New York City Street Lights To Go LED 303
eldavojohn writes "Wired has a short piece on NYC's new street light project. I don't think we need to belabor the many benefits that LEDs hold over traditional light bulbs, but the finishing touches are being addressed, and they will hopefully be put into place sometime next year. This design won a competition back in 2004, and OVI has been whittling down the prototypes. At $1.175 million, this sounds like a pretty cheap deal considering the DOE forked over $21 million to 13 R&D projects along the same lines."
Re:flicker crashes (Score:4, Insightful)
Assuming the line voltage is run through a full wave bridge rectifier, there would be a 120 Hz flicker, imperceptible to most people. Toss a large capacitor across that DC output and you've got dramatically less ripple.
true but then you also have 100 times the surge current when you turn them on, or a slow turn on.
What you say is of course obvious to any EE, and yet i've never actually seen a single 120v LED lamp made that way. One wonders why.
Won't anyone think of the astronomers? (Score:4, Insightful)
Are there any major observatories near NYC? (hmm large mountains close to NYC?)
Are these new lights narrow or wide spectrum?
See: http://en.wikipedia.org/wiki/Light_pollution [wikipedia.org]
Re:Isn't HPS more efficient? (Score:5, Insightful)
Some of the newer LEDs can go above 100 lumens/watt [gizmodo.com].
One thing about HPS is that it spreads light everywhere, whereas LEDs are more directed, which you want in a streetlight facing down. Omnidirectionalness can be fixed with good fixture design, but most cities use crummy fixtures.
Re:flicker crashes (Score:4, Insightful)
These aren't headlights, they're street lamps. Do you really care if it takes them 3 minutes to warm up?
And even assuming they have ballasts featuring accelerated warm-up, the starting current will still be as much as double the normal operating current requirements. Really though, the starting current is negligible in the grand scheme of efficiency comparisons.
I'm not an expert on line voltage LED units designed to replace incandescents, but I would imagine including a bridge rectifier and capacitor would increase the cost and pose significant design constraints due to the components size.
Re:flicker crashes (Score:4, Insightful)
Just because you don't have some trait doesn't mean that other people don't. In this case, that trait is how fast your eyes can see. Congratulations, you have slower eyes.
I am one of those people. It isn't just "flicker", I can see the image-black-image-black pattern of the CRT at 60Hz without doing any tricks like waving my hand in front of the monitor or using the side of my vision.
I can't stand to be in the same room as a CRT monitor running at 60Hz, it is almost physically painful to see. When I had a CRT I had to run it at 85Hz to be able to use it for any period of time, but still had to make the text white on black, turn the brightness down, and such.
If it doesn't bother you, then imagine replacing every CRT with a strobe light running fast, as bright as the monitor. That would be annoying and distracting, right?
Imagine that tail lights of cars and buses were red strobe lights. Around here, that is actually a reality, with most of the new buses and some new cars having tail lights running at 60Hz. It is extremely obvious to me, where I can instantly point out which cars in a long line have blinking LED tail lights.
Re:flicker crashes (Score:2, Insightful)
I don't notice any flicker as well. I have noticed that some lights have blocks of LEDs failing rather quickly after installation though. Entire sections of turn arrows and squares in circular lights that have gone out look rather weird. It may be a brand/manufacturer issue though since I see this in the larger metro area but not in the suburb where I live even though the suburb has had them longer.
Makes you wonder if they'll have the same issues with chunks failing in these lights.
Re:Giant LED light bulbs (Score:3, Insightful)
Could be, but an LED that uses phosphors eliminates any interest in my book because it means the color spectrum is a spiky mess.... :-) Either way, though, I'd gladly accept much less efficiency to get better light quality. I hate CFLs (even the so-called daylight CFLs) so much that I'm planning to start stockpiling incandescent bulbs soon in preparation for the U.S. ban on them. That cold, lifeless lighting just really bugs me.
Re:Giant LED light bulbs (Score:5, Insightful)
Why can't they make a single led the size of a lightbulb instead of 100 small led's.
Is it possible to make a single, huge led?
I don't know. Maybe it's the same reason that they can't make a tungsten filament the size of a whole light bulb. Instead, they keep selling us a tiny wire the size of a pubic hair surrounded by a huge void filled with argon gas. This has been going on for well over a century, and they never seem to fix it.
We have lights. Stop spending, cut taxes. (Score:3, Insightful)
I'm not one of those wacky conservative nuts but here in NY, we're about to be forced to pay all new kinds of taxes on various things such as Non Diet, Soft Drinks.
I'm all for the LED's if they're better in the long run and cheaper than maintaining the current lights but is it necessary right now?
Our politics are all screwed up here in NY. Its the blind leading the blind... literally.
Re:flicker crashes (Score:4, Insightful)
I don't know what I hate more on slashdot .... seeing somebody spout off when it's obvious to anybody with even passing familiarity in the field in question that they're full of it, or seeing somebody get shat upon when they ask a perfectly valid question in an attempt to try to learn something new
Re:flicker crashes (Score:1, Insightful)
Idiot design...
First of all, you would need twice the number of LEDs. You would gain a small efficiency saving as you would save 1.4volts voltage drop in the bridge rectifier, but at 120v or whatever the US supply is at, this is pretty small. LEDs are expensive...
Secondly, you still get 120hz flicker, so it doesn't save you anything over a bridge rectifier.
Re:We have lights. Stop spending, cut taxes. (Score:3, Insightful)
Is it?
Cost of running existing bulbs for the next 5 years: $10 million
vs.
Cost of replacing with LEDs: $2 million
Cost of running LEDs for the next 5 years: $2 million
Numbers are pulled out of thin air, but I wanted to illustrate a point - it sometimes pays to replace something that is working.
Presumably whomever is in charge of the replacement has done this math, and found it comes out ahead to go ahead and switch before the old bulbs burn out.
There's also the issue that there's usually more than replacing a bulb, which requires more downtime. If it takes 5 days to convert, they can schedule a traffic policeman, have everything ready, and do the conversion when it's convenient. The alternative is to start that 5 day clock as soon as the bulb blows, which may take 7 or 10 days now because the resources aren't ready. In the meantime, there's no traffic light.
There's also the issue of the technicians maintaining both types of lights.
So - the economics and logistics probably both favor early replacement, rather than as the old bulbs blow.
Re:Bad plan in snowy environment... (Score:3, Insightful)
But you've found a flaw. I hope engineers are working on resolving this before it becomes a mess. It shouldn't be too difficult since LEDs to produce some heat (just not the 95% lost to heat in incandescents!) Engineers need to learn human psychology and politics and recognize that overcoming such glitches early on are crucial to encourage acceptance. More than three decades since the 1970s energy saving concepts and solar houses became popular, the backlash over bad implementations is still strong enough to keep them from gaining significant market share now even that solar/efficiency technology is 30 years better, the cost is 30 years lower and oil is 30 years higher.