The present disclosure describes heat exchangers for converting thermal energy stored in solid particles to electricity. Electro-thermal energy storage converts off-peak electricity into heat for thermal energy storage, which may be converted back to electricity, for example during peak-hour power generation. The heat exchanger for converting thermal energy stored in solid particles to electricity enables the conversion of thermal energy into electrical energy for redistribution to the grid. In some embodiments, pressurized fluidized-bed heat exchangers may achieve efficient conversion of thermal energy to electricity by providing direct contact of the solid particles with a gas stream.

The present disclosure describes heat exchangers for converting thermal energy stored in solid particles to electricity. Electro-thermal energy storage converts off-peak electricity into heat for thermal energy storage, which may be converted back to electricity, for example during peak-hour power generation. The heat exchanger for converting thermal energy stored in solid particles to electricity enables the conversion of thermal energy into electrical energy for redistribution to the grid. In some embodiments, pressurized fluidized-bed heat exchangers may achieve efficient conversion of thermal energy to electricity by providing direct contact of the solid particles with a gas stream.

Methods and systems are provided for a Brayton cycle system. In one example, a system for an air Brayton cycle includes a chamber that can receive a first energy source and a second energy source, a turbocharger, and a motor/generator coupled to a shaft of the turbocharger between a compressor and a turbine.

A compact axial turbine configured to operate with high density working fluid is described. The turbine comprises an axial majority cantilevered turbomachinery shaft. Rotor assemblies and nozzle spacers communicate torque through turbine shaft splines, allowing them to be slid off the shaft for quick replacement in the field. The compact axial turbine houses turbomachinery within a separable inner casing encircled by a cartridge sleeve, thereby forming a cartridge which can itself be removed as a single component.

A powerplant is provided for an aircraft. This powerplant includes an engine and an energy recovery system. The engine includes an engine combustor, an engine turbine, a flowpath and a fluid delivery system. The flowpath extends out of the engine combustor and through the engine turbine. The fluid delivery system is configured to provide fluid hydrogen and fluid oxygen for combustion within the engine combustor to produce combustion products within the flowpath. The energy recovery system includes an energy recovery system condenser, an energy recovery system pump, an energy recovery system evaporator and an energy recovery system turbine. The energy recovery system pump is configured to pump liquid water from the energy recovery system condenser to the energy recovery system evaporator. The energy recovery system evaporator is configured to transfer heat from the combustion products into the liquid water to evaporate at least some of the liquid water into water vapor to drive the energy recovery system turbine.

In a main flow passage, a first heat exchanger, a first heat storage unit, a second heat exchanger, and a second heat storage unit are connected by a heating medium flow passage. The main flow passage allows a heating medium to be circulated. A sub flow passage includes a shortened flow passage which is a part of the heating medium flow passage and branches from the heating medium flow passage between the second heat exchanger and the second heat storage unit and extends to the first heat storage unit. The sub flow passage allows circulation of the heating medium between the first heat storage unit and the second heat exchanger. A first heating means in a middle of the shortened flow passage, the first heating means heating a passing heat medium, and a switching means conducting switching between the main flow passage and the sub flow passage are provided.

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.

Efficient energy storage is provided by using a working fluid flowing in a closed cycle including a ganged compressor and turbine, and capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. This system can operate as a heat engine by transferring heat from the hot side to the cold side to mechanically drive the turbine. The system can also operate as a refrigerator by mechanically driving the compressor to transfer heat from the cold side to the hot side. Heat exchange between the working fluid of the system and the heat storage fluids occurs in counter-flow heat exchangers. In a preferred approach, molten salt is the hot side heat storage fluid and water is the cold side heat storage fluid.

Efficient energy storage is provided by using a working fluid flowing in a closed cycle including a ganged compressor and turbine, and capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. This system can operate as a heat engine by transferring heat from the hot side to the cold side to mechanically drive the turbine. The system can also operate as a refrigerator by mechanically driving the compressor to transfer heat from the cold side to the hot side. Heat exchange between the working fluid of the system and the heat storage fluids occurs in counter-flow heat exchangers. In a preferred approach, molten salt is the hot side heat storage fluid and water is the cold side heat storage fluid.

The invention relates to a method for storing energy and for dispensing energy into an energy supply grid by means of a pressurized gas storage power plant, which has at least one first storage chamber and at least one second storage chamber separate from the first, wherein in order to store energy pressurized gas is taken from the lower-pressure storage chamber, is compressed by means of a compression machine and the compressed pressurized gas exiting the compression machine is routed into the other storage chamber; in order to dispense energy pressurized gas is taken from the higher-pressure storage chamber, is routed through an expansion machine and the expanded pressurized gas exiting the expansion machine is transferred into the other storage chamber, wherein the expansion machine dispenses energy to the energy supply grid, wherein the pressurized gas is heated by means of a heating device prior to or upon supply to the expansion machine. The invention also relates to a corresponding pressurized gas storage power plant and to a computer program for carrying out the method.