Hill Phoenix, Inc.

Kim G Christensen

John D Bittner

Jeffrey E Newel

J Scott Martin

David K Hinde

Paul Hallett

Tony Mills

Scott J Martin

Systems and methods for controlling pressure in a COrefrigeration 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 COrefrigeration system. The gas bypass valve is fluidly connected with an outlet of the receiving tank and arranged in series with a compressor of the COrefrigeration 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 COrefrigeration 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.

Systems and methods for pressure control in a CO2 refrigeration system

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

Refrigeration system with oil control system

Systems and methods for pressure control in a COrefrigeration system

A COrefrigeration system includes a COrefrigeration subsystem that provides cooling for a refrigeration load using carbon dioxide (CO) as a refrigerant. The COrefrigeration system further includes a direct COheat exchange subsystem that uses the COrefrigerant from the COrefrigeration subsystem to provide heating or cooling for a building zone. The direct COheat exchange subsystem includes a heat exchanger that exchanges heat directly between the COrefrigerant and an airflow provided to the building zone.

COrefrigeration system with direct COheat exchange for building temperature control

An integrated COrefrigeration and air conditioning (AC) system for use in a facility includes one or more COcompressors configured to discharge a COrefrigerant 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 COrefrigerant 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 COliquid and an outlet configured to discharge a COvapor. The AC compressor is arranged in parallel with the one or more COcompressors and is configured to receive COvapor from both the AC evaporator and the receiver.

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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.

CO2 refrigeration system with hot gas defrost

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.

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Aarhus V, Denmark

Kim G Christensen