On the optimal design of multistage thermoelectric coolers

Abstract

We perform optimal designs of two applicable configurations of multistage thermoelectric (TE) coolers, with serial and separate electric currents flowing through each stage, respectively. The finite-rate heat transfers between the coolers and reservoirs are taken into account. A general optimization method is developed, with which the cooling power and coefficient of performance (COP) for the two types of TE cooler can be maximized, respectively. The optimal design parameters are numerically calculated with reference to commercially available TE materials. It is proven that TE coolers with separate electric current can provide not only more cooling power per thermocouple but also a higher COP. An approximately identical temperature ratio Ti-1/Ti (i = 1.....n) is found at each stage of both coolers at the above two extreme operating points.