3D study of the impact of aspect ratio and tilt angle on the thermoelectric generator power for waste heat recovery from a chimney

Abstract

In this paper, 3D study is presented for the effect of the tilt angle on the waste heat recovery from a vertical chimney by using thermoelectric generators (TEGs) cooled at their cold sides by natural convection. The aspect ratio impact (distant between two consecutive TEGs to TEG length) on the TEG performance is studied. The tilt angle changes from 0 to 15° and the aspect ratio varies from 1.5 to 4 for three vertically aligned TEGs modules mounted on the chimney wall. 3D mathematical model coupling the thermal-electric TEGs and fluid models is presented and it is programmed and solved numerically by ANSYS-Fluent software. A constructed experimental setup validates the numerical solution. The results indicate that the present mathematical model presents well the 3D results of the TEGs modules on the chimney wall. For TEGs limited number or large chimney surface area, increasing the distance between each two successive TEGs to four its length increases the TEGs output power by about 45%. Tilting the chimney wall toward the flue gases has a positive effect on the TEGs output power and tilt angle of 15° increases the uppermost TEGs power by around 5% with slight effect on the lower TEGs power.