Effect of design shape factor on exergonic performance of a new modified extended-tapering segmented thermoelectric generator system

Abstract

The present theoretical analysis focused on the investigation of a new design extended and tapering segmented pin configuration based thermoelectric generator (TEG) incorporating with modified bismuth and lead telluride materials. With the current design, the system can operate at two different cold junctions. Effect of thermal performance, i.e., heat transfer rate from the cold and hot side, maximum efficiency, overall efficiency, second law efficiency, entropy generation, normalized work and efficiency ratios on the variation of designed shape factor, load resistance ratio, temperature ratio, and p-n junction lower temperature difference have been considered. Results revealed that variation in designed shape factor has a significant influence on overall efficiency for temperature ratios, and nearly a 13.83% decrease in overall efficiencies is observed for the variation in shape factor ξ, −0.38 to 0.5. The temperature ratio significantly affects the length ratio of the segmented pin. The exergy efficiency of 16% and the maximum efficiency of 22% is observed, which may be due to the thermodynamic irreversibility linked between the heat transfer systems. The entropy of generation has minimal effect for the load resistance variation with a figure of merit 2.5, and the maximum efficiency is observed at a higher load resistance ratio value of RL/RO = 3.1, compared to the output work ratio. This implies that for the new modified design TEG, the maximum output work is not obtained at the point of maximum efficiency. Thus, the present modified design TEG provides a higher power output than traditional designs incorporating identical pins. © 2020 Elsevier Ltd