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LEDs - Do the Benefits Outweigh the Cost?
7x7 asks: "We keep hearing about the latest and greatest thing to come out of LED technology, and every article seems to give an over-view of the topic. How LEDs consume little electricity and last a long time, etc. However the manufacturing process involves super hot ovens and expensive componants. Do the requirements necessary in the manufacture LEDs and LED componants out-weight the requirements for standard bulbs over 10 years? One LED light can last ten years, but contains dozens of LEDs. Has anyone seen or performed an evalutation to see if the trade-off is really anything to speak of?"
I wish the bulb that burned out in my truck's dashboard had been an LED to begin with.
It cost $95 to change it.
--I am an extreme flashlight fiend, I mean I got dozens of them. My LED flashlights are just a sheer joy. The bulbs don't burn out or pop in temp extremes, I got literally years of normal use off a set of batteries. Most of them will run for days if you just turn them on and leave them on, I've tried it. a regular flashlight lasts a couple of hours max usually. I took one of my first ones, a ccrane model, and read several books at night on one set of batts, just to see how they did "real world". Just outstanding.
I switched several years ago from 12 vdc incandescents to fluorescents for my interior lighting in my RV I live in,got a good boost in performance, but as soon as the LEDs get a scosh cheaper in a normal 12 vdc config for area lighting I will switch to them instead.
Previous Ask Slashdot discussions on LED lighting, LED Light Fixtures for the Home? and Which LED Flashlight Do You Use?
I've got a fever and the only prescription is more COBOL.
It seems to me that if the power usage of those LEDs is much lower than that of a bulb, then yes, there is a very good chance of the LEDs being less damaging to the environment.
Don't underestimate the power savings you can achieve over a ten year period.
I suffer from attention surplus disorder.
I think the question asks about the total cost of manufacturing/consumables used to run LEDs vs fluorescent vs incandescent bulbs. I'd also throw in the environmental impact as well.
Incandescence are pretty simple to make now and don't contain much in the way of harmful chemicals, just glass and tungsten (older ones used a leaded compound for the base.) But the monetary and environment costs of the electricity are high.
fluorescents contain mercury, but I don't believe they are too hard to manufacture (correct me if I'm wrong.) They are currently the cheapest to run from an electricity point of view, but LEDs are rapidly (yes, there is more electrically efficient lighting out there, but not in the brightness range that most offices and homes require.)
LEDs use some nasty chemicals to manufacture, but the end product is fairly harmless (it contains tiny amounts of some harmful things, but the LEDs last such as long time that, imho, the impact is very small when depreciated over its lifespan.
From a battery-operated point of view, LEDs are the way to go. Fluorescents require some bulky voltage and signal conversion and don't run the battery completely empty. LEDs are strong, light weight, and very energy efficient. Plus batteries contain their own nasty chemicals. I just can't wait for portable fuel-cells!
As always, it depends on the use.
I haven't seen anything about manufacturing costs, so maybe I'm not answering your question, but in use:
In traffic lights, a burned out bulb is a hazard, and expensive to change.
Brake lights and taillights are dangerous to lose, and they get shaken around. That's why in many cars if your brake or taillights go out, your dash lights go out too as a reminder.
Flashlights are typically low temperature bulbs where incandescents are more inefficient, especially after the battery voltage starts to drop off. Besides, they get dropped, so LEDs are a win there too.
Fluorescents are the most effecient, but for household lighting I don't like their color or sixty Hertz visible hum. (Any specific recommendations for a compact fluorescent that has a good color & a nice ballast that doesn't flicker sixty times a second?)
The LED geeks know LEDs aren't always better as far as power consumption goes.
http://www.pioneernet.net/optoeng/LED_FAQ.html#Q7
http://misty.com/people/don/lede.html
I saw a nice use of LEDs in a remote campsite. There were solar collectors on the roof of the bathroom, and little banks of a few LEDs that lit the bathrooms at night.
An LED seems smaller, but the incandescent in a mini-maglite puts out much more light than a white LED of the same size.
Assembly is the reverse of disassembly.
A high-efficiency red LED puts out about 2.5 mW of luminous energy in its emission band, and consumes 120 mW of power. That's 3% efficiency. The rest is dissapated as heat. Incidentally, that's why LEDs have a large footprint (the luminous area is very small); so the heat can spread out and the junction characteristics don't change. Incandescents emit light energy outside the visible band, unlike LEDs. This is where most of the power goes, not heat. Thus, incadescent lights achieve about 15 lumens per watt, flourscents get about 50 per watt. Contrary to popular belief, LEDs are in between, the high efficiency models get about 25 lumens per watt.
The most efficient LED right now is %32. You can't buy these yet... they will be used in lights that operate like flourescent lights since they emit UV. This will be the ideal, long-lasting but low power light source.
LEDs are not economical when a flourscent light with electronic ballast can be used in the same situation. In scenarios where the extra electronics required by a flourscent light are too bulky or not enough power is available- this is where LEDs shine. That is why they are the flash-light champs.
Fuck Beta. Fuck Dice
From the voltage drop you quote (1.7 V) that must be a single colour (probably red?) LED. The 20W flourescent is (I assume) closer to white. If you look at white leds they're far less efficient than the basic red and green varieties. The loss of efficiency puts them below flourescent lighting. I don't have any sources to hand to back this up I'm afraid.
Of course, LEDs can be used to make very cool light enclosures that can't be achieved with other technologies.
If we're talking car lighting (brake or tail lights) then LEDs win out easily, 'cos they've got to be red anyway.