Effect of angle of attack and wind direction on limiting input heat flux for solar assisted thermoelectric power generator with plate fin heat sink

Abstract

This paper focuses on establishing the dependence of limiting value of input heat flux for solar assisted thermoelectric generators (TEG) on Angle of Attack (AOA) and wind direction of heat sink of TEG. Current study investigates the limiting input heat flux for TEGs with allowable hot side temperature of 150 °C. A fin block with eight fin configuration and fin length of 60 mm is chosen as heat sink configuration for TEG. Computational Fluid Dynamics (CFD) model is developed and analyzed in this work after validation with published experimental results. CFD model consists of four TEGs encapsulated within a target block and a finned block, placed within a domain which simulates low speed wind tunnel. Air flow in the wind tunnel simulates the outdoor wind conditions. Concentrated solar flux is applied on the face of target block. Effect of ambient air temperature on limiting input heat flux is also studied. Dependence of limiting input heat flux on Angle of Attack (AOA) and wind direction, which arises due to the two axis tracking of Sun by Fresnel lens concentrator has been quantified and it is observed that maximum limiting input heat flux occurs at 30° AOA. Maximum limiting heat flux reaches 24,000 W/m2 for 30° AOA under 5 m/s wind velocity. It is also observed that maximum input heat flux varies by 42.49% with change in wind velocity from 1 to 5 m/s. Maximum limiting input heat flux occurs at 45° for horizontal rotation. Area of square array Fresnel lens concentrator varies by 6.29% for 5 m/s wind velocity when AOA is considered to when AOA is not considered for calculation of Fresnel lens area.