Posted by nicksanspam on December 22, 2008, 10:29 pm
Right, altho a transpired mesh absorber (eg dark window screen)
would improve efficiency.
Posted by schooner on December 22, 2008, 10:38 pm
As would any absorber plate, such as a flat plate or say aluminum ducting.
But then that is more parts isn't it? ;-)
Posted by nicksanspam on December 23, 2008, 11:39 am
The back of the box can be the "absorber plate." Slower-moving air near
the inside surface of the glazing improves solar collection efficiency, but
an absorber plate with air moving behind it may not add much, compared to
a box that is deep enough to make a low air velocity near the glazing.
A transpired mesh can be more efficient, since it can keep cool room air
vs sun-warmed air between the mesh and the glazing and block some
reradiation from the back of the box to the glazing.
Posted by schooner on December 23, 2008, 11:52 am
So there is no value in keeping warmed air away from the glazing as is the
case in a collector plate with air behind only? I would think in colder
climates that this would be better than allowing the glazing to come in
contact with any of the circulating air would it not? Also would help
preventing condensation on the glazing as well. Also wouldn't having a
collector plate with more surface area, such as with the ducting tubes also
increase heat transfer from the absorber to the circulating air?
Posted by Father Haskell on December 24, 2008, 2:04 am
On Dec 22, 5:29pm, nicksans...@ece.villanova.edu wrote:
How does mesh compare to corrugated aluminum, painted
black? Rather easy to make the stuff from flashing with
a homemade press.