Marine refrigerating equipment is used for shipboard refrigeration of products as well as for air conditioning the quarters of passengers and crew. Shipboard refrigeration is necessary for the preservation of perishables in transit and foodstuffs to be used by passengers and crew. Marine refrigeration is also used for maintaining certain cargo products in liquid form that would otherwise evaporate when stored at ambient conditions. A Typical ship stores or cargo refrigeration plant consists of a compressor, motor, condensor, receiver, evaporators, and controls. A typical air-conditioning unit consists of a compressor, motor, condenser, receiver, water chiller, and controls.