A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.

A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.

A vaporizer for heating a liquid phase fuel, the vaporizer comprising a reservoir having a least one wall for containing a liquid and a heat-conducting fluid within the reservoir. A heating core extending into the reservoir such that the heating core is in fluid contact with the heat-conducting fluid and the heating core has an inlet through which the liquid phase fuel will flow and an outlet through which the vaporized liquid phase fuel will flow. A heating passage having at least one open end extending at least partially within the reservoir such that at least a portion of an exterior surface of the heating passage is in fluid contact with the heat-conducting fluid. A heat source communicating with the open end of the heating passage to heat the heating passage, which in turn heats the heat conducting fluid and the liquid phase fuel within the heating core to vaporize the liquid phase fuel.

A vaporizer for heating a liquid phase fuel, the vaporizer comprising a reservoir having a least one wall for containing a liquid and a heat-conducting fluid within the reservoir. A heating core extending into the reservoir such that the heating core is in fluid contact with the heat-conducting fluid and the heating core has an inlet through which the liquid phase fuel will flow and an outlet through which the vaporized liquid phase fuel will flow. A heating passage having at least one open end extending at least partially within the reservoir such that at least a portion of an exterior surface of the heating passage is in fluid contact with the heat-conducting fluid. A heat source communicating with the open end of the heating passage to heat the heating passage, which in turn heats the heat conducting fluid and the liquid phase fuel within the heating core to vaporize the liquid phase fuel.

The present invention relates to a hybrid domestic fireplace, configured to burn a fuel mixture of a first combustible fuel and a second combustible fuel, comprising a combustible long chain hydrocarbon fuel, the fireplace comprising: a mixing device, configured to mix the first fuel and the second fuel to form the fuel mixture and, a first fuel supply, configured to supply the first fuel to the mixing device, a second fuel supply, configured to supply the second fuel to the mixing device, and a burner, configured to combust the fuel mixture, wherein the mixing device is further configured to heat the second fuel to a mixing temperature, and wherein the mixing device is configured to mix the first fuel with the heated second fuel to form the fuel mixture.

The present invention relates to a hybrid domestic fireplace, configured to burn a fuel mixture of a first combustible fuel and a second combustible fuel, comprising a combustible long chain hydrocarbon fuel, the fireplace comprising: a mixing device, configured to mix the first fuel and the second fuel to form the fuel mixture and, a first fuel supply, configured to supply the first fuel to the mixing device, a second fuel supply, configured to supply the second fuel to the mixing device, and a burner, configured to combust the fuel mixture, wherein the mixing device is further configured to heat the second fuel to a mixing temperature, and wherein the mixing device is configured to mix the first fuel with the heated second fuel to form the fuel mixture.

A monolithic heat exchanger body for inputting heat to a closed-cycle engine includes heating walls and heat sink, such as heat transfer regions. The heating walls are configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis of an inlet plenum. Adjacent portions of the heating walls respectively define corresponding heating fluid pathways fluidly communicating with the inlet plenum. At least a portion of the heat sink is disposed about at least a portion of the monolithic heat exchanger body. The heat sink includes working-fluid bodies including working-fluid pathways that have a heat transfer relationship with the heating fluid pathways. Respective ones of the heat transfer regions have a heat transfer relationship with a corresponding semiannular portion of the heating fluid pathways. Respective ones of the heat transfer regions include working-fluid pathways fluidly communicating between a heat input region and a heat extraction region.

A constant density heat exchanger and method of operating are provided. The constant density heat exchanger includes a housing extending between a first end and a second end and defining a chamber having an inlet and an outlet. A first plate is positioned at the first end of the housing and rotatable about an axis of rotation such that the first plate selectively allows a working fluid to flow into the inlet of the chamber. A second plate is positioned at the second end of the housing and rotatable about the axis of rotation such that the second plate selectively allows the working fluid to flow out of the outlet of the chamber. The first plate and the second plate are rotatable about the axis of rotation so as to hold a volume of the working fluid at constant density as a heat source imparts thermal energy thereto.

An example system can include a combustion chamber of a power-generation gas turbine, a radio-frequency power source, a direct-current power source, a resonator, and a fuel conduit. The resonator can be electromagnetically coupled to the radio-frequency power source and have a resonant wavelength. Further, the resonator can include (i) a first conductor, (ii), a second conductor, and (iii) a dielectric between the first conductor and the second conductor. The resonator can be configured to provide at least one of a plasma corona or electromagnetic waves. The fuel conduit can be configured to couple to a fuel source and have a fuel outlet for expelling fuel into a combustion zone of the combustion chamber. A portion of the fuel conduit is disposed within the first conductor.

A method of operating a gas turbine engine, the engine including an engine core with a turbine, a compressor, a combustor arranged to combust a fuel, and a core shaft connecting the turbine to the compressor; a fan upstream of the engine core; a fan shaft; a main gearbox that receives an input from the core shaft and outputs drive to the fan via the fan shaft; a primary oil loop system to supply oil to lubricate the main gearbox; and a heat exchange system to transfer heat between the oil and the fuel, the oil having an average temperature of at least 180? C. on entry to the heat exchange system at cruise conditions. The method includes transferring heat from the oil to the fuel to lower the fuel viscosity to a value of less than or equal to 0.58 mm.sup.2/s on entry to the combustor at cruise conditions.