Thermophotovoltaics for space power applications

Thermophotovoltaic (TPV) energy conversion has long been considered a potential replacement for thermoelectrics in radioisotope powered deep space power systems. In this application, TPV offers significant potential improvements in both efficiency and mass specific power (W/kg), performance which is considered mission enabling for a variety of mission concepts. TPV systems powered by concentrated solar energy have also been proposed for inner planetary solar system missions. This concept takes advantage of TPV's ability to store energy for shadow periods in the form of heat energy rather than as electrical energy (batteries), as is commonly done for photovoltaic power systems. The simplicity and large number of power cycles offered by the thermal energy storage offers potential system benefits compared to a photovoltaic / battery system. Recent efforts in the development of radioisotope TPV (RTPV) at Creare have resulted in the demonstration of converter efficiencies in excess of 19%. Several independent system mass analyses have been performed for the Creare RTPV system and they predict specific powers above 10W/kg at the system level. Trades have suggested increasing the rejection temperature can result in a 50% reduction in radiator area while only suffering a 15% reduction in mass specific power.