Solar hot air collector design - pop can vs metal screen
 

This is a great comparison done by Gary over at builditsolar. He built two smaller solar collectors, one made with pop cans as the collector material, and the other one was made with metal screen. He then tested them quite throughly. The result were that both collectors performed nearly identical, but each had its strengths and weaknesses in other areas. I suggest checking out the article. Thanks for the great write up and testing Gary!

DIY Solar Air Heating Collectors: Pop Can vs Screen Absorbers

http://ecorenovator.org/forum/attach...1&d=1447262969

Great article! His work led me to choosing the screen absorber for my small 4X8 setup a few years ago. Looking to expand this year to domestic hot water.

Cool, care to share some info and pics on your build?

Sure Daox. I'll post a few pics here and a brief overview. Then I'll post a build thread as I realize I never did do that.

I built a solar hot air panel as more of a proof of concept than anything else. I didn't really believe that it would work here in Winnipeg with our extreme winter conditions. Now that I have a few years of results to convince myself otherwise, I have bigger plans.

It's a very simple design using bug screen as the collector. Two layers. Box is plywood and spruce.

It was meant to stand vertically, but I was overruled as it looked, well, really big standing up. So I modified it to stand on it's side. Concessions! I didn't even make the inlet at the new bottom of the panel, more like the middle of one side. I was just too tired from work and struggling to get the thing up already.

Glazing is Suntuff, single layer. Insulation 1 1/2" cyano... whatever it's called. The hot tolerant metal sheathed stuff from John Mansville. I worked at a building supply company and knew they had this as dead stock that hadn't moved in 2 years. Got a sweet deal.

http://ecorenovator.org/forum/member...air-panel.jpeg

This is the panel outside the house. It's in the back yard and since our whole neighbourhood is on a funny angle, I aligned the panel to true south. Hence the funny looking orientation relative to the house. I used 4" drain pipe as the ducting and in hindsight should have gone 6". This thing gets pretty hot in the spring and fall, and that's lost efficiency. The ducting is insulated (can you believe I ran it for a whole year with no insulation???) with regular fiberglass duct insulation. It's not rated for outside. It's still ok after 1 year, but I should protect it with something.

http://ecorenovator.org/forum/member...air-panel.jpeg

Here's the back. I know I know. You see a section of duct not even insulated! Well at least that's the cold side. Stuff costs $50 for a box and I only need 4'. Remember, proof of concept. It still works pretty good. And yes, I know my downpipe from the roof looks pretty hokey. I used vinyl siding to encase the plywood frame and roll roofing on top to keep the rain off it.

http://ecorenovator.org/forum/member...-overview.jpeg

Here's a general view of my messy basement... and the inside ducting. Uses one of those radon fans to run it. Very smooth and quiet. I can't hear it running unless I turn off the furnace fan or get really close.

http://ecorenovator.org/forum/member...ut-centre.jpeg

Intake, panel and output are all wired with temperature sensors. Cheap Bios units I got from Walmart for $9 each. I cut the wires and put a long run of network wire from the panel and ducting to a spot on the main floor in the middle of the house where I have my little weather station. Nothing fancy, just an old school barometer. I still want to tidy this up a bit.

More pics in my albums if you want to check it out.