soda can passive hot air panel, worth the hassle?

[confused]

Haaaa!!!


In that case if you ever get the idea that you can get free additional air by using an orifice plate and a check valve, based on the venturi effect, into the airline from your compressor, don't act on it.
That was my latest wheeze, which was dead before the starters gun went off.
Happily it cost me a 5 cent coin with a hole drilled in it and a check valve which I can use when I get another gift from the Muse's of madness.
Regards
Confused (and likely to stay that way)


ps
It will work fine if your working into ambient pressure, like a compressed air blower.

[MikeSolar]

Mike
tried it, fiddled with it, swore at it, tore it down!

To be fair I didn't use a fan but by then I was already disenchanted by the whole thing.

Regards
Confused

I haven't actually made on myself but I make a sorts of things and failed more times than I can count You need to use a fan to create the turbulence which promotes heat transfer. I am a wet head (generic term for water heating guy) and not so fond of air heat but if it works...it works.

[confused]

Mike
tried it, fiddled with it, swore at it, tore it down!

To be fair I didn't use a fan but by then I was already disenchanted by the whole thing.

Regards
Confused

[SolarHeater]

Soda Can Heater Alternative

Hi Mike,

I am currently editing a new manual I've written on how to build a better and easier solar air heater. I am a former industrial oven builder and have taken the same concepts we used in industrial ovens and created a very simple and affordable design for my heater.

I started out trying the soda can method first, but I quickly lost interest in the process due to the labor and mess involved. Knowing how to build a simple heat plenum, I thought of an alternative to cans that anyone could build using common materials available at the local building store.

I also didn't want to use glass in the design as glass is expensive and of course dangerous to work with for the average person. It's also very heavy and doesn't lend itself to building a very portable heater. And of course, a good hail storm or stray baseball can break the glass.

And finally, I decided right away that there would be no wood in my solar heater design, as wood is also expensive, requires power saws and it is also heavy.

I've gotten temperatures up over 220 degrees on fall days, and about 150 on below freezing days, so this thing gets really hot. I include a link to a fantastic blower with temperature controller as well as a standard blower available at the building store. It can be easily run with a solar panel if one wants to use it off grid say for an RV or at the cabin etc.

[...]

[RecBeatriceb]

Soda can heater

My son made me a soda can heater for the chicken coop at the end of last winter. He said it cost $50 and when he tried it in his drive way in Portland, Maine in was below freezing and the air coming out registered 115 degrees. The coop is 8 by 10 and He's afraid it might "cook" the hens. I am planning on having three more made for the house.
Love free heat!

[MikeSolar]

Here is the original one with patents and real testing. It is quite copyable, although they might complain

http://www.cansolair.com/

[russ]

Just use Dow XPS foam board - easy to find and cheap - won't burn when you put a match to it.

[Denver Dave]

My obstacle is the mounting board

I did a test 2 years ago with a 2 ft x 2 ft x 1 inch silver covered foam board and about 50 or so beer / pop cans painted black with holes punched in the bottoms. I wrapped the entire thing in window shrink wrap and cut air slits in the top and bottom for the air.

On fairly cold days in Colorado, but with good sun, and calm wind, the panel put out air at the top at 180 degrees. For this prototype, there was no fan, but the hot air was definitely coming out. My concern and my obstacle was that I was concerned that under certain conditions that the foam board might catch on fire. I've been trying to find a fire resistant light foam board or Insulate http://www.energyboom.com/emerging/insulation-mushrooms become available in my area, but I haven't found anything. Any ideas?

For my next prototype I have an 8 ft by approx 2 ft by 2 inch foam board and one clear 8 foot ridged roof panel. I think I'll get another one that is dark for the bottom. I don't think this will catch on fire, but how sure am I. I'm planning on a small fan (ideas?), but this could fail and the panel overheat. The south wall under the eaves, get's quite warm, even in the winter - not a good place for a fire.

= = = = = =
Also fire resistant foam panels that are not toxic when heated might be handy for insulating interior north walls.

[smokie]

can heater

I made one and I like It a lot. Its gotten up to around 95 on 30 degree days. I think it would put out more if I could get more air flow. I just have a small 12 volt pc fan, ran off a small solar panel.

[russ]

Hi Pappio - Welcome to Solar Panel Talk!

It just depends on how much time you want to spend on the unit.

The downspout with baffles would be much quicker and easier - unless one is constrained on space the area can easily be taken care of.

[Pappio]

First post, forgive me if I maek a mess of it.

Keep the task in mind. Sunlight hits an object and warms it, we need to get the heat out of the object into the air. Two things that help this are air turbulence and surface area.

The cans have a big advantange over downspouts because if made with holes in the ends smaller than the can, the air passing through will become turbulent and strip the heat off the metal surface more effectively.

Second advantage is the remaining end material of the can increases the area of metal exposed to the air flow. This is like having fins attached to the inside of the can to help heat the air. A bunch of baffles inside will increase turbulence, but unless they are firmly attached to the outside of the can they won't increase the heat transfer area.

Smaller holes slow the air flow, but they should be worth it. Haven't made tests, my gut says holes about half the diameter of the can would be about right.

[russ]

Agreed- the down spouts would be easier and one can rig a string of baffles to insert in the down pipe to provide turbulent flow for better heat transfer.

[Naptown]

Search downspouts here some have had some experience using downspouts instead of cans. certainly easier.

[matt2602]

Just Made one - Not Sure

I'm just about finished making one of these soda can heaters and I don't think I'd do it the same way again. It takes a long time to deal with the cans and I don't see why you wouldn't get just as good results if you used a flat sheet of aluminum flashing.

[russ]

I saw where someone used a small drill press and a hole saw. They would use one of the polyurethane (or similar) beer can holders to grip the can by hand.

They claimed it went real fast.

I tore the tops out with a pair of side cutters and plan to knock the other end off with a disc grinder - no drill press available.

Russ