Suction line accumulator

Suction line accumulator

A suction line accumulator is considered mandatory on all systems 2 HP and larger in size, and is recommended for all units. The purpose of the accumulator is to intercept any liquid refrigerant which might flood through the system before it reaches the compressor, particularly on start-up or on hot gas defrost cycles. Because crankcase heaters or a pumpdown cycle are not always operative on transport units, the accumulator is the best protection that can be provided for the compresor. 

Provisions for positive oil return to the crankcase must be provided, but a direct gravit flow is not acceptable since this would allow liquid refrigerant to drain to the crankcase during shutdown periods. Capacity of the accumulator usually should be minimum of 50% of the system charge, but the required size will vary with system desing. Tests are recommended during the design phase of any new unit to determine the minimum capacity for proper compressor protection.

An external souece of heat is desirable to accelerante the boiling of the liquid refrigerant in the accumulator so that it may return to the compressor as gas. Mounting in the condenser air stream or near the compressor will normally be satisfactory.