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Posted on 09/21/2007 5:55:06 AM PDT by Uncledave
Everlasting light Sep 6th 2007 From The Economist print edition
Energy: Researchers have developed an environmentally friendly light bulb that uses very little energy and should never need changing
ALTHOUGH it symbolises a bright idea, the traditional incandescent light bulb is a dud. It wastes huge amounts of electricity, radiating 95% of the energy it consumes as heat rather than light. Its life is also relatively short, culminating in a dull pop as its filament fractures. Now a team of researchers has devised a light bulb that is not only much more energy-efficient—it is also expected to last longer than the devices into which it is inserted. Moreover, the lamp could be used for rear-projection televisions as well as general illumination.
The trick to a longer life, for light bulbs at least, is to ensure that the lamp has no electrodes. Although electrodes are undeniably convenient for plugging bulbs directly into the lighting system, they are also the main reason why lamps fail. The electrodes wear out. They can react chemically with the gas inside the light bulb, making it grow dimmer. They are also difficult to seal into the structure of the bulb, making the rupture of these seals another potential source of failure.
Scientists working for Ceravision, a company based in Milton Keynes, in Britain, have designed a new form of lamp that eliminates the need for electrodes. Their device uses microwaves to transform electricity into light. It consists of a relatively small lump of aluminium oxide into which a hole has been bored. When the aluminium oxide is bombarded with microwaves generated from the same sort of device that powers a microwave oven, a concentrated electric field is created inside the void.
If a cylindrical capsule containing a suitable gas is inserted into the hole, the atoms of the gas become ionised. As electrons accelerate in the electric field, they gain energy that they pass on to the atoms and molecules of the gas as they collide with them, creating a glowing plasma. The resulting light is bright, and the process is energy-efficient. Indeed, whereas traditional light bulbs emit just 5% of their energy as light, and fluorescent tubes about 15%, the Ceravision lamp has an efficiency greater than 50%.
Because the lamp has no filament, the scientists who developed it think it will last for thousands of hours of use—in other words, for decades. Moreover, the light it generates comes from what is almost a single point, which means that the bulbs can be used in projectors and televisions. Because of this, the light is much more directional and the lamp could thus prove more efficient than bulbs that scatter light in all directions. Its long life would make the new light ideal for buildings in which the architecture makes changing light bulbs complicated and expensive. The lamps' small size makes them comparable to light-emitting diodes but the new lamp generates much brighter light than those semiconductor devices do. A single microwave generator can be used to power several lamps.
Another environmental advantage of the new design is that it does not need mercury, a highly toxic metal found in most of the bulbs used today, including energy-saving fluorescent bulbs, fluorescent tubes and the high-pressure bulbs used in projectors. And Ceravision also reckons it should be cheap to make. With lighting accounting for some 20% of electricity use worldwide, switching to a more efficient system could both save energy and reduce emissions of climate-changing greenhouse gases.
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Oh great! Now we can cook our brains for light!.............
How long will the microwave generator last?
What is the “cose effectiveness of the lamp?”
In this case, turn on the microwave and the lights go on.
It'll be rough having prohibited late night snacks. You put something in the microwave, and the bedroom light goes on.
hmm, i’m sure they are greatly scaled down since all they have to do is get a couple lights going vs defrost 5 pounds of frozen spaghetti sauce, but I would def like to see how they set this up. I love reading about new techs and it def looks like these guys were thinking outside of the box on this one.
But why does it have to be put in the environmentalism template? Why can't it just be seen as more energy efficient and leave it at that? We'd save money. Good enough for me.
Which means it's 100% efficient if the heat is on.
We repair and restore antique lamps at our place of business. In the winter, I don't use any other heat source to heat our shop except lamps. Turn on about 50 lamps and the place really heats up. We keep the lamps off in the summer.
I realize the lowly incandescent bulb is not energy efficient, but I love it's warm, amber light. I hate those bright curly-cue light bulbs that everyone keeps pushing on me. When I have one of those on, I feel like I'm in a dentist's chair, having my teeth worked on. Not cozy, not cozy at all.
Would be great for difficult to reach light sources such as high ceiling, remote, etc. where the cost of replacing standard bulbs is magnified by manpower expenses
Well, in a sense yes, but keep in mind electric heat is the most expensive way to heat a house. 100% Efficient? Yes. Cost effective? No.
Burner contains no electrodes
No luminance or color degradation of the emission due to interaction of the burner chemistry with the electrodes.
Manufacture of the burner is simple and very low cost.
Burner contains low pressure gas fill
Burner remains intrinsically safe even when subject to catastrophic failure.
No explosion risk to users.
Burner chemistry can be tuned to give
primarily molecular excitation or atomic excitation
More uniform spectral content that better matches a black body radiator.
Emission can be tuned by modifying burner chemistry Varying the chemistry of the metal halide salt mix allows the spectral emission to be tuned to the needs of specific applications. This includes various color temperature variants of “white light”, “UV light” or exclusively “IR light”.
Burner is mounted in a metalized low-loss dielectric resonator
Use of a metalized low-loss dielectric resonator allows the microwave component dimensions to be condensed compared to air-based cavities.
Microwave interface unit supplying power to antenna in a metalized low-loss dielectric resonator block limits reflected power to <0.5% of incident power The simple microwave interface unit offers a low cost solution for protecting the power amplifier at burner ignition. Circuitry is reduced to a minimum, and no feedback system is required to modify the amplifier operating frequency.
Amplifier can be designed using solid state or magnetron power sources Allows designers to choose a solution that meets the technical and commercial needs of individual applications.
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