Aluminum pop/beer can solar heater

Shodo Spring wrote:I'm sold! Will definitely build one of these when I get my farm (soon) or if it's not soon, on my present house. A question about location: people put solar heaters in greenhouses, where they get a little less sun but are protected from those below-zero days we still have in MN. Do folks recommend inside the greenhouse or not?

in mn the sun is only 54 degrees above the horizon in winter, this is a rather steep pitch for a panel of anything but it will keep the snow falling off of it wont it. you also I think have to worry about snow piling up at the base, in particular cloggin up the intake and sucking up the heat by piling snow around the heater. Inside a greenhouse I havent heard of but it seems to me if you went to the trouble of building a greenhouse, you would want to use the solar energy collected in it for the solar greenhouse, not to mention that whatever glazing you are using will likely block part of the sunlight.

Just off the top of my head, I am thinking if you could, mount at a rather steep slope outside so most of the time the snow will simply fall off of the panel (this is a unit which is functioning in winter now year round) and raise it off the ground a bit. The sun is at its lowest in december but the coldest months come after, maybe maximize to the angle of the january sun.

Looking at the post above this, perhaps putting it in the barn in summer would help it function longer .

Larry Schlicker wrote:Just got my pop/beer can solar heater going today. I built this heater this past summer but just now got it installed and going on my container cabin now called the Taj MaLodge  .
It outside temp was 40 degrees
It was 56 degrees at the cold air intake
Exhaust temp was 104 degrees
Airflow is powered by a 12 volt 110cfm cage motor.
I think if my panel faced the sun at a more direct angle the exhaust would be a little better, keep in mind that our sun here in ok is at it's lowest point of the year, so as we advance towards spring and the sun starts its climb back up, the exhaust heat will keep climbing with the sun. Yehaaaaaaaaaa!!!
Here are a few pics of it.

Hi. pal fantastic work...although unless i have missed something I would thought that as heat rises you outlet may have been better placed with the header being at the furthest point from the inlet!! Feel free to educate me if Im of the mark here

Shodo Spring wrote:I'm sold! Will definitely build one of these when I get my farm (soon) or if it's not soon, on my present house. A question about location: people put solar heaters in greenhouses, where they get a little less sun but are protected from those below-zero days we still have in MN. Do folks recommend inside the greenhouse or not?

Please post back if you put one in your greenhouse. I am interested to know how that would work.

Here is a website that tested the pop can approach to something using screens. It would appear that the screen is the big winner:



source

Brice Moss wrote:

j_cornelissen wrote:
taking the fan out of the equation means you don't hve to worry about cold air being pumped in on a cloudless day!

the convection loop can and will reverse itself if the cans are colder than your inside air like say at night, so you either need to be mindfull of the system or install some type of automation to shut off the airflow

Would it make sense to power a 12v fan with a small solar panel? Then the fan would only run when sun is working and no power would be needed.

Yes, that's what I use in mine - a fan recycled from an old HP server, powered by a small solar panel. I have mounted it in a bottom inlet of the heater, it pushes air into it.

how do you prevent the reverse flow during the night when the cabin is heated?  Do you cover a inlet?  Other wise the heater is doing the exact opposite by pull in the heated air and cooling it.

There is a method one can utilize that involves building something similar to a trap on a drain line the prevents back draft.  I incorporated on my solar heater, works great and is maintenance free.  No opening or closing or blocking inlets/exhaust.

I dont know if my sketch makes sense.  I can explain it better if interested.

Whats better then a screen is a curved surface.  If you look in the drywall area at a home improvement store, you will see a rounded corner bead made out of thin steel.  Those are incredible for collectors.  My lil secret.