Enhancing Thermal, Electrical Efficiencies of a Miniature Combustion-Driven Thermophotovoltaic System

Methods to enhance the thermal and electrical efficiencies through novel design of combustion and thermal management of the combustor in a miniature thermophotovoltaic (TPV) system are proposed, discussed, and demonstrated in this paper. The miniature TPV system consists of a swirling combustor surrounded by GaSb PV cell arrays. The swirl combustor design, along with a heat-regeneration reverse tube and mixing-enhancing porous-medium fuel injection, improves the low illumination and incomplete combustion problems associated with typical miniature TPV systems. A reverse tube is used to enforce swirling flame attachment to the inner wall of the emitter by pushing the swirl recirculation zone back into the chamber and simultaneously redirecting the hot product gas for reheating the outer surface of the emitter. The porous medium fuel injector is used as a fuel/air mixing enhancer and as a flame stabilizer to anchor the flame. The miniature TPV system, using different combustor configurations, is tested and discussed. Results indicate that the proposed swirling combustor with a reverse tube and porous medium can improve the intensity and uniformity of the emitter illumination, and can increase the thermal radiant efficiency. Consequently, the overall thermal efficiency and electrical output of the miniature TPV system are greatly enhanced. Copyright (C) 2009 John Wiley & Sons, Ltd.