Air Conditioning: Evaporator
The task of the evaporator is to cool and dry the air.
Heat is extracted from the air that flows over the outside of the evaporator housing. In this way, cooled air is directed into the passenger compartment. In the evaporator the heat is transferred from the warm air to the cold refrigerant. The refrigerant then begins to boil and evaporates.
The refrigerant, in liquid form, is injected into the evaporate in precisely measured volumes. The refrigerant evaporates as a result of the sudden drop in pressure and emits heat energy during this process.
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 vehicle 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. Water that 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.
The refrigerant volume that is measured by the throttle valve is injected into the evaporator. As soon as the refrigerant enters the cooling pipes, it evaporates due to the drop in pressure. During this process, heat is also extracted from the cooling pipes. The cooling pipes and the entire evaporator cool immediately. The refrigerant gas is then drawn out using the compressor.
The airflow through the evaporator is cooled and dried, and then forwarded to the passenger compartment via the air distribution ducts.
During this process, the moisture in the air condenses on the evaporator flanges. Dust, pollen, etc., which is deposited on the damp evaporator is rinsed away. This cleans and dries the air.