if the sun shines as little in NE Minnesota as it does in SE MN

But even if it does not provide ALL your heat, it could provide a supplement.

Actually in my one winter in outdoor Wisconsin, I found that on sunny days in my mobile home, just opening the curtains meant that I did not need a fire on a sunny day, even a cold sunny day. It was warmer (20s, 30s, 40s) cloudy days that meant I needed to burn wood to keep warm.

But when I say "warm" I only mean 65 degrees or so.

lives in Canada? Sells them in Canada, they work in Canada just fine.

You simply have to build it correctly.

a toque?

Canada may have sunshine, but Minnesota, because it is to the west of Lake Michigan, mostly does not.

See, clouds come rolling over the prairie and then they reach Lake Michigan, where they have to line up to take the ferry at Manitowoc. Which can only take so many at a time.

So they back up and stack up over Wisconsin and Minnesota, often backing up all the way to Marshall, if not Ivanhoe. It can take weeks to clear those cloud jams, and by then, the next batch of clouds comes rolling in.

I used to joke in Richland Center, Wisconsin on a sunny spring day "Remember, we only get 100 hours of sunshine a year, we don't want to use them all up in March."

Maybe part of this polar thing.

at the University of Minnesota.

So I tend to think of Minnesota as "where the sun don't shine".

Maybe that's because I grew up in the sunshine state.

Hooray free and inexpensive heat.

Mine leaned out the window.

I wonder how the heat effects the foam liner especially at the top of the stack.

I can think of several modifications that might make this work better.

not that I know much about it though. If you go through all of the trouble of insulating the back and sides of the panel, why not use insulated thermo pane glass on the front? It seems like heat would escape through the single layer Plexiglas front panel.

think alike!

So what would you use? Lexar is pretty good. I'd silicon it to the box myself to absolutely prevent heat loss, but I can't really think of a readily available material that would work better to allow in heat and transmit it to the coils (the beer cans).

you could even double them up using silicone as a seperator..

If you insulate against the entry of the sun, you're preventing the box from working efficiently.

duh

What other readily available material could be used?

Hot air rises, that would promote air circulation by displacing the cold air and forcing it upwards. Another alternate would be to put the exhaust and intake both at the bottom with a dividing wall in the center of the lower plenum, this would create a two pass system that would double the exhaust temperature. Also with the intake at the bottom it would be easier to add and change the air filter.

Hot air will rise, as you said, and naturally exit at the top of the device, drawing in cold air at the bottom of the device. This is known as the stack effect or chimney effect. To what purpose are you suggesting to reverse this flow?

With natural circulation, on a sunny summer day this device will be putting heat into the building because it does not require a fan to function. Flipping it eliminates this issue (technically mitigates would be more accurate, he should also install a damper to shut off air flow). It also promotes natural circulation inside the structure and creates a more uniform temperature inside the building instead of having all the heat build up at the roofline (where it could potentially leak out depending on insulation).

Here in NE Ohio, the lake keeps us cloudy more often than not.

I think this is something we could do. I'd love to convert our house to add this to the heating system. I'll have to show this to some handy people and see what can be done.

That's like the solar oven projects (which I built one, I couldn't resist). It will heat and cook food even if it is like 30F outside. Easy as pie, and really neat. Flat black paint retains heat if you cover the object you cook in with it, then create an environment that traps heat. Nothing else is really required!

Really...this is the best example I've seen in a while of what makes humans so fascinating. that and the Free Porn sites...oops...did I just write that?

Let the sun shine inside!

Between this and the Hobbitt House that guy built by himself, I could almost live off the grid.

http://www.cnn.com/2013/08/01/tech/wikihouse-build-your-own-house/index.html?iref=allsearch