The object of this invention is to increase the life of the displacer and stem seals of the reciprocating displacer of a Gifford McMahon (GM) cryogenic expander. The seal comprises a ring that is relatively long and thin and uses the pressure difference across the seal, acting behind the ring, as the primary force to bring the ring into contact with the cylinder and stem walls. The pressure difference across the seal ring pushes the ring to one end of the groove, and the friction force pushes the ring in the same direction while it is moving. The sealing force is distributed over a larger area compared with a conventional backed “O” ring thus reducing the wear rate and increasing the seal life.

The object of this invention is to increase the life of the displacer and stem seals of the reciprocating displacer of a Gifford McMahon (GM) cryogenic expander. The seal comprises a ring that is relatively long and thin and uses the pressure difference across the seal, acting behind the ring, as the primary force to bring the ring into contact with the cylinder and stem walls. The pressure difference across the seal ring pushes the ring to one end of the groove, and the friction force pushes the ring in the same direction while it is moving. The sealing force is distributed over a larger area compared with a conventional backed “O” ring thus reducing the wear rate and increasing the seal life.

Facility and method for hydrogen refrigeration, comprising a hydrogen circuit to be cooled, comprising:—a first and a second set of heat exchanger(s) arranged in series for exchanging heat with the hydrogen circuit to be cooled;—a first cooling device for exchanging heat with the first set of heat exchanger(s) comprising a refrigerator that operates a refrigeration cycle of a first cycle gas;—a second cooling device for exchanging heat with the second set of heat exchanger(s) comprising a refrigerator that operates a refrigeration cycle of a second cycle gas having a molar mass of less than 3 g/mol, the refrigerator of the second cooling device comprising, arranged in series in a cycle circuit: at least one centrifugal compressor, a cooling member, an expansion member and a member for reheating the second expanded cycle gas;—a system for mixing at least one additional component having a molar mass greater than 50 g/mol with the second cycle gas before it enters the at least one centrifugal compressor and a member for purifying the mixture at the outlet of the at least one compressor configured to remove the at least one additional component up to a determined residual content and located upstream of the first set of heat exchanger(s).

A pneumatically driven cryogenic refrigerator operating primarily on the Gifford-McMahon (GM) cycle is switched from cooling to heating by a switch valve between a rotary valve and a drive piston that causes the displacer to reciprocate. The rotary valve has ports at two radii, one that cycles flow to the displacer and a second that cycles flow to the drive piston. Two ports cycle flow to the top of the drive piston, the “cooling” port optimizes the cooling cycle and the “heating” port provides a good heating cycle. A switch valve that changes the flow from one port to the other can be linearly or rotary actuated. The rotary valve does not reverse direction.

A pneumatically driven cryogenic refrigerator operating primarily on the Gifford-McMahon (GM) cycle is switched from cooling to heating by a switch valve between a rotary valve and a drive piston that causes the displacer to reciprocate. The rotary valve has ports at two radii, one that cycles flow to the displacer and a second that cycles flow to the drive piston. Two ports cycle flow to the top of the drive piston, the “cooling” port optimizes the cooling cycle and the “heating” port provides a good heating cycle. A switch valve that changes the flow from one port to the other can be linearly or rotary actuated. The rotary valve does not reverse direction.

A cooling system includes a compressor configured to pressurize carbon dioxide to form pressurized carbon dioxide, a mixer configured to generate mixed refrigerant in which the pressurized carbon dioxide and solvent in a liquid state, a depressurization apparatus provided downstream from the mixer and configured to depressurize the mixed refrigerant, a separator configured to separate carbon dioxide in a gas state from the mixed refrigerant, a heat exchanger configured to exchange heat between the mixed refrigerant cooled through depressurization and a fluid to be cooled, and a second heat exchanger configured to cool the carbon dioxide or the mixed refrigerant using vaporized carbon dioxide or the mixed refrigerant.

The invention provides a heat transfer system and a method for operating a heat transfer system in which a heat transfer fluid comprising or consisting of a phase change material (PCM) circulates in a cooling circuit. A combined state of phase value of the heat transfer fluid is determined based on information obtained from a sensor system including a temperature sensor and an electrical resistance sensor realized as two separate sensors or as one combined temperature-and-electrical-resistance sensor. The system and method can securely and effectively prevent a possible blocking of the channels of an indoor heat exchanger of the system by solidified PCM and an unwanted deposition of solid PCM (crystals) on heat transfer surfaces of the indoor heat exchanger.

The invention provides a heat transfer system and a method for operating a heat transfer system in which a heat transfer fluid comprising or consisting of a phase change material (PCM) circulates in a cooling circuit. A combined state of phase value of the heat transfer fluid is determined based on information obtained from a sensor system including a temperature sensor and an electrical resistance sensor realized as two separate sensors or as one combined temperature-and-electrical-resistance sensor. The system and method can securely and effectively prevent a possible blocking of the channels of an indoor heat exchanger of the system by solidified PCM and an unwanted deposition of solid PCM (crystals) on heat transfer surfaces of the indoor heat exchanger.

A gas turbine engine may include a deep heat recovery system, such as a deep heat recovery super critical carbon dioxide (sCO2) system. The deep heat recovery system may include two-stage cooling of the working fluid (such as carbon dioxide—CO2) where at least one of cooling stages is recuperative by transferring heat from the working fluid to a flow of compressed air being supplied to a combustor included in the gas turbine engine. The deep heat recovery system may operate in a supercritical cycle, or in a transcritical cycle depending on the temperature to which the working fluid is cooled during a second stage of the two-stage cooling. The second stage of the two-stage cooling includes working fluid-to-air heat rejection where the air is ambient air.

A gas turbine engine may include a deep heat recovery system, such as a deep heat recovery super critical carbon dioxide (sCO2) system. The deep heat recovery system may include two-stage cooling of the working fluid (such as carbon dioxide—CO2) where at least one of cooling stages is recuperative by transferring heat from the working fluid to a flow of compressed air being supplied to a combustor included in the gas turbine engine. The deep heat recovery system may operate in a supercritical cycle, or in a transcritical cycle depending on the temperature to which the working fluid is cooled during a second stage of the two-stage cooling. The second stage of the two-stage cooling includes working fluid-to-air heat rejection where the air is ambient air.