Demand-responsive Lighting - A Field Study

Demand-responsive buildings utilize control mechanisms to reduce their electricity use during periods of high grid-wide demand, primarily to aid utilities in maintaining grid stability. Dimming lighting is proposed as one such demand response mechanism, and several laboratory studies have explored the speed and extent of dimming that is either noticeable or acceptable to occupants. We conducted a field study to examine whether these laboratory findings could be applied in real buildings with commercial lighting control systems. The study, conducted during summer months, included an open-plan office with 330 dimmable luminaires, and a college campus with 2300 dimmable luminaires across several buildings. In the office building we conducted two afternoon demand response trials, which dimmed lights by up to 35 percent over 15-30 minutes. The power reduction achieved was 5.2 kW (23 percent), and 5.3 kW (24 percent), respectively. At the campus site we conducted three afternoon demand response trials, which dimmed lights by up to 40 percent over 1-30 minutes. The power reduction achieved was 15.2 kW (18 percent), 7.7 kW (14 percent), and 11.3 kW (15 percent), respectively. There were no lighting-related complaints to facilities management throughout the afternoons of the trials. Based on prior laboratory studies and this field study we suggest guidelines for dimming lighting as a demand response strategy.