Illuminating deveopments
Light bulbs siphon a lot of juice out of the grid, which makes them perfect targets for anyone trying to conserve power. Compact fluorescents (CFLs) have been leading the charge, armed with mercury vapor and phosphor that emits far more light per watt than hot incandescent bulbs. But they’re toxic and expensive, so engineers are looking for alternatives.
Enter LEDs, light-emitting diodes. They can be twice as efficient as CFLs and 10 times as efficient as incandescent bulbs. But they’re expensive, complex structures of gallium nitride crystals, reflectors and even sapphires. Until now. Researchers at Perdue University have figured out how to make LEDs using good-old silicon wafers. The new process could mean LEDs that compete, price-wise, with CFLs and even incandescent bulbs. And the new LEDs are efficient—between 47 to 64 percent efficient. Compare that to an incandescent bulb’s paltry 10 percent and you can see how the new lights could save a ton of electricity.
That’s not all. LED manufacturer OSRAM has developed a new LED that’s significantly brighter than existing bulbs. They’ve managed to push 500 lumens out of a single 1-mm-square LED. To put things into perspective, a 100-watt incandescent bulb puts out about 1700 lumens. The new LEDs are also extremely efficient, cranking out about 136 lumens per watt. Again, a 100-watt incandescent only manages about 17 or 18 lumens per watt. OSRAM plans to put the new bulbs on the market within a year. Possible uses include small projectors, automobile lights and interior lighting for the home.
If that wasn’t enough, the startup Vu1 is producing a new type of light bulb altogether. They’re called ESL (electron stimulated luminescence) and they use electrons to directly stimulate a layer of phosphorus on the inside of a bulb. It’s the same technology that makes the old-timey tube TVs glow. The company claims that their bulbs emit about 40 lumens per watt. The light, they say, matches incandescent light in color and quality. The bulbs should be available in September 2008 for about $12 a piece. Not cheap, but on par with the price of a dim-able CFL.
So what difference will all these newfangled bulbs make? The US uses a third of its energy for lighting. Engineers at Perdue estimate that switching out incandescent bulbs could cut US energy consumption by about 10 percent.



