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Old April 15th 08, 09:06 PM posted to rec.aviation.piloting
Jim Logajan
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Posts: 1,958
Default More fuel for thought

wrote:
Both of you are ignoring the fact that you get that only if the angle
beteen the sun and your collector is 90 degrees, otherwise you have
to multiply by the sine of the angle to get the real energy per unit
area.


I didn't ignore that aspect out of ignorance or oversight. I'm not
trying to write a treatise on the subject after all. And anyway, we also
"ignored" clouds, fog, smoke, bug splatter, and night too. It didn't
seem relevant to the underlying point. Which I took to be the amount of
power in sunlight. (Solar powered aircraft have been built and set
records, after all.)

Jim Logajan wrote:
Real world system efficiencies of 40% should be possible today -
using solar thermal (e.g. solar troughs).


Lab efficiencies are already around 40%.


Real-world heat engine efficiencies of 36% have been observed in power
plants:

http://en.wikipedia.org/wiki/Heat_en..._performa nce