dasfx
Newly Enlightened
Saw this this morning, nice to see them catch up.
http://www.thewbalchannel.com/travelgetaways/2604540/detail.html
http://www.thewbalchannel.com/travelgetaways/2604540/detail.html
Another state sees the LED light
- Thread starter dasfx
- Start date
Sell! sell! sell! Sell your GE stock now while the gettin's good!
Seriously, I can't imagine any city waiting too long to do this if the technology already exists in plug-n-play format. It seems like a no brainer unless the city's mayor's brother-in-law works for an incandescent lightbulb distribution center!
Seriously, I can't imagine any city waiting too long to do this if the technology already exists in plug-n-play format. It seems like a no brainer unless the city's mayor's brother-in-law works for an incandescent lightbulb distribution center!
DBrier
Enlightened
A friend of mine is traffic engineer in New Hampshire and they had problems with the LED traffic lights. When it gets cold and snows, snow and ice builds up on the traffic lights and block the light. LEDs didn't put out enough heat to melt the snow like regular incandecant bulbs. They added heaters to the fixtures. Their electric cost stayed the same, but like the article said, their maintenence went way down.
dasfx
Newly Enlightened
Whoo hooo, looks like that post put me over the newbie limit /ubbthreads/images/graemlins/smile.gif
[ QUOTE ]
DBrier said:
A friend of mine is traffic engineer in New Hampshire and they had problems with the LED traffic lights. When it gets cold and snows, snow and ice builds up on the traffic lights and block the light. LEDs didn't put out enough heat to melt the snow like regular incandecant bulbs. They added heaters to the fixtures. Their electric cost stayed the same, but like the article said, their maintenence went way down.
[/ QUOTE ]
We have that problem back in CO. All of the new stoplights I have see so far are LED at home, and they didn't have heaters last winter. Maybe they will figure it out this year.
-Mike
DBrier said:
A friend of mine is traffic engineer in New Hampshire and they had problems with the LED traffic lights. When it gets cold and snows, snow and ice builds up on the traffic lights and block the light. LEDs didn't put out enough heat to melt the snow like regular incandecant bulbs. They added heaters to the fixtures. Their electric cost stayed the same, but like the article said, their maintenence went way down.
[/ QUOTE ]
We have that problem back in CO. All of the new stoplights I have see so far are LED at home, and they didn't have heaters last winter. Maybe they will figure it out this year.
-Mike
Steelwolf
Flashlight Enthusiast
I would have though, with the heater, the electric costs would only be elevated during winter when they had to switch it on. Otherwise, during summer, there should be good savings.
Talking about LED traffic lights, Perth has had one running as a test case at a junction in Northbridge. Unlike the models used in Singapore lights, these use coloured LEDs rather than the water clear types. So when the evening sun shines on them, it is hard to tell which is on, same problem as when they used incandescent.
But Hotfoot mentioned that the water clear LEDs suffer from a different problem, that of the plastic in the LED lens going yellow after a year or two of exposure to sunlight (UV light). This may reduce the output below the level required for safe operation long before the LED has reached its half-life and so reduce the life span of the traffic lights and the benefits associated with it.
Any comments?
Talking about LED traffic lights, Perth has had one running as a test case at a junction in Northbridge. Unlike the models used in Singapore lights, these use coloured LEDs rather than the water clear types. So when the evening sun shines on them, it is hard to tell which is on, same problem as when they used incandescent.
But Hotfoot mentioned that the water clear LEDs suffer from a different problem, that of the plastic in the LED lens going yellow after a year or two of exposure to sunlight (UV light). This may reduce the output below the level required for safe operation long before the LED has reached its half-life and so reduce the life span of the traffic lights and the benefits associated with it.
Any comments?
Bernhard
Newly Enlightened
The LED plastic going yellow? Are they not using similar material used in newest number plate cover, that guaranteed not to get yellow in 10 years?
JJHitt
Enlightened
[ QUOTE ]
Steelwolf said:
I would have though, with the heater, the electric costs would only be elevated during winter when they had to switch it on.
[/ QUOTE ]
Actually, the biggest part of opperating costs with traffic lights is not the electric costs, but maintenence and replacement.
Don Klipstein's site goes into this in very great depth at:
http://members.misty.com/don/lede.html
Brief Quote from the above page:
Why LEDs have 10x the efficiency of incandescent in traffic lights
One minor reason is that incandescent traffic light bulbs are not as efficient as "standard" incandescents. Incandescent traffic light bulbs ( traffic signal lamps ) are designed to withstand the vibration of trucks passing over potholes, and are designed to last usually 8,000 hours. Being turned on and off a lot is not much of a factor (explanation somewhere in my Incandescent Lamp File), but it might be a little significant if it has to be turned on and off nearly a million times in its design life expectancy. With the design compromised to keep on ticking after a good 3 years in a traffic light, its efficiency is only about 60-65 percent of that of a "standard" incandescent of similar wattage. So an LED 10 times as efficient as this is only 6 times as efficient as a regular incandescent. More below why LEDs can be 6 times as efficient as a regular incandescent in a traffic light while good white LEDs are hardly any more efficient than regular incandescents!
The major reason is that traffic lights are colored. The red and green lenses block about 70 percent of the light! In addition, LEDs normally specialize in producing a particular color of light. There is no such thing as an efficient white LED chip - the usual white LEDs have a fluorescent substance over a blue LED chip to convert some of the blue light to a broad spectral band from red to green. The red and green LEDs used in modern LED traffic signal units are slightly more efficient (sometimes substantially more efficient) than white LEDs. (Yellow does not play a major role in energy savings since red and green are used so much more than yellow.)
Add to this the fact that LEDs can be made in custom-designed molded "bulbs" with tailored optical properties. This makes it a little easier to get light concentrated to where it needs to go and waste less power in producing light where one does not need as much.
Given all of this, one can see why a bunch of LEDs drawing somewhere around 12 watts can do as good a job in a traffic light as the usual 116 watt incandescent traffic signal bulb!
Steelwolf said:
I would have though, with the heater, the electric costs would only be elevated during winter when they had to switch it on.
[/ QUOTE ]
Actually, the biggest part of opperating costs with traffic lights is not the electric costs, but maintenence and replacement.
Don Klipstein's site goes into this in very great depth at:
http://members.misty.com/don/lede.html
Brief Quote from the above page:
Why LEDs have 10x the efficiency of incandescent in traffic lights
One minor reason is that incandescent traffic light bulbs are not as efficient as "standard" incandescents. Incandescent traffic light bulbs ( traffic signal lamps ) are designed to withstand the vibration of trucks passing over potholes, and are designed to last usually 8,000 hours. Being turned on and off a lot is not much of a factor (explanation somewhere in my Incandescent Lamp File), but it might be a little significant if it has to be turned on and off nearly a million times in its design life expectancy. With the design compromised to keep on ticking after a good 3 years in a traffic light, its efficiency is only about 60-65 percent of that of a "standard" incandescent of similar wattage. So an LED 10 times as efficient as this is only 6 times as efficient as a regular incandescent. More below why LEDs can be 6 times as efficient as a regular incandescent in a traffic light while good white LEDs are hardly any more efficient than regular incandescents!
The major reason is that traffic lights are colored. The red and green lenses block about 70 percent of the light! In addition, LEDs normally specialize in producing a particular color of light. There is no such thing as an efficient white LED chip - the usual white LEDs have a fluorescent substance over a blue LED chip to convert some of the blue light to a broad spectral band from red to green. The red and green LEDs used in modern LED traffic signal units are slightly more efficient (sometimes substantially more efficient) than white LEDs. (Yellow does not play a major role in energy savings since red and green are used so much more than yellow.)
Add to this the fact that LEDs can be made in custom-designed molded "bulbs" with tailored optical properties. This makes it a little easier to get light concentrated to where it needs to go and waste less power in producing light where one does not need as much.
Given all of this, one can see why a bunch of LEDs drawing somewhere around 12 watts can do as good a job in a traffic light as the usual 116 watt incandescent traffic signal bulb!
LED-FX
Enlightened
[ QUOTE ]
Sell! sell! sell! Sell your GE stock now while the gettin's good!
[/ QUOTE ]
Not heard of Gelcore then ;-):
http://www.gelcore.com
The big 3 lighting companies are intent on staying the big three.GE has Gelcore, Osram have Osram Opto and Philips is a partner with HP in Lumileds.
Almost all the new install traffic lights here in Edinburgh are LED.
Plastic yellowing is something no one likes to talk about, some older white LEDs can see huge drops in output over a few thousand hours due to yellowing. Power density within the LED is very high from UV output from the dice.
Whose going to try and claim on an old numberplate....?
Adam
Sell! sell! sell! Sell your GE stock now while the gettin's good!
[/ QUOTE ]
Not heard of Gelcore then ;-):
http://www.gelcore.com
The big 3 lighting companies are intent on staying the big three.GE has Gelcore, Osram have Osram Opto and Philips is a partner with HP in Lumileds.
Almost all the new install traffic lights here in Edinburgh are LED.
Plastic yellowing is something no one likes to talk about, some older white LEDs can see huge drops in output over a few thousand hours due to yellowing. Power density within the LED is very high from UV output from the dice.
Whose going to try and claim on an old numberplate....?
Adam
