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The first half megawatt - Page 6

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Posted by Curbie on April 10, 2011, 9:24 pm
 
wrote:


Can you cite this 300-400 sun claim???

These "most efficient cells" can dissipate the heat???

Correct me if I'm wrong, at 1 kWh/m2 (or 317 btu/ft2) doesn't a PV
cell convert <20% of solar energy to electricity and >80% to heat???
Rough math:

1000 (Wh/m2) * .80 (%) = 800(Wh/m2) or 254 (btu/ft2) of heat to
dissipate at 1 sun and 280 (kWh/m2) or 88 (kbtu/ft2) at 350 suns,
seems like an awful lot heat to dissipate.

NREL's PV-watts starts reducing the efficiency of PV cells at 45C
(113F).

Curbie

Posted by Malcom \"Mal\" Reynolds on April 11, 2011, 5:13 am
 


Of course that is an awful lot of potentially valuable heat that could be
collected and used for other purposes. I'd imagine it could even power an Air
Conditioner

Posted by Giga2 on April 7, 2011, 7:00 pm
 

OK, seems like it should work tho!



Posted by Giga2 on April 7, 2011, 8:20 am
 

Even if the roof needs replacing it would be easy enough to remove the
panels, refurbish them (probably just give them a good clean and new
contacts) and put them back up afterwards. And they will protect the roof
presumably.



Posted by Giga2 on April 7, 2011, 8:18 am
 

Sure but the actual devices in themselves seem like they should be very
robust.



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