Abstract: A CO2 refrigeration system includes a plurality of compressors configured to circulate a CO2 refrigerant, a suction line configured to deliver the CO2 refrigerant to the compressors, an oil separator configured to separate oil from the CO2 refrigerant, and an oil return line configured to deliver the oil from the oil separator to the suction line. The oil mixes with the CO2 refrigerant in the suction line before reaching the compressors.

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 CO2 refrigeration system includes a plurality of compressors configured to circulate a CO2 refrigerant, a suction line configured to deliver the CO2 refrigerant to the compressors, an oil separator configured to separate oil from the CO2 refrigerant, and an oil return line configured to deliver the oil from the oil separator to the suction line. The oil mixes with the CO2 refrigerant in the suction line before reaching the compressors.

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: 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 CO2 refrigeration system includes a plurality of compressors configured to circulate a CO2 refrigerant, a suction line configured to deliver the CO2 refrigerant to the compressors, an oil separator configured to separate oil from the CO2 refrigerant, and an oil return line configured to deliver the oil from the oil separator to the suction line. The oil mixes with the CO2 refrigerant in the suction line before reaching the compressors.

Abstract: An integrated CO2 refrigeration and air conditioning (AC) system for use in a facility includes one or more CO2 compressors configured to discharge a CO2 refrigerant at a higher pressure for circulation through a circuit to provide cooling to one or more refrigeration loads in the facility and a receiver configured to receive the CO2 refrigerant at a lower pressure through a high pressure valve. The integrated system further includes an AC module configured to deliver a chilled AC coolant to AC loads in the facility. The AC module includes an AC evaporator and an AC compressor. The AC evaporator has an inlet configured to receive CO2 liquid and an outlet configured to discharge a CO2 vapor. The AC compressor is arranged in parallel with the one or more CO2 compressors and is configured to receive CO2 vapor from both the AC evaporator and the receiver.

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 using CO2 as a refrigerant includes a receiver having a liquid outlet connected to expansion valves, which are connected to evaporators, which are connected to the suction side of the compressor. The receiver includes a second gas outlet connected to a second pressure reduction device, to reduce the energy consumption in CO2 cooling systems and to protect the compressors against liquid CO2 by heating the suction gas. The second pressure reduction device is connected by tubing to a first heat exchanging device, which is integrated in the receiver, so that gas that is evaporated in the top of a receiver can be used for cooling the liquid part of the same receiver.

Abstract: An integrated CO2 refrigeration and air conditioning (AC) system for use in a facility includes one or more CO2 compressors configured to discharge a CO2 refrigerant at a higher pressure for circulation through a circuit to provide cooling to one or more refrigeration loads in the facility and a receiver configured to receive the CO2 refrigerant at a lower pressure through a high pressure valve. The integrated system further includes an AC module configured to deliver a chilled AC coolant to AC loads in the facility. The AC module includes an AC evaporator and an AC compressor. The AC evaporator has an inlet configured to receive CO2 liquid and an outlet configured to discharge a CO2 vapor. The AC compressor is arranged in parallel with the one or more CO2 compressors and is configured to receive CO2 vapor from both the AC evaporator and the receiver.

Abstract: A refrigeration system using CO2 as a refrigerant includes a receiver having a liquid outlet connected to expansion valves, which are connected to evaporators, which are connected to the suction side of the compressor. The receiver includes a second gas outlet connected to a second pressure reduction device, to reduce the energy consumption in CO2 cooling systems and to protect the compressors against liquid CO2 by heating the suction gas. The second pressure reduction device is connected by tubing to a first heat exchanging device, which is integrated in the receiver, so that gas that is evaporated in the top of a receiver can be used for cooling the liquid part of the same receiver.