Wijesooriyage, Waruna Dissanayaka1; Rosendahl, Lasse2; Brown, David R.4; Snyder, G. Jeffrey4
1 Department of Energy Technology, The Faculty of Engineering and Science, Aalborg University, VBN2 Fluid Mechanics and Combustion, The Faculty of Engineering and Science, Aalborg University, VBN3 The Faculty of Engineering and Science, Aalborg University, VBN4 Materials Science, California Institute of Technology
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, Ca3Co4O9 and Al-doped ZnO are used as the p- and n-leg thermoelectric materials, respectively. For the U-TEG design, constantan and Ca3Co4O9 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/cm2, the volumetric power density was 0.18 W/cm3 and 0.44 W/cm3, 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.
Journal of Electronic Materials, 2015, Vol 44, Issue 6, p. 1834-1845
TEG; Thermal shorting; Thermoelectric; Thermoelectric generator; Unileg; Volumetric power density