A heat recovery engine (5) including a compressor (15) to increase pressure, density and temperature of a gas stream flowing in a closed loop within the engine, with the gas stream at base system pressure (10) at a compressor inlet; an expander (30) to reduce the pressure of said gas stream when compressed to just above said base system pressure, at the same time receiving power from the gas stream; a recuperator (20) to transfer thermal energy from downstream gas stream of said expander (30) to downstream gas stream of said compressor (15), thereby increasing the temperature of said downstream gas stream of said compressor (15) at approximately constant pressure; a heater (25) to provide further heat energy to said gas stream at approximately constant pressure after exit from said recuperator (20); a heat source (40) and a means (45) for transferring heat energy from said heat source (40) to said heater (25); a cooler (35) to cool said gas stream prior to compression in said compressor; a heat energy transfer device to transfer heat from aid cooler (35) to the environment; an operability device to ensure the operation of said compressor and said expander, and to take off surplus power either mechanically or electrically; a plurality of insulated ducts to transfer said gas stream between said compressor (15), recuperator (20), heater (25), expander (30) and cooler (35).

Systems and methods for variable pressure inventory control of a closed thermodynamic cycle power generation system or energy storage system, such as a reversible Brayton cycle system, with at least a high pressure tank and an intermediate pressure tank are disclosed. Operational parameters of the system such as working fluid pressure, turbine torque, turbine RPM, generator torque, generator RPM, and current, voltage, phase, frequency, and/or quantity of electrical power generated and/or distributed by the generator may be the basis for controlling a quantity of working fluid that circulates through a closed cycle fluid path of the system.

Systems and methods relating to variable pressure turbines are disclosed. A power generation system may include a closed cycle system configured to generate power, a combustor, and a control system. The closed cycle system may include a working fluid circulating in a closed cycle path. The combustor may provide thermal energy to the working fluid. Further, the control system may be configured to determine to increase an amount of power generated by the closed cycle system, and in response to the determination to increase the amount of power generated by the closed cycle system, cause an increase in pressure of the working fluid in the closed cycle path.

Power generation systems are described. The systems include a shaft, a compressor operably coupled to a first end of the shaft, a turbine operably coupled to a second end of the shaft, a generator operably coupled to the shaft between the compressor and the turbine, and a working fluid arranged in a closed-loop flow path that flows through each of the compressor and the turbine to drive rotation of the shaft. The shaft includes an internal fluid conduit configured to receive a portion of the working fluid at one of the first end and the second end and convey the portion of the working fluid through the generator to the other of the first end and the second end, wherein the portion of the working fluid is rejoined with a primary flow path of the working fluid.

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.

Electrical/mechanical power is derived from oxycombustion of hydrocarbons, preferably LNG, in a first of two nested cycles each operating on a Brayton cycle to provide a source of power, without mixing of working fluids between the two cycles. Each cycle employs CO.sub.2 as a working fluid, the first cycle operating under low pressure conditions in which CO.sub.2 is sub-critical, and the other cycle operating under higher pressure conditions in which CO.sub.2 is supercritical. The first cycle serves as a source of heat for the second cycle by gas/gas heat exchange which cools the products of combustion and circulating working fluid in the first cycle and heats working fluid in the second cycle.

Electrical/mechanical power is derived from oxycombustion of hydrocarbons, preferably LNG, in a first of two nested cycles each operating on a Brayton cycle to provide a source of power, without mixing of working fluids between the two cycles. Each cycle employs CO.sub.2 as a working fluid, the first cycle operating under low pressure conditions in which CO.sub.2 is sub-critical, and the other cycle operating under higher pressure conditions in which CO.sub.2 is supercritical. The first cycle serves as a source of heat for the second cycle by gas/gas heat exchange which cools the products of combustion and circulating working fluid in the first cycle and heats working fluid in the second cycle.

A waste heat recovery system, based on a Brayton cycle, comprises a heater configured to circulate carbon dioxide vapor in heat exchange relationship with a hot fluid to heat the carbon dioxide vapor. An expander is coupled to the heater and configured to expand the carbon dioxide vapor. A compressor is configured to compress the carbon dioxide vapor fed through a cooler and a heat exchanger is adapted to circulate the carbon dioxide vapor from the expander to the cooler in heat exchange relationship with the carbon dioxide vapor from the compressor to the heater, wherein the expander and the compressor are mechanically coupled volumetric machines.

In order to improve an expansion installation for obtaining electrical energy from heat by means of a thermodynamic circulation procedure, comprising an expansion device, which is operated by an expanding working medium of the thermodynamic circulation procedure, and a generator driven by the expansion device, it is proposed that the expansion installation should be provided with a rotational speed sensor, which is coupled to a shaft of the expansion installation that rotates proportionally to a rotor of the generator, and which takes the form of an electrical sensor generator that generates an electrical sensor signal.

A system includes a rotary liquid piston compressor configured to exchange pressure between a liquid and a supercritical fluid. The rotary liquid piston compressor includes a rotor configured to exchange pressure between the liquid and the supercritical fluid as the rotor rotates. The rotor defines channels that extend through the rotor. The rotary liquid piston compressor further includes barriers configured to block mixing between the liquid and the supercritical fluid. The barriers rest within the rotor. Each channel of the channels is configured to receive a barrier of the barriers.