Overview: Thermoelectric power conversion is promising for waste heat recovery in a broad variety of transportation and building systems. While this promise has increased over the past 15 years due to research on thermoelectric materials, several problems prevent commercial implementation. The proposed work addresses these problems including i) the lack of interface and packaging materials that yield acceptable system efficiency and system reliability, ii) the need for thermoelectric materials combining optimal thermal, electrical, and mechanical properties at high combustion temperatures, and iii) the absence of detailed impact assessments for consumer systems such as water heaters. Professor Goodson and his students are well-poised to make these developments given a long track record of thermal characterization and modeling research. PEEC funding will supplement and create a critical mass around a lower level of seed funding from Bosch Corporation on thermoelectric waste heat recovery for a commercial water heater system.
Background and Methodology: Thermoelectric power conversion is among the most effective technology for near-term efficiency improvements in building and transportation systems. A thermoelectric generator (TEG) uses waste heat from a combustion process to generate an electrical current and power, thereby improving the overall efficiency of the system. Recent improvements in thermoelectric materials using nanostructuring, i.e., nanopillars and nanospheres, have promised improved efficiency, but these improvements have not been realized due to practical thermal transport problems at interfaces.
The proposed work measures and optimizes the properties of nanostructured thermoelectric materials and their interfaces and provides practical experiments demonstrating improvements in efficiency. Research on determining thermoelectric properties will use nanosecond time-domain thermoreflectance, picosecond pump-probe photothermal reflectance, and cross-sectional IR imaging. The microscale heat transfer laboratory of Prof. Goodson is well-poised to address these problems of TEG technology because of a proven track record of thermal device characterization expertise, and the group is developing a novel carbon nanotube interface material that can improve TEG system integration. Furthermore, the group will leverage collaborations with an interdisciplinary combination of industry and academic groups.