This is Progress.
I have exactly one LED area light, standard Edison base, mostly because I am curious. At $30 a pop, these things are not likely to be hot sellers.
This particular bulb is remarkably bright for the power. I have it on my front porch, running 24/7 (it would be difficult to rig this location with a timer or light detector). I intend to use some at the cabin on my 12V solar system, particularly in my wife's kitchen cabinets, where a very cool lamp is preferable.
The efficiency of LED bulbs is, on paper at least, about the same as CFL.
Their advantages are marginal, and difficult to justify at the price. They may have some niche markets.
CFL bulbs do not come on to full brightness instantly. LEDs do.
CFLs contain mercury and some nasty phosphors. LED's contain gallium arsenide. Probably in a form harder to release.
LEDs tend to make a bluer light. They are available in colors, and there are a few in which you can adjust the RGB colors to make a custom lighting.
LEDs may be able to run on a dimmer (at least some can), or on other electronic switch devices not compatible with CFL switching supplies and ballasts.
LEDs make a nice light strip.
If you want a spot light, LEDs are a natural, but recently I have seen CFL reflector bulbs.
They come in a candelabra base, so may be a viable choice to replace incandescents in some light fixtures. But frankly, a new light fixture is probably cheaper. My present home came with a 10-lamp candelabra in the dining room, equipped with 60-watt bulbs. That's 600 watts! Blindingly bright, heated the room up instantly, and I took the fixture down within my first day in the place.
LEDs "fail gracefully." Most LED traffic lights I have seen have at least on string of dead lamps, but still keep going. Most other light sources die when they die. For traffic lights and radio towers they definitely make sense on the labor to replace them, and safety issues when they fail.
I have also experienced short life in some CFL applications. This includes fractured tubes that would release some mercury vapor. But I'm crazy anyway so I doubt anyone would notice a change.
Nobody mentioned the old "CircLites". I've got one that has been running 20 years ... and I think it is as efficient as a CFL.
LED flashlights are so remarkably good I doubt I will buy anything else. The batteries last forever! The light is excellent. The cost has dropped dramatically, to a few bucks, or ten for ten bucks in a package deal recently.
This particular bulb is remarkably bright for the power. I have it on my front porch, running 24/7 (it would be difficult to rig this location with a timer or light detector). I intend to use some at the cabin on my 12V solar system, particularly in my wife's kitchen cabinets, where a very cool lamp is preferable.
The efficiency of LED bulbs is, on paper at least, about the same as CFL.
Their advantages are marginal, and difficult to justify at the price. They may have some niche markets.
CFL bulbs do not come on to full brightness instantly. LEDs do.
CFLs contain mercury and some nasty phosphors. LED's contain gallium arsenide. Probably in a form harder to release.
LEDs tend to make a bluer light. They are available in colors, and there are a few in which you can adjust the RGB colors to make a custom lighting.
LEDs may be able to run on a dimmer (at least some can), or on other electronic switch devices not compatible with CFL switching supplies and ballasts.
LEDs make a nice light strip.
If you want a spot light, LEDs are a natural, but recently I have seen CFL reflector bulbs.
They come in a candelabra base, so may be a viable choice to replace incandescents in some light fixtures. But frankly, a new light fixture is probably cheaper. My present home came with a 10-lamp candelabra in the dining room, equipped with 60-watt bulbs. That's 600 watts! Blindingly bright, heated the room up instantly, and I took the fixture down within my first day in the place.
LEDs "fail gracefully." Most LED traffic lights I have seen have at least on string of dead lamps, but still keep going. Most other light sources die when they die. For traffic lights and radio towers they definitely make sense on the labor to replace them, and safety issues when they fail.
I have also experienced short life in some CFL applications. This includes fractured tubes that would release some mercury vapor. But I'm crazy anyway so I doubt anyone would notice a change.
Nobody mentioned the old "CircLites". I've got one that has been running 20 years ... and I think it is as efficient as a CFL.
LED flashlights are so remarkably good I doubt I will buy anything else. The batteries last forever! The light is excellent. The cost has dropped dramatically, to a few bucks, or ten for ten bucks in a package deal recently.
My big problem with CFL is that even though they are supposed to last a long time, and the way I use them they do, they lose brightness with time. My "100W" equivalent bulb dims to 60 or even 40 in a few standard incandecent lives. So even though it still "works", it doesn't really function as it should. Makes the economic equation difficult to resolve.
Are you factoring in the replacement costs over time? Remember these liberal idiot cities have unionized maintenance employees with huge salary, benefit, and pension costs. The rated lifespan of the LED array traffic lights I've seen as high as 100,000 hours, though I see an awful lot of them with failures of individual LEDs that cast a lot of doubt on even 20,000 hours.Diogenes wrote:At $400.00 per unit, an LED lens assembly would never pay for itself. Fortunately, Liberal idiot cities who have no common sense whatsoever, using tax payer money, started ordering massive quantities of these things, and as a result of the laws of supply and demand, more companies got into the business to take advantage of these suckers, and through economies of scale, new technology, and competition, the prices for a Standard Red LED assembly (Made by General Electric e.g.) are now around $50.00, and as a result, they will recover their cost within 3-4 years (@ $0.10/KWH) and start saving money thereafter.
Just considering an additional factor...D Tibbets wrote:Playing with some numbers...
Energy:
. Electricity cost= $0.1/ Kwh
Lifetime:
. incandescent light bulb = 1000 hr
. CFL = 10,000 hr
. LED = 100,000 hrs
Cost per bulb:
. incandesant $0.50
. CFL $ 5
. LED $50
Fixed Maintenance Labour Cost:
. $50 Per Fitting (for industrial office, inclusive of time for administrative purchasing, stores tracking, obtaining items from stores, distraction from usual work tasks)
Incandescent light bulb at 60 watts x 100 bulbs for 100,000 hrs. = $5650 = $50 bulb cost + $600 electric cost (6,000 Kwh) + $5000 maintenance
CFL at 15 watts x 10 bulbs for 100,000 hrs. = $700 = $50 bulb cost + $150 electricity cost (1500 Kwh) + $500 maintenance
LED at 5 watts X 1 bulb for 100,000 hrs*. = $150 = $50 bulb cost + $50 electricity cost (500 Kwh) + $50 maintenance
In theory there is no difference between theory and practice, but in practice there is.
An LED bulb running 24/7 would have to last 11.4 years to reach that 100,000 hours. For some applications that may be worthwhile.
But how about my closets? There you are talking maybe 6 minutes of use a day, or 0.1 hours. So how many years of use is that? No payback. I was amused when my energy-hog house came with all incandescent lighting, except the cheap flourescents in the closet, which failed within the first year. I replaced them with incandescent. I've changed every other light I can to CFL. Many of the ceiling light fixtures require candelabra bulbs and are still incandescent.
For an application that burns a bulb less than a few hours a day, you will likely die before you hit the replacement of the lamp. Lifetime energy savings become a joke because you will never hit that lifetime.
But how about my closets? There you are talking maybe 6 minutes of use a day, or 0.1 hours. So how many years of use is that? No payback. I was amused when my energy-hog house came with all incandescent lighting, except the cheap flourescents in the closet, which failed within the first year. I replaced them with incandescent. I've changed every other light I can to CFL. Many of the ceiling light fixtures require candelabra bulbs and are still incandescent.
For an application that burns a bulb less than a few hours a day, you will likely die before you hit the replacement of the lamp. Lifetime energy savings become a joke because you will never hit that lifetime.
Watch out for diminishing returns.
Let's say you have determined that you will replace your old gas-hog 15 mpg road barge with an efficient compact such as, let's say, a Ford Focus, at around 34 mpg. Nice move.
Now you have the Focus, and you want to improve even more. You discover that you can get a hybrid capable of 55 mpg. The first change improved mileage by 19 mpg. The second would improve by 21 mpg. Worthwhile, right?
Probably not. You already invested around $20k getting most of the improvement. Going from 15 mpg to 55 mpg is a nice savings, but if you actually calculate the dollar amount and the gallons, you have to drive a heckuva lot of miles to justify the change from 34 to 55.
Which is your red flag. Why have you set your life up so you have to drive so much you can justify the hybrid? If you only drive occasionally, that road barge may make more sense overall, as it does not require a new vehicle to be built. If you live close to work and shopping, and walk or bike mostly, that's the real savings. My wife drives a SUV, but only 2 miles to the train station, for her daily commute to DC.
No light bulb saves more energy than one that is turned off.
Let's say you have determined that you will replace your old gas-hog 15 mpg road barge with an efficient compact such as, let's say, a Ford Focus, at around 34 mpg. Nice move.
Now you have the Focus, and you want to improve even more. You discover that you can get a hybrid capable of 55 mpg. The first change improved mileage by 19 mpg. The second would improve by 21 mpg. Worthwhile, right?
Probably not. You already invested around $20k getting most of the improvement. Going from 15 mpg to 55 mpg is a nice savings, but if you actually calculate the dollar amount and the gallons, you have to drive a heckuva lot of miles to justify the change from 34 to 55.
Which is your red flag. Why have you set your life up so you have to drive so much you can justify the hybrid? If you only drive occasionally, that road barge may make more sense overall, as it does not require a new vehicle to be built. If you live close to work and shopping, and walk or bike mostly, that's the real savings. My wife drives a SUV, but only 2 miles to the train station, for her daily commute to DC.
No light bulb saves more energy than one that is turned off.
I see this analysis similar to Bussared's reasoning that utilizing existing coal plant steam systems with a heat generating Polywell makes more economic sense than completly tearing down the existing coal plant and building a dedicated Polywell system in its' place. Yes, your milage will be better, but the economies will hurt, especially in the short term.Tom Ligon wrote:Watch out for diminishing returns.
Let's say you have determined that you will replace your old gas-hog 15 mpg road barge with an efficient compact such as, let's say, a Ford Focus, at around 34 mpg. Nice move.
Now you have the Focus, and you want to improve even more. You discover that you can get a hybrid capable of 55 mpg. The first change improved mileage by 19 mpg. The second would improve by 21 mpg. Worthwhile, right?
Probably not. You already invested around $20k getting most of the improvement. Going from 15 mpg to 55 mpg is a nice savings, but if you actually calculate the dollar amount and the gallons, you have to drive a heckuva lot of miles to justify the change from 34 to 55.
Which is your red flag. Why have you set your life up so you have to drive so much you can justify the hybrid? If you only drive occasionally, that road barge may make more sense overall, as it does not require a new vehicle to be built. If you live close to work and shopping, and walk or bike mostly, that's the real savings. My wife drives a SUV, but only 2 miles to the train station, for her daily commute to DC.
No light bulb saves more energy than one that is turned off.
So, replace things as they reach the end of their usefull life, don't start from scratch, unless the differences quickly overwhelm other considerations.
Also, of course conservation/ less use is the most economical of all.
Dan Tibbets
To error is human... and I'm very human.
scareduck wrote:Are you factoring in the replacement costs over time?Diogenes wrote:At $400.00 per unit, an LED lens assembly would never pay for itself. Fortunately, Liberal idiot cities who have no common sense whatsoever, using tax payer money, started ordering massive quantities of these things, and as a result of the laws of supply and demand, more companies got into the business to take advantage of these suckers, and through economies of scale, new technology, and competition, the prices for a Standard Red LED assembly (Made by General Electric e.g.) are now around $50.00, and as a result, they will recover their cost within 3-4 years (@ $0.10/KWH) and start saving money thereafter.
Not at all. When something doesn't reach payback on it's only merit (cost of operation) it cannot possibly reach payback by adding a deficiency.
scareduck wrote: Remember these liberal idiot cities have unionized maintenance employees with huge salary, benefit, and pension costs. The rated lifespan of the LED array traffic lights I've seen as high as 100,000 hours, though I see an awful lot of them with failures of individual LEDs that cast a lot of doubt on even 20,000 hours.
I suppose I should have clarified that my calculations were based on the average life expectancy. I've seen good quality products go 5+ years, and poor quality products last not even 1 year.
Assuming an LED lens assembly saves .1 kwh / hour over an incandescent lamp (an assumption favorable to the LED) and if electricity costs $0.10/kwh then it works out to a penny an hour in savings. Since there are 8760 hours in a year, this works out to a savings of $87.60 per year if operated full time.
Since Red traffic signals do NOT stay on 100% of the time, this does not apply. Assuming they stay on for 50% of a traffic signal cycle, that would cut the savings in half to $43.80/year in cost savings.
At this rate, based on electricity savings alone, a $400.00 Red LED assembly would have to operate for ten years just to pay back it's initial cost. As of yet, i've never seen one that lasted that many years, let alone that many hours of operation. The cost of hiring someone with a bucket truck to put it in hasn't even been added either.
Green LEDs are even worse, and Amber LEDs are worse still. Amber lights on a traffic signal typically are on for no longer than 4-6% of the entire cycle. This works out to an electrical power savings of $4.38 cents per year. It would take almost a hundred years to break even in power savings. (at $400.00 / LED)
Fortunately, the liberal spending profligacy resulted in enough interest from manufacturers that the prices had to succumb to the free market, and now they are quite practical at $50.00 for a Red LED assembly.
I would not care to calculate the cost of its energy use, but in terms of hours of operation, I would double-dog-dare LED bulb manufacturers to top this incandescent lamp:
http://www.centennialbulb.org/
There are a few others around the world that also show remarkable longevity.
http://www.telegraph.co.uk/news/newstop ... -bulb.html
http://www.centennialbulb.org/
There are a few others around the world that also show remarkable longevity.
http://www.telegraph.co.uk/news/newstop ... -bulb.html
Talk about simultaneity! No sooner did this topic start than I got the following warning via my work safety guy.
How to Dispose of Compact Fluorescent Lamps
When disposing of burned out "old school" light bulbs, most people weren't too concerned about whether they broke in the garbage bag. But the stakes have changed with the newer energy-saving compact fluorescent lamps (CFLs). That's because CFLs contain toxic mercury, albeit in small amounts, that can be released if the bulbs break during disposal.
Within the past few years, many workers in China who work in plants that make CFLs have been poisoned by mercury exposure. Mercury can cause damage to the nervous system, respiratory system, digestive system and kidneys. High levels of exposure can cause death due to respiratory failure.
The US Environmental Protection Agency (EPA's) Energy Star program recommends that these steps be taken in the event that a CFL or fluorescent tube breaks:
1. Open a window and keep people out of the room for at least 15 minutes.
2. Then use disposable rubber gloves and a piece of stiff paper or cardboard to pick up as many fragments of glass and powder as you can. Use sticky tape to pick up the smallest pieces and then wipe the area with a damp paper towel.
3. Double-bag (in plastic bags) all cleanup materials and seal the bags.
4. Wash your hands after handling the bags.
5. If the bulb breaks and fragments land in carpeting, all but the smallest particles should be gathered on stiff paper or cardboard before the area is vacuumed. Then dispose of the vacuum bag or empty and wipe out the canister if the vacuum is bagless. Place the vacuum bag and other debris in a doubled plastic bag and then into the trash.
The markets will make that decision.So, replace things as they reach the end of their usefull life, don't start from scratch, unless the differences quickly overwhelm other considerations.
As with much in capitalist efficiency improvements, creative destruction is painful in direct proportion to how useful it is. I wouldn't worry a lot about disruption; meddling for stabililty's sake can easily lead to the kind of coddling corporatist stagnation that afflicts Europe.
n*kBolt*Te = B**2/(2*mu0) and B^.25 loss scaling? Or not so much? Hopefully we'll know soon...
I believe Your logic is flawed. If you are concidering the duty cycles of a traffic light, you have to compare all three lights together- three LEDs vs three incandescents- combined the light is effectively on all the time except the short time as the lights switch. I think this would favor the LEDS as incandescents conduct significantly more curret (less resistance) as they heat up in each cycle. Also, the on -off cycles wear the incandescents out much faster (one reason a rare incandesent bulb has lasted so long (it is never turned off)). I don't know how LEDS compare in this regard.Diogenes wrote:...
Assuming an LED lens assembly saves .1 kwh / hour over an incandescent lamp (an assumption favorable to the LED) and if electricity costs $0.10/kwh then it works out to a penny an hour in savings. Since there are 8760 hours in a year, this works out to a savings of $87.60 per year if operated full time.
Since Red traffic signals do NOT stay on 100% of the time, this does not apply. Assuming they stay on for 50% of a traffic signal cycle, that would cut the savings in half to $43.80/year in cost savings.
At this rate, based on electricity savings alone, a $400.00 Red LED assembly would have to operate for ten years just to pay back it's initial cost. As of yet, i've never seen one that lasted that many years, let alone that many hours of operation. The cost of hiring someone with a bucket truck to put it in hasn't even been added either.
Green LEDs are even worse, and Amber LEDs are worse still. Amber lights on a traffic signal typically are on for no longer than 4-6% of the entire cycle. This works out to an electrical power savings of $4.38 cents per year. It would take almost a hundred years to break even in power savings. (at $400.00 / LED)...
If an incandesent bulb (or a combination of three) uses 100 watts continously, a LED might use 20-30 watts or less. That is a difference of 70 watts for an hour or 70 W hr. At 10 cents per KW Hr that is $0.007 per hr, $0.168 per day, and $61 per year. I'm not sure where your 0.1 K Wh savings comes from . For that to apply the incandesent bulbs would have to be stronger than my 100 w example, or the LED efficiency advantage would have to be even higher. Using your 0.1 kwh advantage I get $87 / yr.
I don't know where your $400 per LED signal light comes from, but if accurate and an incandescent bulb cost $1 per bulb, and the incandescent needs to be changed every 6 months (~ 4000 hr lifetime for a bulb that is cycled once/minute seems generous) and assuming a LED has 10 times that life time (and more forgiving failure modes) then the energy saving over 5 yrs needs to be added to the replacemant costs X 10.
Lets see... Energy savings of $87/yr X 5 yr= $437
Add that the replacement costs of $10 (generous) to $50 (quoted above) gives ad additional cost of $100 to $500 for the incandescent system. Multiply that by thousands of lights in a city adds up to savings of tens of thousands dollars per year. Not huge amounts for a large city, but still, a no brainer, provider the replacement is introduced as the incandescent bulbs fail. If there are additional costs (if need to re[place entire signal light box) the situation becomes more murky.
Dan Tibbets
Last edited by D Tibbets on Thu May 20, 2010 8:25 pm, edited 1 time in total.
To error is human... and I'm very human.
Cost of one LED element going in a LED assembly = $0
Cost of two going = $0
Cost of max no of tolerable failures +1 = $400 [replace head]
now compare...
cost of one filament bulb going = $1,000,000
...this being the settlement made by the local Authority for an injury accident caused by someone having a collision at a junction when they thought it was good to go.
Move on.. you're boring me.
Cost of two going = $0
Cost of max no of tolerable failures +1 = $400 [replace head]
now compare...
cost of one filament bulb going = $1,000,000
...this being the settlement made by the local Authority for an injury accident caused by someone having a collision at a junction when they thought it was good to go.
Move on.. you're boring me.
Doing it that way just adds confusion. The efficiencies for Red, Amber and Green LEDs are not Equal, (Red = 10-12 Watts, Amber = 22.2 Watts, and Green = 12 watts) neither are the costs. Currently, a Red LED assembly is about $50.00. I think the greens are around $70.00, and the Ambers are $90.00 .D Tibbets wrote:I believe Your logic is flawed. If you are concidering the duty cycles of a traffic light, you have to compare all three lights together- three LEDs vs three incandescents- combined the light is effectively on all the time except the short time as the lights switch.Diogenes wrote:...
Assuming an LED lens assembly saves .1 kwh / hour over an incandescent lamp (an assumption favorable to the LED) and if electricity costs $0.10/kwh then it works out to a penny an hour in savings. Since there are 8760 hours in a year, this works out to a savings of $87.60 per year if operated full time.
Since Red traffic signals do NOT stay on 100% of the time, this does not apply. Assuming they stay on for 50% of a traffic signal cycle, that would cut the savings in half to $43.80/year in cost savings.
At this rate, based on electricity savings alone, a $400.00 Red LED assembly would have to operate for ten years just to pay back it's initial cost. As of yet, i've never seen one that lasted that many years, let alone that many hours of operation. The cost of hiring someone with a bucket truck to put it in hasn't even been added either.
Green LEDs are even worse, and Amber LEDs are worse still. Amber lights on a traffic signal typically are on for no longer than 4-6% of the entire cycle. This works out to an electrical power savings of $4.38 cents per year. It would take almost a hundred years to break even in power savings. (at $400.00 / LED)...
If you add the costs together and add the savings together, you are in effect using the RED assemblies to subsidize the money losing AMBER assemblies.
It comes from making the calculations easy by fudging the actual numbers a bit. In most applications which I am familiar with, a 116 Watt 10,000 hour traffic signal lamp (Hytron or Duratest) is used. As a Red LED assembly draws 12 watts, ( General Electric Gelcore model DR6) Since 12 watts is pretty close to 10% of 116 watts, I fudge it a bit just to make the numbers easier to work without a calculator. Since you are saving almost 100 watts by changing them, it works out to 100 watt/hours per hour, which is a penny at $0.10/kwh.D Tibbets wrote: I think this would favor the LEDS as incandescents conduct significantly more curret (less resistance) as they heat up in each cycle. Also, the on -off cycles wear the incandescents out much faster (one reason a rare incandesent bulb has lasted so long (it is never turned off)). I don't know how LEDS compare in this regard.
If an incandesent bulb (or a combination of three) uses 100 watts continously, a LED might use 20-30 watts or less. That is a difference of 70 watts for an hour or 70 W hr. At 10 cents per KW Hr that is $0.007 per hr, $0.168 per day, and $61 per year. I'm not sure where your 0.1 K Wh savings comes from .
D Tibbets wrote: For that to apply the incandesent bulbs would have to be stronger than my 100 w example, or the LED efficiency advantage would have to be even higher. Using your 0.1 kwh advantage I get $87 / yr.
For the entire set of Three, yes, that is correct.
D Tibbets wrote: I don't know where your $400 per LED signal light comes from,
That was the cost of a Red LED assembly when they first came out for traffic signal applications. Current price is around $50.00 . My point was, Idiot liberal cities were buying them at the $400.00 price! They were also buying the Amber and Green assemblies at that price when they became available.
D Tibbets wrote: but if accurate and an incandescent bulb cost $1 per bulb, and the incandescent needs to be changed every 6 months
Not even close. A good quality incandescent traffic signal lamp lasts 4 years easy. For Green or Amber lamps, even longer. (I have several friends/acquaintances who are traffic engineers. We talk about this stuff from time to time. )
D Tibbets wrote: (~ 4000 hr lifetime for a bulb that is cycled once/minute seems generous) and assuming a LED has 10 times that life time (and more forgiving failure modes) then the energy saving over 5 yrs needs to be added to the replacemant costs X 10.
Lets see... Energy savings of $87/yr X 5 yr= $437
Add that the replacement costs of $10 (generous) to $50 (quoted above) gives ad additional cost of $100 to $500 for the incandescent system. Multiply that by thousands of lights in a city adds up to savings of tens of thousands dollars per year. Not huge amounts for a large city, but still, a no brainer, provider the replacement is introduced as the incandescent bulbs fail. If there are additional costs (if need to re[place entire signal light box) the situation becomes more murky.
Dan Tibbets
It really is a no brainer. The math just didn't work out economically. (I mean originally, when LED's were $400.00 each. The math still doesn't work for the Amber LED's and it sometimes doesn't work for the greens.)
The point I was making was that nobody in the Major liberal cities who switched out their incandescents for LEDs en mass bothered to do the economic calculations, or if they did, they simply didn't care that they were losing money.
Some may have argued that the longer life LED's might result in less liability to the Cities, (no accidents caused by burned out lamps) and so therefore it could be justified in that regard. But other than that caveat, it was just typical government bureaucrats being stupid as usual. Fortunately, it had a serendipitous effect. It spurred competition which eventually brought the cost down.
chrismb wrote:Cost of one LED element going in a LED assembly = $0
Cost of two going = $0
Cost of max no of tolerable failures +1 = $400 [replace head]
now compare...
cost of one filament bulb going = $1,000,000
...this being the settlement made by the local Authority for an injury accident caused by someone having a collision at a junction when they thought it was good to go.
Move on.. you're boring me.
This is more an example of the cost of out of control litigation than anything else. Traffic Lamps have been failing ever since they were invented around 90 years ago. Here in the US, the MUTCD (manual on uniform traffic control devices) specifies you must have at least TWO signal heads for a primary direction. An effort to reduce predictable accidents by adding redundancy.
Of course since everyone has INSURANCE there are no more risks in life, and so therefore one wonders why someone needed to fork over the $1,000,000.00 .
What do you suppose the cost would be for a head?
p.s. This also overlooks the fact that LED signals fail too. This doesn't stop this sort of issue, it just moves it a few years further into the future.