Performance enhancement of a natural-gas-fired high-temperature thermoelectric generation system: Design, experiment and modelling optimization

Abstract

High-temperature thermoelectric generation (TEG) system that driven by combustion is an efficient way for simultaneously providing heat and electric power, but its application prospect is restricted by very low ratio of electric power to heat supply. In this work, an annular high-temperature TEG system is extended by adding medium-temperature TEG modules, and correspondingly a novel two-stage annular multi-hole burner with baffle construction is specially designed to replace original single-stage annular multi-hole burner. The optimal geometric dimensions of the new burner are obtained by conducting a simplified 2D model in ANSYS. Experiment results show that, due to the new burner design, the inner-wall temperature of the high-temperature TEG module is averagely increased by 73 K, bringing an electric power rise of 14.8%; in comparison with the single-stage high-temperature TEG system, the total electric power generation of the high- and medium-temperature coupled TEG system is greatly improved by 73.8%. To further improve the electric performance of the high-temperature TEG module, a well-developed multi-physics field coupled model which containing 2D combustion reactions in the new burner and 1D multi-physical thermoelectric (TE) effects is established to reveal the optimal length and number of TE element, and to assess the optimization of cold-side heat sink.