The Efficiency of Light Shelves According to Latitudes in Office Buildings

Light shelf is one of the improved daylight systems, helping to contribute to energy saving by using daylight effectively. Many regional studies have been conducted on light shelf efficiency especially in recent years. This original paper investigates the effect of different latitudes (0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees) on the light shelf efficiency on a sample unit for 3 different (3m, 3,9m, 4,8m) office heights. First, the most suitable light shelf conditions are determined for each condition by using Ecotect & Radiance softwares in CIE* Standard Overcast Sky and then the desired daylight intervals for offices are compared without and with light shelf. Consequently, it is determined that the light shelf increases the desired daylight levels in all latitudes for 3 different office heights and light shelf efficiency generally diminishes with the increase in office heights between 0 degrees-15 degrees latitudes and increases with the increase in office heights between 30 degrees-75 degrees latitudes. In addition to that, the distribution of daylight levels are analysed in plans and the results are presented to designers interested in daylight efficient design.