Hi yaffle,
The major problem that has affected the tungsten lattice lamp is
two-fold: firstly, the technology was not in any way "household-ready"
when it was announced, as much as the initial press release gave that
appearance. The inventors and Sandia knew at the time that it would
not replace incandescent bulbs anytime soon, and if it did eventually
replace any types of the bulbs, it might only be for specialized
commercial uses such as electric powered cars. Secondly, the
technology that is more likely to be seen in households anytime soon
is the LED, and the bulb can't compete with the LED at this time.
A big obstacle to the tungsten bulbs is the development of the LED
(light emitting diode). Many people believe that LEDs are the future
of lighting and will replace incandescent lamps altogether. This seems
to have stalled the possible spread of the new tungsten lamp.
The press release for the new filament was grand:
"Now a microscopic tungsten lattice ? in effect, a tungsten filament
fabricated with an internal crystalline pattern ? developed at the
Department of Energy?s Sandia National Laboratories has been shown to
have potential to transmute the majority of this wasted infrared
energy (commonly called heat) into the frequencies of visible light.
This could raise the efficiency of an incandescent electric bulb from
5 percent to greater than 60 percent.
By doing so, it would greatly reduce the world?s most vexing and
important power problem ? the required excess electrical generating
capacity and costs to homeowners caused by inefficient lighting, as
well as the environmental damage accompanying unnecessary power
generation."
http://www.sandia.gov/media/NewsRel/NR2002/tungsten.htm
Here are some possible reasons behind the delay to market:
1. The product was never intended for wide commercial
release/replacement of regular incandescent bulbs in the first place
(at least anytime soon). By contrast, it will need new developments in
nanotechnology in order to become a viable product.
Despite what the original press release stated, Sandia seems to have
had less in mind for the new filament than trying to bring it to the
home of the average incandescent user in the near future. First of
all, the filament didn't even give off a visible light! (amazingly
enough)
http://www.sciencentral.com/articles/view.php3?article_id=218392029&cat=3_5
"Right now, when [inventor Shawn] Lin heats his tungsten
photonic-crystal filaments, they give off much more infrared light
than the original solid tungsten filaments, a very promising result.
But although infrared light's wavelength is close to that of daylight,
it is still invisible.
Lin thinks that tiny, inexpensive slivers of his tungsten
photonic-crystals might eventually replace solid tungsten filaments
inside light bulbs. His photonic crystals also might help power
electric generators, engines and equipment more efficiently. But
first, he must shrink his crystals? lattices even smaller, to a size
where they can manipulate wavelengths of visible light.
?Nanotechnology is of crucial importance? to Lin?s efforts, and he
expects to need at least another two years to build the crystal he
needs."
I could not find any new updated stories on Lin's progress, but it
seems that he may have been putting too soon of a timeline on the
availability of nanotechnologies. Nanotechnology will certainly become
widely used, but it has not yet.
The crystallized structure and lab construction involving photonic
elements could be more expensive to reproduce at the mass level than
existing incandescent bulbs (and therefore not be price-competitive at
this time). Sandia had more specific, grander plans in mind for the
bulb than mere takeover of existing incandescents.
"This greater useful output offers the possibility of a superior
energy source to supercharge hybrid electric cars, electric equipment
on boats, and industrial waste-heat-driven electrical generators."
http://www.sandia.gov/news-center/news-releases/2003/other/planck-lin.html
In addition, Sandia realized that LEDs were the next wave, and even
said at the time that their incandescents might form the next wave of
the future AFTER LEDs. (Not a good sign of their possible immediate
commercial availability).
"If these results at 1.5 microns can be extended to the visible
spectrum, ramifications of this work may help form the next generation
of lighting after the currently more mature LED technology."
2. The product is still in the the early development stages.
"It is too early in the development of the product to make any
predictions of the likely cost implications and transformation
potential."
http://www.mtprog.com/ApprovedBriefingNotes/BriefingNoteTemplate.aspx?intBriefingNoteID=101
3. Other products are currently more efficient for everyday usage.
LEDs and flourescents:
"The best white LEDs on the market emit 25 lm/W, which is almost twice
as efficient as an equivalent tungsten-filament light bulb, but barely
a third as good as a fluorescent tube."
--The Economist
While the photonic lattice filament would bring the bulb's efficiency
closer to that of the flourescent, it still would not be able to
complete with the white LED.
4. Lamp life.
The lamps will last about 1,000 hours, about the same as other
incandescent lamps. In contrast, LEDs and OLEDs will last 100,000
hours and flourescents will last 10,000 hours.
A closer look at the LED.
The new tungsten filament seems to be too expensive to bring to
everyday households and the research that would be required for making
it suitable/available/inexpensive would also be prohibitive. Sandia
prefers to spend research dollars on the LED these days. Lighting
companies are convinced that the LED is the wave of the future.
Already, new traffic lights and flashlights are lit by LEDs.
Eventually, it seems that everything will be. Here is an article in
the Economist which "illuminates" the issue:
http://www.economist.com/displaystory.cfm?story_id=1365100
A rundown of LEDs' benefits:
--They are expensive to produce but will be more efficient and last
much longer than flourescents or incandescents. At the same time,
manufacturing costs are coming down. They don't flicker like
flourescents. They don't have any glass parts or dangerous elements
such as filaments. When LEDs seem to be the wave of the future, it's
understandable that no one is spending too much time bringing to
market a more efficient incandescent. That would be akin to someone
bringing forth a larger floppy disk rather than turning to CD
manufacturing.
Sandia Laboratories itself is convinced of this fact, as seen by their
news headlines page here:
http://lighting.sandia.gov/Xlightingnewsheadline.htm
which contains news of new lighting developments. Every single one of
the new developments has to do with LEDs. They seem to be the wave of
the future, and Sandia has acknowledged that.
In addition, the very technology that Sandia used to develop the new
tungsten filament, the photonic lattice crystalizaton method, is used
now in LEDs to make them more efficient. Since they are already more
efficient in the first place, the tungsten filament is left far behind
in efficiency. It could be made more efficient by the Sandia lab
researchers and possibly come into play for hybrid cars in the future,
but seeing one in someone's household anytime soon is unlikely.
I hope this answers your question. If you need any clarifications, let
me know and I'll be glad to help.
--keystroke-ga |
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