Guest post by Yes, actually. The old-school, inefficient, heat-generating incandescent bulbs are all but history, CFL (compact florescent) bulbs taking the pedestal what with how relatively inexpensive and efficient they are when it comes to both electricity consumption and overhead cost. However, even these may have a short-lived supremacy as British scientists developed a new way of “growing” the material needed for LEDs on silicon instead of sapphire wafers, which was the original and somewhat expensive way of doing it. Because of this, household-grade lights of LED nature can be produced for under $5.00 and last up to sixty years. LEDs are three times more efficient than CFLs, last substantially longer, and contain no mercury, so they’re even more environmentally friendly. These wonder-bulbs are supposed to be available to consumers within two years. It is estimated that if these new bulbs were to be installed in every home and office, it would cut electricity used on lighting by 75%. I’ll take twenty of those, please.
There are a few LED bulbs out now, but they are expensive. I refuse to buy CFL Bulbs due to their mercury and, in my experience, they last only a few months longer than incandescent bulbs making them more expensive on average. Oddly, this news was out back around October of last year.
LEDs! I want ’em.
LEDs were (are) relatively expensive, but note the article said that now the scientists can grow the stuff needed on silicon wafers instead of sapphire ones– making the production substantially cheaper– around $5.00– and even selling these for $10.00, divide that cost over even 30 years (half the expected life) and the cost of electricity saved… that’s one cheap bulb.
I’m all for the LED takeover, though. Imagine changing a bulb your grandfather installed in the same house over half a century before? That would be a strange moment, indeed!
Edited 2009-02-04 08:12 UTC
Yep, heard that news back around October.
Do you include the cost of the electricity used in this cost estimate?
Actually, yes. It ends up being a wash.
Same for me. I dislike CFLs because they contain mercury, and because of their white light (personal taste). I prefer yellow light. CFLs also emit strong electromagnetic radiations, which can contribute to cancer if exposed for too long and too close.
Mercury: Yes, they need to be disposed of properly; the powers-that-be have done a poor job of ensuring that this happens. However, lots more mercury comes out of coal-fired power plants. As for personal danger, this is mostly a myth (spread repeatedly by Rush Limbaugh – maybe somebody can explain exactly why).
Electromagnetic radiations: Do you mean ultraviolet light? Sure, but very little compared with moderate exposure to the sun. If you mean something else, please be specific.
At least we agree that color preference is personal.
Edited 2009-02-04 13:49 UTC
Yes, there are also UV radiations. More:
And:
Lots of good info here: http://www.mastsanity.org/index.php?option=com_content&task=view&id…
Also: http://www.medicalnewstoday.com/articles/125371.php
Because he’s a denialist. The only reason for using CFLs is to reduce energy consumption, which reduces global heating. But since Limbaugh denies global heating, and thinks energy consumption is good for economy, he is anti-CFL, and as these nuts do, they spread propaganda (i.e. lies).
There are yellow CFLs, though the color’s called “warm white”.
… British scientists developed a new way …
Until we sell it to the Americans.
and not (entirely) switching to CFL until then.
I actually have a few CFL, and am very disappointed: not only they don’t last much longer than incandescent, and nowhere as advertised, but the quantity of light they emit declines progressively until they fail.
I noticed that when it got harder for me to read in my home office.
15 years ago, I had halogen lamps in every room, super bright. But with the environmental/economic situation, we are slowly going back to the “dark ages”.
I hope these LED bulbs reverse the trend and become ubiquitous.
The next step would be to make sheets of these, to apply them on walls or ceilings for diffuse yet powerful lighting.
Many bulbs meet they’re early death by other means, such as surges in electricity, faulty wiring thats good enough most of the time, but unstable enough to kill bulbs like they were hired to do so. That along with temp/humidity fluctuation, physical damage, or poor workmanship in the bulb, not to mention you have no idea how certain materials age under the new duty’s they have been given, you may find in a couple years some of the parts that make up the bulbs deteriorate in ways you never thought. So while its good to have longer lasting solutions on the horizon, its very unlikely they will reach the lofty goals they are talking about.
I already have LED lighting in my home. They are ealy generation, though, so they are not powerful enough for anything other than atmospheric lighting.
Still, it’s fun to do the math for these bulbs, and come to the conclusion that the energy spent flicking the switch twice a day to turn them on and off is actually more than when you leave them on all the time
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I would be very interested in seeing that math, because frankly, I don’t believe it.
In the past I’ve heard the same myth about incandescent bulbs. And while it’s certainly true that those have a peak current when switched on (mainly because they’re cold at the time) which is many times their normal current, that’s easily outweighed by the energy needed to light the bulb for any appreciable amount of time.
For example, let’s be very pessimistic about those incandescent bulbs, and say that the peak current is 100 times their normal current, and it lasts for a full second. Even then switching it on would only take the energy equivalent for lighting the bulb 100 seconds.
(Actually, more realistic values according to http://en.wikipedia.org/wiki/Incandescent_light_bulb#Electrical_cha… are a peak current of 15 times normal, and a duration of 0.1 seconds. This results in a switch-on using the energy equivalent to only 1.5 seconds of normal operation.)
I can see LED lighting having some extra energy usage at switch-on too, although not so much the effect described above. LEDs operate at much lower voltage than the 230/120V usually present in light fixtures, so they need a power supply to convert the voltage. Switching on such a power supply will indeed cause an extra inrush current.
To be honest, I find it much more difficult to guesstimate the amount of energy lost in this case, also because it depends on more factors (nominal voltage and current to LEDs, linear or switching voltage regulator). At the risk of boring you to death, I’ll try though:
Let’s assume a linear voltage supply, because they use a (relatively) big capacitor for storing energy to overcome “ripples” in the voltage. This is the primary element that needs a lot of energy on switch-on, which is essentially useless after the supply is switched off. Let’s take a big one, one you’re more likely to find in a nice amplifier than in a LED power supply: 10.000 uF. Finally, let’s assume there’s some 24 volt across that capacitor (I’ve got LED strips here that need 24 volt, so that seems reasonable).
For the energy stored in a capacitor the following formula applies:
E = 1/2 * V * Q^2, with
Q = V * C
where V=voltage, Q is charge stored in the capacitor, and C is the capacitance.
So E = 1/2 * V^3 * C^2
= 1/2 * 24^3 * (10^-2)^2
= 69 J
Which means that under these (IMO pessimistic) assumptions, even when your LEDS use only 1W, the energy lost on switch-on is only equivalent to 69 seconds of normal operation!
Whichever way you look at it, you would be hard pressed to inflate the numbers enough to justify not switching off the lights for the 6 to 8 hours a day that you sleep.
The compact fluorescent have gotten a lot better in the last few years; they now last absolutely ages. I have half fluorescent and half halogen oyster lights, and the oysters lights blow all the time. It’s been over a year since I’ve had to change any of the compact fluorescent lights.
What sort of bulbs are used in traffic lights? I know some of the recent ones are LEDs, but what did they use before? You never see a traffic light with a single dead bulb, nor would you want to 🙂
What about pre-LED traffic lights? Probably incandescent, operated at a slightly lower voltage than for normal domestic use. For relevant equations, see http://en.wikipedia.org/wiki/Lamp_rerating
For lot’s more, see the section “Voltage, light output, and lifetime” in http://en.wikipedia.org/wiki/Incandescent_light_bulb
I remember seeing a few years ago what were obviously LED’s for red and green, but not for orange.
I wonder what color these next gen LED bulbs will be? Can they produce “warm” natural light or just stark white?
I’d guess the “stark white” you think of is due to the awful “white” LED bicycle headlights, etc, which are actually blue (or violet?) LED’s with fluorescent coating. Next gen could be tunable multiple-chip lamps (vary the current through each of red, yellow, green, blue, violet, etc) where you can have your “warm” olde-yellow
and I can have my bright, exciting, sunny 5900K white.
I was an early adopter of CFL’s (2 to 6 straight tube sections, as much as 8 inches long). Over the years they got much cheaper, and somewhat better. The lifetime always seemed shorter than claimed and has always been very inconsistent, even within the same batch. Several went up in smoke, literally. Others just flickered out after a few weeks or even days. Others lasted many months. I use them because I really like the light of the bluish “sunlight” type; can’t stand the more usual yellowish ones (seem more yellowish than the old ones). Like many others, I see them only as a stopgap until LED’s fully arrive. I look forward to LED’s using several individual-color chips which can be custom tuned to whatever spectrum I want.
There are significant disadvantages (besides the cost) with the current LED technology:
Light quality: Most cool-white LEDs have spectra that differ significantly from a black body radiator like the sun or an incandescent light. The spike at 460 nm and dip at 500 nm can cause the color of objects to be perceived differently under cool-white LED illumination than sunlight or incandescent sources, due to metamerism,[48] red surfaces being rendered particularly badly by typical phosphor based cool-white LEDs. However, the color rendering properties of common fluorescent lamps are often inferior to what is now available in state-of-art white LEDs.
Area light source: LEDs do not approximate a “point source†of light, but rather a lambertian distribution. So LEDs are difficult to use in applications requiring a spherical light field. LEDs are not capable of providing divergence below a few degrees. This is contrasted with lasers, which can produce beams with divergences of 0.2 degrees or less.
Blue Hazard: There is increasing concern that blue LEDs and cool-white LEDs are now capable of exceeding safe limits of the so-called blue-light hazard as defined in eye safety specifications such as ANSI/IESNA RP-27.1-05: Recommended Practice for Photobiological Safety for Lamp and Lamp Systems.
Blue pollution: Because cool-white LEDs (i.e., LEDs with high color temperature) emit much more blue light than conventional outdoor light sources such as high-pressure sodium lamps, the strong wavelength dependence of Rayleigh scattering means that cool-white LEDs can cause more light pollution than other light sources. It is therefore very important that cool-white LEDs are fully shielded when used outdoors. Compared to low-pressure sodium lamps, which emit at 589.3 nm, the 460 nm emission spike of cool-white and blue LEDs is scattered about 2.7 times more by the Earth’s atmosphere. Cool-white LEDs should not be used for outdoor lighting near astronomical observatories.
Edited 2009-02-04 14:50 UTC
All of those are pretty easy to solve, though, through the use of filters, diffusers, etc.
Edited 2009-02-05 08:40 UTC
Actually is isn’t so easiy. If the peaks in waveform, are filtered, as you suggest, that would also take away from the perceived brightess. This in turn would require more LED’s and more power. In addition filters can not fix the dips in the waveform, therefore, the quality will continue to be subpar to non-LED. Diffusers can not completely solve the inherent problems and they can also decrease the brightness.
Again, though, that’s relatively easy to solve given the high efficiency of LEDs. You can double the number of LEDs in a given fixture and still come out ahead of CFLs.
Personally, I like the idea of combining a red, green and blue LED into a single fixture, and you can then control the colour that comes out by varying the the levels of RGB.
No, LEDs won’t be perfect, but they will be plenty Good Enough.
CFL bulbs are a crock of shit designed to make money. Lets think about this for a sec. We have incandescent bulbs that contain nothing really harmful. Glass, aluminum, filament, and whatever gas they have in them (or vacuum). They are cheap to produce, and completely harmless to the environment if broken.
Compare that with CFL. CFL’s are made in China. Therefore they have to be shipped all the way to the US which uses a lot of oil. Plus they have mercury, which is toxic. So you can’t throw them away, they have to go to a hazardous waste plant. If broken, you house become a toxic waste site. Yay! They don’t last as long as expected and cost 2-3 times as much. Now as for energy, if they are like normal fluorescent lights, they have a transformer built into them. This sucks up a lot of power to charge. It used to be that turning on the lights cost more than to run them all day. How many times do you turn on and off the lights in your home?
You seem to be misinformed about CFL’s, TechGeek.
“There’s a lot of misleading information out there,” said Joel Hogue, president of Elemental Services and Consulting, an Ohio-based company specializing in the cleanup of sites contaminated with mercury. “But when people learn the facts, the level of hysteria dies down.”
Like with many other household products, Hogue said, the use of CFLs requires some commonsense precautions. But if a bulb breaks, his company’s clean-up services are not required.
“There’s an extremely small amount of mercury in those bulbs,” Hogue said. “It’s a very minimal risk” and can easily be cleaned up at home.
One CFL contains a hundred times less mercury than is found in a single dental amalgam filling or old-style glass thermometer, according to the U.S. Environmental Protection Agency (EPA).
A compact fluorescent bulb can produce the same amount of light for less than quarter of the energy and last eight to ten times as long. A switch to CFLs would save an average household about 50 U.S. dollars a year in electricity bills, according to government estimates. (Source: National Geographic)
The back of the CFL packaging says that the bulb must be recycled through a recycling center that can deal with mercury. IE, a hazardous waste center. It says right on the box you can’t just throw it away.
As for the amount of mercury, how much mercury is safe if you have children in the house? Also, your quote says that a clean up crew doesn’t have to be called. Great. So what does Jane the housewife do when bulbs break? She wipes it up and probably throws it away. How much mercury is released into the environment? Any is a bad thing.
As for life span, I have no direct knowledge of them. But there are light bulbs which have been running constantly since 1901.
Now lets talk about costs. CFL’s cost about 4 times as much as regular bulbs. Assume regular bulbs which are rated 2-3 yrs in life span only last 2. Assume that the CFL lasts 8 yrs. The cost of the actual bulbs equals out in the long run. So it comes down to electricity basically.
The CFLs have to be shipped all the way from China. Factor that into the amount of energy not saved by using them. Plus, what if you live in one of the many areas where hydro electric is used to generate power. With CFLs you are wasting fuel on getting them here to save electricity that was produced cleanly in the first place.
While I won’t argue that CFL’s don’t save electricity, which is a good goal, combined with the environmental concerns, I don’t think they are as eco friendly as they are being promoted to be.