Abstract: A cascade refrigeration system including an upper portion having at least one modular chiller unit that provides cooling to at least one of a low temperature subsystem having a plurality of low temperature loads, and a medium temperature subsystem having a plurality of medium temperature loads. The modular chiller unit includes a refrigerant circuit having at least a compressor, a condenser, an expansion device, and an evaporator. An ammonia refrigerant which may have entrained oil from the compressor circulates within the refrigerant circuit. An oil recycling circuit removes some oil from the ammonia refrigerant for return to the compressor. An oil pot collects oil accumulated in the evaporator and an oil return line drains oil from the oil pot to an ammonia accumulator or directly to the compressor.

Abstract: A cascade refrigeration system includes an upper portion. The upper portion includes at least one modular chiller unit that provides cooling to at least one of a low temperature subsystem having a plurality of low temperature loads, and a medium temperature subsystem having a plurality of medium temperature loads. The modular chiller unit includes a refrigerant circuit, an ammonia refrigerant, an ammonia refrigerant accumulator, and an oil separation system. The refrigerant circuit includes at least a compressor, a condenser, an expansion device, and an evaporator. The ammonia refrigerant is configured for circulation within the refrigerant circuit. The ammonia refrigerant accumulator is configured to receive the ammonia refrigerant from the evaporator. The oil separation system is configured to remove oil from the ammonia refrigerant.

Abstract: A cascade refrigeration system includes an upper portion having at least one modular chiller unit that provides cooling to at least one of a low temperature subsystem having a plurality of low temperature loads, and a medium temperature subsystem having a plurality of medium temperature loads. The modular chiller unit includes a refrigerant circuit having at least a compressor, a condenser, an expansion device, and an evaporator. An ammonia refrigerant mixed with a soluble oil circulates within the refrigerant circuit. A control device may be programmed to modulate the position of the expansion device so that a superheat temperature of the ammonia refrigerant near an outlet of the evaporator fluctuates within a substantially predetermined superheat temperature range to positively return soluble oil from the evaporator to the compressor.

Abstract: A cascade refrigeration system includes an upper portion. The upper portion includes at least one modular chiller unit that provides cooling to at least one of a low temperature subsystem having a plurality of low temperature loads, and a medium temperature subsystem having a plurality of medium temperature loads. The modular chiller unit includes a refrigerant circuit, an ammonia refrigerant, an ammonia refrigerant accumulator, and an oil separation system. The refrigerant circuit includes at least a compressor, a condenser, an expansion device, and an evaporator. The ammonia refrigerant is configured for circulation within the refrigerant circuit. The ammonia refrigerant accumulator is configured to receive the ammonia refrigerant from the evaporator. The oil separation system is configured to remove oil from the ammonia refrigerant.

Abstract: A cascade CO2 refrigeration system includes a medium temperature loop for circulating a medium refrigerant and a low temperature loop for circulating a CO2 refrigerant. The medium temperature loop includes a heat exchanger having a first side and a second side. The first side evaporates the medium temperature refrigerant. The low temperature loop includes a discharge header for circulating the CO2 refrigerant through the second side of the heat exchanger to condense the CO2 refrigerant, a liquid-vapor separator collects liquid CO2 refrigerant and directs vapor CO2 refrigerant to the second side of the heat exchanger. A liquid CO2 supply header receives liquid CO2 refrigerant from the liquid-vapor separator. Medium temperature loads receive liquid CO2 refrigerant from the liquid supply header for use as a liquid coolant at a medium temperature. An expansion device expands liquid CO2 refrigerant from the liquid supply header into a low temperature liquid-vapor mixture for use by the low temperature loads.

Abstract: A C02 refrigeration system has an LT system with LT compressors and LT evaporators, and an MT system with MT compressors and MT evaporators, operating in a refrigeration mode and a defrost mode using C02 hot gas discharge from the MT and/or the LT compressors to defrost the LT evaporators. A C02 refrigerant circuit directs C02 refrigerant through the system and has an LT compressor discharge line with a hot gas discharge valve, a C02 hot gas defrost supply header directing C02 hot gas discharge from the LT and/or the MT compressors to the LT evaporators, a flash tank supplying C02 refrigerant to the MT and LT evaporators during the refrigeration mode, and receiving the C02 hot gas discharge from the LT evaporators during the defrost mode, and a control system directing the C02 hot gas discharge through the LT evaporators and to the flash tank during the defrost mode.

Abstract: A C02 refrigeration system has an LT system with LT compressors and LT evaporators, and an MT system with MT compressors and MT evaporators, operating in a refrigeration mode and a defrost mode using C02 hot gas discharge from the MT and/or the LT compressors to defrost the LT evaporators. A C02 refrigerant circuit directs C02 refrigerant through the system and has an LT compressor discharge line with a hot gas discharge valve, a C02 hot gas defrost supply header directing C02 hot gas discharge from the LT and/or the MT compressors to the LT evaporators, a flash tank supplying C02 refrigerant to the MT and LT evaporators during the refrigeration mode, and receiving the C02 hot gas discharge from the LT evaporators during the defrost mode, and a control system directing the C02 hot gas discharge through the LT evaporators and to the flash tank during the defrost mode.

Abstract: A cascade CO2 refrigeration system includes a medium temperature loop for circulating a medium refrigerant and a low temperature loop for circulating a CO2 refrigerant. The medium temperature loop includes a heat exchanger having a first side and a second side. The first side evaporates the medium temperature refrigerant. The low temperature loop includes a discharge header for circulating the CO2 refrigerant through the second side of the heat exchanger to condense the CO2 refrigerant, a liquid-vapor separator collects liquid CO2 refrigerant and directs vapor CO2 refrigerant to the second side of the heat exchanger. A liquid CO2 supply header receives liquid CO2 refrigerant from the liquid-vapor separator. Medium temperature loads receive liquid CO2 refrigerant from the liquid supply header for use as a liquid coolant at a medium temperature. An expansion device expands liquid CO2 refrigerant from the liquid supply header into a low temperature liquid-vapor mixture for use by the low temperature loads.

Abstract: A cascade CO2 refrigeration system includes a medium temperature loop for circulating a medium refrigerant and a low temperature loop for circulating a CO2 refrigerant. The medium temperature loop includes a heat exchanger having a first side and a second side. The first side evaporates the medium temperature refrigerant. The low temperature loop includes a discharge header for circulating the CO2 refrigerant through the second side of the heat exchanger to condense the CO2 refrigerant, a liquid-vapor separator collects liquid CO2 refrigerant and directs vapor CO2 refrigerant to the second side of the heat exchanger. A liquid CO2 supply header receives liquid CO2 refrigerant from the liquid-vapor separator. Medium temperature loads receive liquid CO2 refrigerant from the liquid supply header for use as a liquid coolant at a medium temperature. An expansion device expands liquid CO2 refrigerant from the liquid supply header into a low temperature liquid-vapor mixture for use by the low temperature loads.

Abstract: A cascade refrigeration system includes an upper portion having at least one modular chiller unit that provides cooling to at least one of a low temperature subsystem having a plurality of low temperature loads, and a medium temperature subsystem having a plurality of medium temperature loads. The modular chiller unit includes a refrigerant circuit having at least a compressor, a condenser, an expansion device, and an evaporator. An ammonia refrigerant mixed with a soluble oil circulates within the refrigerant circuit. A control device may be programmed to modulate the position of the expansion device so that a superheat temperature of the ammonia refrigerant near an outlet of the evaporator fluctuates within a substantially predetermined superheat temperature range to positively return soluble oil from the evaporator to the compressor.

Abstract: A cascade CO2 refrigeration system includes a medium temperature loop for circulating a medium refrigerant and a low temperature loop for circulating a CO2 refrigerant. The medium temperature loop includes a heat exchanger having a first side and a second side. The first side evaporates the medium temperature refrigerant. The low temperature loop includes a discharge header for circulating the CO2 refrigerant through the second side of the heat exchanger to condense the CO2 refrigerant, a liquid-vapor separator collects liquid CO2 refrigerant and directs vapor CO2 refrigerant to the second side of the heat exchanger. A liquid CO2 supply header receives liquid CO2 refrigerant from the liquid-vapor separator. Medium temperature loads receive liquid CO2 refrigerant from the liquid supply header for use as a liquid coolant at a medium temperature. An expansion device expands liquid CO2 refrigerant from the liquid supply header into a low temperature liquid-vapor mixture for use by the low temperature loads.

Abstract: A refrigeration system includes a first cooling system having a refrigerant in thermal communication with a heat exchanger device to provide a first cooling source. A second cooling system has a coolant in thermal communication with the heat exchanger device and a refrigeration device is configured to receive the coolant. A third cooling system is configured to provide a second cooling source to the coolant when the first cooling source is unavailable, so that a pressure of the coolant does not exceed a predetermined level when the first cooling source is unavailable.

Abstract: A refrigeration system for objects is disclosed. The system includes a refrigeration device and a defrost system. The refrigeration device provides a case or container defining a space for the objects, a first heat exchanger associated with the container for cooling a fluid communicating with the space to cool the objects and a second heat exchanger to receive a heat supply from an air source for warming the fluid. A system for cooling articles is also disclosed. The system includes a space configured to contain the articles, a first element to provide cooling of the articles within the space, a first coolant source to refrigerate the space by cooling the first element in a first state, and a second coolant source to elevate a temperature of the first element in a second state.

Abstract: A system for refrigeration of products includes a case having a compartment defining a space configured to receive the products. A first heat exchanger is configured to cool a fluid communicating with the space to cool the objects. A second heat exchanger is configured to receive a heat supply from an air source to warm the fluid. At least one coolant supply line and at least one coolant discharge line are configured to direct the fluid in communication with the space.

Abstract: A temperature controlled service case for storage and display of chilled or frozen products, including at least one compartment for product storage, at least one access opening providing entrance to the compartment, at least one shelf within the compartment for holding product, and refrigeration operatively associated with the compartment for maintaining a selected temperature therein. The refrigeration includes at least one cooling coil above the shelf with a cooling medium flowing therethrough, and cooling within the shelf with a cooling medium flowing therethrough. Coolant supply is also provided for supplying cooling medium to the cooling coil and shelf.

Abstract: A temperature controlled service case for storage and display of chilled or frozen products, including at least one compartment for product storage, at least one access opening providing entrance to the compartment, at least one shelf within the compartment for holding product, and refrigeration operatively associated with the compartment for maintaining a selected temperature therein. The refrigeration includes at least one cooling coil above the shelf with a cooling medium flowing therethrough, and cooling within the shelf with a cooling medium flowing therethrough. Coolant supply is also provided for supplying cooling medium to the cooling coil and shelf with separate coolant supply and discharge lines from the coolant supply to the cooling coil and shelf. In accordance with a further embodiment, the shelf is divided into separate sections. In accordance with a still further embodiment, means are provided to warm the coolant for at least one of said cooling coil and shelf.

Abstract: A system for refrigeration of products includes a case having a compartment defining a space configured to receive the products. A first heat exchanger is configured to cool a fluid communicating with the space to cool the objects. A second heat exchanger is configured to receive a heat supply from an air source to warm the fluid. At least one coolant supply line and at least one coolant discharge line are configured to direct the fluid in communication with the space.

Abstract: A refrigeration system includes a first cooling system having a refrigerant in thermal communication with a heat exchanger device to provide a first cooling source. A second cooling system has a coolant in thermal communication with the heat exchanger device and a refrigeration device is configured to receive the coolant. A third cooling system is configured to provide a second cooling source to the coolant when the first cooling source is unavailable, so that a pressure of the coolant does not exceed a predetermined level when the first cooling source is unavailable.

Abstract: A refrigeration system for objects is disclosed. The system includes a refrigeration device and a defrost system. The refrigeration device provides a case or container defining a space for the objects, a first heat exchanger associated with the container for cooling a fluid communicating with the space to cool the objects and a second heat exchanger to receive a heat supply from an air source for warming the fluid. A system for cooling articles is also disclosed. The system includes a space configured to contain the articles, a first element to provide cooling of the articles within the space, a first coolant source to refrigerate the space by cooling the first element in a first state, and a second coolant source to elevate a temperature of the first element in a second state.

Abstract: A non-compression cascade refrigeration system 30 for refrigerating a closed refrigerated space includes a cascade condenser 34 in heat exchange relationship with a primary evaporator 24, a cascade evaporator 28 positioned in the refrigerated space 40 and a liquid and vapor separator 42. A first coolant delivery conduit 44 delivers liquid coolant from the cascade condenser 34 to the separator 42 which then provides the coolant through a second coolant delivery conduit 46 to the cascade evaporator 28 for cooling the refrigerated space 40. A first coolant return conduit 50 returns the coolant from the cascade evaporator 28 to the separator 42 where the return coolant is separated into liquid and gaseous coolant, such that the liquid coolant is directed to the second delivery conduit 46 for reuse in the cascade evaporator 28 and the gaseous coolant is directed to a second coolant return conduit 52 and returned to the cascade condenser 34.