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January 29, 2016 -
The incandescent light may not be dead after all. Researchers at MIT have found a way to use nanotechnology to capture and reuse the waste heat generated by an incandescent filament to increase the lamp's luminous efficiency even above levels available with current LED technology.
Typical incandescent light bulbs only convert between 2 and 3 percent of the energy they consume into visible light. This inefficiency is what has led them to be replaced by more efficient CFL and LED technologies, which respectively achieve efficiencies up to 15 and 20 percent, says MIT in a release announcing their researcher's findings. The technology being researched at MIT could theoretically increase incandescent bulb efficiency to 40 percent, though the first proof-of-concept model only reached an efficiency of 6.6 percent.
Researchers surrounded a 3,000K tungsten filament with "a cold-side nanophotonic interference system optimized to reflect infrared light and transmit visible light," according to their report in Nature Nanotechnology. MIT explains how the technology works. Basically, the nanotechnology bounces the waste heat back at the filament instead of letting it escape. The filament reabsorbs this heat, and re-emits it as visible light. Because of the way the photonic crystal itself is constructed with thin layers sequenced just right to only let visible light out, the heat just keeps getting recycled, says MIT.
Beyond improving light bulbs, researchers anticipate the technology could be used to improve the performance of thermo-photovoltaic devices. These systems use heat to make a material glow, and a photovoltaic absorber generates electricity by capturing this light, explains MIT.
The Nature Nanotechnology article where the MIT researchers published their findings can be found here.
Find out which incandescent lamps used in commercial facilities were phased out and which got an exemption in this Building Operating Management article.
This Quick Read was submitted by Naomi Millán, senior editor of Building Operating Management magazine, email@example.com.