![]() ![]() Volume 11 Issue 2
|
September 2010
|
![]() |
![]() |
||||
AbstractDynamic outdoor lighting varies light level (or other characteristics) automatically and precisely in response to factors such as vacancy or the type of use of an outdoor space. Topics addressed in Lighting Answers: Dynamic Outdoor Lighting include: strategies for implementing dynamic outdoor lighting installations; technologies used; energy, environmental, and cost benefits; and potential liabilities and barriers. The applications discussed in this report include parking lots, parking garages, outdoor walkways, and streets, which are the most common places where dynamic outdoor lighting might be found. IntroductionThe National Lighting Product Information Program (NLPIP) defines dynamic outdoor lighting as outdoor lighting that varies light output, spectral content, intensity distribution or other characteristics of the light automatically and precisely in response to factors such as ambient light levels, vacancy or the type of use of the outdoor space. Recently, there has been an interest in dynamic outdoor lighting because enabling technologies are becoming more cost-effective and because dynamic outdoor lighting has the potential to reduce energy use and light pollution. While dynamic lighting can include many different control schemes, most new dynamic outdoor lighting installations reduce light levels and electric power through switching or dimming during periods of low occupancy, so this report focuses on these types of installations. Dynamic outdoor lighting systems could also temporarily increase light levels, such as after sports events or concerts when pedestrian and vehicle traffic around a stadium are substantially increased. Temporary increases in light levels could be useful for public safety, for example, following an accident or crime, or during nighttime road repair work. In addition to varying light levels, dynamic outdoor lighting could also vary other characteristics of light, such as its spectral or intensity distribution, but because NLPIP did not identify any installations of this nature, they are not discussed in this report. Outdoor lighting installations that use photosensor or time clock controls for dusk-to-dawn operation are not discussed in detail either because they are already in widespread use. There are two factors that may hinder a greater use of dynamic outdoor lighting. One is the lack of familiarity with cost-effective technologies, especially given the prevalence of high-intensity discharge (HID) lamps, which are widely perceived as difficult to modulate over time. HID lamps are used in most outdoor lighting systems (Navigant Consulting 2002) and are likely to continue to be the dominant outdoor light source technology for many years. Uncertainty about the economic and technological feasibility of dynamically controlling this family of technologies is probably a major reason that dynamic outdoor lighting with HID lamps is not widely used. The legal liability of dynamic outdoor lighting is another factor hindering the widespread use of this technology. Because dynamic outdoor lighting generally involves reductions in light levels, the subsequent reduced visibility might become a liability to property owners, depending on the jurisdiction. This Lighting Answers summarizes NLPIP’s findings about dynamic outdoor lighting technologies, control strategies, and potential benefits and drawbacks. The applications discussed in this report include parking lots, parking garages, outdoor walkways, and streets, which are the most common places where dynamic outdoor lighting is found.
|
||||
|
|