ICT2014 Abstracts

Thermoelectric generator (TEG) is a promising technology for automotive waste heat recovery. Directly converting waste heat to electricity reduces the load on the vehicles engine by powering various vehicle components that would otherwise rely on the alternator. TEGs, due to their solid-state and compact nature, are well suited for application in automotive vehicles. In this work, we designed and fabricated a high-temperature TEG using our nanostructured bulk Half-Heusler (HH) thermoelectric materials of significantly enhanced figure of merit. Nanostructured HH materials offer a low-cost, high-performance, and reliable option for TE power generation. A thermoelectric module of unique device-packaging architecture is at the core of our TEG, with 10% heat-to-electricity conversion efficiency at temperature difference of 500 ^oC. To optimize the TEG and maximize fuel efficiency improvement, a multi-physics model was developed to simulate the heat exchanger and thermoelectric devices. Using this model, we were able to optimize the TEG design to maximize thermal and thermoelectric efficiency, and to minimize exhaust pressure drop and thermal stress. A small-displacement engine of approximately 2.0 liters serves as the platform for the TEG integration. Our initial thermoelectric generator prototype shows a power output of over 150 W with the given exhaust temperature and mass flow rate of our platform vehicle. The average temperature difference across the TE modules was 350 ^oC, the average pressure drop across the heat exchanger was 1.8 KPa. Prototype testing results are in line with those predicted using our multi-physics model. Our future work will involve collaborations with automotive industry partners for vehicle integration and testing. Further integration into vehicles can ultimately lead to a commercial path of increased fuel efficiency using robust and cost effective thermoelectric generation devices.