Abstract: A supermarket refrigeration system may include a plurality of supermarket refrigeration cases, each including an evaporator and an associated compressor connected downstream therefrom. A common condenser is connected downstream from the compressors, and a receiver is connected downstream from the common condenser and upstream from the evaporators. A liquid header extends throughout the supermarket and connects the receiver and the evaporators. A discharge header extends throughout the supermarket and connects the compressors to the common condenser. An oil-bearing refrigerant mixture may circulate through a refrigerant circulation path to lubricate the compressors without undesired pooling and without an oil separator. The system may further include a selectively operable defrost circuit which uses hot refrigerant mixture for defrosting.

Abstract: A housing for roof top refrigeration equipment has a metal frame supporting at least one compressor unit on a building roof. A pair of end panels and a roof panel are attached to the frame with the roof panel being leakproof to protect the equipment in the housing. A hinged access panel is attached to the frame and has a closed position and an open position and a pair of panel support members to hold the panel in an open position so that the side panel forms a roof canopy in the open position for sheltering a person working on the equipment in the housing. An electrical box is attached to the exterior of one of the end panels and has an access opening thereinto for rapid access to the power for the refrigeration equipment.