PERFORMANCE INVESTIGATION OF A TWO-STAGE THERMOELECTRIC COOLER WITH INHOMOGENEOUS MATERIALS

A novel model of two-stage thermoelectric cooler with inhomogeneous thermal conductivity in steady-state operating condition is established. The modification of the constant properties model allows controlling the distribution of Joule heat. Considering internal irreversibilities of the thermoelectric cooler, expressions for the cooling capacity, COP, and exergy efficiency are derived. By utilizing numerical methods, the temperature profile along the thermoelectric legs is presented. The optimal operating regions are explored. The COP vs. cooling capacity describing optimal operating regions in inhomogeneity materials are plotted. Meanwhile, the influence of the main parameters such as the variation of thermal conductivity distribution, cold-end temperature and the number of thermoelectric modules on the cooling performance is discussed in detail. Results indicate that the cooling capacity, COP and exergy efficiency are improved compared to those of homogeneous two-stage thermoelectric coolers when an appropriate inhomogeneous property parameter is applied. The work can provide guidance on design of actual two-stage thermoelectric coolers with inhomogeneous materials.