https://youtu.be/dnXHrPFils4
Some of these were not edited too well (or much) and just 'raw' filmed while I worked.  I tried to explain what I was doing and in this case I edited the video a little but to speed things up etc.

https://youtu.be/Pfs9JgCEoqA
and the last one I did (as far as I can tell)...

I find this cool, I would like to give it a try one day, but the sheer amount of work involved just seems overwhelming.
I wonder if you could easily substitute the cans for some other cheap alternative.  I can't think of any good ideas off hand... but maybe the tube roll from wrapping paper, wrapped in tin foil, or some other metal tubing...  I wonder if the characteristics, gauge of metal, diameter of the can, all play a role on the amount of heat this can generate.  If someone had the time, money, and desire to test this with larger cans (I'm thinking those king cans of beer) and then again with smaller cans (like the little V8 cans) to see which works best or if the only real factor that counts is the overall size of the panel (amount of sunlight trapped).  If it is just a matter of square footage, then a single sheet of metal might work just as well.... must be some scientists on this forum that can help out. 

I had once tried something, cost me a couple hundred in hose, to make a solar heater for our pool.  The thing weighed a ton (dry) and even more with water filled.  I started with a hole in the center of a wooden frame and gradually circled a garden hose around and around making a spiral of hose.  I can't remember now, I think it was 400-500 feet of hose.  Then it was all spray painted black, and a sheet of plexi-glass laid over top.  When you first started to run water through it, the water was hot from sitting there... but that heat quickly dissipated with flow.  I never got the right speed down, needed to run a valve off the main pump diverting water... just was more trouble that it was worth, and it weight so bloody much that I couldn't move it around to face the run and was afraid to put it on the roof of my shed. 

Just FYI, we used to have a pool and a solar pool water heater. It was a store bought unit. The basis was a black rubber-like mat that was molded with grooves in the material. IIRC it was about  4 or 5 feet wide and 12 feet long with the grooves running lengthwise. The grooves were sized to hold black tubing with a 1/4" ID to be press fitted into them. The tubing ends fitted to a length 2 inch PVC pipe. Lots of fittings glued into holes in the PVC. Two header pipes; one for water going in and one for water exiting.

The black mat absorbed the heat, the tubing circulated the water. I don't recall the heat gain but it was enough to get the water hot enough to over heat the pool on a summer day. It used the standard pool pump.

The aluminum can solar air heater works because the aluminum can material is very thin. Heat transfer from the outside to the inside almost instantly. Thicker material would likely work but maybe not so well in less than optimal sun. It works because there is lots of surface area to transfer the heat and many air channels to spread the air flow out. A single sheet of flat metal would require a method to provide many separated air channels to ensure the air flow was spread out.

I made an air collector back in the 80's. I used light gauge sheet aluminum (4 ft wide x 10 ft long) that a local sheet metal shop bent lengthwise with a series of alternating 90 degree bends. (Wish I had a picture) About 2 inches between bends. When viewed from the end it has a zig zag appearance. Both sides were painted flat black. The sheet fitted into a metal box the shop also made. The back side of the box was insulated with rigid fiberglass insulation and covered over with HD aluminum foil. The "accordioned" aluminum sheet was fitted tightly against the foil covered insulation. Header boxes were constructed at both ends with 6 inch air duct fittings. The front face was sealed with a clear fiberglass sheet. That was a problem until I found panel material that would not yellow after a few years. It did work but we took it down a few years back when we needed to reconfigure that side of the house for parking a travel trailer. The solar panel had been mounted on that side wall of the house and was no longer going to have the sunshine. I sold it off and have no idea where it now is.

Aluminum down spouts work well I've read.  Actually, the best results are from black window screen I believe.  But this was something I wanted to try so I began to collect cans   I'm going to make another soon and will get more video.

Here is the result I logged at the cabin.  Heater is set at 65 degrees and facing south.

That is 65 degrees of angle.

Temp logger shows 4hrs of production above 100F and about 3.5hrs of real heating.  Enough to heat up the porch for sure once it's fully insulated.  Actually, it heats the porch, the lack of insulation however let's it out.

Aluminum down pipe should be great.   They sell gutter to trough adapters so making headers should be easy enough.  We don't drink pop and I only drink bottled beer, save for a few Guinness.

I've also seen variations of these where flexible dryer hose or ducting is used in-place of the cans.  Just snaked through the box so it takes up as much of the inside as possible.  Painted flat black.

I think anything aluminum will work really.  Just a matter of making sure the air is slow enough through the system to heat up and the outlet has a good fan on it to suck the air through once hot.  Mine does very well in the sun as it is so I plan to make another (we've collected a lot of cans for it).

Takes a fair amount of work but is pretty cheap.

google low profile solar hot air project.  site owner is scott .  downspouts, black screen, fans, efficiency charts, etc.  good forum.

Done that   I googled, Binged, Yahood and generally searched far and wide for all sources.

https://youtu.be/rAzUMeK9bKE
here is a new one for you.  Just trying to narrate (a first for me) the build in pictures.

Free heat is really cool 

Will it work passively or do you have to use the fan?

It works well as a passive unit but the fan will draw more air into the unit thereby creating more heat.  The fan units are pretty inexpensive and easy to set up but I have a large battery bank to run a fan off so it was an easy thing to do.  I plan a passive unit,  though I may add a fan later, for the south wall of the cabin.

https://youtu.be/YYyf-5bJqhg
Here's a new one for you.  Nevermind the mess (it seems I never have time on these short trips to clean up and organize but I will soon!)

Note:  Outside air temp at 6am was 20F.  So in reality the heater is responsible for rising the temp in the porch over 60 degrees!!!

Once I finish this install and get the porch finished (I plan to do so this spring and will start next weekend on the battery box) I do believe this heater will raise the temp in the porch to above 90F!  If so then I think my plan to stick ducting through the wall into the cabin (two 6" baffled ducts with 24v motors on them to open the baffles) should actually work!  I figure once the porch reaches 90F at the inverter I could open the ducts and let them remain open until the porch drops to 70F then close them to retain the rest of the heat overnight.

Then I plan to install a second one of these on the south wall of the cabin (to the right of the porch) and plumb it into the cabin with a 12v computer fan (4") hooked up to a snap switch and 12v solar panel to move air once the panel warms up.  It won't be as effective as this crazy mass air moving monster of a fan but it will be quieter (and I may find something smaller that works similarly).  With luck, I should be able to arrive to a cabin that isn't 18F when it's 10F outside and the sun is shining.  That's the idea anyway

good luck... I'll watch for updates.

Your posts inspired me to read up on solar air heaters.  Seems like in a small well insulated cabin they could provide a large percentage of the heat. 

Thanks for sharing these videos...now I have another project to add to the list. 

Quote from: OlJarhead on February 04, 2018, 02:19:32 PM
Aluminum down spouts work well I've read.  Actually, the best results are from black window screen I believe.  But this was something I wanted to try so I began to collect cans   I'm going to make another soon and will get more video.

And I thought it was the beer inside the cans you really wanted 

LOL except I don't drink beer....I think I've had maybe 3 in the last decade.

Now if there was a way to make a heater out of Evan Williams bottles

That would mean A LOT of bourbon!   That is partly why I asked about different options.  I don't drink anything out of a can, in fact I don't drink beer or soda pop, even water I drink from the faucet and not from a bottle.  I think I may play with some of these on a small scale and see how they work.  For the passive/active part, I had purchased some solar powered fans a couple years ago for an outhouse project that never got started.  I wonder if that might be a good option, since you only really want circulation when there is sun present, so having the fans activate when the sun is out and stop when the sun goes away might be a good option. 

What is your channel's name?  I wanted to subscribe but couldn't seem to navigate there from the embedded video.  I'm 50 Acres & a Cabin.

Quote from: Mike 870 on February 11, 2018, 06:26:36 PM
What is your channel's name?  I wanted to subscribe but couldn't seem to navigate there from the embedded video.  I'm 50 Acres & a Cabin.

This should take you to his channel: https://www.youtube.com/user/TheOljarhead/featured

Quote from: Adam Roby on February 11, 2018, 10:24:24 AM
That would mean A LOT of bourbon!   That is partly why I asked about different options.  I don't drink anything out of a can, in fact I don't drink beer or soda pop, even water I drink from the faucet and not from a bottle.  I think I may play with some of these on a small scale and see how they work.  For the passive/active part, I had purchased some solar powered fans a couple years ago for an outhouse project that never got started.  I wonder if that might be a good option, since you only really want circulation when there is sun present, so having the fans activate when the sun is out and stop when the sun goes away might be a good option.

The screen (black) is the most efficient of them all I believe.  But any aluminum can, downspout etc, will work.

The fans should still have a snap switch the heater can first build up heat before the cans come on.  When my box hits 110F the fan kicks on and usually drops about 10F at first but then the sun overpowers the can and it rises well above 180F.  Having the snap switch between the panel positive (or neg) and the fan is all that would be needed.

Quote from: pmichelsen on February 11, 2018, 10:48:03 PM
This should take you to his channel: https://www.youtube.com/user/TheOljarhead/featured

Thanks for sharing.

I don't do a lot of videos really, maybe a few a year at most but I try to make them on something I find interesting   I'm no pro though!  Pretty much just an el cheapo canon digital camera, cheap tripod and away I go.

Cool thanks,  I'm subscribed. I'm about in the same boat.  I'm hopeing to to get better at it as I go along.