Influence of leg sizing and spacing on power generation and thermal stresses of thermoelectric devices

The influence of leg dimensions and spacing on power-generation and thermo-mechanical performance of thermoelectric devices was investigated using numerical and statistical analyses tools. Bismuth-telluride based thermoelectric device models with rectangular-prism and cylindrical legs were simulated for a temperature range of 20-120 °C and various leg heights between 1 and 5 mm, widths/diameters between 1 and 2 mm, and spacing between 0.5 and 1.5 mm. Predicted power output, conversion efficiencies, and thermal stresses were validated with less than 8.9%, 1.2%, and 6.6% variations respectively. It is found that both leg width and height have a significant effect on power generation and thermal stresses: The relationship between power generation performance and thermal stress levels is inverse. Although leg spacing has effect on thermal stress and conversion efficiency, its effect on power output is negligible.