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Wayne's Air Collector -- Questions

I sent these questions to Schooner/Wayne -- the answers are pasted in below:

Is the glazing material glass? or polycarbonate?

The glazing is actually Lexan, just single pane.  The frame is slightly 
curved on the front to give the Lexan a bowed out appearance.  This was done 
so the Lexan would keep its shape and not flutter in wind, and also will 
always expand out when it heats up and not buckle and warp unevenly.

Wondering what are you using for the "extruded alum frame"?

The extruded aluminum frame is from the big advertising signs you see and 
minimalls, 7-11 and such to hold the lighted signage, we get it direct from 
a sign company.

It would be interesting to hear your experiences with the selective paint?  I 
have heard it can be difficult to work with?

As far as I know the selective paint has been easy to work with so far, 
spraying it on is fairly easy and it dries quickly from what my father has 
said, you can also brush it on where needed although they suggest as thin a 
layer as possible.  It is the same selective paint used on many of the hot 
water systems and we get it from a local company that builds solar hot water 
panels.

I'm trying to sort out the advantages/disadvantages of using the alum tubes as 
the absorber.  One potential advantage I could see to the round tube absorbers 
is that if the full circumference of the tubes heats up, then you have 3 times 
the heat transfer area from the absorber to the air that a single flat plate 
absorber would.  Can you tell if the tubes heat up all the way around?

Our thoughts on the aluminum tubes is the same as yours but no we haven't 
tested it around the tube per se.  On an early panel before we balanced the 
airflow we had one tube that didn't get a lot of air and the foam board 
behind it showed signs of heat so I would say it is working as expected. 
The other advantage of it is the rough surface that helps increase the 
surface area and angles that it can collect sun on and also the fact it 
gives a rough surface to the airflow to break up any laminar flow that could 
happen on a smooth surface.  We basically looked at the can idea and to us 
it seemed less than ideal, too much effort and not the best airflow and lots 
of areas for leakage.  I'll see if we can get some temp readings somehow 
from the back and sides, however is difficult to do in the assembled panels.

I'll try and get some more info posted on the website.  Its been a work in 
progress, so far I believe my father has built around 5 panels, each one 
changing slightly, better materials, etc.  The current aluminum frame 
version is the latest and seems to be the best thus far in terms of weight, 
performance, and overall looks.

And this note from Wayne:

Cost for materials  would be $900-1000 cdn. that's with fan and
electronic controller, and speed controller for fan. I will get some
more pictures of aluminum, motor, etc and have them posted.  The paint
is very easy to spray. Just checked mine today and 54 deg in , coming
out at 95 deg at 1300fpm with a 5 in opening , so giving 0ver 6000
btus. That is out side on my test panel.  I have seen as high as 7600
btus per hour but it has to be a good sun day.   I have built 7 and
have orders for 4 more now.  Wayne

Also, note that one of the pictures shows some of the tubes partially blocked by off. 
These partial blockages of some tubes are arranged so that each tube gets equal airflow.

Gary 9/21/06