Four words that I thought I’d never write: incandescent lightbulbs are back.
If you’re like me, you’d written off these antiquated orbs of inefficiency as dead and buried following the conclusion of the seemingly never-ending political grudge match otherwise known as the Great Lightbulb Wars. You'd embraced the federally mandated phase-out of incandescent bulbs as a good thing, a chance to invest in low-wattage lighting options that require swapping out every few years, not every few months. After all, Edison himself would have likely been totally cool with trying something innovative and new — despite the fact that the innovative and new (read: CFL and LED bulbs) looked weird and didn’t cast quite the same reassuring buttery glow as incandescents.
If you’re like me, you'd moved on.
Yet here we are at the top of 2016 discussing an incandescent lightbulb — a new incandescent lightbulb developed by a team of researchers at the Massachusetts Institute of Technology that, thanks to a breakthrough in nanotechnology, promises to be even more efficient than LEDs.
My first question is why? Why would researchers want to resurrect a lightbulb “thought to be way on its way to oblivion” and render it more efficient?
No doubt that the incandescent lightbulb, a popularly hoarded home item that's now largely viewed as an outmoded emblem of government overreach, is a wonderful, world-changing invention. Its form is iconic and the light that it produces is matchless. (Many LED bulbs, however, have succeeded in closely mimicking the real deal.) Yet incandescents always functioned better as Lilliputian space heaters than actual light-emitters, given that 95 percent of the energy that they consume is wasted as heat.
The MIT team, which includes professors Marin Soljačić, John Joannopoulos and Gang Chen, haven’t necessarily reinvented the incandescent bulb. Nor do they want to do away with LEDs and CFLs and usher in a new era of incandescents. They've simply set out to solve an old problem using new technology.
Via MIT News:
‘LEDs are great things, and people should be buying them,’ Soljačić says. ‘But understanding these basic properties’ about the way light, heat, and matter interact and how the light’s energy can be more efficiently harnessed ‘is very important to a wide variety of things.’
Key to the technology on display with these next-gen incandescents is a two-stage “light recycling process” in which infrared radiation produced by a conventional tungsten filament is captured by photonic crystals-based filter wrapped around the filament itself. Acting as nano-mirrors, the crystals — “made of Earth-abundant materials” — reflect the energy back to the filament itself so that the radiation, instead of being wasted as heat, is reabsorbed and harvested to produce visible light.
That second step makes a dramatic difference in how efficiently the system converts electricity into light. One quantity that characterizes a lighting source is the so-called luminous efficiency, which takes into account the response of the human eye. Whereas the luminous efficiency of conventional incandescent lights is between 2 and 3 percent, that of fluorescents (including CFLs) is between 7 and 15 percent, and that of most compact LEDs between 5 and 15 percent, the new two-stage incandescents could reach efficiencies as high as 40 percent, the team says.
The breakthrough, unveiled in the journal Nature Nanotechnology, is no doubt impressive if a touch confounding to those of us who don't dedicate our time and energy to nanophotonics. It’s easiest just to think of these incandescents as self-recycling bulbs that harness a source of waste and transform it into a source of energy.
So does the technology signal a comeback for the incandescent? Maybe, but I wouldn’t hold your breath, Michele Bachmann.
Applying light-recycling technology to commercial lighting is just a small piece of a very complex puzzle as the MIT team investigates other applications in which this groundbreaking thermal emissions-controlling process could be more immediately beneficial.
However, as Soljačić explains to the BBC, he would not “exclude the possibility of” incandescent bulbs reemerging in an entirely more efficient form. And it's not totally out of the question considering that incandescent bulbs themselves aren't outlawed ... the most popular wattages just have to be manufactured to meet efficiency standards established in 2007.
“Thomas Edison was not the first one to work on the design of the lightbulb, but what he did was figure out how to mass produce it cheaply and keep it stable longer than 10 hours, these are still the two critical criteria," says Soljačić. "These are the questions we are trying to answer now.”
“We have this huge challenge that the world is facing right now, global warming and energy efficiency and this gives you one more tool in the toolbox to meet that huge challenge," Soljačić adds. "We are very excited about the potential though."
Via [BBC], [MIT News]