Slashdot Mirror
Why LEDs Don't Beat CFLs Even Though They Should
TaeKwonDood writes "LEDs don't beat CFLs in the home yet, but it's not simply because PG&E is getting rich making people feel like they are helping the environment buying CFLs made in China that are shipped to the US using a lot more fossil fuels than they save. It's a problem of indication versus illumination. However, some new discoveries are going to change all that."
LEDs are not traditionally used for illumination not only because of the costs of LEDs, but because of the complex optics required to distribute the light. it's rare to see LEDs used for illumination, though it is making an entrance for some applications, like flashlights and even headlamps. As LED prices continue to come down and LED optics technology improves and cost stabilize, conventional LED lamp retrofits will become commonplace. Take a look at LEDtronics for some examples.
Until earlier this year (when they stopped production in favor of CFLs), GE was still manufacturing their incandescent bubls in the US.
Do you even lift?
These aren't the 'roids you're looking for.
If a 25W CFL replaces a 100W incandescent bulb, and the CFL lasts 8000 hours, it will save 600 KWHrs of energy. .11 gallons of diesel for the journey. That is about 6 KWHrs of energy.
If a shipping vessel can hold 35,000 tons of cargo and the shipping weight of a CFL is 1/2 pound, the vessel can hold 140 million bulbs. Of course there is not enough space for them all, but they can ship with heavier items, and I am assuming costs are allocated by weight.
If a 7,000 mile journey burns 875 tons of fuel, or 15.75 million gallons, then each bulb is allocated
Therefore, the shipping costs don't even come close to negating the energy savings.
Note that you can't get white light at 683 lm/W. The lumen has an efficacy curve approximating the human eye response. 683 lm/W implies a perfectly efficient monochromatic 555nm (green) light. An ideal black body is limited to about 95 lm/W; however that's not the ideal output either (the UV and IR components aren't helpful). Actual efficiency for white light is probably limited to 100-200 lm/W, and will depend on how green you allow your white light to be.
Actually, I have never found a LED bulb nor any CFLs that with a confortable color spectrum.
Also, most inexpensive CFLs lose their brightness very quickly and need to be replaced far sooner than what the manufacturer would have you believe.
No sig for the moment.
You are either buying CFLs from a completely incompetent manufacturer, or simply have a bizarre situation where reality is bending around you.
I replaced all bulbs in my home with CFLs three years ago. None have burned out to date, and I saw a small but measureable decrease in home energy use, as my home energy costs are very stable. Everyone I know who has replaced all or some of their bulbs have had the same experience.
There's demonstrable energy savings to be had, and a measureable lifespan increase simply due to the physics of CFL versus incandescent.
I've got a nice, tungesten-coloured LED right here that emits nearly omnidirectional light if I just remove the lens that comes with it. I don't think directionality is really any kind of inherent problem, just a manufacturing issue.
I have had the CFL in my hallway for 15 years.
I haven't changed a lightbulb in at least five, and even that was because somebody hit it with a broom handle. I don't remember much from when I was a kid but those other types of lights would die every now and then.
You're doing it wrong.
It is no longer uncommon to be uncommon.
As for shipping, CFLs are quite a bit heavier than a twisted tungsten wire, so shipping a container of CFLs the same distance as a container of incandescent bulbs could well cost more too.
Except that commercial shipping is usually done by volume not weight. Only if the weight is extremely excessive does it matter for pricing. Shipping containers are usually charged by the container, not by the weight. They have a weight *limit*, but that is not the same thing. I can't imagine hitting the weight limit of a container with any kind of light bulb.
Trucks are the same way for large quantities.
Even those who arrange and design shrubberies are under considerable economic stress at this period in history.
Then there is something seriously wrong with your wiring or the bulbs you buy. The claims are sometimes overdone on the packaging, but it was much worse back in 2001 than now. Also, some manufacturers are more reliable than others (feit electric at Costco and Sylvania at lowes, other places, seem to be good for certain models). The Walmart brand Great Value seems to be horrible, at least in my experience.
I've had enclosed Par 38 CFLs (23w) die on me with some regularity although it has gotten a little better the last year. OTOH the enclosed Par 20 (13w CFL) have been absolutely solid since 2004, after a bad first run.
My longest lasting lights about 10 regular 13 watters --60w equivalent-- enclosed exterior ones. They started in all temps from (-5F to 100F). They used to be dusk to dawn for the first 3 years, so I guess 12 hours a day on average through the year, then the solar cell went bad on several 2 3-lamp posts and so 6 lights were running continuously for about a year (busy year). When I fixed that, put a timer in to start at dusk and turn off rougly midnight.
Through those 6 years, about 5 lights went bad. Keep in mind, they were running around probably 4,380 hrs a year. One year it was the max 8,760 with no breaks. And now, it's down to 2,190. This is probably due to them being on for extended periods and not constantly switched on and off which wears on a ballast and kills the shoddy ballasts fast.
CFLs are a type of fluorescents, and if the ballast is shoddy, you can forget it. Also had to replace every fluorescent ballast in a section of newly constructed office space once as one in an entire row (same manufacturer) went bad one at a time in a short period. Doesn't meant fluorescent tech is bad, means it was either a bad manufacturer or bad run. BTW, there can be bad fluorescent tubes as well, Philips seems to be good while the much cheaper Sylvania contractor packs are shit.
Just how it goes. Go to some CFL forums and learn. Have no experience with dimmers though. Don't have a one.
GE Energy Smart CFL's are a pretty good approximation of the spectra of incandescent (2700K 82CRI). They are available at Sam's Club (and I believe Walmart). I've been using them for about 3 years now and just replaced my first bulb. Since I live in the Cleveland area and grew up going to their holiday lighting show I'm thinking about returning the failed unit myself and seeing if I can find out why it failed =) Btw GE rates their bulbs to fall off ~20% from initial peak so using a 14W (75W equivalent) for reading lamps is probably a minimum.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Not entirely. CFLs are fluorescent lamps. They produce ultraviolet light which a fluorescent layer of different phosphors on the inside of the tube converts into visible light. This conversion isn't 100%. Most CFLs do therefore emit a very small amount of UV light. (If, and only if, you leave the phosphors out, you get the kind of tubes which are used in tanning beds.)
Where this argument enters bullshit territory is that the problem is worse with CFLs than with incandescents. Incandescent lights are black body radiators. In order to create a "whiter" light, the temperature of the filament must be increased. This also increases the amount of UV light. If you use halogen lights, make sure you buy bulbs with UV filter fronts, because halogen bulbs really produce noteworthy amounts of UV lights.
A 20' container is approx 19' x 7' x 7' or 1.6M cubic inches (it's a bit bigger, but I left room for pallets, etc).
If a CFL + packaging is 3" x 4" x 6" = 72 in^3 then you can fit around 22,000 of them into a 20' container
This site claims you can ship a 20' container from China to the US for $3800 USD
Let's say that 75% of the shipping cost goes toward fuel, the rest goes to labor, paying off the ship, container rental, etc. Sounds reasonable.
I'm going to use Diesel for the energy calculations. I know that ships run off bunker fuel, not diesel, but I have to think that the cost per unit of energy for bunker fuel is cheaper than diesel since it's less refined, so by using Diesel I'm being conservative. Right now you can buy diesel for under $2/gal, so with 75% of $3800, we can buy 1425 gallons of diesel.
Diesel has 38 MJ of energy per liter (143 MJ/gal), or 40KWh according to the units command.
So, each light bulb uses 40KWh / 22,000 = 1.8 KWh (1800 Wh)of energy
A 29 Watt CFL can replace a 100 Watt incandescent bulb, so that's a 71 watt savings... 1800Wh / 71 W = 25 hours
Sooooo....a CFL will save the energy used to ship it in about 25 hours of operation. CFL's are supposed to last 5000 hours, so over its lifetime, it will save over 200 times more energy than used to ship it. (of course, this is only this shipping energy, and ignores the extra energy that it took to manufacture the CFL it as compared to an incadescent. I don't know how to do that math).
No, it's valid if they're both made extra-nationally, but in different places. Most incandescents are actually made in the United States by GE, but the vast bulk of the remainder are made in Mexico, and shipped up by rail, which is far more efficient than slow-boating them from China. It turns out that there are more than one country outside of America, and that those countries aren't actually all in the same location.
Of course, if anyone actually did the math, they'd find out that the energy cost of shipping is offset by the energy savings in usage in under three days; sometimes I wonder whether people have any idea how many lightbulbs fit on a large boat, or how little fuel a large boat actually needs.
But hey, made up math is great for making arguments, right?
StoneCypher is Full of BS
But typically LED-based "white" lighting is a series of discreet spectra between red and blue, rather than a continuous spectra from red to blue; color temperature by itself is not a sufficient metric for comparison.
Incandescent bulbs will last 7 times longer if you run them dimmed to 90% brightness, and they will last 20 times longer if dimmed to 50% brightness. The output from a Dimmer Switch is very chopped up power, not smooth at all.
CFL bulbs will give you 10+ years of service if you leave them on for at least 30 minutes everytime you turn one on. Not good for use in bathrooms or inside refrigerators.
We are Dead Stars looking back Up at the Sky
Sure about that?
The bulbs themselves are actually not that cheap to produce. In the theatrical lighting world, we have various fixtures that accept HID lamps, very similar to those used in an LED projector.
Although they're not quite as expensive as what you'd put in the projector, they are standardized, and still cost up to $200 a pop.
I imagine that the projector companies are profiting a good bit, although HID lamps are most certainly not cheap to manufacture.
-- If you try to fail and succeed, which have you done? - Uli's moose