A Ray Tracer for optimizing solar concentrating systems: The case of discretized Compound Parabolic Concentrator

Abstract

Concentrating solar systems use reflective surfaces to concentrate sunlight onto a small area, where it is absorbed and converted to heat. Many classes of concentrating collectors such as Compound Parabolic Concentrators (CPCs), parabolic dish and parabolic trough are available, each with different concentrating ratio and maximum absorber temperature, depending on the type of applications. A simplified 3D Compound Parabolic Concentrator (CPC) with 2 rings and 4 sectors has been designed. The designed CPC is cost effective as it requires only 8 mirrors to cover the reflector surface. It does not require sun tracking, but have capability to accept incoming solar radiation over a relatively wide range of angles. For further capturing of the solar radiations, tilting of the CPC during a day can be made a few times. This study aims to model the discretized 3D CPC using the ray tracing, to optimize the CPC for achieving optimal interceptions on a 0.2 m diameter cylindrical absorber, placed inside the CPC. The ray tracing methodology is presented together with the results of the interceptions on the cylindrical absorber using the discretized CPC. Results show the effect of tilting the discretized CPC is not very strong as the interception values are slightly reduced and the curves a little bit not symmetric around the normal sun angles.