Keeping the Lights On

Keeping the Lights On Keeping the Lights On Keeping the Lights On?Change can be difficult. When youve spent your whole life with a certain way of overcoming the darkness, you dont necessarily jump at the chance to find a new light. But with rising costs and falling energy efficiency, it looked as if the day of the incandescent light bulb had ended. Familiar and pleasing to the eye though they were, it still appeared it was time for them to go the way of the eight-track player.But a gruppe at MIT has been working on new technology that just might help the incandescent light bulb stay alive and compete with both light emitting diode (LED) bulbs and compact fluorescent lamp (CFL) bulbs. The answer may be looking you in the mirror.Our S3Tec Energy Frontier Research Center, funded through the Department of Energy, had a team working on ways to tailor the emission of a hot surface, says Professor Gang Chen, the head of the department of engineering at MIT. Electricity converting into light efficiency is interesting. It can be infrared when youre talking about incandescent, which is not useful. But maybe reflecting light on a cold surface could help and the konzeptioning went forward.Chen says the setup is that wavelengths would go through filament material, hit a mirror-like substance, a photonic crystal, and reflect until it heats up to give light to the bulb. The eye picks up the light easier this way, he says, adding that it helps with part of the issue of incandescent efficiency.Theoretical (top) and experimental (bottom) iso-frequency contours of photonic crystal slabs superimposed on each other. Image MITIt can go beyond just lighting a room potentially, with an added benefit being that some of the energy could be recycled in effect, he says. There is also the possibility that this can translate to areas like thermo-photovoltaics but more exploration would need to be done here, he says.The next steps include further demonstrating the efficiency to understand ju st where it might rank as a competitor to LEDs and CFLs. We need to do a better technology assessment in how it will do against the energy-efficient bulbs now being sold and to see whether this is just a niche market or something bigger, he says. Its definitely been a good starting point.For Chen, its been energizing just watching people run with old technology and make it come to life. Sometimes it just takes the right timing with design tools in place and good energy, he says. Its been great to see whats happened so far.Regardless of its future, the incandescent light bulb remains a marvel, one more example of Thomas Edisons well-known persistence, which has been lighting homes since the 19th century. This latest work doesnt necessarily mean people will some day stop buying the energy-efficient LED and CFL bulbs but it shows that old technology doesnt necessarily have to be thrown away. Sometimes we need to look at how it might work differently. It does get you thinking about how this all started, he says. The bulb itself is an amazing invention.Eric Butterman is an independent writer.Learn more about the latest energy technologies atASMEs Power and Energy. For Further Discussion We need to do a better technology assessment in how it will do against the energy-efficient bulbs now being sold and to see whether this is just a niche market or something bigger.Prof. Gang Chen, MIT