Estimating illuminance through vertical light pipe in Surabaya, Indonesia

Abstract

Light pipes provide daylight and enhance the lighting conditions of buildings. Guidelines and other information of light pipe performance are necessary to meet standard lighting requirements. In locations near the equator, there is a potential supply of daylight that can be used strategically by vertical light pipes to bring light into buildings. Previous studies in Southeast Asian Countries have suggested that Malaysia has great potential to utilize vertical light pipe mechanism. Whereas, Thailand faces challenges to use vertical light pipe due to the low illuminance it receives from the sun.  Countries that are positioned close to the equator have greater potential to use vertical light than countries that are further away. However, the vertical light pipe mechanism has yet to be studied and applied in Surabaya, Indonesia. Therefore, this study presents the potential performance of the vertical light pipe strategy and its application in Surabaya, Indonesia. In this study, various pipe configurations were considered and analyzed, namely: three pipe diameters of 0.6 m, 0.8 m, and 1.0 m and the length of pipe was from 1 – 6 m. A simulation study in DIALux 4.13 was performed on four critical dates under varying sky conditions: clear, intermediate, and overcast. The results demonstrated that a vertical light pipe strategy in Surabaya, Indonesia has high potential to increase the quality and quantity of light between the hours 9:00 and 15:00. The research showed that pipes with diameter of 0.8 and 1.0 m were the most usable in typical sky conditions. However, the pipe with diameter of 0.6 m obtained an adequate illuminance level under clear skies, but it would not provide a sufficient illuminance level under intermediate nor overcast conditions. The final section suggests a model for predicting levels of illuminance from vertical light pipes.