The importance of automatic control using occupancy sensors for electric lighting concerning energy issues

摘要

In the scope of a joint project between Istanbul Technical University and Berlin Technical University, measurements concerning illuminance levels and room occupancy have been made in two office rooms of Istanbul Technical University for two years. This study focuses on the measurements taken in one of these rooms, in which the lighting was solely under the influence of the users. The room has been equipped with a passive infrared occupancy sensor, which was not connected to the power system but only functioned to monitor the presence of a user. The readings of the occupancy sensor in this room showed that, the users left the lights on for significant periods of time, even when the room was unoccupied. Setting out from this finding, calculations have been made in order to obtain the amount of energy savings that could have been made if the occupancy sensors were connected to the power system. The results show that, the energy savings potential for an office per year is in the level of 370 kWh, 310,5 kWh of which can be maintained through the utilization of an occupancy sensor. It is evident from these results that even without using relatively expensive solutions such as automatic control systems equipped with dimming mechanisms, the usage of a system that turns the lights off only when the rooms are unoccupied provides very important savings on the energy used for lighting.