Electrical performance optimization of a transverse-Seebeck-effect-based tubular thermoelectric generator for waste heat recovery

A tubular thermoelectric generator (TTEG) composed of alternating Bi0.5Sb1.5Te3 and constantan conical rings was proposed, which could be used for recovering waste heat from the automobile exhaust gas and was expected to have better electrical performance than Ni/Bi0.5Sb1.5Te3 TTEG; however, its thermoelectric performance still needs to be optimized. Therefore, in this study, the effects of tilt angle, inner diameter, and material layer thickness on the open-circuit voltage (OCV) and power density of the TTEG were studied using numerical simulation, and the optimized parameters corresponding to the maximum OCV and power density were determined. A tilt angle of 35.9° and a layer thickness of 0.75 mm are suggested as the final optimization plan to increase the OCV. The OCV reaches 0.25 V, which is 47.1% higher than the OCV of the previous Ni/Bi0.5Sb1.5Te3 TTEG; moreover, the tilt angle of 25° and the layer thickness of 0.75 mm are adopted as the final optimization plan to increase the power density. The power density reaches 1131.2 W/m2 and demonstrates an 18.8 % enhancement. In addition, the power density of the new TTEG can be as much as 1.14-2.92 times that of the Ni/Bi0.5Sb1.5Te3 TTEG when the tilt angle is larger than 20°. These conclusions indicate that the thermoelectric performance of the TTEG has been substantially improved, which is of great significance in promoting its industrial application.