Liquid receiver
Also known as: receiver, liquid tank
Short definitionThe pressure vessel that collects liquid refrigerant leaving the condenser. It holds the surplus as load and season change, and takes the whole charge during service.
The amount of refrigerant in the system is fixed, but the amount in circulation is not. The liquid held inside the condenser changes between summer and winter, and the evaporator load shifts through the day. The receiver absorbs the difference. Liquid drains from the condenser into the vessel, is drawn off at the bottom, and passes through the filter drier and sight glass to the expansion valve.
Its volume is chosen from the charge: on pump-down it must take all the refrigerant without exceeding 80% full. Long pipe runs or a large evaporator increase the charge, and the vessel grows to match. It carries shut-off valves, a level indicator and a relief valve or fusible plug. Very small hermetic units and critically charged appliances have no receiver; the charge is calculated exactly.