SIMULATION WORKS ON INTERIOR ILLUMINATION WITH NATURAL DAYLIGHT

Solar light is a safe and clean energy. The use of natural light in office buildings is an effective way of energy saving. At present, the amount of electricity consumed by the lighting system occupies about 20%~30% of the total electricity consumption especially in office buildings in Japan [1]. Therefore, it is obvious that using daylight in the office space for illumination will be a great innovation. However, natural light source has variability and is difficult to control. In this research, we have proposed a method of attaching multiple blind reflectors to windows that can reflect light from the window to the ceiling, and then the diffused light from the ceiling is used for room lighting. In order to evaluate the energy saving amount when using such a lighting system on bright shining days, office lighting environment with various conditions throughout the whole year was simulated by using the daylighting system of our self-made simulator.