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Refrigeration Accumulator

Refrigeration Accumulators are designed to protect against damage to the compressor. Its purpose is to store any excess liquid refrigerant and oil that may have not boiled off in the evaporator

The accumulator is situated between the evaporator and compressor in the suction line.(pipe running between the two components)

Liquid cannot be compressed and therefore will eventually damage the compressor, often known as "slugging".  This is when a compressor tries to compress liquid. 

Also a large enough quantity of liquid can remove oil off of the bearings causing rapid wear and breakdown.

Accumulators collect small amounts of oil and refrigerant into the suction line so as not to cause compressor damage. When the liquid refrigerant enters the accumulator it strikes a deflector plate that causes anything liquefied to rest in the holding tank.