The Receiver Drier
Receiver driers are similar to the accumulator used on fixed orifice tube systems. They both clean and remove moisture from the system. There are some key differences. The receiver drier is located on the high side of the system, between the condenser and the evaporator. The accumulator is located on the low side, between the evaporator and the compressor on fixed orifice tube systems.
The receiver drier is also a liquid storage tank for the refrigerant flowing from the condenser to the expansion valve. It ensures that liquid refrigerant is ready for the expansion valve under all operating conditions. At the most demanding times of the day, the opening expansion valve relies on this storage tank to provide the evaporator with liquid refrigerant.
Refrigerant from the condenser enters the receiver drier through the inlet port. The vapor rises to the top, while the heavier liquid refrigerant drops to the bottom. It passes through the filter and desiccant before it's stored at the bottom of the tank. As the expansion valve opens and closes, liquid refrigerant is drawn into the outlet port tube of the receiver drier, through the high-pressure line, and onto the expansion valve.