Embodiments of gas-fired appliances which generate sufficient electricity to be self-powered include water heaters, space heaters, air conditioning units, and electric power and steam cogeneration systems. In such apparatus, gas is burned in a porous ceramic surface combustion burner. The high temperature surface of the burner includes a narrow band quantum emitting substance such as a rare earth metal oxide and preferably ytterbium oxide. Relatively shorter wavelength radiation from this quantum emitting surface illuminates photovoltaic cells having an absorption spectrum matched to the emission spectrum of the burner surface for generating sufficient electricity for powering the appliance. An infrared absorbing filter removes relatively longer wavelength radiation which would otherwise heat the photovoltaic cells. The cells are cooled, preferably by a portion of the utility fluid heated by the appliance. This enhances both the thermal efficiency of the appliance and the photovoltaic conversion efficiency of the cells.
CROSS REFERENCE TO RELATED APPLICATIONS AND DISCLOSURE DOCUMENTS
This application is a continuation-in-part of U.S. patent application Ser. No. 864,088 filed May 16, 1986 (now abandoned). It is also a continuation-in-part of U.S. patent application Ser. No. 48,961 filed May 11, 1987, now U.S. Pat. No. 4,793,799, which is a continuation of U.S. patent application Ser. No. 659,074 filed Oct. 5, 1984, (now abandoned) which was a National application corresponding to International Application No. PCT/US84/01038 filed July 3, 1984, which was a continuation-in-part claiming priority of U.S. patent application Ser. No. 517,699 filed July 25, 1983 (now abandoned).
A hybrid power assembly includes a thermophotovoltaic (TPV) power conversion module for converting radiant thermal energy into electrical power, and a battery in electrical communication with the TPV power source and rechargeable by electrical power generated by the TPV power source.
Efficient thermophotovoltaic conversion can be performed using photovoltaic devices with a band gap in the 0.75-1.4 electron volt range, and selective infrared emitters chosen from among the rare earth oxides which are thermally stimulated to emit infrared radiation whose energy very largely corresponds to the aforementioned band gap. It is possible to use thermovoltaic devices operating at relatively high temperatures, up to about 300.degree. C., without seriously impairing the efficiency of energy conversion.
A superemissive combustion device of this invention comprises a porous distributive layer and an apparatus for delivering a fuel/oxidizer mixture to an upstream face of the porous distributive layer. A superemissive advanced emissive matrix in is disposed within an active flame zone downstream from the porous distributive layer. The emissive matrix is in the form of a three dimensional matrix of radiating bodies that is optically thin to electromagnetic radiation. The emissive matrix is either formed from or includes a coating of a superemissive material that is selected to emit photons within a predetermined wavelength range when thermally stimulated. The emitted photons are received by one or more photovoltaic cells disposed adjacent the matrix.
A thermophotovoltaic generator provides a greater power output while maintaining a compact, simplistic structure. The generator includes a burner having adjustable fuel and air flows, an infrared radiation emitter suspended above the flame nozzle of the burner and a cylindrical receiver surrounding the emitter. The emitter is a conical infrared emitter connected to the burner by wires. The emitter is positioned above the burner nozzle such that the emitter is immersed in the generated hydrocarbon flame. The emitter material catalyzes combustion on its surface. Infrared energy radiated by the heated emitter is collected by a cylindrical receiver that completely encircles the emitter. The receiver includes a flexible circuit having an inner surface, an outer surface, opposite ends, top and bottom edges and bending regions. First and second rows of low bandgap cells are connected to the top and bottom edges of the circuit, respectively, away from the bending regions. Copper contact pads are placed on the top cell bonding side of the circuit. A thin, polyimide insulating layer is placed over the outer surface of the circuit and the contact pads, and a thin metal sheet is located under the insulating layer. Heat sinks having aluminum air cooling fins are bonded to the metal sheet. The receiver is rolled into a cylinder, with opposite ends of the circuit connected and with the inner surface of the circuit positioned closest to the emitter. By dramatically increasing the emitter surface area in the flame and by increasing the low bandgap cell packing density of the receiver, greater power outputs are realized.
In a gas-fired stove or oven, gas is burned in a porous ceramic surface combustion burner which generates selective emissive radiation in a narrow band. The high temperature surface of the burner includes a narrow band quantum emitting substance such as rare earth metal oxide. Relatively shorter wavelength radiation from this quantum emitting surface illuminates process targets having an absorption spectrum nearly matched to the emission spectrum of the burner surface, for a variety of applications such as cooking. The selected emission may be passed through a glass top stove to heat a pot with an absorptive bottom or may pass on through a glass pot to heat the food directly.
