White LED lies: It's great, but Nobel physics prize-winning great? This year's Nobel Prize in Physics went to the three Japanese guys who worked on, and got right, the blue LED. It's an excellent piece of work, enabling a whole new ensemble of energy efficient lamps and colour LED screens, and fully deserving of the prize. And yes, it might well change society in wondrous and wonderful ways. …
"...enables blue LEDs to be produced, and once you've got those to add to red and green ones, white light is possible and the LED light bulb could become reality."
Is the above extract correct?
Although it is certainly possible to purchase an RGB LED, such RGB LED light bulbs or similar RGB LED lighting strips seem to be more commonly sold as a accent lighting or novelty items. Based on what I've seen, most (virtually all?) LED lighting is based on LEDs using UV or Blue plus White or Yellow phosphor. Available as Warm or Cool coloured white light.
Am I correct on this point?
That's correct. In practice, most white LEDs don't produce "white" light by mixing primaries. The do it by using a phosphor coating which "downshifts" much of the blue light to longer wavelengths and mixing this with the blue light that penetrates the phosphor layer.
Of course, none of these technologies produce the continuous (black-body) spectrum of an incandescent bulb, although many people seem to believe they do.
@Steve Jones
who says people believe LED's (or whatever) produce a blackbody spectrum, I'm sure they a) don't know what a blackbody spectrum is; b) don't care?
I remember switching to energy saving bulbs some years ago and the feel of my rooms being different from filament bulbs, somehow 'colder', but now I've got used to it and happy in the (presumed) energy saving costs, although I've not tried to isolate this from fluctuating electricity prices; I'm not sure many people check their actual consumption, only how much their bill is (which is the point of the article and the prize award).
R + G + B will ONLY EVER work for a colour display. It's absolutely rubbish even if correct Colour temperature for lighting as the colour rendition is about the worst possible. Perhaps R G & B laser light might be slightly worse.
"White" LED are worse even than CFL or Florescent lamps as the UV LED isn't short enough wavelength for decent phosphors.
Very efficient CCFL, CFL or Florescent lamps are poorer colour rendition than best ones as the best colour uses more phosphors and less efficient ones to get a smoother spectrum with less gaps, spikes, dips etc
Unless there is a new type of UV LED, the White LED will be always poorer rendition. The phosphors wear too. White LEDs also are not as energy efficient as suggested due to PSU losses and less wide angle light.
Halogen is still best colour artificial light, with some less efficient Florescent lamps and CFLs less good.
RGB LED is far better LCD backlight than "White LED", most cheaper "White LED" are a bit purple and CCFL backlight may yellow a little with age, but after a few years the CCFL backlights are superior as backlights to cheap "white" LED. Very few TVs and Notebooks now have good backlights. Built down to a cost.
The AMOLED phone displays are not traditional R , G, and B LEDs, Sony calls the true LEDs, Crystal displays.
Can we even accurately measure it given the signal is mixed with every other electrical device in the home? Sure, we can put meters on individual appliances and work it out but is there any simple way to say "X" is lighting. Does it get more complicated given the ambient light cast off by the myriad devices in our lives like computer and TV screens and the dozens of other devices with luminous displays even if it's just a green led on the router, a red one on the switch and a blue one on the modem? At some point we're just picking, err, nits.
> Does it get more complicated given the ambient light cast off by the myriad devices in our lives like computer and TV screens and the dozens of other devices with luminous displays even if it's just a green led on the router, a red one on the switch and a blue one on the modem?
Depends what you're measuring. If you're measuring the actual cost of bringing your home up to a certain level of litness, yes, that all complicated matters considerably. But if you're measuring the amount that humans spend on lighting, it doesn't. A router may throw a bit of light into a room, but that's a side-effect; when someone spends £50 on a router, they never think "And 30p of that comes out of my lighting budget."
Another factor that is often overlooked is that in a place like the UK where a lot of lighting is used in winter, indoors, and along with heating, then any increase in efficiency is going to be partly offset by the heating system making up for the reduction in waste heat.
Other than that point, I tend to agree with Tim that we will just use more of it if the running cost is reduced.
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No, Colour Temperature isn't the problem, its Colour Rendition, which is rubbish. The directionality is an issue too. LED lighting is ghastly compared to CFL.
RF noise of badly designed SMPSU for LED or Electronic Ballast of CFL can be easily solved. Regulation and enforcement is too lax.
Labelling is misleading .
Since most UK heating is by gas, solid fuel or oil, turning off a 100W incandescent and increasing the output of the CH boiler reduces electricity demand (and hence generation load). Anybody heating their house with electricity who doesn't have a private wind turbine is either unfortunate (renting) or needs a serious rethink (owner), because electricity costs more per Joule than does gas.
Software or engineering, it is almost always better to have something with minimal side effects. An incandescent bulb is around 2-4% efficient as a visible light emitter and most of that light is down the long wave end. There are many situations - street lighting, shop lighting, lighting in summer - where that waste heat is a highly undesirable side effect.
"Anybody heating their house with electricity who doesn't have a private wind turbine is either unfortunate (renting) or needs a serious rethink (owner), because electricity costs more per Joule than does gas."
Gas isn't available to around one in eight of the UK population because they are off the gas grid, and it isn't available in high rise buildings for safety reasons (noting some use communal gas boilers, some use dry electric heat). The cost balance between electric and gas should also take account of the depreciation of a gas boiler (say £150 a year), interest on the capital tied up (say £100 a year), and an annual safety check and clean (say £100). That's £350 a year of hidden costs before you've done anything. And there's a further couple of grand tied up in a wet heating system (say £250 a year, maybe more if you pay for "heating cover"). Added together the standing costs of a wet, gas fired heating system are around £700-800 a year, which would buy around 5 GWh of heat. And that doesn't include the gas supply standing charge, typically a further £100-150 a year (in terms of figures above, the gas standing charge would pay the depreciation on a dry electric system).
Against that a dry electric system is cheap to install and lasts longer so has lower depreciation, and has virtually no maintenance costs. In a typical draughty, poorly insulated house I'd agree gas is a no brainer where available. But in a very well insulated modern house a dry electric system can start to look a credible option. Economy 7 tariffs and storage heaters (with peak top up) can be as cost effective in the longer term as gas in a typical house, even though you'd have higher electricity bills. If I were doing a self build or a self-specify, I'd be looking for passivhaus levels of insulation, and use underfloor dry electric heating, and do without gas at all (that's a pipe dream, or non-pipe dream, depending on how you look at it).
Industry insider hint for those currently on E7 tariffs: Switch supplier twice a year - outside of the heating season you need the cheapest normal non-E7 tariff, during the heating season the cheapest E7 or E10. When switching in spring you're looking for a supplier who will offer you single rate electricity on a dual rate meter, as not all do. Do the sums, see if it works for you. Also, if you've not got night storage heaters, and you're on E7, chances are that you're paying a lot more than you would on a single rate tariff (to be in the money you need 35-40% of all electricity used across the year to be used in the cheaper off peak period). If either the seasonal strategy or the 35% of all power off peak things are news to you, I may have just saved you £150-200 a year, so in lieu of my beer fund, contributions welcome to the RNLI.
Not that long ago in some more northern climes where incandescent traffic signals were replaced with LEDs one problem was that there wasn't enough "waste heat" in winter to remove the snow from in front of the light making them near impossible to see in the day time.
Not that long ago in some more northern climes where incandescent traffic signals were replaced with LEDs one problem was that there wasn't enough "waste heat" in winter to remove the snow from in front of the light making them near impossible to see in the day time.
A typical mark-one problem. They've retro-fitted LEDs into existing enclosures without giving enough thought to the design of the entire system. The mark-two LED traffic light will have a small heater on its front shield / lens connected to a controller that will maintain the lens temperature above freezing point.
It might also have a well-insulated enclosure so that the heat from the LEDs does not go to waste, just as long as that doesn't result in the LEDs overheating in summer! Or maybe an aluminium heatsink that is exposed to the elements, with the LEDs (and cold-weather heater) sealed into it in a suitably weatherproof manner. Maybe the traffic light of the future will look like discs on a pole, rather than boxes of lights on a pole.
+1 to Nigel. I was in Minsk, Belarus last week and most of their traffic lights are thin flat panels with LEDs. They get very cold weather in winter and I'm guessing the lights would not accumulate much snow or need much heat to melt it off.
Here in the UK you see what look like LED array traffic lights but still in a big square box with shrouds - but we don;t get much properly cold weather or snow (practically none last year - and my son got a sledge for Xmas :-(
We had one of our guys bring in his VCR to repair (not the type of thing we normally worked on), we plugged it into the only composite monitors we had there, monochrome green screens. It would serve the purpose well enough in any case.
However, the only tape that was available at that time to test it, was a porno.
In the middle of "testing" the boss looks over our shoulders, and said "As long as it's not a blue movie, that's allright".
I have to agree that a greater prevalence of LED lighting options will lead to more use of lighting. The same holds true in heating, where if you offer people an insulation package for their homes (draught proofing, new boiler, cavity wall and loft insulation), then according to some very good studies, in a third of households the heating bills rise. The term the industry use is "comfort taking", and it's a simple fact of human behaviour.
And that illustrates some of the problems in forecasting demand and energy use, and the partial delivery of claimed benefits. In the move from incandescent to CFL bulbs, the "waste" heat was anything but during the six month or so of the UK heating season. Admittedly using electric bulbs is an expensive way of heating your home compared to gas, but the planet-savers didn't factor in the lost benefits of incandescent filaments, that on a fully adjusted basis were probably around 15% of their energy use. And likewise they didn't allow for the poor light output, poor light quality, and often slow start up of CFLs that caused people to buy a bigger nominal replacement CFL, or to have additional lights on. The only real reason that CFLs have become as widespread as they have is the EU tree-hugger's ban on incandescent bulbs, along with the UK Department of Energy & Climate Change forcing energy suppliers to subsidies or hand out hundreds of millions of CFL's
subsidised from levies on your electricity bill.
Even with LEDs the "crap eco light" problem has not been fully addressed, with lots of low grade harsh bluey-white lights on the market, sometimes low output, and often low reliability at the cheap end of the market. For GU10 halogens, there's plenty of good, reasonably priced LED options with output as good as a halogen, but for other fittings there's a lot of variation, and indeed a lot of crap on the market. At present there's few 100W BC incandescent equivalents available - the CFL versions tend to disappoint, and there's no trustworthy 1600 lumen bulbs I can find.
Curiously enough, one of the biggest benefits of LEDs is in street lighting. The overall energy savings if every street light in the land were LED are modest at around 0.3 GW (cf 2GW for a decent size thermal power station), but the quality of the light is far better, the savings on replacing bulbs half as often add up, and the luminaires (the light fittings) are far better designed with less light spill and darker skies.
"Curiously enough, one of the biggest benefits of LEDs is in street lighting."
In desperate economic moves UK councils are already reducing street lighting almost back to the 18th century levels. My large town switches off all the street lights at midnight - leaving only a few high level clusters on major roads. LED lights would be seen as a source of further economy.
The pitch black result is that any late return from an event requires a torch. Possibly an employment opportunity for link boys - or footpads.
"The pitch black result is that any late return from an event requires a torch. Possibly an employment opportunity for link boys - or footpads."
And just as much of an employment opportunity for paramedics and fire &rescue services:
http://www.theaa.com/newsroom/news-2014/street-lights-night-time-accidents.html
The curious thing is why local government think they are in such desperate economic times. Current public spending is only marginally down from the astronomical levels achieved by notorious traitor Gordon Brown, my council tax is higher than it has ever been, and nationally the public sector is still spending £100 billion a year more than it raises through taxes (and none of that includes billions of pounds of stealth taxes like all the levies on your energy bills, mandated private sector expenses like employee pensions, or the half a billion telly tax).
> The curious thing is why local government think they are in such desperate economic times.
They don't. They're pretending they do in order to blackmail the public. "Nice library you've got here. Be a terrible shame if something were to happen to it. Like, for instance, Westminster threatening my gravy train."
So, just in case you are out after dark a couple of times a month this justifies your local council wasting money on energy every night. What's wrong with a small LED torch in your pocket when you know you are going to be out after dark? for some of us who live in the country this is the only option.
City dwellers don't realise how much energy, and therefore money, is wasted in street lights, shops and offices and floodlights everywhere from the back garden to the local castle walls.
"So, just in case you are out after dark a couple of times a month this justifies your local council wasting money on energy every night. "
Well sod off and live somewhere where there are no street lights then. You may find IS-held Syria to your taste, so lacking in all forms of modern amenity that I'm sure it is doing wonders for the planet.
"My large town switches off all the street lights at midnight - leaving only a few high level clusters on major roads."
LED plus sensors means that they can be dialled back 90%, but still fire up as cars/people go under them (the lamps communicate to adjacent poles, so it's not just the one you're under which lights up). This technology has been around a few years now.
As for energy costs, the single most expensive part of any streetlamp's operation is getting a bloke to change the lamp. Traditional ones are rated in on/off cycles as well as hours, so switching 'em off early may not make them last any longer and does bugger-all to save money overall. That sounds more like someone with a fetish for dark skies (Any amateur astonomers on the council?)
The pitch black conditions and increased nighttime accident rate sounds like a perfect oppportunity for compensation lawyers to wipe out any savings made - and then some.
LED street lanterns tend to use more energy than the sodium ones they replaced. 35w sodium=35w+9w (ballast lossed)=44w. 60w LED +5w gear losses=65w. The main energy saving is the potential to dim them down yes, but unfortunately the GSM based control system is about the most unreliable system the human race has developed.
Uh.
HPS street lamps use significantly more than 35 watts per bulb. Try multiplying that by ten.
As for me, I live where the initial UK trials for LED street lighting were carried out. Going from a HPS section to a LED section is an amazing difference. Yay for white not-piss-yellow street lamps.
Bus-stops are disconnecting from the grid. They harvest enough energy from a solar panel during the day, to run timetable illimination and an LED light in the roof of the shelter. I was surprised when I first encountered one, that the shelter light was bright enough to read a newspaper.
Street lights could do the same thing, if only rules would allow the illumination levels to be dropped. At present there seem to be regulations stating that where there is street-lighting at all, it has to be bright. So you get a ridiculous safety hazard on some main roads, where you get dazzled driving into a street-lit section, and then have lost your night-vision adaptation when you drive out of it. Maintaining the whole road lit to the brightness of a full moon (or maybe just a little brighter) would surely be safer.
"Admittedly using electric bulbs is an expensive way of heating your home compared to gas, but the planet-savers didn't factor in the lost benefits of incandescent filaments, that on a fully adjusted basis were probably around 15% of their energy use. "
Afraid that's simply not true. As a 'planet-saver' who's worked on the nuts and bolts of energy efficiency for nearly a decade, the heat replacement effect has been well understood and factored in to efficiency savings calculations from lighting to appliances and ITC for at least as long. It doesn't make a big difference but it's big enough to be worth factoring in to any saving calculation.
It doesn't make a big difference but it's big enough to be worth factoring in to any saving calculation.
Oh?
I did the sums. Allowing for the much earlier sunset in Winter and the fact that I'm at work during the day, something like three-quarters of my light usage was at the same time as I'm heating my flat. Plus any heat from lights that doesn't warm me, goes to warm my upstairs neighbours. So I have mostly gone back to Halogen-incandescent bulbs.
True, there are greater inefficiencies in electrical generation and distribution, than in high-efficiency (condenser boiler) gas central heating. But there are a lot of old boilers that won't be replaced for decades(*), and a lot of electric-only residences, and a fair number of rural homes that have to use Calor gas or oil or -shock! - coal heating.
(*) [Rant] especially since there's a regulation that requires your existing 15mm gas supply pipe to be upgraded to 22mm as part of any installation of any new boiler, despite the fact that many boilers are designed to work without any problem on a 15mm pipe. So, to the cost of a new boiler, add the cost and hassle of ripping up carpets and floors to install a new pipe, and repairing the damage afterwards. Madness. Oh, and you're no longer allowed to DIY the electrical work. Neither can the gas fitter do it. One of Prescott's jobs-for-ther-lads policies, you are regally required to employ an electrician as well as a gas fitter and a carpet fitter and a plumber. (And a council bureaucrat to keep the records)
Which is why my boiler won't be replaced until I sell my flat. If the new owner can be bothered, that is. [/rant]
Seconded - I suspect the major eco benefit of LED will be the very long life - anyone seen an LCA?
Hopefully that will be as true when/if we get a decent 100W equivalent. CFL especially of the expenisve dimmable variety and halogen have very poor life expectancy - switch cycle limits seem the culprit.
Just bought some 60W equivalents for clusters and been very impressed - if they even come halfway close to the expected lifetime I'll be happy - very high ceilings!
>I suspect the major eco benefit of LED will be the very long life -
Both incandescent and compact fluorescent bulbs are available in long-life versions. The first CFL I bought in the 1980's is still going (outside lamp that requires a ladder to change), and I was buying 2000 hr and 5000 hr incandescents just out of laziness (so I didn't have to change as often).
I suspect that people will continue to buy lamps that require frequent replacement.
although I believe in your numbers about the stability of the amount of money spent, I don't think that comes from more light on our houses. You get more efficient lights, you use more energy on computers, tablets, smartphones, etc.
Our energy consumption is not going to fall, that's for sure, but due to new uses, not for brighter lights indoors.
I don't think that tablets and smartphones are even worth mentioning. With USB power, they'd peak at about 10 watts (5v x 2A max), and the actual average would be much less than that. Consider also that they spend much of their duty cycle on standby - best measured in milliwatts. If you own a cat, then it is almost certainly a larger heat source than your tablet.
The EnergyStar / EnerGuide lables tell the story. Year after year, the latest apppliances and TVs are off the low end of the scale as compares to the min-max range set by the previous year's models. Our new 50-inch TVs are anticipated to require just $14 worth of power per year.
My ongoing attempt to heat my house using consumer electronics is becoming more difficult with each appliance upgrade. I have achieved an annual baseload that is several times the winter hump for electric heating.
In live events, LED sources are already saving significant quantities of electricity. And, yes, at the same time, people are using more and more fixtures, but they use so much less electricity than the discharge / incandescent predecessors that a real decrease in energy usage is happening.
Even more so where it comes to outdoor temporary events. Using LED can mean a more impressive stage / better lit site, while needing a smaller generator, less diesel and smaller, lighter cabling.
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