Thermo-photovoltaic power generator for efficiently converting thermal energy into electric energy

摘要

A thermo-photovoltaic power generator for efficiently converting thermal energy into electric energy including a selective thermal emitter for receiving thermal energy and emitting thermal radiation with black body emissivity over a range of wavelengths, low-bandgap photovoltaic cells responsive to thermal radiation at wavelengths within a particular band of said range of wavelengths and operative to convert such thermal radiation to electric energy, and a band pass filter disposed between the thermal emitter and the photovoltaic cells for transmitting thermal radiation from the emitter at wavelengths within the particular band to the photovoltaic cells, and for reflecting thermal radiation from the emitter at wavelengths outside the particular band back to the emitter.

主权项

1. A device for generating electric energy, comprising:
a heat source for generating heat energy; a thermal emitter operative to receive said heat energy and to emit thermal radiation with black body emissivity; a housing forming a reflective cavity enclosing said heat source and said thermal emitter, and having a transparent window through which thermal radiation emitted by said thermal emitter is passed; photovoltaic cell means located outside said reflective cavity and positioned to receive thermal radiation passing through said transparent window, said cell means being operative to convert thermal radiation within a particular wavelength range into electric energy; and a band pass filter disposed outside of said reflective cavity and between said window and said photovoltaic cell means, said band pass filter having a first cutoff wavelength on one side of said particular wavelength range converted into electricity by said photovoltaic cell means, and a second cutoff wavelength on the opposite side of said particular wavelength range converted into electricity by said photovoltaic cell means, said band pass filter including,
a non-resonant sub-wavelength aperture array consisting of a layer of metallic material forming a reflective thin film disposed between said window and said cell means, and having a film thickness greater than 30 nm and a plurality of transparent openings formed therein, the size and shape of said openings being selected to transmit thermal radiation having wavelengths shorter than said first cutoff wavelength, said reflective thin film being operative to reflect radiation having wavelengths longer than said first cutoff wavelength back to said emitter through said window, anda dichroic cold mirror interposed between said window and said reflective thin film, said dichroic cold mirror being operative to transmit thermal radiation having wavelengths longer than said second cutoff wavelength and to reflect radiation having wavelengths shorter than said second cutoff wavelength back to said emitter through said window, whereby radiation from said thermal emitter having wavelengths within the pass band of said band pass filter is transmitted to said photovoltaic cell means for conversion into electric energy, and thermal radiation having wavelengths outside said pass band is reflected back to said thermal emitter to be re-absorbed thereby to enhance the conversion efficiency of the device.