Material pairing and selection considerations for thermoelectric cooling devices with components dissimilar to Bi2Te3 based alloys

Abstract

Abstract Bi2Te3 based alloys used in commercial thermoelectric devices today remain to be state-of-the-art in material performance. However, as new materials are emerging with merits in other aspects, it is necessary to consider how to construct cooling devices with these new materials effectively. In this paper, a numerical method based on one dimensional transport equations and the concept of relative current density is used to simulate performances of devices under optimized geometry and operation conditions. The materials Seebeck coefficients α are allowed to vary within a realistic range while their zTs are kept constant. It is found that when the two legs are of similar zTs, individual properties have very little influence on device performance at small ΔT, and zT is the only metric to gauge the optimum performance. At large ΔT (relative to maximum achievable ΔT) the α profile has a moderate influence. When two legs have different zTs, device performance will be notably affected by the Seebeck coefficients, especially their magnitudes. This work indicates the limitation of using only zT when comparing different materials’ potential in real devices. General guidance is provided on how to choose materials for each leg for a practical cooling device using emerging new materials.