Modeling and Performance Evaluation of Parabolic Trough Solar Cavity-Type Receivers

This article proposed three new designs about parabolic trough solar cavity-type receivers. The characteristics of these designs were also analytically analyzed. In the paper, the geometrical-optical method is used to analyze the absorptivity of these cavity receivers. The influences of the specular reflection ratio in absorptivity were also discussed. The geometrical-optical method was validated using the Monte Carlo Method. The study showed that the results calculated by different method can agree well. The study also showed that the proposed receiver models have less optical losses than conventional cylindrical/tubular cavity receiver under the limitation of the same-size aperture. Most of radiant energy entering into the cavity is absorbed through the initial reflection. The theoretical absorptivity of these cavities approaches to blackbody. The study also showed that the absorptivity increases monotonously with the proportion of specular reflection and the depth of the cavity.