Receiver Dryer: Description and Operation

From the evaporator the gas flows at low pressure and temperature to the air receiver/dryer.

The air receiver/dryer has several purposes:
- to store refrigerant not required by the system at the particular time;
- to remove any moisture present in the refrigerant by means of a drying agent. A special, new drying agent has been introduced in models from 1993 on (with R134a refrigerant);
- to provide a reserve of refrigerant under different operating conditions, also to compensate for diffusion losses through hose walls and O-rings, and through the compressor shaft seal;
- to return oil to the gas flowing through the compressor.

The air receiver/dryer is designed to prevent the escape of liquid refrigerant (which may damage the compressor).
This is achieved by locating the outlet of the unit in an area where only gas is present.