety
It is well documented that the human performance abilities are reduced in heat. Research carried out in traffic and in a normal car demonstrated that when the passenger compartment temperature is increased from 21 to 27°C (70 to 81°F):
- the risk of the driver missing important traffic information (hazard warnings, traffic signals, signs etc.) increased by 50%.
- driver reaction times where 22% slower.
With an air conditioning system, car travel is both more comfortable and safer.
Dehumidified air feels cooler
Sweat evaporates much more quickly if the air is dry. The skin then feels dry and therefore more comfortable.
When the air entering the passenger compartment encounters the cold evaporator, the humidity in the air condenses on the evaporator. The water drains out under the car via a drain hose. In the event of high humidity, this may be considerable quantities of water, which is often mistaken for a water leak from the engine for example.
The water which condenses binds and takes with it some of the dust and the larger impurities in the air. Therefore the air conditioning system also helps to purify the air.