Dynamic energy savings
To enhance the impact of the technology change, we dim down the lighting whenever it is not in use. That may reduce electricity use by another large portion, so-called dynamic energy savings.
LED lighting is more suitable for this than fluorescents. LED can be switched on and off without limit and is eminently dimmable. Where users are present in the surroundings, dimming may be preferred to switching off: it has a safer, less deserted feel to it.
Modern systems are often dimmed digitally in accordance with the DALI protocol (Digital Addressable Lighting Interface). Each lamp has its own 6-bit address in the (sub)network. For instance, DALI command 125 6 dims lamp number 62 to its lowest possible level. Groups can be defined: command 138 246 dims all lamps of group 5 to 80% of their capacity. Moreover, 'scenes' can be set for various situations. A daytime scene could entail lamps near windows being off and other lamps somewhat dimmed. Command 255 31 turns every lamp to its light level for scene 15. A benefit of DALI control is the option to query remotely whether lamps still work. To control the lighting, we use movement, daylight and occupancy sensors. Which sensor is suitable depends on the situation and the application. The sensors can be connected to a digital dimming network according to the DALI protocol or with a central building automation system, for instance using the KNX protocol.