Abstract: A refrigerated storage or display device includes a pressure relief valve in an insulated wall of an evaporator enclosure and a frosting chamber between the pressure relief valve and the evaporator assembly. The pressure relief valve is heated so that no frost forms on the valve. The frosting chamber can be defined by a baffle that directs air entering through the pressure relief valve to flow along the evaporator. When outside air enters through the valve, moisture forms as frost on the frosting chamber walls and the evaporator. A defrost heater and condensate removal system can remove the frost during periodic defrost cycles. The pressure relief system can be deployed on individual refrigeration system modules of a modular merchandiser kit so that the required amount of pressure relief capacity is automatically provided during field installation.

Abstract: A refrigerator is provided with a refrigerated compartment comprising one or more zones in thermal communication with each other and with each zone independently controlled and operated at a particular temperature. Each zone temperature is controlled by a separate evaporator or heat exchanger. A method for maintaining different temperatures in one or more zones in thermal communication with one another in a refrigerator is also provided.