SBIR-STTR Award

Thermophotovoltaic (TPV) electrical generation is a technology well-suited to the development of highly efficient, compact, lightweight, and reliable sources of electricity. Tn TPV electrical generation, heat generated by combustion is converted to radiant energy by an emitting surface, then to electrical energy by a photovoltaic (PV) cell. The bandgap of the PV cell is tailored to convert the bulk of the infrared (IR) spectrum being emitted. Making the spectrum more monochromatic leads to higher electrical conversion efficiencies; therefore, filteringelements are placed between the emitter and cells to reflect out-of-band radiation back to the combustor for recycling. Theoretically, TPVelectrical generation can exceed 35%. Importantly. TPV generators are totally static; with no moving parts they produce no noise or vibration and can be highly reliable. Essential Research, Inc., teaming with Teledyne Brown Engineering-Energy Systems, propose to develop a rugged TPV power supply to meet the operational requirements requested inthe Army SBIR solicitation: person-portable, 200 W output power, andutilizing liquid, logistic fuels. Our technical approach is to develop a combustor that heats a graybody SiC emitter to moderate temperature (1500 K) . The IR radiation is tailored with a shortpass filter that reflects the near out-of-band radiation back to the combustor for recycling. The in-band radiation is converted to electricity with narrow-bandgap PV cells made from InGaAs deposited on InP.

Benefits:
We plan to prototype a 200 w, man-portable battery charger at the end of Phase II. The unit will be capable of generating electricity from burning tactical, liquid military fuels. The unit will have use in the military as a reliable, silent battery charger and remote power generator. Commercial applications include recreational boating and camping, and off-grid power generation.

Thermophotovoltaic (TPV) electrical generation is a technology well-suited to the development of a highly efficient, compact, lightweight, and reliable source of electricity. In TPV electrical generation, heat generated by combustion is converted to radiant energy by an emitting surface, then to electrical energy by a photvoltaic (PV) cell. The bandgap of the PV cell is tailored to convert the bulk of the near infrared (IR) spectrum being emitted. Theoretically, TPV electrical generation can exceed 30% efficiency. Importantly, TPV generators are totally static; with no moving parts they produce no noise or vibration and can be highly reliable. The company, teaming with Teledyne Brown Engineering - Energy Systems, proposes to develop a rugged TPV power supply to meet the operational requirements requested in the Army SBIR solicitation: person-portable, 200 We output power, and utilizing liquid, logistic fuels. Our technical approach is to develop a combuster that heats a graybody SiC emitter to moderate temperature (1500 degrees K). The in-band radiation emitted by the SiC emitter is converted to electricity with narrow-bandgap PV cells made from InGaAs deposited on InP. The out-of-band IR radiation is reflected back to the emitter for recycling via a back surface reflector (BSR) deposited on the back side of the PV cells. Efficient out-of-band radiation recycling via a BSR is only possible through the use of a novel InGaAs/InP cell design, pioneered at the company and NASA Glenn, called the monolithic integrated module (MIM). The use of MIMs, in place of conventional planar cells, virtually eliminates the need to use separate front surface reflecting elements.

Keywords:
Thermophotovoltaics Electric Generators Monolithic Integrated Modules Thermophotovoltaics Electr