Task 4.2 Investigate Ideal Lamp Light Output Dimming Ratio Required for Different Types of Applications

The overall scope of this project funded by the US Department of Energy (DOE) is to recommend means of reducing barriers to the wide spread use of lighting controls for commercial/industrial (C/I) applications using fluorescent systems. It is important to note that this project is focused on load-shed applications and photoelectric dimming where energy savings and energy management are of central concern. The project does not address architectural dimming found in many conference rooms or residential applications where multiple visual functions requiring different light levels (e.g., audio-visual presentations, conferences) are required to meet occupant objectives. This particular task (4.2) is concerned with switch-dimming, step-dimming and continuous-dimming in spaces dominated by electric lighting. Switch-dimming is switching one or more lamps off within a luminaire; step-dimming is dropping power to all lamps within the luminaire. In every case, the discussion is limited to linear, T-8 fluorescent lighting systems operated with electronic ballasts. Although, consideration of daylight from windows and skylights is implicitly excluded from this task because, ideally, an occupant will not perceive reductions in light levels if a successful photoelectric dimming system is installed, the system performance discussion is applicable to photoelectric dimming as well.