ENERGY CONSERVATION WITH LIGHTING CONTROL TECHNIQUES

Abstract

High-rise commercial buildings are common features in Singapore. These buildings are highly energy intensive and they consume almost 30% of the nation's electricity. According to the studies of energy analysis in the commercial buildings in Singapore by Public Utility Board (1992), it was reported that the air conditioning system has the highest energy consumption. Lighting also consumes energy to certain extent. Lighting not only consumes energy by itself but also generates heat in a building. As a result, it causes a significant additional load on the air conditioning system. Implementing energy conservation measures in lighting system would result in proportionate reduction in air conditioning load, which in turn would reduce the amount of total electricity consumption. There are two means to reduce lighting energy consumption: reducing of load and optimising operating time. In this study, the main focus was on reduction of operating time by the application of lighting control techniques. Lighting control techniques were applied in three different areas: tutorial rooms, a toilet, and a carpark in Nanyang Technological University. The first study was conducted in tutorial rooms where lights were interfaced with existing air conditioning system. It was found that the energy saving was achieved by 84%. The second study was carried out in a common toilet where lights were controlled by an ultrasonic occupancy sensor. It was found that the energy saving was achieved by 43% in school terms and 61% in vacation. The third study was conducted in a carpark where lights were controlled by a photoelectric sensor. This study was based on the effect of integrating daylight with artificial light. It was found that the energy saving was achieved by 56%. The case study of the results demonstrated that energy wastage can be reduced appreciably by lighting controls.