Abstract: A freezer and method of operating a freezer are provided with an adaptive defrost cycle. The freezer includes a controller that operates the freezer to: provide cooling to a cabinet via an evaporator during periodic operational cycles, monitor a time elapsed since a most recent defrost cycle, determine whether the time elapsed is greater than a current defrost interval, and perform a defrost cycle if so. The controller varies the current defrost interval between a first, larger time value and a second, smaller time value based on a plurality of trigger signals in response to various operating characteristics of the freezer monitored by sensors. After each defrost cycle is completed, the current defrost interval is reset to the first, larger time value.

Abstract: A two-stage cascade refrigeration system is provided having a first refrigeration stage and a second refrigeration stage. The first refrigeration stage defines a first fluid circuit for circulating a first refrigerant, and has a first compressor, a condenser, and a first expansion device. The second refrigeration stage defines a second fluid circuit for circulating a second refrigerant, with the second refrigeration stage having a second compressor that is a variable speed compressor, a second expansion device, and an evaporator. A heat exchanger is in fluid communication with the first and second fluid circuits to exchange heat between the first and second refrigerants. A controller stages operation of the first and second compressors and runs the second compressor at an initial speed less than a maximum speed initially when a staging protocol is performed during start up or re-starting of the refrigeration system.

Abstract: A two-stage cascade refrigeration system is provided having a first refrigeration stage and a second refrigeration stage. The first refrigeration stage defines a first fluid circuit for circulating a first refrigerant, and has a first compressor, a condenser, and a first expansion device. The second refrigeration stage defines a second fluid circuit for circulating a second refrigerant, with the second refrigeration stage having a second compressor that is a variable speed compressor, a second expansion device, and an evaporator. A heat exchanger is in fluid communication with the first and second fluid circuits to exchange heat between the first and second refrigerants. A controller stages operation of the first and second compressors and runs the second compressor at an initial speed less than a maximum speed initially when a staging protocol is performed during start up or re-starting of the refrigeration system.

Abstract: A refrigerator of the present invention includes a refrigeration system having a water-cooled condenser and a liquid line heat exchanger for additional cooling with the water, at a position upstream in the direction of flow of water from the cooling that occurs at the condenser. The use of water cooling at these two portions of the refrigeration system improves the energy efficiency of the refrigerator, while also significantly improving temperature responsiveness (e.g., reducing an amount of time necessary to “pull down” the temperature of a cooled space in the refrigerator to a desired set point temperature). The refrigerator may include one or a plurality of refrigeration stages, in various embodiments, and an additional sub-cooling heat exchanger may be provided in the refrigeration system downstream from the liquid line heat exchanger when the refrigerator includes multiple cascaded circuits.

Abstract: A refrigerator for storing products includes a sensor container configured to position at least one temperature sensor within a refrigerated interior in a cabinet of the refrigerator. The sensor container includes a main body portion enclosing a hollow interior space configured to receive a ballast liquid, and a plurality of dry wells which each extend generally horizontally between a closed end within the hollow interior space and an open end. The temperature sensors positioned in the dry wells are surrounded by ballast liquid but are not in direct contact with refrigerated air within the cabinet or the ballast liquid. The temperature measurements therefore approximate the thermal response of products (such as blood) stored in the cabinet without necessitating submersible sensors or a risk of liquid leaks. The temperature measurements may be sent to elements such as a chart recorder, and a display and alarm device associated with the refrigerator.

Abstract: A two-stage cascade refrigeration system is provided having a first refrigeration stage and a second refrigeration stage. The first refrigeration stage defines a first fluid circuit for circulating a first refrigerant, and has a first compressor, a condenser, and a first expansion device. The second refrigeration stage defines a second fluid circuit for circulating a second refrigerant, with the second refrigeration stage having a second compressor that is a variable speed compressor, a second expansion device, and an evaporator. A heat exchanger is in fluid communication with the first and second fluid circuits to exchange heat between the first and second refrigerants. A controller stages operation of the first and second compressors and runs the second compressor at an initial speed less than a maximum speed initially when a staging protocol is performed during start up or re-starting of the refrigeration system.

Abstract: A two-stage cascade refrigeration system is provided having a first refrigeration stage and a second refrigeration stage. The first refrigeration stage defines a first fluid circuit for circulating a first refrigerant, and has a first compressor, a condenser, and a first expansion device that is in fluid communication with the first fluid circuit. The second refrigeration stage defines a second fluid circuit for circulating a second refrigerant, with the second refrigeration stage having a second compressor, a second expansion device, and an evaporator that is in fluid communication with the second fluid circuit. A heat exchanger is in fluid communication with the first and second fluid circuits to exchange heat between the first and second refrigerants. At least one of the first or second compressors is a variable speed compressor.

Abstract: A recirculating bath includes a reservoir for receiving a working liquid, a recirculating pump, and at least one thermal element. The recirculating pump and thermal element are located externally to the reservoir so that the reservoir has an unobstructed working space. The thermal element may be thermally coupled to the working liquid through an interior surface of the reservoir, or the working liquid may be circulated over the thermal element by the recirculating pump in a chamber external to the reservoir. The recirculating bath may also include a lid that provides access to the reservoir by pivoting on a latching hinge. When open, the lid may provide a working surface adjacent to the reservoir. The lid may also include a selector that unlatches the hinge so that the lid can be removed. The recirculating pump may be fluidically coupled to the reservoir via a manifold.

Abstract: An ultra low temperature refrigeration system and technique, includes a cabinet with a storage chamber maintained at a certain temperature range, a door providing a seal with the cabinet when engaged with the cabinet, and a dehumidifying unit connected to the cabinet for dehumidifying the storage chamber within the cabinet.

Abstract: A rack is provided for use with a temperature controlled bath having a housing containing a reservoir with a supply of working fluid and an opening providing access to the reservoir. The rack includes a rack body, and a vessel support supported by the rack body and configured for supporting at least one vessel. The rack further includes a supporting foot assembly supported by the rack body and including a plurality of support feet. Each support foot is configured for movement between a stowed position and a deployed position.

Abstract: A high performance refrigerator includes a cabinet with a refrigerated interior and a refrigeration fluid circuit having first and second evaporators located within the cabinet and separated from the refrigerated interior by an insulating cover. The refrigerator also includes a first damper controlling flow from the refrigerated interior into the first evaporator, a second damper controlling flow from the first evaporator to the second evaporator, and a third damper controlling flow from the second evaporator to the refrigerated interior. The first evaporator operates with refrigerant at a lower temperature than the second evaporator such that substantially all frost formed on the first and second evaporators is collected on a first evaporator coil in the first evaporator. Thus, the first evaporator acts as a sacrificial evaporator that undergoes defrost more frequently than the second evaporator.

Abstract: A high performance refrigerator or freezer includes a cabinet with a refrigerated interior, a first evaporator cover separating a first evaporator compartment within the cabinet from the refrigerated interior, and a refrigeration fluid circuit having a first evaporator located within the first evaporator compartment, a second evaporator, and a three-way valve enabling selective communication of refrigerant to one or both of the evaporators. The second evaporator includes an air diffuser that receives chilled air from the first evaporator compartment and delivers the chilled air into the refrigerated interior. During normal operation, the three-way valve only directs refrigerant into the first evaporator such that the first evaporator cools the cabinet and the chilled air from the first evaporator passively defrosts the second evaporator by sublimation.

Abstract: A storage basket is configured to hold multiple product units such as blood bags within the cabinet of a freezer. The storage basket includes first and second spaced-apart sidewalls and a plurality of inclined shelves extending between and coupled to these sidewalls. The inclined shelves include a plurality of air flow apertures that defined storage receptacles for product units as well as additional flow apertures to ensure minimal hindrance of cooling air flow within the freezer. The storage basket also includes handles that enable easy grasping and movement of multiple product units at once into and out of the freezer. As a result, the amount of time needed to cool product units down to a desired temperature with the freezer is reduced and the storage density within the freezer is increased.