High Temperature Thermoelectric Auxiliary Power Unit for Automotive Applications

While the thermoelectric effects have been known for over 100 years, their traditionally low conversion efficiency for power generation has limited their use to highly specialized applications. With the rapid advancement of thermoelectric materials in recent years, their inherent reliability and power density is being augmented by improvements in efficiency. Recent increases in the figure of merit of materials suitable for operation around 500 °C make them candidates for waste heat recovery, as well as primary power using combustion heaters. The characteristic scalability of thermoelectric generators makes them best suited for low power applications where alternative generators become impractical. However, with the development of thermoelectric device technology in parallel with materials advancements, it may become viable to design thermoelectric generators for auxiliary power in automotive applications. The research presented here represents the initial stages of the development of a thermoelectric power unit (TEPU). While thermoelectric generator technology can be applied to any fuel, this research targets the use of diesel fuel which is readily available for both military and consumer applications and is more easily and safely transported than many alternatives. The use of diesel fuel for a TEPU is enabled by the use of an atomizer technology developed at The Ohio State University Center for Automotive Research. A baseline prototype incorporating this novel diesel fuel atomizer/combustor with conventional thermoelectric materials and heat exchange designs has been constructed and tested. Preliminary data highlights the viability of diesel fuel for thermoelectric power generation as well as the areas which demand further development. This prototype will serve as the baseline for evaluating future designs incorporating advanced materials and novel system designs.