Thermal Performance Prediction of a Trapezoidal Cavity Absorber for a Linear Fresnel Reflector
A trapezoidal cavity absorber for a linear Fresnel reflector concentrator is analyzed and optimized via CFD simulation. The heat loss coefficient is introduced; the influences of ambient temperature, absorber temperature, cavity depth, inclination of side walls, insulation thickness, glass window, and emissivity of selective absorption coating have been studied. The results show that radiation dominates the cavity heat loss, and heat loss through the glass window is higher than through the insulation layer; among these factors, impact of emissivity of selective absorption coating and insulation layer is greater than that of the other factors. The simulation results via CFD prove that cavity with a 100 mm depth shows the best thermal performance among the parameters that have been taken into account.