Abstract: A refrigeration system includes a refrigeration circuit and a coolant circuit separate from the refrigeration circuit. The refrigerant circuit includes a gas cooler/condenser, a receiver, and an evaporator. The coolant circuit includes a heat exchanger configured to transfer heat from a refrigerant circulating within the refrigeration circuit into a coolant circulating within the coolant circuit, a heat sink configured to remove heat from the coolant circulating within the coolant circuit, and a magnetocaloric conditioning unit configured to transfer heat from the coolant within a first fluid conduit of the coolant circuit into the coolant within a second fluid conduit of the coolant circuit. The first fluid conduit connects an outlet of the heat exchanger to an inlet of the heat sink, whereas the second fluid conduit connects an outlet of the heat sink to an inlet of the heat exchanger.

Abstract: Systems and methods for controlling pressure in a CO2 refrigeration system are provided. The pressure control system includes a pressure sensor, a gas bypass valve, a parallel compressor, and a controller. The pressure sensor is configured to measure a pressure within a receiving tank of the CO2 refrigeration system. The gas bypass valve is fluidly connected with an outlet of the receiving tank and arranged in series with a compressor of the CO2 refrigeration system. The parallel compressor is fluidly connected with the outlet of the receiving tank and arranged in parallel with both the gas bypass valve and the compressor of the CO2 refrigeration system. The controller is configured to receive a pressure measurement from the pressure sensor and operate both the gas bypass valve and the parallel compressor, in response to the pressure measurement, to control the pressure within the receiving tank.

Abstract: An evaporative cooling device for a refrigeration system includes one or more heat exchanger coils, a first moisture panel, a second moisture panel, a first nozzle array, a second nozzle array, a moisture sensor, and a controller. The first moisture panel and the second moisture panel are separated by a distance and disposed external to the one or more heat exchanger coils. The first nozzle array is disposed external to the first moisture panel and the second nozzle array is disposed external to the second moisture panel. The first nozzle array and the second nozzle array are configured to provide an atomized spray of electrostatically charged droplets. The moisture sensor is configured to provide a signal representative of a moisture level. The controller is configured to receive the signal representative of the moisture level and control a supply of water.

Abstract: A refrigeration system includes a refrigeration circuit and a coolant circuit separate from the refrigeration circuit. The refrigerant circuit includes a gas cooler/condenser, a receiver, and an evaporator. The coolant circuit includes a heat exchanger configured to transfer heat from a refrigerant circulating within the refrigeration circuit into a coolant circulating within the coolant circuit, a heat sink configured to remove heat from the coolant circulating within the coolant circuit, and a magnetocaloric conditioning unit configured to transfer heat from the coolant within a first fluid conduit of the coolant circuit into the coolant within a second fluid conduit of the coolant circuit. The first fluid conduit connects an outlet of the heat exchanger to an inlet of the heat sink, whereas the second fluid conduit connects an outlet of the heat sink to an inlet of the heat exchanger.

Abstract: A refrigeration system includes a refrigeration circuit and a coolant circuit separate from the refrigeration circuit. The refrigerant circuit includes a gas cooler/condenser, a receiver, and an evaporator. The coolant circuit includes a heat exchanger configured to transfer heat from a refrigerant circulating within the refrigeration circuit into a coolant circulating within the coolant circuit, a heat sink configured to remove heat from the coolant circulating within the coolant circuit, and a magnetocaloric conditioning unit configured to transfer heat from the coolant within a first fluid conduit of the coolant circuit into the coolant within a second fluid conduit of the coolant circuit. The first fluid conduit connects an outlet of the heat exchanger to an inlet of the heat sink, whereas the second fluid conduit connects an outlet of the heat sink to an inlet of the heat exchanger.

Abstract: An evaporative cooling device for a refrigeration system includes one or more heat exchanger coils, a first moisture panel, a second moisture panel, a first nozzle array, a second nozzle array, a moisture sensor, and a controller. The first moisture panel and the second moisture panel are separated by a distance and disposed external to the one or more heat exchanger coils. The first nozzle array is disposed external to the first moisture panel and the second nozzle array is disposed external to the second moisture panel. The first nozzle array and the second nozzle array are configured to provide an atomized spray of electrostatically charged droplets. The moisture sensor is configured to provide a signal representative of a moisture level. The controller is configured to receive the signal representative of the moisture level and control a supply of water.

Abstract: An evaporative cooling device for a refrigeration system includes one or more heat exchanger coils, a first moisture panel, a second moisture panel, a first nozzle array, a second nozzle array, a moisture sensor, and a controller. The first moisture panel and the second moisture panel are separated by a distance and disposed external to the one or more heat exchanger coils. The first nozzle array is disposed external to the first moisture panel and the second nozzle array is disposed external to the second moisture panel. The first nozzle array and the second nozzle array are configured to provide an atomized spray of electrostatically charged droplets. The moisture sensor is configured to provide a signal representative of a moisture level. The controller is configured to receive the signal representative of the moisture level and control a supply of water.

Abstract: Systems and methods for controlling pressure in a CO2 refrigeration system are provided. The pressure control system includes a pressure sensor, a gas bypass valve, a parallel compressor, and a controller. The pressure sensor is configured to measure a pressure within a receiving tank of the CO2 refrigeration system. The gas bypass valve is fluidly connected with an outlet of the receiving tank and arranged in series with a compressor of the CO2 refrigeration system. The parallel compressor is fluidly connected with the outlet of the receiving tank and arranged in parallel with both the gas bypass valve and the compressor of the CO2 refrigeration system. The controller is configured to receive a pressure measurement from the pressure sensor and operate both the gas bypass valve and the parallel compressor, in response to the pressure measurement, to control the pressure within the receiving tank.

Abstract: An evaporative cooling device for a refrigeration system includes one or more heat exchanger coils, a first moisture panel, a second moisture panel, a first nozzle array, a second nozzle array, a moisture sensor, and a controller. The first moisture panel and the second moisture panel are separated by a distance and disposed external to the one or more heat exchanger coils. The first nozzle array is disposed external to the first moisture panel and the second nozzle array is disposed external to the second moisture panel. The first nozzle array and the second nozzle array are configured to provide an atomized spray of electrostatically charged droplets. The moisture sensor is configured to provide a signal representative of a moisture level. The controller is configured to receive the signal representative of the moisture level and control a supply of water.

Abstract: Systems and methods for controlling pressure in a CO2 refrigeration system are provided. The pressure control system includes a pressure sensor, a gas bypass valve, a parallel compressor, and a controller. The pressure sensor is configured to measure a pressure within a receiving tank of the CO2 refrigeration system. The gas bypass valve is fluidly connected with an outlet of the receiving tank and arranged in series with a compressor of the CO2 refrigeration system. The parallel compressor is fluidly connected with the outlet of the receiving tank and arranged in parallel with both the gas bypass valve and the compressor of the CO2 refrigeration system. The controller is configured to receive a pressure measurement from the pressure sensor and operate both the gas bypass valve and the parallel compressor, in response to the pressure measurement, to control the pressure within the receiving tank.

Abstract: A refrigeration system includes a refrigeration circuit and a coolant circuit separate from the refrigeration circuit. The refrigerant circuit includes a gas cooler/condenser, a receiver, and an evaporator. The coolant circuit includes a heat exchanger configured to transfer heat from a refrigerant circulating within the refrigeration circuit into a coolant circulating within the coolant circuit, a heat sink configured to remove heat from the coolant circulating within the coolant circuit, and a magnetocaloric conditioning unit configured to transfer heat from the coolant within a first fluid conduit of the coolant circuit into the coolant within a second fluid conduit of the coolant circuit. The first fluid conduit connects an outlet of the heat exchanger to an inlet of the heat sink, whereas the second fluid conduit connects an outlet of the heat sink to an inlet of the heat exchanger.

Abstract: A secondary coolant refrigeration system powered primarily by a photovoltaic source and by an alternating current (AC) source as a backup is disclosed. The secondary coolant refrigeration system has a pump for pumping secondary coolant fluid through a secondary coolant fluid loop. The system includes a variable frequency drive for controlling the speed of the pump. The variable frequency drive includes drive circuitry configured to provide variable frequency power to the pump via an output interface. The variable frequency drive also includes a first interface configured to receive power from the photovoltaic source and a second interface configured to receive power from the AC source. The circuit is further configured to cause the variable speed drive to be powered by the photovoltaic source when the power received from the first interface is adequate and by the AC source when the power received from the first interface is not adequate.

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 refrigeration system is powered primarily by a photovoltaic source and by an alternating current (AC) source as a backup. A variable frequency drive is used for controlling a powered component of the refrigeration system. The variable frequency drive includes drive circuitry configured to provide variable frequency power via an output interface, a first interface configured to receive power from the photovoltaic source, a second interface configured to receive AC power from the AC source, a DC bus coupled to the drive circuitry and configured to transmit power to the drive circuitry. The drive circuitry receives power from the first interface when the power from the photovoltaic source is adequate to power the drive circuitry and receives power from the second interface when the power from the photovoltaic source is not adequate to power the drive circuitry.

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 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: Systems and methods for controlling pressure in a CO2 refrigeration system are provided. The pressure control system includes a pressure sensor, a gas bypass valve, a parallel compressor, and a controller. The pressure sensor is configured to measure a pressure within a receiving tank of the CO2 refrigeration system. The gas bypass valve is fluidly connected with an outlet of the receiving tank and arranged in series with a compressor of the CO2 refrigeration system. The parallel compressor is fluidly connected with the outlet of the receiving tank and arranged in parallel with both the gas bypass valve and the compressor of the CO2 refrigeration system. The controller is configured to receive a pressure measurement from the pressure sensor and operate both the gas bypass valve and the parallel compressor, in response to the pressure measurement, to control the pressure within the receiving tank.

Abstract: A refrigeration system includes a medium temperature subsystem circulating a coolant in a closed loop between at least one medium temperature chiller and at least one medium temperature load and at least one cascade heat exchanger, and a low temperature subsystem circulating a coolant in a closed loop between at least one low temperature heat exchanger and at least one low temperature load. A cooling circuit is provided for circulating a coolant and includes a first pump and a second pump and a fluid cooler and a valve, and interfaces with the medium temperature chiller and the low temperature chiller. The valve is movable to a closed position to define a first flow path and a second flow path, where the first flow path includes the first pump and the medium temperature chiller and fluid cooler, and the second flow path including the second pump and the low temperature heat exchanger and the cascade heat exchanger.