THERMAL CONTACT RESISTANCE MATCHING TO OPTIMIZE PERFORMANCE IN THERMOELECTRIC GENERATORS

Thermoelectric generators (TEGs) have attracted increasing interest due to their ability to directly convert heat to electricity. However, relatively low conversion efficiency limits their broad applications in the future. One of the crucial factors affecting TEG performance is thermal contact resistance (TCR). In particular, TCR matching at the interfaces of p- and n-type thermoelements strongly affects the heat transfer and hence the TEG performance. In this work, the influence of this TCR matching on TEG performance was studied in detailed by solving three-dimensional coupled thermoelectric equations via the finite-element method. Our results indicate that the optimal output power and conversion efficiency of TEGs can be reached when the TCR at the interfaces of the p-type thermoelement is equal to its counterpart at the interfaces of the n-type thermoelement. Furthermore, optimization of TEG performance by matching the TCR becomes much more obvious when the total TCR is smaller. We then applied our model to the TEG with p-Bi0,2Sb1.8Te3 and n-Bi2Te2.6Se0,4 thermoelectric materials, whose thermoelectric properties are temperature dependent, and found that enhanced TEG performance can also be obtained by TCR matching. The study presented in this work could be useful for guiding the enhancement of TEG performance.