Abstract
It is necessary to improve the thermoelectric property of many thermoelectric materials. The reduction in thermal conductivity (K) and specific resistance (ρ) is effective to improve the effective maximum power (Peff). In this paper, possibility of the improvement in Peff by the addition of good electrical conductor (Ag) to thermoelectric semiconductor (β-FeSi2) was studied as well as the effect of sample length on Peff. Peff has the optimum sample length (Lmax) which makes the Peff maximum. Lmax is estimated by 2K/C, here C is thermal transfer coefficient. When the temperatures of hot and cold end of sample are fixed, Peff of pure Ag is larger than that of β- FeSi2. But, this condition is not realistic, because temperature difference between hot and cold end of sample (ΔT) depends on K, C and L. On the other hand, when the temperatures of heat source and heat sink are fixed, improvement of Peff by addition of Ag is not obtained for parallel and series composite models. Calculations show that the expected improvement of Peff is not observed by the simple addition of good electrical conductor to thermoelectric semiconductor.
