Comparative Study of Solar Optical Fibre and Electrical Light for Daylighting in Tunnel Threshold Zone

In recent years, there has been a considerable increase in traffic accidents in the tunnel region, especially around the threshold and exit zones, due to the inappropriate lighting system of these zones; leading to the loss of humans properties and lives. Therefore, lighting designers strive to improve the illumination issues of the threshold and exit zones which bring about “black hole” and “white hole” effects, respectively. Several solutions are proposed: solar optical fibre lighting system as a natural lighting system and LED, fluorescent lighting system as the artificial lighting system. This paper aims to compare the natural and artificial lighting system to show which lighting system is better and the best solution to solve these issues. The previous study in the Huashuyan tunnel in China, where natural light, solar optical fibre was used to illuminate the threshold zone, is simulated in LITSTAR4D software using a customized HCL-TN LED luminaire of LITPA Сompany. The simulation result is compared with the previous result obtained when the solar optical fibre is used. The simulation outcome gave a satisfying result with an average luminance of 91.15 cd/m2, which is higher than the average luminance required by the threshold zone. However, it is less when compared to the average luminance of 181.31 cd/m2 produced by the solar optical fibre system. The overall uniformity of 0.42 is above the requirements in the CIE88:2004 standards.