The evaporator cools down the warm air from the inside of the vehicle or warm fresh air. Here the air to be cooled is drawn in through a fan (usually radial fan) and is injected after the cooling down through air channels and louvers at appropriate places back into the inside of the vehicle.

The liquid refrigerant is injected several times into the evaporator block. Coil pipes and plates form the evaporator block. The heat necessary for the evaporation of the refrigerant is withdrawn from the passing air which subsequently cools down. A large evaporator surface is provided by the plates and a fast heat exchange ensured.

During the cooling down of the air, the air humidity condenses to water. The condensed water collects in the bottom section of the air conditioner box and is conducted to the open. The thus dehumidified air substantially improves the air condition in the vehicle. An anti-icer protection switch interrupts the power supply to the refrigerant compressor at approx.+ 2° C and in this way prevents an icing up of the evaporator block.

The following schematic illustrates the 1991 Mercedes-Benz G-Class Refrigerant Circuit Diagram:

1991 Mercedes-Benz G-Class Refrigerant Circuit Diagram

1             Compressor
1a           Electromagnetic clutch
2             Condenser
3             Receiver
3a           Filter drier
3b           High pressure switch
3c           Low pressure switch
3d           Sight glass
3e           Fuse
4             Expansion valve
5             Evaporator
6             Temperature switch
6a           Temperature sensor

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