High angular tolerance thin profile solar concentrators designed using a wedge prism and diffraction grating

This paper proposes a novel design for a high angular tolerance thin profile solar concentrator comprised of a wedge prism and diffraction gratings. A concentrated broad solar spectrum of up to 500 nm can be achieved by utilizing two diffraction gratings located on the top and bottom surfaces of the wedge prism. The gratings diffract the incident light guiding it into the wedge prism. The guided light is then projected onto the solar module located at the end face of the prism. With this coupling mechanism, the concentrator’s length-tothickness ratio can exceed 7, the maximum concentration ratio exceeds 3.77, and angular tolerance at 90% of the maximum collection efficiency can reach ±35 and ±3 along the two incident axes and reach ±53 and ±9 at 50% of the maximum collection efficiency, respectively. In addition, the polarization dependence, as a property of the one-dimensional diffraction grating, is suppressed. As a result, the conversion efficiency is enhanced 1.67 times over cases where a single grating is used. Crown Copyright 2012 Published by Elsevier Ltd. All rights reserved.