A transcritical R-744 refrigeration system with a medium temperature section having a plurality of circuits, at least one evaporator receiving an R-744 refrigerant in a medium-pressure liquid state from a receiver and feeding at least one transcritical compressor to compress the R-744 refrigerant from a low-pressure gaseous state into a high-pressure gaseous state to feed a gas cooler and a throttling device to partially condense the R-744 refrigerant into a medium-pressure gaseous-liquid state, the system comprising a pressure reducing valve connected to a discharge conduit of the at least one transcritical compressor and feeding hot gas to a defrost manifold to defrost one of the plurality of circuits of the medium temperature section, wherein the hot gas being fed to the defrost manifold has a pressure value less than or equal to a maximum operating pressure of the at least one evaporator.

The invention relates to a refrigerant for a cooling device (10) comprising a cooling circuit (11) comprising at least one heat exchanger (12), the refrigerant undergoing a phase transition in the heat exchanger, the refrigerant being a refrigerant mixture composed of a fraction of carbon dioxide (CO.sub.2), a fraction of 1,1-difluoroethene and a fraction of at least one other component, wherein the fraction of carbon dioxide in the refrigerant mixture is 45 to 90 mole percent, the fraction of 1,1-difluoroethene being 5 to 40 mole percent.

A subcooling controller includes a sensor and a processor. The sensor measures one or more of a temperature external to a first heat exchanger that removes heat from carbon dioxide refrigerant, a temperature of the carbon dioxide refrigerant, and a pressure of the carbon dioxide refrigerant. The processor determines that one or more of the measured temperature external to the first heat exchanger, the temperature of the carbon dioxide refrigerant, and the pressure of the carbon dioxide refrigerant is above a threshold and in response to that determination, activates a subcooling system. The subcooling system includes a condenser, a second heat exchanger, and a compressor. The condenser removes heat from a second refrigerant. The second heat removes heat from the carbon dioxide refrigerant stored in a flash tank. The compressor compresses the second refrigerant from the second heat exchanger and sends the second refrigerant to the condenser.

A diaphragm pressure regulator includes: a body defining a process surface and including: an exhaust port having a discharge opening, and at least one vent void interconnecting the process surface and the exhaust port; and an inlet port, and at least one process void communicating with the process surface and the inlet port; a reference housing including a cavity defining a reference surface and a reference port in fluid communication with the cavity; and a diaphragm disposed between the body and the reference housing, the diaphragm movable between a first position engaged with the vent voids, and a second position wherein the membrane is not engaged with at least one of the vent voids, wherein a dome is defined between the cavity and the reference side of the diaphragm; and wherein the reference housing includes a sump configured to segregate liquid from the reference side of the diaphragm.

A refrigeration system includes a rotary pressure exchanger fluidly coupled to a low pressure branch and a high pressure branch. The rotary pressure exchanger is configured to receive the refrigerant at high pressure from the high pressure branch, to receive the refrigerant at low pressure from the low pressure branch, and to exchange pressure between the refrigerant at high pressure and the refrigerant at low pressure, and wherein a first exiting stream from the rotary pressure exchanger includes the refrigerant at high pressure in the supercritical state or the subcritical state and a second exiting stream from the rotary pressure exchanger includes the refrigerant at low pressure in the liquid state or the two-phase mixture of liquid and vapor.

Systems and methods for improved heating, ventilation, air conditioning, and refrigeration systems incorporating a plurality of refrigerant circuits. The system can include a compressor having a first compression chamber, a second compression chamber, and a motor. The system can further include a heat exchanger having a first set of microchannel coils and a second set of microchannel coils. The system can have a first circuit fluidly coupled between the first compression chamber and the first set of microchannel coils and a second circuit fluidly coupled between the second compression chamber and the second set of microchannel coils. Further, the first circuit comprises a first refrigerant and the second circuit comprises a second refrigerant.

A refrigeration system includes a rotary pressure exchanger fluidly coupled to a low pressure loop and a high pressure loop. The rotary pressure exchanger replaces a traditional bulk flow compressor. The rotary pressure exchanger is configured to receive the refrigerant at high pressure from the high pressure loop, to receive the refrigerant at low pressure from the low pressure loop, and to exchange pressure between the refrigerant at high pressure and the refrigerant at low pressure, and wherein a first exiting stream from the rotary pressure exchanger includes the refrigerant at high pressure in the supercritical state or the subcritical state and a second exiting stream from the rotary pressure exchanger includes the refrigerant at low pressure in the liquid state or the two-phase mixture of liquid and vapor.

Device for regulating and controlling a flow-through and distributing a fluid in a fluid circuit has a housing with ports connecting fluid lines that are connected across a passage aperture with an interior volume of the housing, a valve element disposed in the interior volume of the housing, a drive element for moving the valve element relative to the housing.

Provided is a chiller and system that may be utilized in a supercritical fluid chromatography method, wherein a non-polar solvent may replace a portion or all of a polar solvent for the purpose of separating or extracting desired sample molecules from a combined sample/solvent stream. The system may reduce the amount of polar solvent necessary for chromatographic separation and/or extraction of desired samples. The system may incorporate a supercritical fluid chiller, a supercritical fluid pressure-equalizing vessel and a supercritical fluid cyclonic separator. The supercritical fluid chiller allows for efficient and consistent pumping of liquid-phase gases employing off-the-shelf HPLC pumps. The pressure equalizing vessel allows the use of off-the-shelf HPLC column cartridges. The system may further incorporate the use of one or more disposable cartridges containing silica gel or other suitable medium. The system may also utilize an open loop cooling circuit using fluids with a positive Joule-Thompson coefficient.

A method of controlling injection into a compressor in a refrigeration cycle is described wherein the method is performed in a refrigeration cycle, which comprises at least a flash tank configured for receiving a refrigerant and separating liquid refrigerant and vapour refrigerant, and a compressor configured for compressing the refrigerant, wherein the compressor comprises a means for compressing, a suction port and an injection port, which is connected to the means for compressing for at least a time instance of the refrigeration cycle, wherein the flash tank is connected to the injection port of the compressor via an injection valve. The method comprises determining a pressure in the flash tank and controlling the injection valve based on the determined pressure in the flash tank.