Design of Cascaded Oxide Thermoelectric Generator

This paper describes the design of twoand three-stage cascaded oxide thermoelectric generators (TEGs) for high-temperature heat recovery using reported data to optimize energy conversion efficiency. We used the general intermetallic compounds Bi2(Se,Te)3 and (Bi,Sb)2Te3 for the low-temperature stages and oxides of TiO1:1, La-doped SrTiO3, NaxCo2O4, and Al-doped ZnO for the higher-temperature stages. A two-stage TEG with TiO1:1 as the p-type material and La-doped SrTiO3 as the n-type material was found to have the highest efficiency at heat-source temperatures below 852K, while the three-stage TEG was slightly more efficient than the two-stage TEG for heat-source temperatures above 852K. For the three-stage TEG, the optimal boundary temperature of the second and third stages was calculated to be 698K; at this temperature, the maximum energy conversion efficiency, 13.5%, was obtained at a heat-source temperature of 1223K. The results showed that the designed twoand three-stage cascaded oxide TEGs have high potential for heat recovery from high-temperature waste. [doi:10.2320/matertrans.MRA2008085]