Redirection of sunlight by microstructured components – Simulation, fabrication and experimental results

• Published in: Solar energy Vol. 86; no. 5; pp. 1660 - 1666
• Main Authors: Klammt, Stephan, Neyer, Andreas, Müller, Helmut F.O.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2012; Elsevier; Pergamon Press Inc
• Subjects: Applied sciences; Daylighting; Energy; Exact sciences and technology; Microreplication; Microstructure; Natural energy; Simulation; Solar energy; Solar radiation; Sunlight guide panel; Ultraviolet radiation; Daylighting; Microstructure; Microreplication; Sunlight guide panel; Performance evaluation; Production system; Prototype; Glass; Experimental study; Daylight; System performance; Manufacturing process; Ray tracing; System simulation; Large scale; Solar radiation; Siloxane polymer; Comparative study; Altitude
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2012.02.034

► We present a non-tracking microstructured daylighting system. ► Simulations show the advantage of combinations of lenslike with prismlike geometries. ► Performance has been shown by large scale industrially produced acrylic panels. This paper presents a non-tracking microstructured light redirecting device, which can be integrated into architectural glass. When fixed in the upper area of a window above eye level it redirects the light from solar altitudes between 15° and 65° and illuminates a room without causing glare. Ray-tracing calculations are employed as a tool for identifying suitable configurations and geometries. The results of the simulations show the advantage of combinations of lens-like with prism-like geometries in comparison to conventional microprism arrays regarding the overall light redirection efficiency as well as the producibility. The redirecting device is more lightweight, gives better integration options and is producible in a more economic manufacturing process as systems with similar performance. Measurements of cast silicone prototypes (100mm×100mm×4mm) confirmed the simulation results. By now the performance has also been shown by large scale industrially produced acrylic panels with dimensions of 1500mm×400mm×4mm.