The U.S. Department of Energy has published the final evaluation report from a retrofit of 32 track lights used to illuminate artwork in the lobby of the Bonneville Power Administration (BPA) headquarters building.
During the demonstration, 12W LED PAR38 lamps replaced 15W and 23W reflector compact fluorescent lamps that were installed in 2001, and comparisons were also made to original 90W halogen PAR38 reflector lamps replaced by the CFLs. This GATEWAY demonstration report provides an overview of project results including lighting quality, power quality, energy use, and life-cycle cost.
Key findings include:
- Although both CFLs emit more light than the PAR38 LED replacement lamp, the narrower light distribution of the LED product concentrated the lumens on the artwork and minimized the amount of light striking the wall above the art.
- Color temperature was around 2700K for all three lamps, but color quality improved with the LED lamping, from a color rendering index (CRI) of 82 for the CFL to a CRI of 93 for the LED. The LED lamp showed improved rendering of red tones in architectural finishes and artwork compared to the CFL products.
- Power quality also improved with these LED lamps, although that is a function of the electronics design of these lamps, rather than a feature of LED lamps universally. Power factor increased from 0.50 or 0.55 for the incumbent CFLs, up to 0.94 for the LED lamp.
- The study did not show rapid payback on the LED installation compared to the CFL products, considering the low electrical rates, the high cost of the LED lamps, and the fact that CFLs are already a fairly efficient light source. Life-cycle cost analysis done with more typical U.S. electric rates shows a payback time in the 7-8 year range compared to the 23W CFL.
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