Improving the efficiency of an exhaust thermoelectric generator based on changes in the baffle distribution of the heat exchanger

A significant amount of the heat is lost in the vehicle exhaust and simply transferred to the environment. Using a thermoelectric generator (TEG), it is becoming possible to convert this heat potential into the electrical energy. In this study, nine types of the heat exchangers in three different groups, namely A, B, and C are modeled in three dimensions and studied using computational fluid dynamics (CFD) analysis with various baffle arrangements to obtain electrical energy from the vehicle exhaust. The modeling of the group A is focused on the effect of the angle and thickness of the baffles at the inlet of the heat exchanger. In the group B, the distances between the baffles and their heights are changed, and group C is focused to model larger baffles with different arrangements. The results show that, the pressure drop is in the permissible range in all the models, and the gas flow velocity in group A is almost similar to what studied in other models; however, the power produced in it is at least 7.25% higher than other models. The best model for the highest generated power is also recommended and discussed. It is also shown that implementation of a deflector will lead to a non-uniform and unidirectional distribution of temperature. The results also reveal that under identical conditions in the middle section of the heat exchanger, reducing the height of the baffles from 8.46 mm to 2.30 mm will result 10.88% decrease in the output power. Furthermore, increasing the distance between the baffles from 5.2 mm to 16.8 mm will cause 3.91% increase in the output power.