A turbo generator rotor assembly is provided and includes a generator, first and second bearings on a compressor-side and a turbine-side of the generator and a combination seal configuration in which leakage from the compressor cools the first bearing, the generator and the second bearing. The combination seal configuration leads to minimal leakage past the turbine with the generator and the first and second bearings being cooled with leakage flow from the compressor.

A facility for generating mechanical energy by means of a combined power cycle is disclosed herein, which includes at least means for carrying out a closed or semi-closed, constituent regenerative Brayton cycle, which uses water as a heat-transfer fluid, means for carrying out at least one Rankine cycle, a constituent fundamental Rankine cycle, interconnected with the regenerative Brayton cycle, and a heat pump (UAX) including a closed circuit that regenerates the constituent regenerative Brayton cycle, as well as to the method for generating energy using the facility.

A facility for generating mechanical energy by means of a combined power cycle is disclosed herein, which includes at least means for carrying out a closed or semi-closed, constituent regenerative Brayton cycle, which uses water as a heat-transfer fluid, means for carrying out at least one Rankine cycle, a constituent fundamental Rankine cycle, interconnected with the regenerative Brayton cycle, and a heat pump (UAX) including a closed circuit that regenerates the constituent regenerative Brayton cycle, as well as to the method for generating energy using the facility.

A system for repowering a coal fired electrical generation plant with natural gas is disclosed. The plant has having high and low pressure steam turbines that drives an electrical generator. The coal fired plant has a regenerative system comprising a plurality of feedwater heaters that supply heated feedwater to evaporators and superheaters that supply steam to the turbines. The repowering system has a gas turbine that drives a second electrical generator where the HRSG is configured to receive the exhaust from the gas turbine and which is heated by a burner so as to generate steam for driving the steam turbines. The feedwater heaters utilize condensate from the said and from steam extractions to supply heated feedwater to the superheaters that feed superheated steam to turbines such that the first generator driven by the turbines is driven at a high percentage of its rated megawatt output.

A system for repowering a coal fired electrical generation plant with natural gas is disclosed. The plant has having high and low pressure steam turbines that drives an electrical generator. The coal fired plant has a regenerative system comprising a plurality of feedwater heaters that supply heated feedwater to evaporators and superheaters that supply steam to the turbines. The repowering system has a gas turbine that drives a second electrical generator where the HRSG is configured to receive the exhaust from the gas turbine and which is heated by a burner so as to generate steam for driving the steam turbines. The feedwater heaters utilize condensate from the said and from steam extractions to supply heated feedwater to the superheaters that feed superheated steam to turbines such that the first generator driven by the turbines is driven at a high percentage of its rated megawatt output.

A heat exchanger includes a shell housing a plurality of tubes and defining an exhaust fluid flow path within a first volume enclosed by the shell. The outer surfaces of the plurality of tubes are in fluid communication with the exhaust fluid flow path. The heat exchanger includes a cap attached to a first end of the shell and defining a second volume. A header is configured to separate the first volume from the second volume, flex with thermal expansion, and define tube inlet and outlet positions. The tube inlets and outlets are in fluid communication with a source fluid flow path, and each tube is substantially U-shaped and defines a flow path of the source fluid within the exhaust fluid flow path. The heat exchanger includes at least one longitudinal flow baffle within the shell configured to reduce an amount of exhaust fluid that may bypass the tubes.

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 system includes a power cycle and a cooling cycle. The power cycle includes a first compressor, a recuperative heat exchanger, a waste-heat heat exchanger, and a turbine. The turbine includes a drive shaft coupled to the first compressor. The working fluid from the waste-heat heat exchanger drives the turbine, the drive shaft, and the first compressor. The recuperative heat exchanger cools the working fluid from the turbine, and at least one ram-air heat exchanger further cools the working fluid from the recuperative heat exchanger. The first compressor is configured to pressurize the working fluid from the at least one ram-air heat exchanger. The cooling cycle includes a pump, an isenthalpic valve, an ambient air heat exchanger, and a second compressor. The cooling cycle cools the working fluid and ambient air and is connected to the power cycle in the at least one ram-air heat exchanger.

Supercritical fluid systems and aircraft power systems are described. The systems include a compressor, a turbine operably coupled to the compressor, a generator operably coupled to the turbine and configured to generate power, a primary working fluid flow path having a primary working fluid configured to pass through the compressor, a separator, the turbine, and back to the compressor, and a secondary working fluid flow path passing through the generator, the compressor, the separator, and back to the generator. The primary working fluid is supercritical carbon dioxide (sCO.sub.2) and the secondary working fluid is a fluid having at least one of a density less than the primary working fluid and a molecular size smaller than the primary working fluid.