Effects and optimization of different parameters on the efficiency of thermoelectric generators

The aim of this study is to determine the thermoelectric modules that can operate more efficiently at higher temperatures by considering the specific mechanical and thermal material properties of the parts used in thermoelectric generators. Thermoelectric modules consist of n and p type semiconductor legs and alumina plates to which they are attached. Copper parts provide the connection between the legs and the plates. The material properties of the copper part are taken in the values in the literature. Elastic modules and thermal expansion coefficients of the remaining parts were determined as parameters by taking them between certain values.. It was found that 2187 different analyzes could be made from the combination of these variable parameters. By using the R program, it was calculated that 176 of all combinations could be selected and analyzed with the D-optimal design method. The thermal stresses in all parts were calculated using the finite element analysis method with the ANSYS program. For the thermal stress values found as a result of the analyzes, regression analyzes were performed and the objective functions were determined. Then, optimization studies were carried out on these objective functions under the determined constraints. These analyzes were applied to rectangular and circular section legs separately. It has been determined how the modulus of elasticity, coefficient of thermal expansion and temperature variable parameters affect the thermal stresses formed in the thermoelectric module. It has been observed that as the temperature difference increases, the thermal stresses on the elbows increase, and lower stress values occur in the circular section elbows compared to the rectangular section.