Numerical simulation 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 influence 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 dominate 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 are greater than the other factors. In this work, cavity with a 100mm depth shows the best thermal performance.