Sunday, February 13, 2011

Hubby's Pop Can Solar Furnace

This is a step by step guide to building your own solar furnace. There are several methods and videos on Youtube. They are all different but they have the same principles behind them. Here is Hubby's.

Here is what it is going to look like when you are thru with it. The size will be different as it changes with your needs.

 Hubby got it up to 225 on a day when the temperature was 32 out side. I could not hold my hand to the hole in the back for very long.
 Here are our drawn plans. The back is 3/4 inch ply wood. The sides are recycled 2x4's he got from work. The head space is roughly 10 inches on his. The boards that hold the cans in place all have holes drilled in them the slightly smaller than the cans so it holds them in place. The whole unit is insulated. All sides even under the cans have insulation. Since hubby used 2x4's he used the insulation that we had left over from our siding. He cut holes in the cans (see description below) and then stacked them together and caulked them. When they were dry he painted the stacks, and the inside of the box flat black. The duct work holes have stiff drier vent pipe on both sides. It is bent down on the inside and left sticking out just enough on the back to attach flexible duct work if needed. He placed a computer fan on the heat out put. This way the cold air comes thru the bottom duct whole and the hot air comes out the top hole. You can make these to sit inside any window that faces the sun. This one was made to be placed out side. The duct work can be ran thru existing duct work or you can remove your screen from your window and place a piece of ply wood with two holes in it for the duct work. The cold air duct work should be on the floor and the heat above the floor. The cover on this one is plexiglass. It is more expensive but it does not break as easily as glass. The top is screwed in with dry wall screws. Hubby has seen a video where they make three very large ones and place them on top of a house. They ran the duct work thru the ceiling and heated the house.
 The cans need to have the top removed. You need to leave the lip on them to make the fit right when you caulk them. Then drill three holes on the bottom. When placing them together try to alternate the holes as this makes the air circulate in a whirlwind effect and heats better.
Once you have them cut and drilled you need to stack them and caulk them together. (I didn't caulk these as I didn't have any caulk open.) Hubby used black caulk. He also sealed any holes in the can that you may get when cutting them with caulk.

You can make them to fit your windows. They sit nicely on the window sill and can be made big or small. His next one will fit into a short long window. Maybe about 5 cans high. Right now he runs the computer fan with a 9 volt battery until we get the solar up and going this summer. (Hopefully)


Small Footprints said...

Wow ... very cool (I mean "hot"). lol

Thanks for posting the how to ... I'm passing it on through all the social networks! :-)

Shelinwa said...

Wow awesome ideas I love your blog too May I follow please?

Jenn said...

Thany you Small Footprints. And it is very nice to meet you Shelinwa.