The effect of receiver geometry on the optical performance of a small-scale solar cavity receiver for parabolic dish applications

Concentrated Solar Power (CSP) can be used as an efficient low cost energy conversion system to produce different types of energy, such as electricity, through the use of concentrated parabolic dish systems. In the study of CSP, most of the researchers focus on the heat losses and their relationships to the receivers' geometries. The present study concentrates on the optical efficiency as well as the flux distribution of the three different geometries: cylindrical, conical and spherical, of a cavity receiver, with the objective of analysing their behaviour using an advanced ray tracing method. The results of this study have shown that there is a connection between the flux distribution on the internal surfaces of the cavities and their optical efficiency. Moreover, the conical shape receiver received, as well as absorbed, a higher amount of reflected flux energy than the other shapes. The optical efficiency reached 75.3%, 70.1% and 71.5% for the conical, spherical and cylindrical shapes respectively at surface absorptivity of 85%. Also, the focal point location depends on the shape of the cavity receiver and its absorptivity. Thereby, there is an optimum distance for each design depending on these two factors. The results of the simulated work are validated using the experimental work found in the literature. (C) 2016 Elsevier Ltd. All rights reserved.