LED Bulbs?
BeaF...@msn.com
considerable, until the utility company raised rates. Now I am
starting
to see LED bulbs. Seem kind of spendy. Anyone have experience with
them?
throw...@dodgeit.com
Won't see them replacing your household lights anytime soon.
Efficiency is about the same or worse than Florescent. I've yet to see
one match the light output of a normal light
Don Klipstein
I have some and I know quite a bit about LEDs.
The latest LEDs coming into production only have about the same
efficiency as fluorescents, and they cost a good order of magnitude more
per watt in initial cost, and they don't last forever (I mostly hear
50,000 hours and I have heard test results of some lasting less than
10,000 hours).
Most white LEDs in products on the shelves now are much less efficient
than fluorescents, mostly closer to incandescents than to fluorescents in
efficiency.
Screw-in LED "bulbs" are in the 1-5 watt range. With efficiency at best
the same as fluorescents, don't expect to see much of these exceeding
the performance of a 7 watt compact fluorescent or a 30 watt incandescent
floodlight or spotlight just yet.
My experience so far, although with units a year or two old already, has
been comparable to or weaker than a 15 watt incandescent in total light
output.
Please be aware of hype in LEDs. They are advancing and will see more
and more applications as they improve. But keep in mind that some have
touted them as more efficienct than fluorescents as far back as the late
1990's!
- Don Klipstein (d...@misty.com)
Seerialmom
The only thing I have LED's in at the moment is my hand-crank
flashlights. I believe there were quite a few LED Christmas lights
recently; more expensive initially but lower cost to run. Many cities
have taken to use the LEDs in traffic lights as well.
I don't think you're the first to notice the correlation between
"lowering your consumption" and rates being raised. I've jumped
through many hoops making my house energy efficient (insulation, dual
pane windows, energy star appliances) but never really seeing any
dramatic decrease in my bill. If I could get "off the grid" through
solar I would (I suppose I could but not sure I want to invest $20,000
to save $120 a month).
Don K
news:1170200408.2...@a34g2000cwb.googlegroups.com...
>
> The only thing I have LED's in at the moment is my hand-crank
> flashlights. I believe there were quite a few LED Christmas lights
> recently; more expensive initially but lower cost to run.
Just wait until you get the bill for the carpel tunnel surgery. ;-)
> Many cities have taken to use the LEDs in traffic lights as well.
That probably has more to do with the high cost and effort to replace
a burnt-out bulb than with LED energy efficiency.
> I don't think you're the first to notice the correlation between
> "lowering your consumption" and rates being raised. I've jumped
> through many hoops making my house energy efficient (insulation, dual
> pane windows, energy star appliances) but never really seeing any
> dramatic decrease in my bill.
You've got cause and effect backwards.
The increasing rates caused you to lower your consumption.
Your lower consumption didn't cause the rates to increase.
Don
Lou
"Don K" <dk@dont_bother_me.com> wrote in message
news:XYednXDIr_Q8QCLY...@comcast.com...
Maybe, maybe not. I don't know the rules current today, but in the past,
state regulatory commissions have approved rate increases when consumption
dropped. The utility built generating plants and entered into contracts
based on estimates of consumption levels, and even if those levels drop,
debt service does not. The theory being, I guess, that more expensive
electricity is better than no electricity.
Michael Black
As energy consumption goes up, they have to keep building new plants,
which can be costly. If they can throttle back each individual's demand,
then the power companies can live longer with existing generators.
Here in Quebec, Hydro keeps wanting to increase rates, with the claim
that it will reduce consumption. Now, they get to play the
"it's good for the environment to reduce consumption" card, yet
given that most of the generators in the province, maybe all, are
hydroelectric, electric useage is not the issue that it is where
coal or oil power plants are located. The reality is that if
they can get homeowners to reduce consumption, that leaves plenty
of electricity with current plants that they can sell off to other
power companies.
One of the conundrums of electricity is that in order to supply
all demands they end up with capacity that isn't used all the time.
If they can cut back in those peak times, they don't have to
add capacity.
It's kind of amusing to see the electric company here wanting
consumers to cut back on useage, given they used to really promote
electricity, and I seem to recall they even gave rebates for people
who switched over to electricity for heating. They want to raise
prices so consumers will cut back, they've deliberately said that,
when in the past they touted the cheap electricity and wanted people
to convert.
Michael
fluffy bunny
I'm not impressed with the volume lighting applications i've seen, such
as the "LED bulb" for sale at Menards and Home Depot, but as directed
beam sources, they're truly amazing.
Many of my fellow hard-core illinois winter bike commuter engineer
friends (real electrical engineers who ride bikes every day) have
converted their bike lights to LED. The results have to be seen to be
believed -- the beam these things throw is amazing, brilliant bright
white, tightly collimated... LED efficiency doubled yet again in the
last year.
They make good bike lights, but i wouldn't light use them in place of a
13 W. florescent tube. Otoh, if you have a spotlight application...
v.good if you're willing to do a little engineering. As of yet, few
worthwhile consumer products are available other than flashlights.
There is a really nice drop-in replacement for Maglite bulbs i saw
recently.
Also, LED's are becoming more and more popular in certain stage lighting
applications.
Look, try, see if you like. calculate power usage and remember that they
should last on the order of 50,000 hours.
.max
Logan Shaw
> I have changed all my light bulbs to flouresent and the savings was
> considerable, until the utility company raised rates.
Aren't you saving even more (with fluorescents, compared to incandescents)
now that the rates are higher? :-)
- Logan
Mike T.
<BeaF...@msn.com> wrote in message
news:1170194924.1...@j27g2000cwj.googlegroups.com...
The LEDs produce intense light in a narrow beam. If you put a diffuser in
front of them, the intensity drops to near zero.
Short answer: LEDs are GREAT for flashlights, useless for household
lighting. Other than night-lites, that is. LED night-lites are great. But
the LED household lighting isn't significantly brighter than
ight-lites. -Dave
Shawn Hirn
"Mike T." <no...@nohow.not> wrote:
A news report I recently heard on a public radio station said that a new
kind of energy efficient LED light bulb is available for residential and
commercial buildings. This news report said that Wal-Mart is the largest
corporate user of energy in the United States and they are buying up
these light bulbs in huge quantities to replace older bulbs in their
stores. They are replacing less efficient bulbs with the new LEDs as the
old bulbs burn out and they are already saving a lot of money on power,
but this also benefits the environment.
Evidently, as a result of Wal-Mart buying so many of these LED bulbs,
the price has gone up high and its hard for consumers to buy them for
home use because the manufacturing isn't up to demand yet, but that's
likely to improve over the next few months.
fluffy bunny
Shawn Hirn <sr...@comcast.net> wrote:
> Evidently, as a result of Wal-Mart buying so many of these LED bulbs,
> the price has gone up high and its hard for consumers to buy them for
> home use because the manufacturing isn't up to demand yet, but that's
> likely to improve over the next few months.
I expect that LED's are going to virtually exterminate hot-filament and
gas discharge lamps in almost all applications over the next decade,
barring niche-applications such as [can't think of any]. They will,
soon, revolutionize the way we think about illuminating our homes and
offices.
In twenty years, old style lamps will be curios, much like kerosene
lamps.
As replace incandescents, they will obviate the need for terawatts of
illumination power over the next few years, and even, by dint of their
incredible reliability, save lives.
Its hard to overstate the breakthrough (or if you prefer, the profound
incremental steps) represented by the recent few years of LED
engineering. The LED flashlights for sale today are impressive, but
they're not state of the art, and the state of the art has a ways to go
before it plateaus. They're truly a modern miracle.
.max
Paul M. Eldridge
replacing the fluorescent lighting inside their refrigeration and
freezer display cases with LEDs at 500 of their U.S. locations, and if
they're happy with the results, they will eventually do the same at
all 6,700 stores world-wide. The primary reason for this change out
is that cold operating environments do not adversely impact LEDs as
they do fluorescents, so for this type of application, they're an
excellent fit. Rest assured, the overhead fluorescent lighting in
their stores will remain intact for many years to come.
Source:
http://www.geconsumerproducts.com/pressroom/press_releases/lighting/gelcore/Walmart_LED_display.htm
For anyone who wants to explore this topic in greater detail, see:
http://www.lrc.rpi.edu/programs/solidstate/pdf/SPIE4776-13_Raghavan.pdf
I can't imagine the conversion of these display cases will have any
material impact on supply and, if anything, it should help drive down
the cost of this technology.
Cheers,
Paul
On Wed, 31 Jan 2007 09:11:19 -0500, Shawn Hirn <sr...@comcast.net>
wrote:
Rod Speed
> Shawn Hirn <sr...@comcast.net> wrote
>> Evidently, as a result of Wal-Mart buying so many of these LED bulbs,
>> the price has gone up high and its hard for consumers to buy them for
>> home use because the manufacturing isn't up to demand yet, but that's
>> likely to improve over the next few months.
> I expect that LED's are going to virtually exterminate hot-filament
> and gas discharge lamps in almost all applications over the next
> decade, barring niche-applications such as [can't think of any].
The most obvious example is where you need heat as well as light.
> They will, soon, revolutionize the way we
> think about illuminating our homes and offices.
Nope, it will just be another evolution.
> In twenty years, old style lamps will be curios, much like kerosene lamps.
The same claim was made when fluoros first showed up, didnt happen.
> As replace incandescents, they will obviate the need for
> terawatts of illumination power over the next few years,
We'll see. Cant see them being viable for exterior large scale lighting any time soon.
> and even, by dint of their incredible reliability, save lives.
> Its hard to overstate the breakthrough (or if you prefer, the profound
> incremental steps) represented by the recent few years of LED
> engineering. The LED flashlights for sale today are impressive, but
> they're not state of the art, and the state of the art has a ways to
> go before it plateaus. They're truly a modern miracle.
The same claim was made when fluoros first showed up, didnt happen.
Seerialmom
> "Seerialmom" <seerial...@yahoo.com> wrote in message
Actually what I was saying is that after doing all these supposedly
energy saving changes on the house not changing behavior otherwise,
the bill did not go down. Our local utilities have been promoting
various rebates on energy efficient appliances and house applications
but I believe the rates had also increased.
Speaking of electric bill....wonder how much I'll get slammed for my
apartment sized freezer running constantly for 4 days? My son left
the door slightly ajar the other day when he put something in it; I
just found out this morning when I saw water underneath and all the
items "frosty". Bleh! Guess I have to defrost when I get home;
luckily items are still frozen.
Paul M. Eldridge
would I pay had I not gone ahead and made these changes?" You did hit
upon an important point though and that's behaviour. Better
technology will only take you so far and beyond that, it comes down to
attitude and behaviour. Your upright freezer may be an
energy-efficient Energy Star model, but if your son isn't careful
about closing the door, your energy costs are going a lot higher than
they need be.
As a simple guess, those four days may have added an extra twenty to
twenty-five kWh to your next bill and given that you didn't lose the
contents (potentially a much greater loss), things could have turned
out far worse. And the good news is that if the freezer is located in
a conditioned space and you are currently heating your home, the
additional out-of-pocket expense is likely to be very low (or nill in
the case of electric heat).
Cheers,
Paul
On 31 Jan 2007 10:42:52 -0800, "Seerialmom" <seeri...@yahoo.com>
wrote:
Don K
news:betatron-4835FE...@ftupet.com...
>
> I expect that LED's are going to virtually exterminate hot-filament and
> gas discharge lamps in almost all applications over the next decade,
> barring niche-applications such as [can't think of any].
I expect they won't.
There're still a few hurdles. Your unbridled optimism reminds me of that
project flow chart where the last step is labeled,
"... and then a miracle happens".
They will,
> soon, revolutionize the way we think about illuminating our homes and
> offices.
>
> In twenty years, old style lamps will be curios, much like kerosene
> lamps.
It all depends on achieving that last step in the flowchart,
you know, the miracle.
>
> As replace incandescents, they will obviate the need for terawatts of
> illumination power over the next few years, and even, by dint of their
> incredible reliability, save lives.
>
> Its hard to overstate the breakthrough (or if you prefer, the profound
> incremental steps) represented by the recent few years of LED
> engineering.
But you did manage to do so anyway. :-)
Don
throw...@dodgeit.com
> On Jan 30, 2:08 pm, BeaFor...@msn.com wrote:
>
> > I have changed all my light bulbs to flouresent and the savings was
> > considerable, until the utility company raised rates. Now I am
> > starting
> > to see LED bulbs. Seem kind of spendy. Anyone have experience with
> > them?
>
> The only thing I have LED's in at the moment is my hand-crank
> flashlights.
Incandescent flashlights are terribly inefficient (even compared to a
household 120V incandescent), as well in the high shock environment of
a flashlight, the durability and long life of LEDs is a plus. As well
they have much better characteristics as the battery dies than an
incandescent. Also, most "white" LEDs have poor colour rendering
quality, and colour temperature. While adequate for something like a
flashlight, I wouldn't want that kind of ugly light lighting my house.
It will take more R&D to improve this.
> I believe there were quite a few LED Christmas lights
> recently; more expensive initially but lower cost to run.
Unfortunately the output of these LED Chrismas lights is quite dim
unless you look at them straight on, and the output is very flickery.
> Many cities
> have taken to use the LEDs in traffic lights as well.
Several factors here. Traffic signals use single colours (Red, Amber
and Green), LED technologies for those colours have been perfected
long ago. Monotone LEDs have better efficiency than white LEDs, and a
better lifespan.
An incandescent bulb in a traffic signal must be a long life, shock
resistant bulb, so immediately you loose a lot of efficiency (compared
to a normal incandescent), and as well, of the white light the bulb
puts off, all light except that of the desired colour is filtered out,
further reducing efficiency. Traffic signals are also very
directional, which is a light pattern LEDs excel at. All in all LEDs
are very well suited for traffic signals. However, I see very few
people lighting their homes with traffic signals.
LEDs are great for certain applications, however it will be a while
yet before they replace general household lighting, IF they replace
general household lighting.
Don Klipstein
in part:
>
>The only thing I have LED's in at the moment is my hand-crank
>flashlights. I believe there were quite a few LED Christmas lights
>recently; more expensive initially but lower cost to run.
They are getting more common every year, and a decent selection is
available at Target during the time of year to get Christmas lights.
I think a major advantage is that LEDs do not burn out the way
incandescents do. Although LEDs are not indestructible and some cheapies
are clunkers that fail somehow, LEDs do not have hot filaments.
- Don Klipstein (d...@misty.com)
Don Klipstein
>
>"Don K" <dk@dont_bother_me.com> wrote in message
>news:XYednXDIr_Q8QCLY...@comcast.com...
>> "Seerialmom" <seeri...@yahoo.com> wrote in message
>> news:1170200408.2...@a34g2000cwb.googlegroups.com...
>>
>> > "lowering your consumption" and rates being raised. I've jumped
>> > through many hoops making my house energy efficient (insulation, dual
>> > pane windows, energy star appliances) but never really seeing any
>> > dramatic decrease in my bill.
>>
>> You've got cause and effect backwards.
>> The increasing rates caused you to lower your consumption.
>> Your lower consumption didn't cause the rates to increase.
>
>Maybe, maybe not. I don't know the rules current today, but in the past,
>state regulatory commissions have approved rate increases when consumption
>dropped. The utility built generating plants and entered into contracts
>based on estimates of consumption levels, and even if those levels drop,
>debt service does not. The theory being, I guess, that more expensive
>electricity is better than no electricity.
However, if plant construction falls below forecasts, this is a cost
that is avoided. Also, less fuel will be needed. As a result, the
customer base as a whole will have less to pay for, even if the per-KWH
rate increases to keep up the bond payments and the bottom line for
stockholders.
Given the obstacles and associated costs for new plant construction
nowadays, I think consumers will save bigtime if these costs are not
incurred.
I just heard stuff from some environmental group opposing two planned
new coal fired plants in Pennsylvania. And it's obvious that oil fired
plants will cost a lot next time oil spikes, natural gas is only a minor
improvement over oil, and it should be obvious how easy it is now to build
nuke plants within 200 miles of anyone's backyard.
Check out how many acres of windmills are needed to replace a gigawatt
or so plant, also what is needed to store 10's of gigawatt-hours for lower
wind times. And I so clearly remember some greenies bragging about a
solar generating facility feeding the grid as a generating station - built
onto the rooftop of a building that consumed more electricity than this
generating station produced!
Oh, I think conservation is in serious order - especially considering
issues of pollution and limitation of the resources that are to this day
the most economical!
- Don Klipstein (d...@misty.com)
Don Klipstein
>
>As energy consumption goes up, they have to keep building new plants,
>which can be costly. If they can throttle back each individual's demand,
>then the power companies can live longer with existing generators.
>
>Here in Quebec, Hydro keeps wanting to increase rates, with the claim
>that it will reduce consumption. Now, they get to play the
>"it's good for the environment to reduce consumption" card, yet
>given that most of the generators in the province, maybe all, are
>hydroelectric, electric useage is not the issue that it is where
>coal or oil power plants are located. The reality is that if
>they can get homeowners to reduce consumption, that leaves plenty
>of electricity with current plants that they can sell off to other
>power companies.
>
>One of the conundrums of electricity is that in order to supply
>all demands they end up with capacity that isn't used all the time.
>If they can cut back in those peak times, they don't have to
>add capacity.
>
>It's kind of amusing to see the electric company here wanting
>consumers to cut back on useage, given they used to really promote
>electricity, and I seem to recall they even gave rebates for people
>who switched over to electricity for heating. They want to raise
>prices so consumers will cut back, they've deliberately said that,
>when in the past they touted the cheap electricity and wanted people
>to convert.
One thing about electric heat: Heating is needed more at colder times
of the day and at colder times of the year. In a lot of areas this does
not increase peak demand since in those areas the annual demand peaks are
in hot times of the day on the hottest days of the hottest time of the
year, for air conditioning.
As a result, in many areas electric heating does not affect the peak
demand and need for ability to supply the peak demand.
It is common practice for electricity to be available at special lower
off-peak rates when billed through meters with clocks to only allow
consumption at lower demand times of the day. A common application of
circuits fed by these is water heaters for supplying hot water. Another
example is how the University of Pennsylvania achieves a good portion of
its air conditioning - that is done by chilled water lines cooled by ice
made at a chiller plant that uses off-peak electricity to make ice that
does the chilling.
- Don Klipstein (d...@misty.com)
Don Klipstein
>
>Incandescent flashlights are terribly inefficient (even compared to a
>household 120V incandescent), as well in the high shock environment of
>a flashlight, the durability and long life of LEDs is a plus.
As for the efficiency of incandescent flashlight bulbs - I would say
same ballpark as 120V ones despite some economies of scale of
incandescents mostly favoring lower efficiency of lower wattage ones.
The biggest reason is that most incandescent flashlight bulbs are
designed aggressively and have design life expectancy mostly 15-35 hours.
A secondary one is that for a given wattage and life expectancy,
efficiency of an incandescent of wattage of around a watt to a few watts
is maximized by designing it for a low voltage typically in the general
ballpark of 6 volts. Mainly, higher design voltage requires a thinner
filament that must operate at a lower temperature (less visible light and
more infrared) for the same life expectancy.
> As well they have much better characteristics as the battery dies than
>an incandescent.
True! Incandescents have energy efficiency varying directly and
somewhat to significantly more than proportionately with applied voltage,
and usually proportionately to roughly the cube (or worse) of the amount
of current flowing through them. On the other hand, most white LEDs have
enerhy efficiency actually alightly increased when they are mildly or
moderately or even moderately severely "underpowered".
> Also, most "white" LEDs have poor colour rendering
>quality, and colour temperature. While adequate for something like a
>flashlight, I wouldn't want that kind of ugly light lighting my house.
>It will take more R&D to improve this.
Believe me, they are working on this. "Warm white" LEDs with color
rendering index of 85 (where maximum is 100) already exist.
>> I believe there were quite a few LED Christmas lights
>> recently; more expensive initially but lower cost to run.
>
>Unfortunately the output of these LED Chrismas lights is quite dim
>unless you look at them straight on,
Improved in recent years! I have seen them!
> and the output is very flickery.
Easy enough to improve by well-enough-known means if enough consumers
feel the need to speak out!
>> Many cities have taken to use the LEDs in traffic lights as well.
>
>Several factors here. Traffic signals use single colours (Red, Amber
>and Green), LED technologies for those colours have been perfected
>long ago. Monotone LEDs have better efficiency than white LEDs, and a
>better lifespan.
As it turns out now, the latest and greatest white LEDs now on the
market now have more lumens per watt than the latest and greatest on the
market of any spectral color. As for what has the most watts of light out
per watt of electricity in - that's blue, since blue LED chips are used in
those white ones. The usual white LEDs including the latest higher
efficiency ones have blue-emitting chips combined with a phosphor that
absorbs some of the blue output and in response fluoresces out a yellowish
output that gets mixed with the remaining unabsorbed blue output to make
white. These white ones have more lumens per watt than the related blue
ones because the human eye is more sensitive to yellow light than to blue
light.
>An incandescent bulb in a traffic signal must be a long life, shock
>resistant bulb, so immediately you loose a lot of efficiency (compared
>to a normal incandescent), and as well, of the white light the bulb
>puts off, all light except that of the desired colour is filtered out,
>further reducing efficiency.
This accounts for red and green traffic signals with incandescents
easily being only about 20% as efficient as household lightbulbs of the
same wattage.
>Traffic signals are also very directional, which is a light pattern LEDs
>excel at. All in all LEDs are very well suited for traffic signals.
>However, I see very few people lighting their homes with traffic signals.
How true!
>LEDs are great for certain applications, however it will be a while
>yet before they replace general household lighting, IF they replace
>general household lighting.
The biggest obstace now is actually the cost of high efficiency white
LEDs. Ones of at most a few watts cost more than 4-foot fluorescent
bulbs, most incandescent bulbs and even promotion-price compact
fluorescents, while high color rendering index warm white versions with
efficiency like that of compact fluorescents have yet to hit the market.
- Don Klipstein (d...@misty.com)
Don Klipstein
>
>A news report I recently heard on a public radio station said that a new
>kind of energy efficient LED light bulb is available for residential and
>commercial buildings. This news report said that Wal-Mart is the largest
>corporate user of energy in the United States and they are buying up
>these light bulbs in huge quantities to replace older bulbs in their
>stores. They are replacing less efficient bulbs with the new LEDs as the
>old bulbs burn out and they are already saving a lot of money on power,
>but this also benefits the environment.
>
>Evidently, as a result of Wal-Mart buying so many of these LED bulbs,
>the price has gone up high and its hard for consumers to buy them for
>home use because the manufacturing isn't up to demand yet, but that's
>likely to improve over the next few months.
I sure haven't heard anything like that yet! Should I go to the WM
nearest me, am I supposed to expect even 1% of the lighting (by lumen
count) that they have done so far with fluorescents to now be being
done with LEDs?
Keep in mind that a 1.2 watt LED costs more than a 4-foot fluorescent
bulb, and I have yet to hear of LEDs other than laboratory prototypes
producing more lumens per watt (at full power) than commonly available
F32T8 4-foot fluorescents.
LEDs are advancing, but it's going to be a while before they advance
enough to be suitable for most room lighting.
- Don Klipstein (d...@misty.com)
Don Klipstein
It's going to be a while and the advance of LEDs is going to be slow.
And the main obstacles now for LEDs are cost reduction. Available now
only in recent months are white LEDs with efficiency getting into the
fluorescent range, with such efficiency at about 1.2 watts per LED with
these LEDs in quantities of thousands costing more than I pay for 4-foot
fluorescents at home centers.
The latest announced laboratory prototype for high efficiency white LEDs
already has about half the efficiency of a white LED based on a phosphor
with 100% quantum efficiency coated onto a 100% efficient blue LED chip.
I see the top efficiency level of efficiency of the laboratory prototypes
already getting into a plateau, while at that level only about 50% above
the efficiency of some very common fluorescent bulbs in common real-world
use.
LEDs are advancing (at about half the pace of advancement of computers
during the years both have existed), they will eventually become a major
light source, but beware the hype!
- Don Klipstein (d...@misty.com)
Rod Speed
> Lou wrote
>> Don K <dk@dont_bother_me.com> wrote
>>> Seerialmom <seeri...@yahoo.com> wrote
>>>> I don't think you're the first to notice the correlation between
>>>> "lowering your consumption" and rates being raised. I've jumped
>>>> through many hoops making my house energy efficient (insulation,
>>>> dual pane windows, energy star appliances) but never really seeing
>>>> any dramatic decrease in my bill.
>>> You've got cause and effect backwards.
>>> The increasing rates caused you to lower your consumption.
>>> Your lower consumption didn't cause the rates to increase.
>> Maybe, maybe not. I don't know the rules current today, but in the
>> past, state regulatory commissions have approved rate increases when
>> consumption dropped. The utility built generating plants and
>> entered into contracts based on estimates of consumption levels, and
>> even if those levels drop, debt service does not. The theory being,
>> I guess, that more expensive electricity is better than no electricity.
> However, if plant construction falls below forecasts, this is a cost
> that is avoided. Also, less fuel will be needed. As a result, the customer
> base as a whole will have less to pay for, even if the per-KWH rate increases
> to keep up the bond payments and the bottom line for stockholders.
> Given the obstacles and associated costs for new plant construction nowadays,
> I think consumers will save bigtime if these costs are not incurred.
That assumes the new capacity is in new plants. Its more
common to just add new generators to existing sites.
> I just heard stuff from some environmental group opposing
> two planned new coal fired plants in Pennsylvania.
Everything is always opposed by those fools, never stops anything.
> And it's obvious that oil fired plants
There's bugger all of those.
> will cost a lot next time oil spikes, natural
> gas is only a minor improvement over oil,
Wrong on the price spikes.
> and it should be obvious how easy it is now to build
> nuke plants within 200 miles of anyone's backyard.
Plenty of the europeans etc manage to do that fine.
> Check out how many acres of windmills are needed to
> replace a gigawatt or so plant, also what is needed to
> store 10's of gigawatt-hours for lower wind times.
Yeah, that's always been a complete wank.
> And I so clearly remember some greenies bragging about
> a solar generating facility feeding the grid as a generating
> station - built onto the rooftop of a building that consumed
> more electricity than this generating station produced!
> Oh, I think conservation is in serious order - especially
> considering issues of pollution and limitation of the
> resources that are to this day the most economical!
The obvious approach is to use nukes. Not a
shred of rocket science whatever required.
Ron Peterson
> In <srhi-DFD342.09111931012...@newsgroups.comcast.net>, Shawn Hirn wrote:
> Keep in mind that a 1.2 watt LED costs more than a 4-foot fluorescent
> bulb, and I have yet to hear of LEDs other than laboratory prototypes
> producing more lumens per watt (at full power) than commonly available
> F32T8 4-foot fluorescents.
That's true for white LEDs which use flourescent material, but
monochrome LEDs can be more efficient on a lumens per watt basis for
applications like stop lights.
It's still taking a large number of LEDs to give an adequate lighting
level. See http://www.sharperimage.com/us/en/catalog/productdetails/
sku__KH150 .
--
Ron
Don K
>
> It's going to be a while and the advance of LEDs is going to be slow.
> And the main obstacles now for LEDs are cost reduction. Available now
> only in recent months are white LEDs with efficiency getting into the
> fluorescent range, with such efficiency at about 1.2 watts per LED with
> these LEDs in quantities of thousands costing more than I pay for 4-foot
> fluorescents at home centers.
>
> The latest announced laboratory prototype for high efficiency white LEDs
> already has about half the efficiency of a white LED based on a phosphor
> with 100% quantum efficiency coated onto a 100% efficient blue LED chip.
> I see the top efficiency level of efficiency of the laboratory prototypes
> already getting into a plateau, while at that level only about 50% above
> the efficiency of some very common fluorescent bulbs in common real-world
> use.
>
About 15 years ago, one of the guys in my lab was working on a project developing
prototypes for self-contained RF plasma lightbulbs. I don't know the power,
but it was certainly under a hundred Watts, but those things put out the
most intense light I ever saw. Apparently they're a lot more efficient than
your typical flourescent bulb. They ended up using them to light up a museum.
Don
Don Klipstein
>On Jan 31, 10:14 pm, d...@manx.misty.com (Don Klipstein) wrote:
>> In <srhi-DFD342.09111931012...@newsgroups.comcast.net>, Shawn Hirn wrote:
>
>> Keep in mind that a 1.2 watt LED costs more than a 4-foot fluorescent
>> bulb, and I have yet to hear of LEDs other than laboratory prototypes
>> producing more lumens per watt (at full power) than commonly available
>> F32T8 4-foot fluorescents.
>
>That's true for white LEDs which use flourescent material, but
>monochrome LEDs can be more efficient on a lumens per watt basis for
>applications like stop lights.
Lumens per watt for colored LEDs exceeding that of the best white
production units that I have already gotten into my grubby mitts?
What? By who? Where and how to get? I don't believe it. For that
matter, best lumens out per watt in is more for white than for any
spectral color for announced laboratory prototypes also as far as I have
heard.
I know a way to get yellow and yellowish-green to improve a little over
the best white ones by means of adding fluorescent materials (to white or
to just their underlying blue chips), but for some reason I have yet to
see a press release in that area.
The big efficiency advantage of LEDs in traffic signals is over the
really lousy efficiency of superlonglife vibration resistant incandescents
that have some, mainly most, of their light blocked by colored filters.
- Don Klipstein (d...@misty.com)
Don Klipstein
You may be talking about sulfur lamps. They gained some press in the
mid-late 1990's, with efficiency in the sodium lamp range and life
expectancy really way up there.
The big problem with those is that their ballasts are magnetrons, with
efficiency maybe 70% or so and life expectancy in the lower 5 figures,
comparable to that of fluorescent bulbs.
The ones deemed most practical were a lot more than a hundred watts,
closer to a kilowatt.
- Don Klipstein (d...@misty.com)
Don K
Possibly sulfur, I wasn't paying much attention, other than it was annoying
the way he'd light up the whole lab when testing it. ;-)
No magnetron, he was generating a plasma with a much lower RF frequency. IIRC he
was using a silicon carbide transistor as an RF source and most of the effort was
to efficiently match impedances for efficiency. The thing was in the shape of
a regular lightbulb.
Don
Chris Malcolm
> On Jan 30, 6:08 pm, BeaFor...@msn.com wrote:
>> I have changed all my light bulbs to flouresent and the savings was
>> considerable, until the utility company raised rates. Now I am
>> starting
>> to see LED bulbs. Seem kind of spendy. Anyone have experience with
>> them?
> Won't see them replacing your household lights anytime soon.
> Efficiency is about the same or worse than Florescent. I've yet to see
> one match the light output of a normal light
Their killer savings area is in flashlights, whose requirement for a
small focussable light source rules out fluorescents. They save a
great deal on battery power. A high power white LED flashlight running
of AAs can now outperform a big incandescent flashlight running of D
cells. The impact this has had on my domestic lighting is that we now
use torches for a lot more things, such as going to the toilet in the
middle of the night, instead of firing up half a dozen big mains
powered lights for several minutes, or even leaving the hall light on
all night "just in case".
--
Chris Malcolm c...@infirmatics.ed.ac.uk DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]
fluffy bunny
"Don K" <dk@dont_bother_me.com> wrote:
> > Its hard to overstate the breakthrough (or if you prefer, the profound
> > incremental steps) represented by the recent few years of LED
> > engineering.
>
> But you did manage to do so anyway. :-)
i forgot to include gaslights (coal gas in illinois) in my soliliquy of
obsoleted lighting technology.
I think the main reason the straight fluor. tube failed to take over in
the residental market was simply its geometry. It was never made into a
consumer-friendly install, and due to its geometry, it suffered from
severely limited installation.
CF's have clearly overcome that hurdle, while recognizing much of their
current popularity upsurge is the result of various economic
subsidizations. So i'd say that finally, the fluorescent tube is
replacing the filament lamp for home use.
Obviously, the tube long ago exterminated the filament in office.
(Aprapos nothing, I've always been a fan of the sodium vapor lamp,
having first seen them illuminating the highway between Ludwigsburg and
Stuttgart some 35 or so years ago. Beautiful, if peaky spectrum.)
Back to the thesis that LED's will displace filament lamps, i base my
position into three trends, and arrive at my 10 and 20 year numbers.
Firstly, i'm assuming the basic engineering of the gap material quantum
efficiency will follow some sort of attenuated Moore's Law for the next
few years. I also consider the issue of the fluorescent downconverter
material spectrum to be effectively a non-issue, and trivially solved.
Given the current state of watts/lumen, LEDs are pretty much in the
[metaphorical boxing] ring with CFs, so any gains above will merely
strengthen their advantage.
So the next two trends necessary for LED to take over are obviously,
production and applications development.
I figure ten years is plenty enough time to capitalize, design and build
enough fabs and necessary upstream supply systems to saturate the market
with LEDs.
Which leaves applications. I think a decade will be long enough for
lighting engineers, architects and interior designers to catch up with
the technology and start incorporating LEDs into their designs. I
forsee a move from direct volume lighting to distributed indirect
lighting. E.g. instead of lighting a room with a volume-illuminating
incandescent ceiling lamp or table lamp, we might imagine a strip of
wall mounted, obliquely directed ceiling washing LEDs for volume
applications.
I expect to see quite rapid replacement of virtually all MR-11/12
fixtures.
By the end of a decade, as the supply and applications pipes are filled,
i expect to see LEDs very much in control of new construction
residential (ok, but probably not for offices) After that happens, it's
just a matter of time for the incandescent supply chain to atrophy,
older systems to be slowly replaced, rising energy costs to militate the
switch over, legislative fiat to make incandescents less attractive, etc.
I think one of the truly irresistable dynamics will be the reliability
of LEDs. This is an area where CF's have truly screwed the pooch. I
know i'm seeing a 5~10% infant mortality for the CFs i get from Menards
(even higher for the pretty colored ones!), and as has been noted, they
haven't endeared themselves with the enclosed-base-up problem.
Consumers are going to be strongly attracted to a product whose claim of
"up to X" years of service has some chance of actually being valid.
10 years/ 20 years. Let us revisit the discussion and see how right i
am. :-)
.max
Rod Speed
> Don K <dk@dont_bother_me.com> wrote
>>> Its hard to overstate the breakthrough (or if you prefer, the profound
>>> incremental steps) represented by the recent few years of LED engineering.
>> But you did manage to do so anyway. :-)
> i forgot to include gaslights (coal gas in illinois)
> in my soliliquy of obsoleted lighting technology.
Irrelevant to your silly claim that incandescents are gone now.
> I think the main reason the straight fluor. tube failed to take
> over in the residental market was simply its geometry.
Nope, most didnt like the light as much as incandescents.
> It was never made into a consumer-friendly install, and due
> to its geometry, it suffered from severely limited installation.
> CF's have clearly overcome that hurdle,
No they havent yet, most obviously with recessed lights.
> while recognizing much of their current popularity
> upsurge is the result of various economic subsidizations.
Thats the real reason, given out for free by quite a few electricity
authoritys and plenty silly enough to try saving on their electricity
bills, even when the life of them ended up with higher total costs.
> So i'd say that finally, the fluorescent tube is
> replacing the filament lamp for home use.
Yes, but that is nothing like your original silly sweeping claim.
> Obviously, the tube long ago exterminated the filament in office.
It didnt do that either, tho it certainly dominates there.
> (Aprapos nothing, I've always been a fan of the sodium vapor lamp,
> having first seen them illuminating the highway between Ludwigsburg
> and Stuttgart some 35 or so years ago. Beautiful, if peaky spectrum.)
And useless where you need anything like accurate color rendition.
> Back to the thesis that LED's will displace filament lamps, i base my
> position into three trends, and arrive at my 10 and 20 year numbers.
You plucked them out of your arse and cant manage
to comprehend that it wont happen like that.
> Firstly, i'm assuming the basic engineering of the
> gap material quantum efficiency will follow some
> sort of attenuated Moore's Law for the next few years.
Moore's law doesnt apply to stuff like light bulbs.
Or cars either.
> I also consider the issue of the fluorescent downconverter
> material spectrum to be effectively a non-issue, and trivially solved.
Have fun explaining how come it never was with long tube fluoros.
> Given the current state of watts/lumen, LEDs are pretty
> much in the [metaphorical boxing] ring with CFs,
Nope, not for area lighting they aint.
> so any gains above will merely strengthen their advantage.
Nope. At the ultimate, what matters is efficiency, cost of
manufacture and basic stuff like how directional the source is etc.
> So the next two trends necessary for LED to take over
> are obviously, production and applications development.
Soorree, fresh out of magic wands to wave.
> I figure ten years is plenty enough time to capitalize,
> design and build enough fabs and necessary upstream
> supply systems to saturate the market with LEDs.
Irrelevant to the basic limitations of that particular technology.
> Which leaves applications. I think a decade will be long enough for
> lighting engineers, architects and interior designers to catch up with
> the technology and start incorporating LEDs into their designs.
Irrelevant to the basic limitations of that particular technology.
> I forsee a move from direct volume lighting to distributed indirect
> lighting. E.g. instead of lighting a room with a volume-illuminating
> incandescent ceiling lamp or table lamp, we might imagine a strip of wall
> mounted, obliquely directed ceiling washing LEDs for volume applications.
That is never going to see that approach universal.
> I expect to see quite rapid replacement of virtually all MR-11/12 fixtures.
More fool you. The same mindless claim was made about
long tube fluoros by fools who didnt have a clue too.
> By the end of a decade, as the supply and applications pipes are filled,
Irrelevant to the basic limitations of that particular technology.
> i expect to see LEDs very much in control of new construction residential
More fool you.
> (ok, but probably not for offices)
Certainly not. Funny that.
> After that happens,
It aint gunna happen.
> it's just a matter of time for the incandescent supply chain to atrophy,
Just another of your silly little fantasys.
> older systems to be slowly replaced, rising energy costs to militate the switch over,
Not to leds it wont.
> legislative fiat to make incandescents less attractive, etc.
That isnt going to happen except in a few places stupid enough to use that approach.
> I think one of the truly irresistable dynamics will be the reliability of LEDs.
That aint what most care about in a domestic situation.
> This is an area where CF's have truly screwed the pooch. I know
> i'm seeing a 5~10% infant mortality for the CFs i get from Menards
> (even higher for the pretty colored ones!), and as has been noted,
> they haven't endeared themselves with the enclosed-base-up problem.
And leds wont have fixed the directional problem that they have.
> Consumers are going to be strongly attracted to a product whose claim
> of "up to X" years of service has some chance of actually being valid.
Nope, not when the alternatives are reliable enough.
> 10 years/ 20 years. Let us revisit the discussion and see how right i am. :-)
You'll be hiding long before that.
fluffy bunny
"Rod Speed" <rod.sp...@gmail.com> wrote:
shut up, tardboi.
Rod Speed
Never ever could bullshit its way out of a wet paper bag.
throw...@dodgeit.com
> throwit...@dodgeit.com wrote:
> > On Jan 30, 6:08 pm, BeaFor...@msn.com wrote:
> >> I have changed all my light bulbs to flouresent and the savings was
> >> considerable, until the utility company raised rates. Now I am
> >> starting
> >> to see LED bulbs. Seem kind of spendy. Anyone have experience with
> >> them?
> > Won't see them replacing your household lights anytime soon.
> > Efficiency is about the same or worse than Florescent. I've yet to see
> > one match the light output of a normal light
>
> Their killer savings area is in flashlights, whose requirement for a
> small focussable light source rules out fluorescents. They save a
> great deal on battery power. A high power white LED flashlight running
> of AAs can now outperform a big incandescent flashlight running of D
> cells. The impact this has had on my domestic lighting is that we now
> use torches for a lot more things, such as going to the toilet in the
> middle of the night, instead of firing up half a dozen big mains
> powered lights for several minutes, or even leaving the hall light on
> all night "just in case".
For night-time lighting I like the 0.25Watt electroluminescent lights
that use about 2 cents of power in a year. I can pick them up at the
Dollarama (CSA / UL approved). Leave one in the hall, and one in the
bathroom and I can use the toilet at night without farting around with
flashlights or normal lights, and it doesn't destroy my night vision.
SMS
> CF's have clearly overcome that hurdle, while recognizing much of their
> current popularity upsurge is the result of various economic
> subsidizations. So i'd say that finally, the fluorescent tube is
> replacing the filament lamp for home use.
Pretty much, though they have their drawbacks. They take a while to
reach full brightness, and they're not good for high-intensity lamps.
For women, putting on make-up in a bathroom lit by fluorescents doesn't
work well.
I was especially pleased to see all the fluorescent bulbs for recessed
lighting. I have a lot of recessed lighting in my house, about 40
recessed fixtures, and they are almost all fluorescent now. I spaced
them a little closer together than I would have if I had been using
incandescent.
LED lamps are great for low intensity applications, but the higher
intensity LEDs (5W Luxeon) generate a lot of heat that is difficult to
manage.
bear...@cruller.invalid
throw...@dodgeit.com wrote:
> For night-time lighting I like the 0.25Watt electroluminescent lights
> that use about 2 cents of power in a year. I can pick them up at the
> Dollarama (CSA / UL approved). Leave one in the hall, and one in the
> bathroom and I can use the toilet at night without farting
Wow. Those are some special lights :-))
throw...@dodgeit.com
> In article <1170371912.190092.101...@q2g2000cwa.googlegroups.com>,
>
> throwit...@dodgeit.com wrote:
> > For night-time lighting I like the 0.25Watt electroluminescent lights
> > that use about 2 cents of power in a year. I can pick them up at the
> > Dollarama (CSA / UL approved). Leave one in the hall, and one in the
> > bathroom and I can use the toilet at night without farting
>
> Wow. Those are some special lights :-))
Helps keep from waking the wife :-)
bear...@cruller.invalid
throw...@dodgeit.com wrote:
WHAT? You don't drug her?
throw...@dodgeit.com
> In article <1170449641.212062.230...@v45g2000cwv.googlegroups.com>,
She drugs herself with Vodka. I only had to add additional drugs to
bring her home the first night. Now yelling and beating her keeps her
in line. She says sumthin' about the booze lessening the pain.
bear...@cruller.invalid
throw...@dodgeit.com wrote:
> She drugs herself with Vodka.
Is that reliable?
> I only had to add additional drugs to bring her home the first night.
Cudgels and dragging by the hair work well, too!
> Now yelling and beating her keeps her in line. She says sumthin'
> about the booze lessening the pain.
You know, there are these new things called "shackles"...
throw...@dodgeit.com
> In article <1170459530.386880.273...@j27g2000cwj.googlegroups.com>,
>
> throwit...@dodgeit.com wrote:
> > She drugs herself with Vodka.
>
> Is that reliable?
>
> > I only had to add additional drugs to bring her home the first night.
>
> Cudgels and dragging by the hair work well, too!
>
> > Now yelling and beating her keeps her in line. She says sumthin'
> > about the booze lessening the pain.
>
> You know, there are these new things called "shackles"...
Not as much fun. Plus then she can't do the cookin' and cleanin'.
bear...@cruller.invalid
throw...@dodgeit.com wrote:
This has been a lot of fun, but I have to stop now. The ol' ball & chain
just got home.
throw...@dodgeit.com
> In article <1170460522.554525.10...@m58g2000cwm.googlegroups.com>,
So? Get her to get you a beer, and bake a pie.
Don Klipstein
Actually rather widely available - most home centers, many drugstores,
some supermarkets, and Radio Shack. And this is old technology - dating
back at least as far back as 1960's, maybe 1950's.
The modern implementations sometimes have the brand name or trademark of
"Indiglo". I am talking about electroluminescent nightlights. Often
these are flattish things that could resemble a
"2-inch-diagonal-measurement flatscreen TV" in appearance.
The photometric efficiency is in the lower end of what I call
"incandescent range". But add to this the usual formulation having a
spectrum quite favorable to night vision (also achievable by many commonly
available green, blue-green and blue LEDs), and it gets easy for a
dark-adapted human to get a hallway and a couple rooms illuminated well
enough to make a late night bathroom trip by a fraction of 1 watt.
However, these do not last forever. Sometimes things go wrong and they
conk out one way or another. Barring that, they degrade from age with a
halflife of only a few years. Properly implemented, colored LEDs do
better.
- Don Klipstein (d...@misty.com)
bear...@cruller.invalid
d...@manx.misty.com (Don Klipstein) wrote:
> Actually rather widely available - most home centers, many drugstores,
> some supermarkets, and Radio Shack.
Yes, but do they all have the same kind of flatulence-suppressive
properties? I think I would have to look at the warranty.
bear...@cruller.invalid
throw...@dodgeit.com wrote:
She's got a gun AND a friend in the roller derby.
Jeff
> fluffy bunny wrote:
>
>> CF's have clearly overcome that hurdle, while recognizing much of
>> their current popularity upsurge is the result of various economic
>> subsidizations. So i'd say that finally, the fluorescent tube is
>> replacing the filament lamp for home use.
>
>
> Pretty much, though they have their drawbacks. They take a while to
> reach full brightness,
That is certainly true for the smaller lamps
and they're not good for high-intensity lamps.
> For women, putting on make-up in a bathroom lit by fluorescents doesn't
> work well.
That appears to be changing. My Photo Club just replaced the color
balanced high intensity hot lamps (lifetime of just a few hours and $7
each) with some color balanced High Intensity CF's for our Print
Competitions. Aside from the much longer lifespan the color of the new
CFs is much better, and that being judged by some color critical people.
Incidentally, it's the B&W prints that really benefit from the new lamps
(much much less metamirism).
>
> I was especially pleased to see all the fluorescent bulbs for recessed
> lighting. I have a lot of recessed lighting in my house, about 40
> recessed fixtures, and they are almost all fluorescent now. I spaced
> them a little closer together than I would have if I had been using
> incandescent.
>
> LED lamps are great for low intensity applications, but the higher
> intensity LEDs (5W Luxeon) generate a lot of heat that is difficult to
> manage.
BTW, just ran across this:
<URL: http://www.theinquirer.net/default.aspx?article=29472 />
Nichia claims to have an LED with 113 lumens/watt and there's another
lab model at 130 lumens. That takes us close to replacing household CF's
with LEDs within the decade.
Jeff
Anthony Matonak
...
> <URL: http://www.theinquirer.net/default.aspx?article=29472 />
>
> Nichia claims to have an LED with 113 lumens/watt and there's another
> lab model at 130 lumens. That takes us close to replacing household CF's
> with LEDs within the decade.
Lasers are more efficient at producing light than LEDs so,
presumably, at some point we'll start seeing lasers used for
general lighting.
Anthony
Don Klipstein
What lasers are more efficient at producing light than LEDs?
The most efficient lasers I ever heard of are infrared diode lasers, and
they have been more efficient than LEDs but LEDs are advancing faster and
just about catching up. I sure never heard of any visible light lasers
more efficient than some LEDs on the market now.
- Don Klipstein (d...@misty.com)
Anthony Matonak
I don't know where I got the idea but a quick google search found
me another fellow who thinks lasers have potential. :)
http://www.repairfaq.org/sam/laserdio.htm#diocss7a
: Consider: Some commercially available high power laser diodes have an
: overall conversion efficiency - electrical power in to optical power
: out - of over 50 percent. Current research is attempting to boost this
: past 80 percent.
:
: Incandescent lamps are only about 5 percent efficient; halogen lamps
: around 7 to 10 percent; and fluorescents, about 15 to 20 percent. High
: brightness LEDS suitable for lighting applications are advancing but
: are currently somewhere around halogen lamps in efficiency (though
: under some conditions, LEDs at low power may exceed 25 percent
: efficiency). But, it's unlikely that the LED could even match the
: laser diode due to the basic physics.
Anthony
Michael Black
> Don Klipstein wrote:
>> In article <45c714dc$0$5821$4c36...@roadrunner.com>, Anthony Matonak wrote:
>>>
>>>Lasers are more efficient at producing light than LEDs so,
>>>presumably, at some point we'll start seeing lasers used for
>>>general lighting.
>>
>> What lasers are more efficient at producing light than LEDs?
>>
>> The most efficient lasers I ever heard of are infrared diode lasers, and
>> they have been more efficient than LEDs but LEDs are advancing faster and
>> just about catching up. I sure never heard of any visible light lasers
>> more efficient than some LEDs on the market now.
>
> I don't know where I got the idea but a quick google search found
> me another fellow who thinks lasers have potential. :)
>
wouldn't be useful if they weren't. SO the fact that you get a nice
read dot on the wall down the hall that's brighter than a flashlight
would give at the distance isn't important. Because you can't do
much in the way of lighting with that little red dot, while you can
do things with the flashlight. (Of course, there are things you
can do with the laser, but it doesn't include lighting.)
MIchael
Don Klipstein
That is several years old and needs to be updated since LEDs have
advanced since then. I think I helped Sam Goldwasser out with
that one around 1999 or 2000 or so.
Meanwhile, those really efficient laser diodes remain all infrared.
- Don Klipstein (d...@misty.com)
Don Klipstein
>But, the point of lasers is that they are a very small beam. They
>wouldn't be useful if they weren't. SO the fact that you get a nice
>read dot on the wall down the hall that's brighter than a flashlight
>would give at the distance isn't important. Because you can't do
>much in the way of lighting with that little red dot, while you can
>do things with the flashlight. (Of course, there are things you
>can do with the laser, but it doesn't include lighting.)
A laser beam can easily be spread out with optics or blurred with a
diffuser. The main problems are cost effectiveness, regulations, speckle
and the fact that visible lasers are not as efficient as currently
available better LEDs. Not even visible lasers costing thousands of
dollars.
- Don Klipstein (d...@misty.com)
Ron Peterson
> In article <1170306957.709652.325...@a75g2000cwd.googlegroups.com>, Ron
>
> Peterson wrote:
> >That's true for white LEDs which use flourescent material, but
> >monochrome LEDs can be more efficient on a lumens per watt basis for
> >applications like stop lights.
> What? By who? Where and how to get? I don't believe it. For that
> matter, best lumens out per watt in is more for white than for any
> spectral color for announced laboratory prototypes also as far as I have
> heard.
I forgot that lumens per watt depends on eye sensitivity to the color.
I was thinking about power efficiency instead.
> The big efficiency advantage of LEDs in traffic signals is over the
> really lousy efficiency of superlonglife vibration resistant incandescents
> that have some, mainly most, of their light blocked by colored filters.
Yes, if monochrome light is desired, LEDs are the way to go.
I was reading an article in IEEE Spectrum where it was explained that
LEDs have a big advantage in tail lights because they can turn on a
few milliseconds faster giving a following car more time to brake.
Seeing that you have some good web pages on LEDs, perhaps you have an
idea when RGB arrays of LEDs will become practical for LCD displays
giving a better color gamut.
--
Ron
Don K
Just to expand a little about the reference to "regulations":
The laser diodes I use for optical links at 1310nm put out around
4 to 10 milliWatts of optical power into a pinpoint when biased at 35 to 45 mA.
If you wanted to use a laser with a diffuser to replace a 100W lightbulb,
you are going to be playing with devices that probably could be modified
into deathrays.
Don
Anthony Matonak
...
> If you wanted to use a laser with a diffuser to replace a 100W lightbulb,
> you are going to be playing with devices that probably could be modified
> into deathrays.
You say that like it's a bad thing. :)
Anthony
Rick
If they can get the color right. How many "white" LED flash lights have
you seen that aren't really white? More like a bluish white. Wanna see
the dear wife put makeup on with those? 8-)
Rick
Don Klipstein
>If they can get the color right. How many "white" LED flash lights have
>you seen that aren't really white? More like a bluish white. Wanna see
>the dear wife put makeup on with those? 8-)
How often does anyone's wife apply makeup by light of any flashlight?
Also, I do agree that LED flashlights have a harsher, more bluish color
than incandescents ones have, but I do see the usual white LEDs having
the advantage over incandescents of not losing any energy efficiency at
all when moderately or moderately severely underpowered, while
incandescents have energy efficiency varying directly and significantly
more than proportionately with magnitude of overpowering/underpowering.
Get two flashlights, one incandescent, both taking same type/number of
battery cells, and both of same photometric output with identical fresh
batteries, with one being anh LED model and the other being an
incandescent model. Turn both on at the same time and see how they run
down, and chances are that the LED one has some usefulness as a flashlight
when the incandescent one is down to the brightness of an idling
cigarette - even if the LED one and the incandescent one had the same
photometric efficiency at "time zero".
- Don Klipstein (d...@misty.com)
Michael Black
> In article <45C9DDB2...@rcn.com>, Rick wrote:
>
>>If they can get the color right. How many "white" LED flash lights have
>>you seen that aren't really white? More like a bluish white. Wanna see
>>the dear wife put makeup on with those? 8-)
>
> How often does anyone's wife apply makeup by light of any flashlight?
>
> Also, I do agree that LED flashlights have a harsher, more bluish color
> than incandescents ones have,
I actually like the light from LED flashlights better than the light
from incandescent flashlights. There seems something unnatural about
the incandescent light, and the LED flashlights provide something that's
missing.
Michael
fluffy bunny
d...@manx.misty.com (Don Klipstein) wrote:
This is one of those double-edged sword things.
I like to periodically remind my fellow bicyclists of this fact -- those
little red tail light blinkies may continue to blink, but after a "few"
(i leave the term undefined) hours of operation, they're just not very
bright, even though they're still the same wonderful red color.
So, when's the last time all the cyclists here changed their blinky
batteries?
.max
A Man
flourescents. LEDs are best suited for short-range illumination, like
under cabinets, or for DC applications (like flashlights). My batteries
last a loooooong time using an LED light.
Frank
"A Man" <u...@ftc.gov> wrote in message
news:MPG.22095e08d...@news.readfreenews.net...
> LED light efficiency (lumens per watt) is still not as good as
> flourescents.
I'm surprised as LED don't have ballast loss like fluorescents especially
when you talk about battery power. I know LED flat screen monitors are not
as efficient as the old style CRT tube monitors or TVs, but I think that
will be changed in the future. LED has came a long way, much further than
fluorescent, from the days of LED clocks and calculators during the early
70s. My bet is fluorescent will go on the path of the incandescent while
LEDs will develop and improve for years to come.
LEDs are best suited for short-range illumination, like
> under cabinets, or for DC applications (like flashlights). My batteries
> last a loooooong time using an LED light.
Don't know what you mean by short-range illumination. Fluorescent is not
know for long-rang either. My LED Mag flash light has more long-range punch
than any flashlights I have, including my 5D cell Mag light. A lot has to do
with the reflector design and getting the LED wattage up. I'm not surprised
if I see indoor applications of LED flood and spot lights much like the
MR-16s a few years ago. Outdoor not so sure, HID still the standard for
illumining large areas.
We have switched to LED exit signs years ago, where it has to be on 24/7,
for efficiency and reliability. A single solid state device like LED has a
life of 100 years while fluorescent, perhaps 30,000 hours at best.
Don Klipstein
>
>"A Man" <u...@ftc.gov> wrote in message
>news:MPG.22095e08d...@news.readfreenews.net...
>> LED light efficiency (lumens per watt) is still not as good as
>> flourescents.
Actually, a few LEDs are now as efficient as fluorescents.
>I'm surprised as LED don't have ballast loss like fluorescents especially
>when you talk about battery power.
Actually, they usually do. One may get thrown off by the "ballast"
often being known as something else - "LED driver" or "dropping resistor",
though the latter is obviously lossy.
LEDs often don't work well and close enough to never have reliable
nearly-constant power draw when connected to batteries.
> I know LED flat screen monitors are not
>as efficient as the old style CRT tube monitors or TVs,
LCD usually has less power consumption per square inch than CRT. To a
lesser extent and maybe not at all in smaller sizes, this is mostly true
of plasma.
> but I think that
>will be changed in the future. LED has came a long way, much further than
>fluorescent, from the days of LED clocks and calculators during the early
>70s. My bet is fluorescent will go on the path of the incandescent while
>LEDs will develop and improve for years to come.
It's going to be a while, due to the high cost of LEDs, in terms of
dollars per watt. One factor complicating this is that white LEDs of the
usual technology have a nonlinearity, where they are most efficient at
rather low power levels, and less efficient at higher power levels.
For example, a Lumileds Luxeon K2 white LED is usually rated to run fine
and dandy with room for error at 1 amp (typically 3.5-4 watts) and maximum
continuous current (with decreased allowance of even internal "junction"
temperature) is 1.5 amps, and power draw then is typically about 6 watts.
However, these are most efficient when the current is less than 350 mA,
and efficiency peaks with current somewhere rough ballpark 100 mA (give or
take a factor of 2), and I think more likely less than more. Power draw
at 350 mA is a little over a watt, and at 100 mA is around .27-.3 watt.
At 350 mA, the top brightness grade in the datasheet for white ones of
the latest "thin film flip chip" version has efficiency (overall luminous
efficacy") that I would call "upper fluorescent range". At 100 mA, I
would say their overall luminous efficacy gets to "best of fluorescents".
I find the most efficient similar white LEDs by Cree and related ones
with Cree chips to do similarly, maybe a hair better but still at reduced
power only or not much past "top end of fluorescent" range.
Consider that these cost a few bucks apiece even in quantities well into
the thousands.
Also consider that LEDs are no better than fluorescents at making heat -
as in whatever energy going in that fails to become light becomes
non-radiant heat - as in the heat materializes in the "bulb". This is as
opposed to incandescent, where roughly ballpark half the energy input
failing to be transformed to visible light comes out as infrared - that
becomes heat, but the heat from that materializes outside the lamp.
The more-compact size of LEDs makes this heat problem even more of an
engineering challenge. Also consider that LEDs get more efficient when
cooler and less efficient when hotter. And that they achieve "rated
performance" when either their heatsinikable surfaces or the hottest
points within their chips (depending on manufacturer) are at 25 degrees C.
>LEDs are best suited for short-range illumination, like
>> under cabinets, or for DC applications (like flashlights). My batteries
>> last a loooooong time using an LED light.
One big reason there: When the batteries weaken, LEDs and incandescents
(including halogens, krypton-filled-incandescents and xenon-filled
incandescents) do two very different things:
Incandescents have their efficiency decrease bigtime and their
electrical resistance decrease when voltage decreases. So when the
battery weakens, incandescents "roughly halfway" maintain their current
consumption, while their energy efficiency drops even faster than their
power input does.
And LEDs on the other hand, have their electrical resistance increase
when voltage decreases. And their efficiency is more constant - even
usually increasing slightly as their power draw decreases from "full" to
"moderately severely underpowered" (where their efficiency usually peaks).
That is a major part of the explanation why an LED flashlight can be at
least fairly or somewhat useful for 30-100 hours on one set of batteries,
while a comparable incandescent one can run down to being dimmer than an
idling cigarette in half as much time or less!
That stuff I explain in slightly greater detail in:
http://www.misty.com/~don/lede.html
However, in the past few to several months I have been finding LED
flashlights on retail shelves/racks (notably at Target and Sears) that
have roughly double-triple the efficiency of most-similar incandescent
ones even with fresh batteries. However, I still found their efficiencies
less than that of most fluorescents (though not less than or only slightly
less than that of most fluorescent flashlights and
battery-powered-lanterns).
<SNIP from there>
- Don Klipstein (d...@misty.com)