Performance analysis of bismuth-antimony-telluride-selenium alloy-based trapezoidal-shaped thermoelectric pallet for a cooling application

•An experimental study has been performed on trapezoid-shaped legs for TEC application.•Microstructural characteristics of synthesized TE materials have been investigated.•A comparison of performance analysis between TEC prototypes has been studied.•Analytical analysis has been carried out and validated with experimental results.•Lower area ratio shows better performance at lower current for the proposed design. The zero emission and chlorofluorocarbons (CFC) free thermoelectric cooling systems have the potential to limit the adverse effect on our climate due to the greenhouse gas emission from traditional cooling technologies. In this paper, a new configuration of thermoelectric cooling system is proposed, which includes trapezoidal-shaped solid-state thermoelectric legs, bismuth-antimony-telluride-selenium alloy, and it is manufactured using environmentally friendly handheld dispenser fabrication method. The synthesized thermoelectric materials are characterized using x-ray powder diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscope (SEM) technologies in order to study the morphology of the materials. Both theoretical and experimental studies are performed on trapezoidal and rectangular prototypes. It is identified that the trapezoidal-shaped leg requires less material (nearly 25% less) and exhibits lower thermal conductance (around 27% less) in comparison with the rectangular-shaped TE leg. Experimental results further show that a maximum temperature difference of 79.4 °C can be achieved from the trapezoidal-shaped prototype at 5A input current which is 10% higher than the rectangular prototype. Besides, an experimentally validated analytical model is used to investigate further the cooling capability, temperature difference, and coefficient of performance of both trapezoidal and rectangular-shaped TEC. A range of area ratio of the hot surface to the cold surface of the TE leg varying from 0.33 to 3 has been studied. In addition, the maximum COP of the trapezoidal-shaped prototype is approximately 32.5% higher than the rectangular prototype. The maximum obtainable cooling rate and temperature difference are almost the same but require nearly 50% less input current to achieve this maximum output with a hot to cold surface area ratio of 0.33.