TechTheDay

Are you one of those who miss the warm glow of incandescent light bulbs? Here’s good news for you. It may not be long before the good old light bulbs stage a comeback. This is because of a recent technological breakthrough that is believed to be able to address the disadvantages that have led to the banning of incandescent bulbs in the European Union and its eventual unpopularity worldwide. Incandescent bulbs have been tagged as non-environment-friendly mainly because of its inefficiency as it converts most of the electricity into heat instead of producing light. This old and largely abandoned tech may get reincarnated with this new development.

The Breakthrough

Massachusetts Institute of Technology researchers have recently developed a method for incandescent bulbs to become more efficient. This method addresses the 5% efficiency disadvantage of incandescent light bulbs. To put things in perspective, fluorescent lamps have an efficiency of up to 15% while LED lamps have about around 5% to 20%, although this efficiency is projected to increase tenfold in the next decades as LED lighting technology matures.

The breakthrough is said to considerably raise the efficiency of incandescent bulbs to around 40% or up to 8 times the efficiency of old-fashioned incandescents. The details of the study have been published in the journal Nature Nanotechnology, listing the following MIT professors as authors: John Joannopoulos, Gang Chen, Ivan Celanovic, and  Marin Soljačić. MIT alumnus and Purdue University physics professor Peter Bermel is also one of the authors.

How Does It Work?

The keyword here is nanophotonics. Yes, there’s nanotechnology involved. The researchers developed a nanophotonic material and a process that recycles the light emitted by incandescent bulbs. Incandescents emit light that are visible and invisible. The heat produced by incandescents is basically invisible light or infrared radiation. What the researchers did is to recycle this invisible light so it can be made into something visible. To do this, they added secondary structures surrounding the filament of a conventional incandescent bulb to capture the infrared radiation and reflect it back to the the filament for re-absorption and re-emission.

These secondary structures are nanophotonic crystals made with Earth-abundant elements subjected to conventional material-deposition tech. The crystals are made as a pile of thin layers laid on a substrate. These crystals effectively filter light, allowing visible ones to pass through and making the invisible radiation bounce back to further heat up the filament and cause the emission of more light. Since the invisible light is unable to escape the bulb, it gets recycled over and over again until more visible light is produced. The researchers, however, did not mention how this infinite recycling process would affect the lifespan of the bulb.

Why the Return of Incandescent Is a Welcome Development

Aside from the more pleasant warm light emitted by incandescent bulbs, something preferred by many, the return of incandescent is welcomed because of the complaints on the toxic components in fluorescent lamps and CFLs. Also, from a business perspective, the short life of these bulbs is a boon considering that the prices of CFLs and LED lights have already dropped significantly over the years. Businesses would prefer having consumers buy the products from them more often.

Caveat

The researchers have not actually produced an incandescent bulb that already reaches the projected 40% luminous efficiency. So far, they were only able to produce one with 6.6%, which is not bad considering that it is already at the level comparable to those of CFL’s. However, based on their studies, they believe that that they are bound to create an incandescent bulb with the desired high efficiency.

Moreover, it’s unfortunate that this new incandescent technology is is not going to return with all the conditions it came with before. For one, the cost of the new bulb is bound to become higher. The new design of the bulb calls for new components and a different manufacturing process. These will most likely raise the price of the bulb. Since the bulb will be touted to be even considerably more efficient than CFLs and LED light sources, definitely, manufacturers will set higher prices for them. Manufacturers will have to invest in new equipment for the manufacture of the bulbs. Moreover, the relatively short lifespan of incandescent bulbs is not going to be eliminated with the dramatic improvement in the new bulb’s luminous efficacy. There’s the possibility that the bulb that will become commercially available will be highly efficient but relatively expensive and short-lived.

Other Applications

It’s an excellent idea combining the traditional look and feel of incandescent bulbs with the energy efficiency technologies of the 21st Century. However, the new technology developed by the MIT researchers is not only applicable to lighting. According to Marin Soljačić, in a news article published on the MIT website, another possible application of the technology they created is the implementation energy conversion schemes for thermo-photovoltaics. Soljačić believes that the core contribution of their work is the ability to control thermal emissions. There is no word yet on the expected commercial ability of this new incandescent technology.