----- Original Message ----- From: "Stephen A. Lawrence" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, December 31, 2006 5:51 AM Subject: Re: [Vo]: Musings on grid-independence and personal alternative energy
> > > thomas malloy wrote: >> Stephen A. Lawrence wrote: >> >>> >>> >>> John Steck wrote: >>> >>>> I might be mistaken, but I think there is a significant performance >>>> drop at >>>> low temperatures with solar cells... someone please correct if wrong. > > Groping around on the web I ran into an off-hand claim that they > actually perform better at low temperatures, here: > > http://www.wagonmaker.com/power.html > > Haven't dug into it any farther at this point. They do perform better when they are cooled. > > >>> >>> What's worse, there's a totally catastrophic performance drop when >>> they're covered with 2" of snow, or an inch or two of ice. >> >> Sounds like a job for electrical heater cables to me. > > That, plus a 45 degree tilt, might be all that's needed. Ideally they should be pointed towards the yearly average of the sun's position in your sky, so in the northern hemisphere they should point south and be tilted wrt the horizontal with an angle equal to the latitude (0° at the equator, 90° at the north pole) > > Then we'd just need to be sure they were well enough anchored to the > roof so that the tilted solar panels wouldn't turn into a "solar sail" > and fly away in the first storm that comes along... In this respect, if your roof already has a pretty steep pitch, you might be better off laying them flat on the roof as Robin suggested. Michel P.S. Wrt your earlier remark about clouds, I believe PV works rather well in diffuse light too. > >> >> >> --- http://USFamily.Net/dialup.html - $8.25/mo! -- >> http://www.usfamily.net/dsl.html - $19.99/mo! --- >> >
