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.
I wouldn’t mind this bulb if it really never does need changing, but I just hope it works better than the low water toilets.
How much for a 100 wattt bulb? Lessee, (1) microwave generator (with shielding), (5) feet of specialized microwave guide tubing, (1) shielded target, ... oh, $800.
But it saves energy!
This last spring, I had to change a bulb. So I took it out and went to Lowes to get another one.
The gal behind the counter was kinda cute. But she objected. I said “This is probably older than you, I bought my house in ‘91”.
She says “No way! I’m 23!”
It was a mercury vapor bulb that sat on top of a 17’ pole that I risked my life getting out. A lamp that had turned on and off faithfully, each and every morning and night, since at least 1991.
I’m not saying light bulbs can’t be improved. But that’s pretty freakin good. Somebody gonna put a bulb up in a pole that’s halfway to the stratosphere, it better burn for awhile, cause I ain’t gonna be changing it once a month!
Well, OK, it might still need a little work.
I doubt it will be on the market for a while, yet. I am curious to see how they managed "A single microwave generator can be used to power several lamps."
The British company did not invent this technology. A Si Valley start-up company Luxim has been perfecting this technology for years and has products already
With our luck, scientists will find that phosgene gas works best.
Like they did with, "Hey, let's create deadly mercury vapor in the thinnest glass container possible and scatter them by the thousands throughout sealed office buildings!"
Evidently not necessarily. It's not like you're trying to locate a SU-27 at 150 miles...
For example, the microwave oven, quietly going about its business, is never given credit for its monumental savings in energy use compared to traditional means of heating and cooking foods.
On the really, really good side, I might finally see something I have been hoping for for years: the mug-sized microwave oven for re-heating coffee...
I believe the promoters of advanced, energy-saving technology would do well to disconnect the subject from the fraudulent hysteria surrounding Global WarmingTM and Climate ChangeTM. Real, useful science shouldn't condescend to lending credence to such unscientific jihads.
Whoa! That's more efficient than my furnace.
That's it. The furnace goes and I'm installing a 40,000 watt light bulb in the basement.
I think it means that you transmit the microwaves from a base station, and each lamp has an antenna that picks up the waves and converts them to DC.
According to this wiki entry, "Microwave power transmission (MPT) is the use of microwaves to transmit power through outer space or the atmosphere without the need for wires. It is a sub-type of the more general Wireless energy transfer methods, and is the most interesting because microwave devices offer the highest efficiency of conversion between DC-electicity and microwave radiative power."
It's been demonstrated for many applications.
Actually, they did. Things have come full circle from when the prototypes were delivered personally to the US in 1942.
"Pity Sir Henry Watson, Watt, with achievements too numerous to mention,
A victim of his own invention!"
When he received a post war speeding ticket based on... you guessed it...
Do you see a difference?
NOT the recomended way to distribute microwaves for use around living things!
Ah. Here I thought it was a technical microwave thing -- like "milli-angstrom radiation in the h-band approaching a cose efficiency of 19%".
You should have faked it and said that's what you meant.
That's the secret behind how it works -- you turn it on, it fries your optic nerve, and you think the room got brighter.
LOL! No, not if you're blasting 10kW of microwaves around the area.
But there are a lot of microwave transmissions around you -- comm links, and such. They can be made very directional, too. If the power density were similar to, say, that of a cell phone, you probably wouldn't have much concern.
The article doesn't say how much power one of these bulbs uses, so it's difficult to say how much microwave power you'd be beaming about.
Could be a long time.. I have had microwave ovens that lasted many years. They don’t tell you the microwave oven thing has a filament in it to make it work.
Not going to be $1.19, is it?
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