Design and Fabrication of a Solar Collector for Daylighting Systems Based on Heliostat Layout

Abstract

The present research proposes a non-imaging concentrator system based on heliostat layout for a daylighting collector. The system consists of small planar mirrors in a modular array operating as a passive solar optical aperture. To simulate and optimize the layout and alignments of the mirrors and to prevent optical losses, a graphical algorithm for the central receiver system is utilized. This radially staggered arrangement is designed with the help of the backward ray tracing concept to achieve a high concentration factor. The accuracy of backward ray tracing has been demonstrated by the forward method. To verify the accuracy of the numerical results, prototypes have been fabricated based on the optimized solution and have been subsequently assessed under solar radiation and a laser setup. The sensitivity analysis is thereafter performed to calculate the sensitivity of the proposed design to the manufacturing inaccuracies. Evaluation of the experimental results obtained for the geometrical concentration ratio shows that the proposed modular daylighting collector has potential application in daylighting for buildings.