Analysis of the effect of a pulsed heat flux on the performance improvements of a thermoelectric generator

Abstract In this work a transient simulation including Joule heating and Peltier effect using Comsol 5.3, is carried out to assess the thermoelectric performance of a bismuth telluride based thermoelectric generator (TEG) under periodic heating and steady state heating. The transient model was experimentally validated in the case of a constant heat source. A periodic pulsed heat source generates a periodic temperature difference ΔT across the TEG legs. While the time average of ΔT is identical to the temperature difference under a constant heat source with equivalent heat flux input, the time average of (ΔT) 2 is larger, resulting in improved output power. Under pulsed heat flux, the maximum enhancement of the output power under periodic heating to the output power under steady state heating (P PH /P SS ) is achieved for a time period of 1000 s and a duty cycle 10%. Moreover, it can be seen that P PH /P SS enhancement is independent of the input heat flux under a given value of a time averaged heat flux 〈q〉. It is found that geometric dimensions of thermo-elements (TE) enhance significantly the thermoelectric performance of the device. However, it is observed that for a given value of leg length (L), the output power becomes independent of L. Hence, this result can facilitate the prediction of TEG performance.