A suitable heat duct shape for a thermoelectric generator cooling system

Abstract

In this research, heat ducts of a gasifier system were designed for power generation from waste heat using the thermoelectric generator (TEG). The commonly used heat duct has a circular shape which is impossible to install a flat thermoelectric module (7×7 cm²). Therefore, a heat duct has to be modified into a circular, a triangular and a square cross-sectional ducts. The cross-sectional area of these three geometries were A'=7.07 cm², 43.5 cm² and 100 cm² for a circular, a triangular and a square crosssectional ducts, respectively. Power generation by using different heat duct shapes, effect of turbulent flow on the efficiency of heat transfer and directions of a cooling system were observed. In conclusion, a square cross-sectional duct is the most suitable shape for power generation using the thermoelectric devices. Even though temperatures along all duct shapes steadily decreased, the temperature profile of a square cross-sectional duct was more homogenous than the other shapes. Installation of a swirl core could create turbulent flow, increased the average temperature for approximately 16-22% compared with a heat duct without a swirl core. A counter flow of a water cooling system also created higher contrast of the temperatures on the surface of hot and cold sides compared with a parallel flow. These solutions can improve the efficiency of heat transfer inside a heat duct.