The U.S.Department of Energy(DOE)has published the final evaluation report from a retrofit of track lighting at the Smithsonian American Art Museum in Washington,DC.During the demonstration,LED PAR 30 and MR16 lamps replaced all traditional incandescent lamps in one gallery and LED PAR 38 and MR16 lamps partially replaced incandescent lamps in two other galleries.This GATEWAY demonstration report describes the selection and testing process,technology challenges,perceptions,economics,energy use,and mixed results of using LED replacement lamps in art galleries housing national treasures.
Key findings include:
•The museum was able to achieve very satisfactory visual results in terms of both color and composition with LED lamps,despite some issues with equivalency,beam angles,and compatibility with the museum's low-voltage track heads and dimming control system.The museum's incandescent lamps could not be replaced one-for-one,but the variety of LED lamps available offered new opportunities to tailor the lighting effects for the specific art works.
•Power use in the gallery completely relamped with LEDs decreased from 3.9 to 1.1 watts per square foot,reducing electricity costs from$2,984 to$816 per year and recovering the higher initial cost of the LEDs in 16 months of operation through energy savings alone.
•Spot-relamping frequency and cost were reduced considerably because of the LED's longer expected life.A 10-year life-cycle cost analysis including maintenance savings,at$0.14 per kWh melded electric rate,found a total present value energy savings of$19,041,with a total present value life-cycle cost savings of$27,891.
•Samples of three LED replacement lamp types used in one gallery were sent for baseline photometric testing and are scheduled for follow-up testing after 4000,8000,and 12,000 hours of use.The PAR 30 lamps tested at 4000 hours remained very stable in terms of color and moderately stable in terms of light output,but the MR16 LED lamps exhibited more change in terms of lumen output and color.
