Researchers develop energy-efficient incandescent bulbs

Traditional incandescent bulbs have been less preferred since the energy efficient LED bulbs came around. Researchers from Massachusetts Institute of Technology and Purdue University may bring incandescent bulbs back in fashion.

More than 95 percent of the energy used in incandescent bulbs is wasted on heat. Now, researchers came up with a technique to turn heat into light.

Instead of letting heat escape the bulbs, a structure surrounding the filament traps the heat, reflects it back to the filament to be reabsorbed and emitted as visible light. The team refers to their process as “light recycling” since it takes unwanted heat energy into something more useful.

The technique has the potential to make incandescent bulbs more efficient than commercial LEDs. In terms of luminous efficiency, incandescent lights is between 2 and 3 percent, that of fluorescents (including CFLs) is between 7 and 15 percent, and that of most commercial LEDs between 5 and 20 percent, the new two-stage incandescents could reach efficiencies as high as 40 percent, the team says.

Their first bulbs only achieved 6.6 percent efficiency, a number already at par with LEDs.

The new findings are reported in the journal Nature Nanotechnology by three MIT professors — Marin Soljačić, professor of physics; John Joannopoulos, the Francis Wright Davis Professor of physics; and Gang Chen, the Carl Richard Soderberg Professor in Power Engineering — as well as MIT principal research scientist Ivan Celanovic, postdoc Ognjen Ilic, and Purdue physics professor (and MIT alumnus) Peter Bermel PhD ’07.