[ExI] pentagon wants orbiting solar power stations

Eugen Leitl eugen at leitl.org
Mon Oct 15 11:29:45 UTC 2007


On Mon, Oct 15, 2007 at 09:12:38PM +1000, Stathis Papaioannou wrote:

> LED's have made incredible leaps in the past year or two, going from
> an efficiency of around 40 lumens/watt to 100 lumens/watt or more for
> devices that can be readily bought for just a few dollars. When you

The best LEDs (not yet commercially available) have twice the lumens/Watt
of best fluorescents. But the 3 W LED spots you can now buy for 25 EUR are
only useful as reading lights and auxiliary lighting, being the 
equivalent of 20 W halogens in the lit field. However metal halide (HQI) 
are much more cost effective -- a 70 W WDL Osram ceiling flooder is 
sufficient for your living room (150 W would be an overkill, though
WDL is slightly dimmer than NDL, and you might have a large/absorbent
living room), at mere 8 EUR/bulb (good for 12 kHours), and some 120 EUR for the
lamp + electronic ballast.

I think in another 5 years LEDs will be more cost effective than HQI.

> see a flashlight not much bigger than your thumb using one of these
> things light up a room brighter than a clunky 3D Maglight it is clear
> that the days of the incandescent lamp are numbered.

Indeed. And good riddance.

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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