For TT and those interested in alternate energy, a link you may not know.

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http://www.earthtoys.com/emagazine.php



Re: For TT and those interested in alternate energy, a link you may not know.



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**I've read four paragraphs, so far and found these two gems:

"...that in the near future, white LED lighting applications will be
powerful and cheap enough to replace incandescent lighting for everyday use
in our homes, in street lights, outdoor signs, and offices."

How far away is this "near future"? 5 years, 10 years, 100 years. Talk about
bullshit.

"When designed properly, an LED circuit will approach 80% efficiency, which
means 80% of the electrical energy is converted to light energy."

Where are these 80% efficient LEDs?

The guy who wrote this nonsense has no clue.


--
Trevor Wilson
www.rageaudio.com.au

 



Re: For TT and those interested in alternate energy, a link you may not know.


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and the datasheet supports your statement. The InGaN super white lamp
datasheet

http://www.lc-led.com/products/500tsw4da.html

gives:

theta = 15 degrees so w = 0.214 Steradians

I = 10Cd

Phi = I*w = 2.14 lm

at 555nm, 1W = 685lm, so 685lm/W
(relative luminosity curve, Optics 10th ed., Freeman, p.330)

luckily they spec wavelength as x,y coordinates in a color space, and
I'm too lazy to figure out the relvant wavelength(s), but an optimistic
answer is to pick 555nm, relative luminosity plummets on eother side of
this.

2.14lm/685lm/W = 3.13mW @ Vf = 3.3V, If = 20mA.

Hang on a minute, thats Pin = 66mW, but we get 3.13mW of visible light.

n = 3.13mW/66mW = 4.7%

pigs arse thats 80% efficient.

I'm picking I'd need to look at the spectral output, and integrate over
that spectrum to get the true optical output power, but there aint no
way its gonna go up by a factor of 20.


and the 100,000 hours is equally laughable. Arrhenius gets in the way,
and buggers LEDs at high currents/temperatures. Anyone who has ever
designed an optocouple circuit into a long-life application will know
how much LEDs degrade over time, and that high lifetime only occurs at
low temperatures and low If.

Cheers
Terry

Re: For TT and those interested in alternate energy, a link you may not know.



 >
 >> http://www.earthtoys.com/emagazine.php
 >
 >
 >
 > **I've read four paragraphs, so far and found these two gems:
 >
 > "...that in the near future, white LED lighting applications will be
powerful and cheap enough to replace incandescent lighting for everyday
use in our homes, in street lights, outdoor signs, and offices."
 >
 > How far away is this "near future"? 5 years, 10 years, 100 years.
Talk about bullshit.
 >
 > "When designed properly, an LED circuit will approach 80% efficiency,
which means 80% of the electrical energy is converted to light energy."
 >
 > Where are these 80% efficient LEDs?
 >
 > The guy who wrote this nonsense has no clue.


and the datasheet supports your statement. The InGaN super white lamp
datasheet

http://www.lc-led.com/products/500tsw4da.html

gives:

theta = 15 degrees so w = 0.214 Steradians

I = 10Cd

Phi = I*w = 2.14 lm

at 555nm, 1W = 685lm, so 685lm/W
(relative luminosity curve, Optics 10th ed., Freeman, p.330)

luckily they spec wavelength as x,y coordinates in a color space, and
I'm too lazy to figure out the relvant wavelength(s), but an optimistic
answer is to pick 555nm, relative luminosity plummets on eother side of
this.

2.14lm/685lm/W = 3.13mW @ Vf = 3.3V, If = 20mA.

Hang on a minute, thats Pin = 66mW, but we get 3.13mW of visible light.

n = 3.13mW/66mW = 4.7%

pigs arse thats 80% efficient.

I'm picking I'd need to look at the spectral output, and integrate over
that spectrum to get the true optical output power, but there aint no
way its gonna go up by a factor of 20.


and the 100,000 hours is equally laughable. Arrhenius gets in the way,
and buggers LEDs at high currents/temperatures. Anyone who has ever
designed an optocouple circuit into a long-life application will know
how much LEDs degrade over time, and that high lifetime only occurs at
low temperatures and low If.

Cheers
Terry

Hi,
is there a chart that shown power eff% for white light, for all the
common forms of lighting? also how do you work this out for sodium
vapour types, where the spectra is "monochromatic" orange, and not green?

Re: For TT and those interested in alternate energy, a link you may not know.


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Hi Ed,

see if you can dig up a copy of this:

Lamps and Lighting, 2nd ed. SI Units
The Staff of Thorn Lighting
ed. S.T. Henderson, A.M. Marsden
pub. Edward Arnold
ISBN 0-7131-3267-1

Cheers
Terry

Re: For TT and those interested in alternate energy, a link you may not know.



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?????????!!!

Huh?  Why pick on me?

TT



Re: For TT and those interested in alternate energy, a link you may not know.


Sorry, I thought you were talking about installing a solar electrical system
recently. I guess I have become mixed up as to who started the post.

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Re: For TT and those interested in alternate energy, a link you may not know.


<top posted to retain format>

That's OK :-)

BTW in my share portfolio I do actually have a Solar Energy
Co   http://www.solco.com.au/ so I am actually trying to do
my bit for the planet already.

So if anyone is actually going to do this
http://www.solco.com.au/products/solco_power_systems_info/gridfeed_systems
there are already products out there.

Cheers TT

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electrical system
the post.



Re: For TT and those interested in alternate energy, a link you may not know.



TT wrote:
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Yeah, but unfortunately the grid-feed inverters are ridiculously
expensive, the solar cells are still ridiculously expensive, and to
claim any government eco re-bate scheme you have to have some
"accredited" solar dude install it all for you. Sucks big time.
I have AGL "Green Power" instead, doesn't cost any extra, and it's 100%
renewable power (including solar).

National Solar House Day is on 11th Sep:
http://www.solarhouseday.com
Well worth visiting.

Dave :)


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