Heat Transfer Issues in Thermoelectric Power Generation

_{(funded by ONR MURI, DOE; students: Bob Harris, Kenny Hu, Chien-Shing Lee; faculty: Professor Harold Schock at Michigan State)}

One challenge is extracting energy from waste heat in hot gases such as the exhaust of a car engine because gases do not transfer heat very efficiently. Another challenge is thermal stress when the hot and cold temperature difference across the TE couple is large (300 K or more) over a short distance (< 5 mm).

Contributions made include:

1. Developed an algorithm and code to study the 3-D heat-transfer and electric current generation in thermoelectric (TE) couples that include conducting plates and insulation material.
2. Performed CFD studies to understand free convection and radiation heat transfer in the cavities between TE legs in TE couples.
3. Performed CFD studies to develop compact heat exchangers for waste-heat recovery that can extract up to 50% of the available energy from the hot gas with reasonable pressure loss.

Representative papers in this area are as follows:

• Hogan, T. and Shih, T.I-P., “Modeling and Characterization of Power Generation Modules Based on Bulk Materials,” Thermoelectric Handbook: Macro to Nano-Structured Materials, Editor: M. Rowe, Taylor and Francis Books, 2005.
• Zhu, B., Schock, H.J., Hogan, T., and Shih, T. I-P., “Natural Convection and Radiation Heat Transfer in High-Temperature Thermoelectric Couples,” AIAA Paper 2006-0574, Aerospace Sciences Meeting, Reno, Nevada, January 2006.
• Harris, R., Schock, H.J., and Hogan, T., and Shih, T., “Heat Transfer and Electric Current Flow in a Thermoelectric Couple,” AIAA Paper 2006-0575, Aerospace Sciences Meeting, Reno, Nevada, January 2006.
• Hu, K., Chi, X., Shih, T.I-P., and Schock, H.J., “Heat Transfer Enhancement in Thermoelectric Power Generation,” AIAA 2009-1210, Jan. 2009.