A combined cycle power generation system for an aircraft includes fuel cell and supercritical CO.sub.2 cycles. The fuel cell cycle includes a compressor and turbine disposed on a first shaft, a fuel cell in fluid communication with the compressor and a fuel source, and a combustor in fluid communication with the fuel cell and the turbine. The combustor is configured to combust partially spent fuel from the fuel cell and produce combustion exhaust gas for delivery to the turbine. The supercritical CO.sub.2 cycle includes a compressor and turbine disposed on a second shaft, a supercritical CO.sub.2 fluid circuit in thermal communication with the combustor and configured to deliver CO.sub.2 to the turbine and compressor, and a heat exchanger in thermal communication with the supercritical CO.sub.2 fluid circuit and a source of cooling fluid. A mechanical linkage is configured to transfer power from the second shaft to the first shaft.

An aircraft system includes a turbine engine having a compressor, a combustor having an inlet and an outlet, and a turbine having an inlet portion and an outlet portion. An auxiliary power unit (APU) is operatively connected to the turbine engine. The APU includes a compressor portion, a generator, and a turbine portion. The compressor portion is operatively connected to the turbine portion through the generator. A source of cryogenic fluid is operatively connected to the turbine engine and the APU. A heat exchange member includes an inlet section operatively connected to the source of cryogenic fluid, a first outlet section operatively connected to the turbine engine and a second outlet section operatively connected to the compressor portion.

Power and cooling systems including a drive system, a power generation unit, and a cooled fluid generation unit. A primary working fluid that is expanded within a turbine of the drive system and compressed within compressors in a closed-loop cycle. The power generation unit includes a generator and a heat source configured to heat the primary working fluid prior to injection into the turbine. T cooled fluid generation unit includes an ejector downstream of the compressors and a separator arranged downstream of the ejector and configured to separate liquid and gaseous portions of the primary working fluid. The gaseous portion is directed to the compressors and the liquid portion is directed to an evaporator heat exchanger to generate cooled fluid.

Control systems and methods suitable for combination with power production systems and methods are provided herein. The control systems and methods may be used with, for example, closed power cycles as well as semi-closed power cycles. The combined control systems and methods and power production systems and methods can provide dynamic control of the power production systems and methods that can be carried out automatically based upon inputs received by controllers and outputs from the controllers to one or more components of the power production systems.

A system includes a first working fluid compressor configured to pressurize a working fluid, and a prime mover coupled to the first working fluid compressor and configured to provide a mechanical input into the first working fluid compressor. An exhaust assembly is coupled to the prime mover and is configured to receive exhaust heat from the prime mover, the exhaust assembly including a generator configured to generate electric current based on the exhaust heat received by the exhaust assembly. A second working fluid compressor includes an electric motor electrically and synchronously coupled to the generator and configured to pressurize the working fluid.

A CO2 bottoming cycle system includes a first compressor operatively connected to a first turbine through a first shaft. A first generator is operatively connected to the first shaft. A second compressor is fluidically connected to the first compressor. The second compressor is operatively connected to a second turbine through a second shaft. A second generator is operatively connected to the second shaft. The first turbine is fluidically connected to the second turbine.

An improved steam engine is provided for operating on a recirculation of superheated air and steam. A gas turbine is including having a first intake, a first discharge and a power output shaft, said power output shaft providing rotation power output generated from a change in entropy of the gas through the turbine. A power turbine superheats the gas discharge and includes a turbocharger in operational communication with an electric DC motor, and a compressor mechanically driven by the turbocharger. The discharge from the compressor forms the turbine steam intake. A water injection system may be further provided for adding steam to the air recirculating circuit. A drive motor operatively coupled to the turbine may be used for startup to bring the turbine up to operational rotation speeds. A DC generator operatively coupled to recharge a battery driving the drive motor or for providing electrical power output.

An improved steam engine is provided for operating on a recirculation of superheated air and steam. A gas turbine is including having a first intake, a first discharge and a power output shaft, said power output shaft providing rotation power output generated from a change in entropy of the gas through the turbine. A power turbine superheats the gas discharge and includes a turbocharger in operational communication with an electric DC motor, and a compressor mechanically driven by the turbocharger. The discharge from the compressor forms the turbine steam intake. A water injection system may be further provided for adding steam to the air recirculating circuit. A drive motor operatively coupled to the turbine may be used for startup to bring the turbine up to operational rotation speeds. A DC generator operatively coupled to recharge a battery driving the drive motor or for providing electrical power output.

An integrated hermetically sealed turboexpander-generator comprises a hermetically sealed casing arrangement, a turboexpander, a compressor and an electric generator, arranged in the hermetically sealed casing arrangement along a common shaft line, supported by active magnetic bearings. Also disclosed is a thermodynamic system using the integrated hermetically sealed turboexpander-generator to convert waste heat from a waste heat source into electric power. One of the turboexpander and of the compressor comprises two sections arranged in an overhung configuration at the ends of the common shaft line.

A thermodynamic apparatus (10) comprising a compressor module (100), a turbine module (200), and a regenerative heat exchanger (300) centred on a central axis (12). The compressor module (100), turbine module (200) and regenerative heat exchanger (300) are arranged in series along the central axis (12) such that the regenerative heat exchanger (300) is provided between the compressor module (100) and the turbine module (200).