Progress Report on BSST-Led US Department of Energy Automotive Waste Heat Recovery Program

As global consumption of energy continues to increase at an exponential rate, the need to find technologies that can help reduce this rate of consumption, particularly in passenger vehicles, is imperative. This paper provides a progress report on the BSST-led US Department of Energy-sponsored automotive thermoelectric waste heat recovery project, which has transitioned from phase 3 and is completing phase 4. Thermoelectric generator (TEG) development will be discussed, including modeling and thermal cycling of subassemblies. The design includes the division of the TEG into different temperature zones, where the subassembly materials and aspect ratios are optimized to match the temperature gradients for the particular zone. Test results for a phase 3 quarter-scale device of the phase 4 high-temperature TEG will be discussed, where power outputs of up to 125 W were achieved on a 600°C hot-air test bench. The design of the TEG, which uses high-power-density segmented thermoelectric elements, has evolved from a planar design in phase 3 to a cylindrical design in phase 4. The culmination of phase 4 includes testing of the generator on a dynamometer at the National Renewable Energy Laboratory with a high-performance production engine.