ICT2014 Abstracts

            Around 40% of the total fuel energy in typical internal combustion engines is rejected to the environment in the form of exhaust gas waste heat. Efficient recovery of this waste heat in automobiles can promise a fuel economy improvement of 5%. The thermal energy can be harvested through thermoelectric generators (TEGs) utilizing the Seebeck effect. Researchers have primarily focused on the use of longitudinal fin based heat exchangers for heat transfer, with thermoelectric modules (TEMs) mounted along the gas flow direction. One drawback to this design is the decreasing temperature and heat flux profile along the flow direction, which leads to poor performance of trailing TEMs located near the TEG outlet. Additionally, this variation in operating conditions complicates system optimization. However, using arrays of hot air jets impinging on TEM surfaces ensures uniform hot side conditions across the TEG design space. The heat transfer to the thermoelectric modules can be improved with high surface heat transfer coefficients and enhancements such as pin fins and flow turbulizers on the target surface.

            In the present work, a conceptual TEG, based on jet impingement, has been analyzed to maximize electric power generation. Various modular configurations have been presented and analyzed using numerical models based on standard correlations. Skutterudite based TEMs designed for high temperature applications have been used for energy conversion. The numerical results have been supported by experiments for a simulated US06 driving cycle. In addition, validated thermal models have been further applied to the optimization of multiple TEG system design variables.