Preliminary Experimental Comparison of the Performance of a Novel Lens-Walled Compound Parabolic Concentrator (CPC) with the Conventional Mirror and Solid CPCs

Abstract

A conventional mirror compound parabolic concentrator (CPC) is limited by its half acceptance angle when pursuing a large geometrical concentration ratio with no tracking. A solid CPC, which is made from solid dielectric materials without notches, can achieve a larger half acceptance angle compared with the conventional mirror CPC of the same geometrical concentration ratio, which is attributed to the optical refraction caused by the dielectric material. However, solid CPCs are heavier and costlier. This paper presents a preliminary experiment on a novel lens-walled CPC. An experimental comparison of the conventional mirror and solid CPCs and the lens-walled CPC with the same geometrical concentration ratios of 2.5 is given for different incidence angles. Here the conventional mirror CPC chose the evaporated aluminium coating as the reflection layer, for short conventional CPC. Transparent acrylic was chosen as both the dielectric material and lens material. The three CPCs were all attached to a PV cell. Through the output characteristics of the cell, the optical performances of these CPCs can be obtained. The results showed that when the incidence angle was smaller than 35°, the optical efficiency of the lens-walled CPC remained above 46.7% and was more stable against incidence angle changes compared with the conventional CPC. It also weighed and cost less than the solid CPC. Thus, lens-walled CPC adequately combines the advantages of conventional and solid CPCs, and has great potential for use in large-scale practical applications.