Traditional outdoor lighting technologies operate at full power throughout the night, even when areas are vacant. This extra load, energy waste and light pollution can be averted by updating the lighting system with energy-efficient light sources and lighting controls. By installing these technologies, adaptive lighting strategies can be implemented that provide the right amount of light when and where it is needed.
Adaptive outdoor lighting systems utilize 1) photosensors to detect ambient daylight levels and turn on the electric light source when needed, and 2) occupancy sensors to detect when a space is occupied/vacant. The sensor sends the status signal, or ‘trigger’, to the lighting system and the system modifies the light levels per the settings deployed during commissioning that are appropriate for the application. Typically, lighting levels are lowered when no one is in the area, saving energy while still providing enough light to meet safety requirements for the application; and lighting levels are increased when an occupant is detected, bringing the light levels up to the recommended amount of illuminance for the application and/or task(s) being performed.
Today, adaptive lighting is considered best practice for numerous outdoor applications and has been widely adopted in building standards by many organizations, including the California Energy Commission and the United States’ Department of Defense (DOD). However, most outdoor security applications remain designed with high, uniform levels of static illumination. Research conducted in 2002 shows that high, uniform light levels have little to no deterrent effect on crime, rather that the elevated levels of illumination typically increase the perception of security for people using the space.
In addition to energy savings and load reduction, CLTC anticipates that adaptive lighting systems implemented in security applications will increase the likelihood of guards detecting intruders by “highlighting” occupants as they trigger strategically placed occupancy sensors. For this strategy to be effective, the sensors must be configured to increase light levels when triggered by an occupant.
CLTC is researching, developing and testing a sensor-based, adaptive lighting system that has the potential to significantly enhance security while dramatically reducing energy use and maintenance costs in high-security Navy installations. This research and development effort is funded by the Office of Naval Research. The project team includes the University of Hawaii's (UH) Hawaii Natural Energy Institute and the California Lighting Technology Center at UC Davis.