'Solid-state' light uses one-10th energy, maker says

Good point, but UV also makes dairy products go off (have you ever left milk out in the sun?); I think it's because it damages the protein.

Hero999 said:

...

Do you work for an LED company?

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Hell no, do you work for a bulb company?

(I design electronics for a living)

Hero999 said:

• LEDs are famous for changing colour over their life time because the phosphor tends to burn out long before the LED. The colour always tends to shift towards the blue end of the spectrum, If its a white LED, it will end up blue, if it's pink it'll still end up blue. I know that there are three chip LEDs but even then the dies don't wear equally and the colours don't always mix very well.

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• 
  
  Current generations of Power white LEDs from LumiLEDs/CREE shift much less, in the 10's of thousands of hours, instead of hundreds of hours like 5mm white LEDs do. But products like the Seoul P4 I've actually watched shift in the hundreds of hours like a cheap 5mm LED, and these cheap asian knockoffs also use epoxy to bond the die to the slug, instead of soldering. I've watched the Seoul P4 loose 12% of it's output in hundreds of hours, shifting a bit over one bin towards blue- which is likely why the lumen output dropped. I've monitored some of the CREE and Luxeon III devices, and actually have seen them increase in output, 3-5% during the first 5,000 hour period.
  
  There is a huge difference between these Power LEDs, and the little 5mm LEDs. But, yes, I have seen the Luxeons shift 1000K in 26,000 hours. I've seen Flourescents, CCFL, and CFL shift further in even less time. Piss poor heatsinking and overdriving LEDs will cause them to shift much quicker.
  
  
  

  Hero999 said:

  [*]Anyone with any sense doesn't enclose the ballasts in the refrigerating compartment so ballast losses increasing the load on the compresser is a non-issue.

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  Nobody said they did. Ballast losses do affect the system lm/W, and you need to include them. However, fluorescent bulbs do consume considerably more power when they are in a cold environment, causing their lm/W numbers to drop very significantly. There are double wall bulbs, and covers that can help, but both of these solutions also impact lm/W.
  
  
  

  Hero999 said:

  [*]LEDs also require ballasts so you can't say that LEDs are better because the ballasts losses are lower. This isn't true, a high quality fluroscent ballast can be >90% efficient and a the same goes for LEDs. The resistor ballasts often used on battery power LEDs are often less efficient than the inverter used to power a CCT.

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  I never said it was true, please stop putting words I didn't say into my mouth- Thank you! Yes you certainly can get expensive high efficiency ballasts for fluorescent bulbs- though they are not as common place as typical ballasts, due to price. The point is that you must include ballast losses in the system numbers.
  
  
  

  Hero999 said:

  Just from my personal experiance:
  

  • I hate the colour light most supposedly white LEDs produce, its harsh on the eye and is normally more blue or dull grey than white. I am aware that there are soft and warm whites available but their efficency is comparatively poor. I like the warm glow of incandescents which even the modern compact fluorescents emulate quite well.
  • I've always found CCTs to be generally better all round performers especially where I want a diffuse light source - a 300mm tube will give me more light than 60 LEDs, uses less power and produces better quality light.

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  • • 
      
      You can buy cool white LEDs that are binned anywhere from a CCT of 4500K to 10,000K. Have you ever had a chance to look at any of the power LED datasheets? See page 12:
      https://www.electro-tech-online.com/custompdfs/2007/03/AB21.pdf
      
      
      Lets take an example:
      
      Thats great, until you realize that you loose 10% in the electronic ballast, and another 20-45% of losses in the fixture itself (and the fixtures are definitely not all created equal).
      
      So, you end up with a 30-55% lm/W loss, right off the top. Then the tubes age, and you loose even more.
      
      Sorry, but they don't even get close to 80 lm/W once they are fixtured.
      
      
      Take one of the super duper high efficiency lamps from GE (usually they are very hard for consumers to obtain unless you go to the right places):
      28 Watts
      48"
      P/N F28T8/SP30/UMX/ECO
      life 24000 (with 12 hours ontime minimum, shorter with less on time)
      Initial lumens 2750
      Mean Lumens 2585
      Color temp 3000K
      CRI 85
      
      Take the mean lumens of 2585 and divide it by 28 Watts:
      92.32 lm/W
      
      10% efficiency loss for the electronic ballast so multiply by 0.9:
      83.09 lm/W
      
      Use a very high end fixture (rarely seen) and get an additional lumen loss of 20%, so multiply by 0.8:
      66.47 lm/W
      
      Or take a average fixture with 35% losses, so multiply by 0.65:
      54.01 lm/W
      
      
      Funny how things get so hyped up and folks only consider initial lumen peak efficiency, no ballast losses, and no fixture losses. Together, the impact can be very significant.
      
      
      Doing the same for the special 8':
      8’ T8 XL EXTRA-LIFE WATT-MISER® PLUS ENERGY SAVING LAMPS
      54 Watt
      P/N F96T8/XL/SP30/WMP
      Life 29000 (with minimum 12 hour on time)
      Life 24000 (with minimum 3 hour on time)
      Initial Lumens 5800
      Mean Lumens 5450
      Color temp 3000K
      CRI 84
      
      5450 lumens / 54 Watts:
      100.93 lm/W
      
      10% Ballast losses:
      90.83 lm/W
      
      20% high end fixutre losses:
      72.67 lm/W
      
      35% average fixture losses:
      59.04 lm/W
      
      
      Total system losses can be astounding, once you look into them...
      
      .
      
      Now you can go with Double-coat lamps have a coat of halo-phosphor and a coat of tri-phosphor. Double-coat lamps which have a thick tri-phosphor coat are fairly expensive but have very good color rendering properties. They are known by the trademarks SPX, Designer 800 series, etc..
      
      Phosphor
      The fluorescent product line uses two different phosphor systems. One phosphor system (halophosphate) uses calcium chloro-fluoro-phosphate, with small amounts (less than 1-2% by weight the phosphor) of antimony and manganese, both of which are tightly bound in the phosphor matrix. The second phosphor system (SP/SPX) uses a mixture of rare earth elements such as lanthanum, and yttrium as either an oxide or as a phosphate, along with a barium/aluminum oxide. These phosphors produce better lamp efficiency and color rendition. The phosphor components may vary slightly depending on the color of the lamp (cool white, warm white, etc.). Also, in some lamps designed for reduced power consumption, a thin coating of tin oxide is placed on the inside of the glass prior to coating the glass with the phosphor.
      
      
      Poking around on GE's website, I found some uber efficiency SPX phophor bulbs, from GE's datasheets:
      
      ULTRA ENERGY SAVING T8 LAMPS 4’ T8 ECOLUX® HIGH LUMEN T8 Medium Bipin (G13)
      
      F32T8/XL/SPX30/HL/ECO
      24000 hours Life @ with 3 hours minimum on time
      Initial lumens 3100
      Mean lumens 2915
      Color temp 3000K
      CRI 85
      
      F32T8/XL/SPX35/HL/ECO
      24000 hours Life @ with 3 hours minimum on time
      Initial lumens 3100
      Mean lumens 2915
      Color temp 3500K
      CRI 85
      
      F32T8/XL/SPX41/HL/ECO
      24000 hours Life @ with 3 hours minimum on time
      Initial lumens 3100
      Mean lumens 2915
      Color temp 4100K
      CRI 82
      
      F32T8/XL/SPX50/HL/ECO
      24000 hours Life @ with 3 hours minimum on time
      Initial lumens 3000
      Mean lumens 2820
      Color temp 5000K
      CRI 80
      
      
      If you take one of the really high end electronic ballasts, such as:
      GE LFL UltraMax™ Electronic High Efficiency Multivolt Instant Start Ballast and break things out properly, and pair it up with the ULTRA ENERGY SAVING T8 LAMPS 4’ T8 ECOLUX® HIGH LUMEN T8 Medium Bipin (G13) F32T8/XL/SPX41/HL/ECO the actual tested info boils out as follows (doesn't include fixture or diffuser losses):
      
      Pairing of the latest uber high end latest generation bulb and ballast combo:
      Ballast Product Code 49706
      Bulb P/N F32T8XLSPX41HCVG
      System Watts 25
      Initial Lumens 2387
      Mean Lumens 2244
      Initial 95.48 lm/W
      Mean 89.76 lm/W
      Color Temp 4100
      CRI 82
      **broken link removed**
      
      Feel free to pair up these elite ballasts with various lamps of your choosing:
      **broken link removed**
      
      
      If one would like to obtain these very special high end ballasts, you can buy them by the case of 10 for 23.99 each (239.90 total)(suggested retail is 95.88 ea):
      http://www.goodmart.com/products/660211.htm
      
      An even better deal these very special high end ballasts, in a two bulb version, you can buy them by the case of 10 for 25.99 each (259.90 total)(suggested retail is 125.06 ea), they are currently discounted from 55 dollars wholesale price:
      http://www.goodmart.com/products/744612.htm
      
      However, efficiencies are a little bit worse with the same bulb and dual lamp ballast, and the mean lm/W works out to 87.06 lm/W (3% less efficiency).
      
      
      Government Agencies get a very serious discount on these ballasts, an example from the North Carolina Department of Administration:
      https://www.electro-tech-online.com/custompdfs/2007/03/ballastpricing.pdf
      
      
      Anyhow, after all the arm waving, jumping up and down, and specmanship you are still looking at only a mean 89.76 lm/W for the bulb and ballast combo. (keep in mind, mean and average are not the same...)
      
      
      And that is before fixture and diffuser losses...
      
      Use a very high end fixture (rarely seen) and get an additional lumen loss of 20%, so multiply by 0.8:
      71.81 lm/W
      
      Or take a good fixture with 35% fixture losses, so multiply by 0.65:
      58.34 lm/W
      
      Or take a bargain fixture, with 25% reflector losses and 30% diffuser losses, which is 52.5%, so multiply by 0.475:
      42.7 lm/W
      
      
      And before I forget, these numbers can drop further, if the bulb is not maintained at it's optimum operating temperature.
      
      
      Not much better than my earlier example after all...reality really sucks. What is interesting is how building designers will skimp on lighting components, saving 100,000 dollars, but the building owner will typically end up spending more than that for energy costs for lighting in the first year. IMHO, a little education needs to take place...
      
      
      Remember, it really is ignorant to use the raw bulb lm/W numbers, one must include ballast, reflector, and diffuser losses- a.k.a. system losses.
      
      
      The typical bulb spectrum of the GE ultra high efficiency SPX phosphor bulbs:
      
      **broken link removed**
      
      .
      
      Recent developments in LED lighting fixtures, testing at 60 lm/W, with a CRI of 92, and color temperatures (CCT) of 2700K and 3500K, with 50,000 hours to 70% output, will be hitting the market in the mid 2007 timeframe. Cost is expected to be 50-60 USD. They also do not include hazardous materials like Mercury found in fluorescent bulbs, and are impact resistant, and do not loose lifetime when turned off and on often, like fluorescent bulbs do. This product specifically goes after the Incandescent bulb:
      **broken link removed**
      
      Their website:
      **broken link removed**

Hell no, do you work for a bulb company?

(I design electronics for a living)

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Sorry for that, I thought you were too much of an LED lover and you know such a lot about them.

I like LEDs too, I just wouldn't choose them for anything other than: downlighting, indicators and torches etc.

And that is before fixture and diffuser losses...

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I still don't know what you're talking about with regards to fixture losses. Most of the fixtures at work are open frame, the tube has no diffuser and maybe a small mirror on the back to reflect the light back. I can't see how they're anything less than 90% efficient, there are no diffuser losses and the mirror looks pretty reflective to me, most of the ballasts are no electronic. I don't see how the reflectors on those LEDs are any more reflective or their ballasts any more efficient. The older fluorescents where I work are a totally different kettle of fish, the diffusers have turned yellow after years of UV exposure and gathering dust and those old magnetic ballasts get very hot.

All I'm saying is when you compare two technologies you have to talk about like with like. It's no good comparing 1960s fluorescent fittings with the latest LEDs.

You can buy cool white LEDs that are binned anywhere from a CCT of 4500K to 10,000K. Have you ever had a chance to look at any of the power LED datasheets?

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Well I want 2700K warm white, but the efficiency does drop with colour temperature as the phosphor is converting more of the blue to longer wavelengths, there again I suppose the eye is more sensitive to red and green so you do gain at the same time and fluorescent tubes are on a level playing feild here because they also have phosphors. This might not be true thought, I don't know is if possible for a phosphor to absorb one photon of high energy UV and re-radiate two photons of red light?

Try visiting my site, and scroll down towards the bottom of the page, to the section for Optiforms Reflector Coating Comparision, follow that link.
**broken link removed**

When looking at the chart, in case you are not aware of it, the visible range is roughly 400nm-700nm.

Even extremely mirror polished aluminum will quickly drop down to the 80% range as it rapidly builds up an oxide on the surface. Other coatings like Bright Nickel will put you into the 60% reflectance range, another common reflector "mirror" coating is Rhodium- it is in the 78% range. Protected Al and Protected silver coatings are becomming more popular, they coat them with a silicon dioxide overcoat, but I have not see it in stock fixtures, however, you can spend 20 dollars to get the special mirror material for short aquarium lights. They charge a lot, but the basic material is mass produced now, and ranges 0.50 to 1.00 USD per square foot- way too expensive for fixtures- their profit margins on fixtures are quite nice...

There is a problem with downconversion, where there are losses due to the Stokes effect. Toyoda-Gosei made a UV die LED, with three different available phosphors, I think they came out four years ago. Not too common on this side of the ocean.

If you were not aware of it, about a year or two ago, 280nm UV LEDs came out. They were developed for military decontamination purposes, with a civilian side off-shoot for a long lasting water purfication UV source:
https://www.electro-tech-online.com/custompdfs/2007/03/uvtop280.pdf

Anyhow, there are a number of other references around those given on my website page, if you'd like to compare some other reflector materials, or learn more.

NewBie/Jarhead said:

Even extremely mirror polished aluminum will quickly drop down to the 80% range as it rapidly builds up an oxide on the surface. Other coatings like Bright Nickel will put you into the 60% reflectance range, another common reflector "mirror" coating is Rhodium- it is in the 78% range.

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But less than 50% of the useful light is reflected of the mirror; this means that even if the mirror were only 50% efficient the overall fitting would still be over 75% efficient so a birght nickel fitting will give a total efficiency of 80%.

If you were not aware of it, about a year or two ago, 280nm UV LEDs came out. They were developed for military decontamination purposes, with a civilian side off-shoot for a long lasting water purfication UV source:
https://www.electro-tech-online.com/custompdfs/2007/03/uvtop280-1.pdf

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Sounds horribly inefficient, a germicidal tube will be far superior. There again I can understand that the military don't want to have to abort the mission due to tube breakages and they don't want to carry around fragile tubes.

Do you think that something like this can ever work ?

If car exhausts were made from stainless steel then they would last longer than the car they were attached to. What happes to the exhaust companies when nobody needs to buy a replacemet.

A light bulb that lasts 20 years or so, what happens when everybody uses them. How do you keep production running. What happens to the current manufacturers of light bulbs. Unemployment up again

rmn_tech said:

If car exhausts were made from stainless steel then they would last longer than the car they were attached to.

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My former (1981) Volvo exhaust was made of stainless steel. Came with a lifetime warranty (not 50,000 or 100,000 miles - lifetime.) It happens that the hangers still wear out and weren't covered.