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Might CFL lightbulbs be a thing of the past in the not-too-near future? Article here.
SustainableBusiness.com News
A "revolution" in the way we illuminate our world is imminent, according to a paper published this week by two professors at Rensselaer Polytechnic Institute.
Innovations in photonics and solid state lighting will lead to trillions of dollars in cost savings, along with a massive reduction in the amount of energy required to light homes and businesses around the globe, the researchers forecast.
A new generation of lighting devices based on light-emitting diodes (LEDs) will supplant the common light bulb in coming years, the paper suggests. In addition to the environmental and cost benefits of LEDs, the technology is expected to enable a wide range of advances in areas as diverse as healthcare, transportation systems, digital displays, and computer networking.
"What the transistor meant to the development of electronics, the LED means to the field of photonics. This core device has the potential to revolutionize how we use light," wrote co-authors E. Fred Schubert and Jong Kyu Kim.
Schubert is the Wellfleet Senior Constellation Professor of Future Chips at Rensselaer, and heads the university's National Science Foundation-funded Smart Lighting Center. Kim is a research assistant professor of electrical, computer and systems engineering. The paper, titled "Transcending the replacement paradigm of solid-state lighting," will be published in the Dec. 22, 2008 issue of Optics Express.
Researchers are able to control every aspect of light generated by LEDs, allowing the light sources to be tweaked and optimized for nearly any situation, Schubert and Kim said. In general LEDs will require 20 times less power than today's conventional light bulbs, and five times less power than "green" compact fluorescent bulbs.
If all of the world's light bulbs were replaced with LEDs for a period of 10 years, Schubert and Kim estimate the following benefits would be realized:
With all of the promise and potential of LEDs, Schubert and Kim said it is important not to pigeonhole or dismiss smart lighting technology as a mere replacement for conventional light bulbs. The paper is a call to arms for scientists and engineers, and stresses that advances in photonics will position solid state lighting as a catalyst for unexpected, currently unimaginable technological advances.
"LEDs have the potential to tremendously reduce pollution, save energy, save financial resources, and add new and unprecedented functionalities to photonic devices. These factors make photonics what could be termed a benevolent tsunami, an irresistible wave, a solution to many global challenges currently faced by humanity and will be facing even more in the years to come," the researchers wrote.
Possible smart lighting applications include rapid biological cell identification, interactive roadways, boosting plant growth, and better supporting human circadian rhythms to reduce an individual's dependency on sleep-inducing drugs or reduce the risk of certain types of cancer.
In October, Rensselaer announced its new Smart Lighting Research Center, in partnership with Boston University and the University of New Mexico, and funded by an $18.5 million, five-year award from the NSF Generation Three Engineering Research Center Program.
Website: http://smartlighting.rpi.edu
Nate not trying to be a jerk here I know you are just passing a message, but it is pretty much propoganda absent of facts and mis-leading
natescape If all of the world's light bulbs were replaced with LEDs for a period of 10 years, Schubert and Kim estimate the following benefits would be realized: Total energy consumption would be reduced by 1,929.84 joules Electrical energy consumption would be reduced by terawatt hours Financial savings of $1.83 trillion Carbon dioxide emissions would be reduced by 10.68 gigatons Crude oil consumption would be reduced by 962 million barrels The number of required global power plants would be reduced by 280
For outdoor, there is nothing better than low pressure sodium for efficiency at a whopping 200 Lumens per watt.
Yes LEDs come in different colors, none of which are very useful or appealing for area lighting to the Human eye with a CRI of 70. Variations of CCT (color correlated temperature) at different viewing angles present another obstacle against widespread use of white LED. It has been shown, that CCT variations can exceed 500 K, which is clearly noticeable by human observer, who is normally capable of distinguishing CCT differences of 50 to 100 K in range from 2000 K to 6000 K, which is the range of CCT variations of daylight.
LEDs also have limited temperature tolerance and falling efficiency as temperature rises. This limits the total LED power that can practically be fitted into lamps that physically replace existing filament & compact fluorescent.
Then there is the problem diffusion of LED light. It is very coherent light similar to a LAZER. Great for task lighting and flaslights, but horrible for area lighting.
Now LED's do have a place today and has some great uses as traffic lights, flashlights, automotive, stage, bicycle, billboards, and landscaping. But as of today they are not the best or even a good choice for general purpose area lighting.
Then there is the dirty little secret or trick of how LED manufactures measure the light or Lumens output. Remember I said the light is coherent like a Laser. Well they measure the light output in the focused beam. Move just out of the beam and you got squat.
Quality CFL’s cost around $2 for a 15 watt and last about the same 10,000 to 15,000 hours and give good quality light. To match that with a LED would mean about a 20 watt which does not exist and would cost around $75 to $100. What a deal huh?
Dereck
No need to apologize, your post is great! That's part of the reason I post stuff like this, so the experts can point out the fallacies and issues with the idea.
LED has a poor $/value today but those numbers are coming down fast. Whilst I always appreciate the value argument that Dereck brings in, its only valid today. From what I know about LED's, they are cheaper to make once the science is paid for.
As to the lumens point, there are a huge number of parameters to consider. Here is a link that is an interesting read of LED vs Neon signage whereas neon clearly comes out the winner. But there are some big qualifiers, the article is a few years old and as Marcus noted, that industry is moving like gangbusters. There are breakthru's that sit on the shelf because companies are still working on the breakthru's of last year and the year before....
And the Apples and Peas point that applications can really differ. An example I know well is that LED's will find great applications in the greenhouses of the world. Its not photosynthesis that we are looking for, the sun is the only affordable way to do this horse power of plant growth. It has to do with keeping the plants 'awake' for more than 12 hrs in the northern/southern parts of the globe during the winters. Its why I cant grow a tomato in Wisconsin from Nov to March. By quick flashing of the correct lighting, I can keep the tomato plants 'on'. Back in the day, UWMad PostDoc worked (an im sure published it cuz it looked neat) on a very fast moving lighting system that was kinda cool and did the job but was far too expensive to be practical. There is no light system better than LED for this task. and there are already a few Canadian companies implementing this technology. There are reasons that we use HPS in the greenhouses and T5's for germination. One is 100 yr old technology and the T5's I prefer over MH, a 100 yr old technology. In the real world, we keep the things we like and get the new stuff that works the best. I suspect LED's to be the same.
flectere si nequeo superos, Achaeronta movebo! -Virgil
Here's another article on LEDs, with the claim that Gallium Nitride (GaN) made on silicone instead of sapphire could lead to a breakthrough in cost.
ScienceDaily (Jan. 30, 2009) — A new way of making LEDs could see household lighting bills reduced by up to 75% within five years. Gallium Nitride (GaN), a man-made semiconductor used to make LEDs (light emitting diodes), emits brilliant light but uses very little electricity. Until now high production costs have made GaN lighting too expensive for wide spread use in homes and offices.
However the Cambridge University based Centre for Gallium Nitride has developed a new way of making GaN which could produce LEDs for a tenth of current prices.
GaN, grown in labs on expensive sapphire wafers since the 1990s, can now be grown on silicon wafers. This lower cost method could mean cheap mass produced LEDs become widely available for lighting homes and offices in the next five years.
Based on current results, GaN LED lights in every home and office could cut the proportion of UK electricity used for lights from 20% to 5%. That means we could close or not need to replace eight power stations.
A GaN LED can burn for 100,000 hours so, on average, it only needs replacing after 60 years. And, unlike currently available energy-saving bulbs GaN LEDs do not contain mercury so disposal is less damaging to the environment. GaN LEDs also have the advantage of turning on instantly and being dimmable.
Professor Colin Humphreys, lead scientist on the project said: “This could well be the holy grail in terms of providing our lighting needs for the future. We are very close to achieving highly efficient, low cost white LEDs that can take the place of both traditional and currently available low energy light bulbs. That won’t just be good news for the environment. It will also benefit consumers by cutting their electricity bills.”
GaN LEDs, used to illuminate landmarks like Buckingham Palace and the Severn Bridge, are also appearing in camera flashes, mobile phones, torches, bicycle lights and interior bus, train and plane lighting.
Parallel research is also being carried out into how GaN lights could mimic sunlight to help 3m people in the UK with Seasonal Affective Disorder (SAD).
Ultraviolet rays made from GaN lighting could also aid water purification and disease control in developing countries, identify the spread of cancer tumours and help fight hospital ‘super bugs’.
Funding was provided by the Engineering and Physical Sciences Research Council (EPSRC).
About GaN LEDs
A light-emitting diode (LED) is a semiconductor diode that emits light when charged with electricity. LEDs are used for display and lighting in a whole range of electrical and electronic products. Although GaN was first produced over 30 years ago, it is only in the last ten years that GaN lighting has started to enter real-world applications. Currently, the brilliant light produced by GaN LEDs is blue or green in colour. A phosphor coating is applied to the LED to transform this into a more practical white light. GaN LEDs are currently grown on 2-inch sapphire. Manufacturers can get 9 times as many LEDs on a 6-inch silicon wafer than on a 2-inch sapphire wafer. In addition, edge effects are less, so the number of good LEDs is about 10 times higher. The processing costs for a 2-inch wafer are essentially the same as for a 6-inch wafer. A 6-inch silicon wafer is much cheaper to produce than a 2-inch sapphire wafer. Together these factors result in a cost reduction of about a factor of 10.
Possible Future Applications