Published June 2015 | public
Journal Article

Unileg Thermoelectric Generator Design for Oxide Thermoelectrics and Generalization of the Unileg Design Using an Idealized Metal

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Abstract

The unileg thermoelectric generator (U-TEG) is an increasingly popular concept in the design of thermoelectric generators (TEGs). In this study, an oxide U-TEG design for high-temperature applications is introduced. For the unicouple TEG design, Ca_3Co_4O_9 and Al-doped ZnO are used as the p- and n-leg thermoelectric materials, respectively. For the U-TEG design, constantan and Ca_3Co_4O_9 are employed as conductor and semiconductor, respectively. The reduced current approach (RCA) technique is used to design the unicouple TEG and U-TEG in order to obtain the optimal area ratio. When both the unicouple TEG and U-TEG were subjected to a heat flux of 20 W/cm^2, the volumetric power density was 0.18 W/cm^3 and 0.44 W/cm^3, respectively. Thermal shorting between the hot and cold sides of the generator through the highly thermally conducting conductor, which is one of the major drawbacks of the U-TEG, is overcome by using the optimal area ratio for conductor and semiconductor given by the RCA. The results are further confirmed by finite-element analysis using COMSOL Multiphysics software. Furthermore, the U-TEG design is generalized by using an idealized metal with zero Seebeck coefficient. Even though the idealized metal has no impact on the power output of the U-TEG and all the power in the system is generated by the semiconductor, the U-TEG design succeeded in producing a higher volumetric power density than the unicouple TEG design.

Additional Information

© 2014 The Minerals, Metals & Materials Society. Received July 15, 2014; accepted December 2, 2014; published online December 20, 2014. W.W. and L.R. gratefully acknowledge the Danish Council for Strategic Research for financial support for the current work through the OTE-Power Project under the Program Commission on Sustainable Energy and Environment (Contract No. 10-093971). G.J.S. and D.R.B. acknowledge the Air Force Office of Science Research MURI FA9550-12-1-0002. D.R.B. acknowledges the support of the Resnick Institute.

Additional details

Created:
August 20, 2023
Modified:
October 23, 2023