Techno-economic evaluation of an optical fiber based hybrid solar lighting system

Optical fiber solar lighting systems are an appealing approach for illumination applications with the aim of reducing energy consumption and greenhouse gas emissions from artificial lighting. This study presented the design, construction and assessment of an optical fiber based hybrid solar lighting system for illumination of interior spaces. The proposed system combines the features of optical fiber daylighting technology and photovoltaic power generation technology. Specifically, a secondary light concentrator was designed to improve the uniformity of flux distribution and solve the overheating problem of PMMA fibers. The technical feasibility of the hybrid solar lighting system was validated using the fabricated prototype in a 5 m(2) darkroom during a whole day test. Experimental results showed that, an average illuminance of 105 lx at a distance of 2 m from the end of optical fiber bundle was achieved, saving 316.82 kWh and reducing 251.24 kg carbon dioxide emissions every year in the studied case. Finally, cost analysis of the proposed hybrid solar lighting system was carried out and compared with three conventional lighting systems. The total payback period of the hybrid solar lighting system was 3.7 years and further reduced to 1.7 years in mass production. In the studied case, the hybrid solar lighting system was economically competitive after 2 years and 12 years of operation in comparison with a 100 W incandescent bulb lighting system and a 30 W T8 fluorescent lamp lighting system, respectively.