Modified optical fiber daylighting system with sunlight transportation in free space

• Published in: Optics express Vol. 24; no. 26; pp. A1528 - A1545
• Main Authors: Vu, Ngoc-Hai, Pham, Thanh-Tuan, Shin, Seoyong
• Format: Journal Article
• Language: English
• Published: United States 26.12.2016
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.24.0A1528

We present the design, optical simulation, and experiment of a modified optical fiber daylighting system (M-OFDS) for indoor lighting. The M-OFDS is comprised of three sub-systems: concentration, collimation, and distribution. The concentration part is formed by coupling a Fresnel lens with a large-core plastic optical fiber. The sunlight collected by the concentration sub-system is propagated in a plastic optical fiber and then collimated by the collimator, which is a combination of a parabolic mirror and a convex lens. The collimated beam of sunlight travels in free space and is guided to the interior by directing flat mirrors, where it is diffused uniformly by a distributor. All parameters of the system are calculated theoretically. Based on the designed system, our simulation results demonstrated a maximum optical efficiency of 71%. The simulation results also showed that sunlight could be delivered to the illumination destination at distance of 30 m. A prototype of the M-OFDS was fabricated, and preliminary experiments were performed outdoors. The simulation results and experimental results confirmed that the M-OFDS was designed effectively. A large-scale system constructed by several M-OFDSs is also proposed. The results showed that the presented optical fiber daylighting system is a strong candidate for an inexpensive and highly efficient application of solar energy in buildings.