Reflective Sunlight Lighting System For Tunnel Entrance Section

With the rapid development of economy,the number of expressway tunnel in China has gone up.The tunnel requires 24 hours-lighting to ensure traffic safety because of its special structure.At tunnel portal,“black hole” and “white hole” effects are easily caused by high-contrast brightness in and out the tunnel,which seriously affect traffic safety.Therefore,the lighting at the tunnel portal is required to be enhanced.However,it is estimated that energy consumption of tunnel entrance section occupied 40% of all energy consumption.Fortunately,but this section is close to the bright environment outside.If sunlight could be transmitted into this section for enhance lighting,the energy consumption of tunnel lighting could be greatly reduced.Even more encouraging,the lighting of the entrance section can be self-adaptive to bright environment outside.To ensure the performance of high energy efficiency,low cost,and tracking precision for sunlight illumination system,a reflective solar illumination system is proposed for the entrance section of tunnel.Main works have been concentrated on designs of system,mechanical structure,and the light distribution.Moreover,a primary experiment is conducted to validate the effectiveness of this scheme using the developed prototype.Contents of the thesis include following aspects:(1)By combining the advantages of existing sunlight illumination systems and the illumination requirements of tunnel entrance section,a reflective sunlight illumination system based on sun tracker directional reflector was proposed.(2)According to the principle of sun tracker directional reflector,mechanical structure of device was designed.Stress analysis was carried out in order to determine the feasibility of mechanical structure of system.Finally,the prototype of directional reflector device was manufactured according to the design.(3)Light distribution design of entrance section was carried out for an actual tunnel.Reflective sunlight illumination system based on sun tracker directional reflector was modeled and simulated in software.According to the national standard,the average illuminance of road surface at entrance section was calculated,as well as the number of system needed for lighting.(4)Qualitative experiment was carried out in experimental tunnel at Chongqing Communications Research and Design Institute.As the result showed,the feasibility of system was initially confirmed,and the inadequacies existing in the system that needed further improvement were discovered too.