It is a kind of multistage wave rotor refrigerator which could be used in the field of gas expansion refrigeration. The refrigerator is mainly composed of a casing, a left end cover, a right end cover, a wave rotor, a central shaft, a high pressure inlet nozzle, a medium pressure outlet nozzle and a drive mechanism. Within the structure of the refrigerator, 2-8 times unsteady expansion of gas could get realized, which improves the refrigeration efficiency under large pressure ratio. Extending the structure of the refrigerator and changing the structure of end cover could help realize multistage expansion refrigeration of gas. The double opening structure of oscillation tubes could help the refrigerator work regularly with high moisture content of gas. This refrigerator is a gas expansion refrigeration device that uses moving unsteady pressure waves in oscillation tubes to realize the separation of the heat and cold of gas. Improvement of refrigeration efficiency could be done by recycling expansion work in the form of pressure energy that formed by expansion of high pressure gas.

A cryocooler includes an expander provided with an expander motor including a motor rotary shaft, a displacer that changes a volume of an expansion space of a working gas by reciprocating linearly by the motor rotation shaft rotating, and a rotary valve that controls intake and exhaust of the working gas into the expansion space by rotating by the motor rotation shaft rotating, a pressure sensor that measures a pressure of the working gas and outputs a measurement signal indicating the measured pressure, and a controller that receives the measurement signal, detects a feature point appearing periodically in the measured pressure during an operation of the cryocooler, acquires a motor drive waveform indicating a command rotation speed of the motor rotary shaft determined to vary within one rotation of the motor rotary shaft, and outputs the motor drive waveform in synchronization with the feature point appearing periodically.

A method for operating a cryocooler includes: connecting a second compressor in series with a first compressor on a high pressure line or a low pressure line; connecting a buffer volume to the low pressure line via a supply valve; executing initial cooling for cooling an expander from an initial temperature to a cryogenic temperature in a state where the second compressor and the buffer volume are connected to the cryocooler; and executing a steady operation of maintaining the expander at the cryogenic temperature after the initial cooling. The execution of the initial cooling includes supplying a working gas to the expander by using the first compressor and the second compressor, and controlling the supply valve to keep a pressure of the high pressure line within a preset appropriate pressure range based on the measured pressure of the high pressure line.

A dual rail heat pump cycle includes a low-temperature heat source; a two stage, high-temperature heat exchange process through which, in operation, heat is exchanged with a thermal medium; and a working fluid circuit. The working fluid circuit includes an expansion process; a compression process; a recuperation process, and a pair of parallel flow paths. The recuperation process is interposed between the expansion process and the compression process and has a high-pressure side defined by the compression process and a low pressure side defined by the expansion process. The pair of parallel flow paths between the recuperation process and the high-temperature heat exchange process on the high-pressure side of the recuperation process.

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.

A gas turbine engine has a compressor section, a combustor, and a turbine section. An associated fluid is to be cooled and an associated fluid is to be heated. A transcritical vapor cycle heats the fluid to be heated, and cools the fluid to be cooled. The transcritical vapor cycle includes a gas cooler in which the fluid to be heated is heated by a refrigerant in the transcritical vapor cycle. An evaporator heat exchanger at which the fluid to be cooled is cooled by the refrigerant in the transcritical vapor cycle. A compressor upstream of the gas cooler compresses the refrigerant to a pressure above a critical point for the refrigerant. An expansion device expands the refrigerant downstream of the gas cooler, with the evaporator heat exchanger being downstream of the expansion device, and such that the refrigerant passing through the gas cooler to heat the fluid to be heated is generally above the critical point.

A gas turbine engine has a compressor section, a combustor, and a turbine section. An associated fluid is to be cooled and an associated fluid is to be heated. A transcritical vapor cycle heats the fluid to be heated, and cools the fluid to be cooled. The transcritical vapor cycle includes a gas cooler in which the fluid to be heated is heated by a refrigerant in the transcritical vapor cycle. An evaporator heat exchanger at which the fluid to be cooled is cooled by the refrigerant in the transcritical vapor cycle. A compressor upstream of the gas cooler compresses the refrigerant to a pressure above a critical point for the refrigerant. An expansion device expands the refrigerant downstream of the gas cooler, with the evaporator heat exchanger being downstream of the expansion device, and such that the refrigerant passing through the gas cooler to heat the fluid to be heated is generally above the critical point.

The present disclosure is directed to an aircraft power generation system including a reverse Brayton cycle system, a gas turbine engine, and a gearbox. The gas turbine engine includes a compressor section, a turbine section, and an engine shaft. The compressor section is arranged in serial flow arrangement with the turbine section. The engine shaft is rotatable with at least a portion of the compressor section and with at least a portion of the turbine section. The reverse Brayton cycle system includes a compressor, a driveshaft, a turbine, and a first exchanger. The driveshaft is rotatable with the compressor or the turbine, and the compressor, the first heat exchanger, and the turbine are in serial flow arrangement. The gearbox is configured to receive mechanical energy from the engine shaft and transmit mechanical energy to the reverse Brayton cycle system through the driveshaft.

A cooling system for an aircraft includes an air intake, a heat exchanger configured to receive air passing into the air intake when the aircraft is operating at Mach speed, and configured to receive compressed refrigerant from a first compressor at a first pressure, an evaporator positioned within the aircraft and configured to receive heated air from a compartment within the aircraft, at least one of an expansion device and an expansion machine, and the compressed refrigerant rejects heat in the heat exchanger to the air, expands in the at least one of the expansion device and the expansion machine, and receives heat in the evaporator from the heated air.

A cooling system for an aircraft includes an air intake, a heat exchanger configured to receive air passing into the air intake when the aircraft is operating at Mach speed, and configured to receive compressed refrigerant from a first compressor at a first pressure, an evaporator positioned within the aircraft and configured to receive heated air from a compartment within the aircraft, at least one of an expansion device and an expansion machine, and the compressed refrigerant rejects heat in the heat exchanger to the air, expands in the at least one of the expansion device and the expansion machine, and receives heat in the evaporator from the heated air.