Electrical Power from Thermal Energy Scavenging in High Temperature Environments

Physical Sciences Inc. and Purdue University propose to develop a novel approach to scavenging heat from high intensity thermal environments encountered during space missions and converting this thermal power to electrical power at high efficiency. Examples include extremely hot heat shields during vehicle entry into planetary atmospheres (Mars/Venus probes) and during high speed ascent through planetary atmospheres (Sample return from Mars/Venus), hot claddings of radioisotope thermoelectric generators used for powering outer planetary spacecraft and multi-decade planetary bases (Mars/Venus/Lunar), as well as combustors/nozzles of space and launch propulsion systems, specifically, nuclear propulsion systems of renewed interest. The technology is also applicable commercially to high temperature sources encountered in terrestrial systems, such as portable electrical power converters from machinery (engines, stoves) used by soldiers and civilians in outdoor environments, In this STTR we will develop an integrated metal hydride (MH) system and spectrally-tuned thermophotovoltaic power converter (PC) system that can extract heat during periods of high thermal intensity and convert it to electricity at greater than 25 percent efficiency. The MH system provides the high temperature reservoir needed for PC operation.In Phase I, for the PC system, we demonstrated feasibility of fabricating a critical emitter component in larger areas (5 cm x 5 cm), and for the metal hydride (MH) system, we experimentally characterized the MH decomposition reactions. In Phase II, we will produce and functionally characterize an integrated engineering prototype of the MH-PC heat scavenging electrical power generator system, fully tested in the laboratory and in simulated thermal-vacuum environments, together with an analytical model of the functional system. We will identify candidate facilities (e.g., NASA/Stennis) for field testing of the system in Phase III.