The warm glow of traditional light bulbs could return to homes and replace cold-looking LEDs, thanks to research conducted by a team at Massachusetts Institute of Technology (MIT).
The team has found a way to make incandescent bulbs ? which produce light as a result of heat ? more efficient by using nanotechnology to recycle the wasted infrared energy.
The updated design includes a traditional filament that is heated as normal. However, secondary structures made from specially developed crystals surround the wire, capturing the waste radiation and reflecting it back to the filament to be re-absorbed and re-emitted as visible light.
Because the waste heat is returned back to the filament, less energy is needed to keep it warm. "It recycles the energy that would otherwise be wasted," said MIT professor Marin Solja?i?.
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Filament bulbs developed by Thomas Edison in the late 19th century illuminate by heating a thin tungsten wire to temperatures around 2,700 degrees Celsius. This produces a broad spectrum of light and a warm appearance, but wastes more than 95 per cent of the energy as heat.
For this reason, the bulbs have slowly been phased out over the past few years in favour of more efficient compact fluorescent bulbs (CFLs) and light-emitting diode bulbs (LEDs). However, these options emit a colder, harsher light that is less atmospheric in the home.
The aim of ...