Performance analysis of thermoelectric generation system with controlled heat distribution

Abstract

The number of automobiles is rising, but much of the fuel energy is wasted through exhaust gas. Thermoelectric power generation (TEG) technology can be used to recover waste energy from automobile exhaust, but its effective application is limited for low conversion rate of thermoelectric generation. Considering the continuous operating temperature limit of thermoelectric generation materials and its influence on the exhaust system, the model of a new type of thermoelectric power generation system with double collectors was proposed. The three-dimensional steady-state model of the fluid structure coupling system between exhaust gas and thermoelectric device was established, and the test bench was carried out. The influence of controlled heat distribution on the voltage and output power was analyzed by simulation and experiment. The results show the optimal opening ratio (ωopt) of thermoelectric power generation system increases with the rise of temperature, which is a linear function. The optimal opening ratio was close to 1 at high input temperature (predicted to be 984 K). With the input temperature of 673 K, heat energy distributed to each thermoelectric module was about 0.5 W and 0.3 W when opening ratio was set to 0.1 and 1 respectively, and the output power could be increased from 86.1 W to 95.2 W by controlling the heat distribution (the optimal opening ratio = 0.5). However, the optimal opening ratio was still less than 1 when the input temperature was as high as 723 K, which indicates that uneven distribution may be a better choice for most gas conditions.