Compact DC electric power generator using low bandgap thermophotovoltaic cell strings with a hydrocarbon gas burner fitted with a regenerator

A thermophotovoltaic generator having a linear burner-emitter-regenerator comprising a lower burner-emitter section and an upper regenerator section, wherein the burner-emitter section comprises an outer emitter tube and a coaxial inner burner tube having a smaller diameter than the outer tube, the inner tube having a closed top end and an open bottom end for fuel supply, the burner tube having an array of fuel discharge ports for producing flame jets, the ports being arranged along the length of the burner tube in a pattern for providing a tailored temperature profile along a length of the emitter tube for providing a uniform infrared energy output along the length of the emitter tube, wherein combustion air and fuel velocities are sufficiently low to avoid flame-outs, and wherein the flame jet ports are sufficiently small, and operating temperatures of the burner tube are sufficiently low, and volume of primary air supplied with the fuel is sufficiently low to avoid flame flashback into the burner tube.

A thermophotovoltaic generator having a linear burner-emitter-regenerator comprising a lower burner-emitter section and an upper regenerator section, wherein the burner-emitter section comprises an outer emitter tube and a coaxial inner burner tube having a smaller diameter than the outer tube, the inner tube having a closed top end and an open bottom end for fuel supply, the burner tube having an array of fuel discharge ports for producing flame jets, the ports being arranged along the length of the burner tube in a pattern for providing a tailored temperature profile along a length of the emitter tube for providing a uniform infrared energy output along the length of the emitter rube, wherein combustion air and fuel velocities are sufficiently low to avoid flame-outs, and wherein the flame jet ports are sufficiently small, and operating temperatures of the burner tube are sufficiently low, and volume of primary air supplied with the fuel is sufficiently low to avoid flame flashback into the burner tube, wherein the emitter tube comprises a silicon carbide tube having a wall thickness for providing heat conduction both circumferentially and axially and for avoiding local temperature spikes otherwise resulting from impingement of individual jets of flame.

A thermophotovoltaic generator having a linear burner-emitter-regenerator comprising a lower burner-emitter section and an upper regenerator section, wherein the burner-emitter section comprises an outer emitter tube and a coaxial inner burner tube having a smaller diameter than the outer tube, the inner tube having a closed top end and an open bottom end for fuel supply, the burner tube having an array of fuel discharge ports for producing flame jets, the ports being arranged along the length of the burner tube in a pattern for providing a tailored temperature profile along a length of the emitter tube for providing a uniform infrared energy output along the length of the emitter tube, wherein combustion air and fuel velocities are sufficiently low to avoid flame-outs, and wherein the flame jet ports are sufficiently small, and operating temperatures of the burner tube are sufficiently low, and volume of primary air supplied with the fuel is sufficiently low to avoid flame flashback into the burner tube, further comprising axial grooves on a surface of the emitter tube for increasing emissivity and for partially columnating infrared energy from the emitter tube for directing rays of infrared energy predominantly in a radial direction rather than isotropically.

A thermophotovoltaic generator having a linear mounted series-parallel connected photovoltaic cell string assembly comprising a heat sink having first and second opposite surfaces, a plurality of strings of photovoltaic cells responsive in the infrared region to wave lengths at least as long as 1.7 .mu.m wherein the cells are mounted on the first surface of the heat sink and wherein the second surface of the heat sink has plural fins for cooling of said cells, further comprising an infrared energy emitter for radiating energy to the cells, a multipane window mounted in front of the cells between the emitter and the cells for reducing heat transfer by thermal convection of hot air from the emitter, said window having a coating for reflecting infrared energy with wavelengths longer than 2 .mu.m and for transmitting shorter useful wavelengths.

A thermophotovoltaic generator comprising a central coaxial burner and an emitter surrounding the burner, plural linear parallel thermophotovoltaic cell strings partially surrounding and facing the burner for converting infrared energy received from the burner to DC electric power, a hydrocarbon fuel and air mixture source connected to the burner, a regenerator connected to the burner for increasing the temperature of the flame from the burner, for increasing efficiency of utilization of energy from the fuel, for increasing the amount of infrared energy radiated from the emitter to the photovoltaic cells, for increasing output of the cells and for reducing cost per watt of cell electrical output, further comprising reflector panels partially surrounding the emitter except for the spaces occupied by the thermophotovoltaic cell strings for directing the infrared energy emanating radially from the burner-emitter and concentrating the energy on the cell strings and for providing uniform infrared energy along a length of each photovoltaic cell string.