Abstract: A method and apparatus for controlling compressors in a cascade vapor compression system. The process may include controlling the operation of a first compressor based on a constant band control, and controlling the operation of a second compressor based on a proportional band control. Controlling the first compressor based on the constant band control may include operating the compressor at a constant setting if first measurements are within a range associated with a first setpoint. It may also include proportionally adjusting the operation of the first compressor if the first measurements are outside the range. Further, controlling the second compressor based on the proportional band control may include operating the compressor based on one of a plurality of proportional bands, each proportional band having a different proportional factor. Controlling the second compressor operation may further include switching between these proportional bands based on a second measured parameter.

Abstract: An embodiment of a system for changing a temperature of a packaged biologic substance includes a chamber configured to receive the packaged biologic substance. In addition, the system includes a refrigeration assembly configured to change a temperature of the packaged biologic substance. Further, the system includes an auxiliary heat exchanger at least partially positioned in the chamber, the auxiliary heat exchanger including at least one heat pipe.

Abstract: A refrigeration module of a cold space chamber has a blower and an evaporator. A method of controlling the refrigeration module includes defrosting a coil of the evaporator to form a volume of warm air surrounding the coil. The method includes circulating a refrigerant through the evaporator after defrosting the coil, to cool the coil. The method includes operating the blower in a series of pulses to control introduction of the volume of warm air into the cold space chamber.

Abstract: An embodiment of a cold storage system includes a chamber defined at least in part by an outer door and a refrigeration assembly operably coupled to the chamber. In addition, the cold storage system includes a metallic shelving assembly positioned in the chamber. The shelving assembly has a plurality of shelves that each include a front lateral frame member, a back lateral frame member, and a guide coupled to and spanning between the front and back lateral frame members. The guide includes a planar, horizontal guide surface. Further, the cold storage system includes a storage pan positioned at least partially above the guide surface. The storage pan includes an elongate runner extending below and along a bottom side of the storage pan. The elongate runner at least partially includes a polymer and is configured to slidably engage the guide surface.

Abstract: The present invention provides a system and method for an improved multistage, cascade refrigeration system using hot gas defrost to rid the evaporator of ice build-up which accumulates over time, while the air in the evaporator enclosure remains below the freezing point of water. The present invention thus provides greater defrost flexibility with increased ease of design and implementation than current refrigeration systems, which allows for more robust hot gas defrost function for multistage refrigeration systems, such that it is unaffected by temperature changes of the condensing fluid (ambient air temperature for air cooled condensers, water temperature for water cooled condensers), and can be readily adapted to any refrigerant suitable for a selected temperature range.