Posted by schooner on December 10, 2005, 4:30 pm
Just wondering if anyone has noticed any increase in their air collector
temps due to sun reflection from snow. Does this have any impact on the
collector or is the reflected sun of no advantage?
Posted by daestrom on December 10, 2005, 7:49 pm
It's a very real thing. In some areas that get a lot of snow, you can get
more energy if you mount the collecter vertical on a south wall than if you
mount it at latitude minus 23 degrees. The loss in direct radiation because
non perpendicular angle can be made up for in the gain in ground reflected
The only 'hitch' is you need a nice open area to the south from the
collector that is covered with snow.
Under 'Global solar radiation', the radiation reflected from the ground is
discussed. They suggest that an albedo of 0.2 is typical for green
vegetation. I think snow can be as high as 0.9.
Posted by SolarFlare on December 10, 2005, 8:16 pm
This is a thermal group. I doubt there would be much
"thermal" radiation off snow. PV?...definitely.
in their air collector
have any impact on the
of snow, you can get
south wall than if you
direct radiation because
gain in ground reflected
south from the
reflected from the ground is
typical for green
Posted by daestrom on December 10, 2005, 9:53 pm
Or you might want to read the whole manual
The albedo correction is used to correct the total solar radiation received
(btu/ft^2) for windows to determine heat gain from solar radiation.
Posted by Robert Scott on December 10, 2005, 9:56 pm
On Sat, 10 Dec 2005 15:16:00 -0500, "SolarFlare"
Why would you think that? The snow is not heating up and
re-radiating, if that what you're thinking. The snow is acting like a
mirror, passively reflecting the energy together with all its
potential for thermal use. A mirror does not need to get hot to be
effective in a concentrating solar collector. The only disadvantage
of snow reflection is that it reflects in all directions. So to be
effective in enhancing a solar collector, you need to have snow spread
out over a wide area, as viewed from the collector.