Posted by Sundug on August 6, 2007, 8:34 pm
I have just been given 3 4x4' evacuated tube arrays made by Sunmaster
of Corning NY. Does anyone have any experience with these or similar
evacuated tube arrays?
I`m specifically concerned about dirt accumulation in the parabolic
trough reflectors. I`m wondering about the feasibility of adding a
sheet of tempered glass over the entire array. If I did, would pebble
finish, like is on my flat plate, or clear be better with this sort of
collector? BTW, I`m getting around the original leakage problems by
going to a heat pipe inside the tubes to move heat to the manifold, as
described here- http://www.fossilfreedom.com/manifolds.html Thanks,
Posted by Solar Flare on August 7, 2007, 3:39 am
Evacuated means there is a vaccuum there and no dirt can accumulate in
Posted by Tater on August 8, 2007, 2:51 am
dirt accumulates im MY vaccum
hee hee hee
Posted by Mike Scaife on August 8, 2007, 11:08 am
Some of the units I have looked at have external stainless steel reflectors
mounted under each evacuated tube, yes they rapidly get dirty untill the
next heavy rain. The latest ones I have looked at dont have them, probably
for that reason.
They would have to be very good for their small surface area, most arrays
for home installations seem to be only 20 to 30 tubes, is this enough ??,
when compared to double the area for the same price using flat panels.
Posted by gary on August 9, 2007, 1:48 pm
If you look at the SRCC Directory of SRCC Certified Solar Collector
They give output for a lot of evacs and flat plates under the same
conditions -- so you can compare them directly.
To my eye, they have very nearly equal output per square foot of
collector area for typical water heating conditions.