Occupancy sensors in schools help to turn off unwanted lights that may have been left on by students or teachers leaving in a hurry. The two types of occupancy sensors that are used in schools are motion detectors and carbon dioxide sensors. Motion sensors work on the principle that if someone is within the room, a certain amount of activity or movement can be detected. On the other hand a carbon dioxide sensor has the added benefit of being able to determine the number of people in the room. This can be connected to the HVAC system to maintain the room’s lighting and temperature at an appropriate level of comfort.
Ultrasonic occupancy sensors can be installed in the lobbies of schools to ensure that lighting is turned down in the lobbies and hallways automatically when there are no occupants. Microphonics-type sensors combine a microphone with a passive infrared sensor (PIR) in order to detect human occupancy in a room. These sensors work well in areas where there are number of obstacles such as rooms with several cubicles. The motion is first detected using PIR and then the microphone turns on to listen to noise levels within the room. These sensors are able to filter out background noises. The best place for occupancy sensors in schools are gymnasiums and stack areas of libraries.
The installation of energy efficient lighting is another option for energy savings in schools. Using energy efficient fluorescent bulbs can cut costs drastically. Combined with occupancy sensors, the life of the bulb can often be prolonged. Class rooms may also be equipped with photocells in order to ensure that the lights are dimmed if there is an adequate amount of natural light available. Sensors may also be used to switch on lights around the campus grounds when natural light falls below a certain limit. These may be combined with timers which will switch of these lights at a particular time when the school is not being used.
Occupancy sensors can be used effectively in rest rooms. The lights can be turned on and off in a rest room depending on whether it is being used or not. Sensors can also be used to switch exhaust fans on or off, based on occupancy.
Other tips to ensure that schools are energy efficient include the use of plug load controls. Plug load controls can turn appliances on or off when ever someone enters a room. A plug load control has a number of power sockets attached to a sensor which detects occupancy and triggers appliances that are connected to the board. Exit signs in a school should be replaced with LED signs as these are more energy efficient.
