Great article in last week's Business Week magazine...
http://www.businessweek.com/articles/2012-05-10/chattanoogas-radio-operated-streetlamps (http://www.businessweek.com/articles/2012-05-10/chattanoogas-radio-operated-streetlamps)
QuoteAlmost a third of Chattanooga’s annual energy bill comes from old high-pressure sodium streetlamps. At any given time 5 percent of the bulbs are burned out, and they sometimes go on during the day, needlessly adding to electric bills. “You’ve got a certain amount of lights out but you have no idea where they are, so workers literally drive around in a truck looking for them, and it’s a real waste,†says David Crockett, director of the city’s office of sustainability.
After deciding to replace the streetlamps with light-emitting diodes (LEDs) that can cut energy use by 70 percent, Chattanooga officials discovered a local company with a further cost-saving proposal: a radio-controlled system that can also slash maintenance expenses. Combined, the changes promise dollar savings of 75 percent to 80 percent.
please....we can't even get all the traffic lights converted to LED's. Most of the time many of the historic street lights installed around downtown and other neighborhoods are half out.
There has been a big jump in LED technology just in the last year. Proof of longevity will delay widespread use in the utility field for another year or so, but then you will see widespread deployment.
For consumers, Home Depot has just greatly expanded their offerings in LEDs in the past several months. Take a look!
LED's are great. The problem is the initial costs are still about 3-4 times that of the traditional low-pressure or high-pressure sodium.
The savings come in the form of life-cycle costs due to reduced maintenance but cities and utilities still find it tough to fork out the extra coin up front. Things are changing and the price points are steadily falling. So give it another 2 to 3 years and almost all new roadway lighting will be LED.
Quote from: Dog Walker on May 21, 2012, 05:36:27 PM
There has been a big jump in LED technology just in the last year. Proof of longevity will delay widespread use in the utility field for another year or so, but then you will see widespread deployment.
For consumers, Home Depot has just greatly expanded their offerings in LEDs in the past several months. Take a look!
Longevity fo the LED's aren't the concern, its the electronic driver that is the weak link. Furthermore, LEDs are very easily overheated causing premature failure therefore requireing additional technology to keep them cool during Florida's hot summer nights.
LEDs typically also have a built-in ability to dim the light source allowing an empty roadway to be lit at say 50% of normal and with a built in motion sensor they can illuminate to full brightness as oncoming traffic moves in. Similar to the way the freezers in Publix light up as you approach and turn off after you pass.
Quote from: Jason on May 21, 2012, 05:47:48 PM
Quote from: Dog Walker on May 21, 2012, 05:36:27 PM
There has been a big jump in LED technology just in the last year. Proof of longevity will delay widespread use in the utility field for another year or so, but then you will see widespread deployment.
For consumers, Home Depot has just greatly expanded their offerings in LEDs in the past several months. Take a look!
Similar to the way the freezers in Publix light up as you approach and turn off after you pass.
OK... I never noticed that and will have to make a special trip to Publix to witness... Damn you Jason... :D
LEDs are more expensive? I just bought a 12 pack of GE LED bulbs from Sams for $3.99
One of the other problems with LED's is the actual light output. Looking directly at a street signal, shows brightly. Trying to read a book about 10 feet away is almost impossible. The light intensity diminishes at a much greater rate than conventional light. This is why they are too bright to look at directly close up.
QuoteOne of the other problems with LED's is the actual light output.
I am pretty sure that Chattanooga would not have replaced all their lights with LEDs if they were a safety risk for nighttime driving. But, we will see how they work out for them. They are the wave of the future.
That problem is easily solved with a diffuser. The technology is actually mature now and many cities (http://en.wikipedia.org/wiki/LED_street_light#Notable_installations) have already installed them. It would be nice to have them here.. I'm sick of the sodium vapor lights.
Quote from: BridgeTroll on May 22, 2012, 08:51:28 AM
Quote from: Jason on May 21, 2012, 05:47:48 PM
Quote from: Dog Walker on May 21, 2012, 05:36:27 PM
There has been a big jump in LED technology just in the last year. Proof of longevity will delay widespread use in the utility field for another year or so, but then you will see widespread deployment.
For consumers, Home Depot has just greatly expanded their offerings in LEDs in the past several months. Take a look!
Similar to the way the freezers in Publix light up as you approach and turn off after you pass.
OK... I never noticed that and will have to make a special trip to Publix to witness... Damn you Jason... :D
Have fun running up and down the aisles! Not sure if all publix's have this though. Try a newer store.
I'm pretty sure the Riverside Publix has them.
QuoteLEDs are more expensive? I just bought a 12 pack of GE LED bulbs from Sams for $3.99
There are deals to be had, however, the light bulbs you bought are likely not nearly as bright as a traditional Edison style incanscent which cost about 50 cents.
QuoteOne of the other problems with LED's is the actual light output. Looking directly at a street signal, shows brightly. Trying to read a book about 10 feet away is almost impossible. The light intensity diminishes at a much greater rate than conventional light. This is why they are too bright to look at directly close up.
Colored LEDs (or any colored light source for that matter) lose at least 50% or more of the usable light output because of the lenses or filters used to produce the color.
Light sources for our purposes are measured in Lumens. And lumens per watt is used when refering to the effeciency of a light source. Right now, commercially, indandescent light bulbs produce about 15-20 lumens-per-watt. Fluorescent tubes sit around 80 and LEDs range anywhere from 30 to 90 (but the labs have been producing over 120). The large range of light output of LEDs is due to the lack of consistency within the manufacturing world, and the plethora of uses. Because the LPW values of LED are still comparable to fluorescent, the major selling point of LEDs is the longevity (if the quality is high). You truly get what you pay for. The 'el cheapo residential grade screw base LED light bulbs are not likely to last anywhere near as long as advertised and many still complain about the lack of light output, but hey, they use a lot less energy right?
I could ramble for hours about the pros and cons, as well as the nuts and bolts of the industry. The short of it all is that LEDs will likely become the dominant light source in the next few years as the standards and technology catch up to each other.
The technology and brightness have changed so much just in the past year that we have replaced all of the PAR-20 bulbs in our kitchen with LED's and have much more light (lumens) than we did with the 50 Watt PAR-20 incandescent bulbs that were replaced.
We have an antique chandelier in the dining nook that took 5 little 20Watt incandescent bulbs. We have replaced them with 5 3-Watt LED and now have too much light over the table.
If you haven't looked at household LEDs in the past three or four months you are missing the advances that have occurred. Be careful though. Keep you receipts. There is a lot of inaccurate information about lumens and color temperature on the packaging. We've had to take some bulbs back.
i replaced my outside floodlights with LED's, more expensive upfront, but so far so good.
That is good news DW. I haven't been staying up on the latest residential grade stuff.
Did you select the warmer colored bulbs or are they the bright white?
Quote from: Jason on May 23, 2012, 10:43:30 AM
That is good news DW. I haven't been staying up on the latest residential grade stuff.
Did you select the warmer colored bulbs or are they the bright white?
We started with the Phillips "warm" led bulbs, but they were almost yellow. So we returned them and now have all "cool white", which isn't the blue-white of the earlier LEDs. My wife says that they give more accurate color rendering to what they are shining on. I'm color-blind as a dog and am not qualified to have an opinion except that I can see if something is too yellow.
We're very happy with the results of the change over. Only thing wrong is that the 3 Watt little bulbs in the fixture over the dining table are too bright and cannot be dimmed. When we want softer, mood lighting for dinner now, I just reach up and unscrew a couple of them.
Our entire kitchen/great room/ dinette area of 900 Sq Ft, lighted up like a circus with everything blazing only takes about 60 Watts. I'm trying to break my habit of wandering through a room turning off the lights. Why bother?
Your mention of the color rendering is a huge positive of LED lighting, especially with the blue-white bulbs (4000+ degrees kelvin). LEDs produce a more complete color spectrum which renders colors MUCH better and gives the illusion of having more light. Many manufacturers in the commercial world continuously argue that because of the better color rendering, you don't need as much light.
Quote from: Jason on May 24, 2012, 08:48:39 AM
Your mention of the color rendering is a huge positive of LED lighting, especially with the blue-white bulbs (4000+ degrees kelvin). LEDs produce a more complete color spectrum which renders colors MUCH better and gives the illusion of having more light. Many manufacturers in the commercial world continuously argue that because of the better color rendering, you don't need as much light.
I could not agree more. Everything just sparkles and glows.