A system for using excess energy of a power generation system and an sCO2 (supercritical carbon dioxide) stream to store and generate power. An air separation unit uses the excess energy to cool and liquify ambient air into liquid nitrogen (L-N2) and liquid oxygen (L-O2). The L-O2 and L-N2 are stored until energy is desired. An L-O2 energy discharge path has an oxygen heat exchanger that vaporizes and heats the oxygen, a combustor that combusts the oxygen and fuel to produce exhaust, and a first turbine is driven by the exhaust to produce energy. An L-N2 energy discharge path has a nitrogen heat exchanger that vaporizes and heats the L-N2, thereby providing expanded nitrogen, and a second turbine is driven by the expanded nitrogen to produce energy. Heat for the heat exchangers on both discharge paths is provided by the sCO2 stream.

An air cycle machine is provided. The air cycle machine can be included an environmental control system of an aircraft. The air cycle machine can include a turbine comprising a plurality of inlet gas flow paths, a compressor driven by the turbine from a shaft, and a fan driven by the turbine from the shaft.

A thermal management system includes a first heat source assembly including a first heat source exchanger, a first thermal fluid inlet line extending to the first heat source exchanger, and a first thermal fluid outlet line extending from the first heat source exchanger; a second heat source assembly including a second heat source exchanger, a second thermal fluid inlet line extending to the second heat source exchanger, and second a thermal fluid outlet line extending from the second heat source exchanger; a shared assembly including a thermal fluid line and a heat sink exchanger, the shared assembly defining an upstream junction in fluid communication with the first thermal fluid outlet line and second thermal fluid outlet line and a downstream junction in fluid communication with the first thermal fluid inlet line and second thermal fluid inlet line; and a controller configured to selectively fluidly connect the first heat source assembly or the second heat source assembly to the shared assembly.

Gas turbine engines are described. The gas turbine engines include a compressor section, a combustor section, a turbine section, and a nozzle, wherein the compressor section, the combustor section, the turbine section, and the nozzle define a core flow path that expels through the nozzle. A waste heat recovery system is operably connected to the gas turbine engine, the waste heat recovery system having a working fluid. An auxiliary cooling system is configured to provide cooling to a working fluid of the waste heat recovery system.

A thermal management system including a fluid flow mechanism. The fluid flow mechanism includes an electric machine. A conduit is formed through the electric machine allowing a heat transfer fluid to flow therethrough. The fluid flow mechanism includes a flow device configured to provide a first portion of the heat transfer fluid to a first heat exchange circuit and a second portion of heat transfer fluid to a second heat exchange circuit. The conduit is in fluid communication with the second heat exchange circuit.

Techniques for utilizing excess heat generated by an oven to generate electricity are provided. In one example, an oven can comprise a coolant pathway positioned adjacent to a hollow space within the oven, wherein the hollow space can contain heat. The oven can also comprise a chamber in fluid communication with the coolant pathway. The oven can further comprise a turbine in fluid communication with the chamber and an outlet. Moreover, the oven can comprise a generator connected to the turbine, wherein rotation of the turbine can power the generator.

Aircraft power plants including combustion engines, and associated methods for recuperating waste heat from such aircraft power plants are described. A method includes transferring the heat rejected by the internal combustion engine to supercritical CO.sub.2 (sCO.sub.2) used as a working fluid in a heat engine. The heat engine converts at least some the heat transferred to the sCO.sub.2 to mechanical energy to perform useful work onboard the aircraft.

A system includes a recirculation conduit that recirculates working fluid and a permanent magnet generator module in communication with the recirculation conduit. The working fluid from the recirculation conduit drives the permanent magnet generator module.

Processes, systems, and apparatus are provided for using a common working fluid for one or more turbines for processing a process gas and for the furnace for the pyrolysis process used to produce the process gas. The turbine(s) are operated based on a modified Allam cycle to produce power for operating one or more compressors and/or refrigerators involved in processing of the process gas while producing a reduced or minimized amount of CO.sub.2 that is released as a low-pressure gas phase product. Integrating the pyrolysis furnace with the working fluid loop can provide further benefits.

An electric power generation system receives a gas flow at a heater, heats the gas flow at the heater with a heated fluid from a waste heat process, and directs the heated gas flow to a turbine wheel of an electric generator. The heated gas flow drives rotation of the turbine wheel, and in response to rotating the turbine wheel, electrical current is generated by the electric generator. Generated electrical current is then directed to power electronics.