A Try at Solar Water Heating Collector With Fins From Soda Pop Cans


A message on the Yahoo Solar Heat group about the possibility of building a solar water heating collector that used collection fins made from recycled aluminum soda pop cans got me out into the garage to see if the same method I use on the $1000 Solar Water Heating Collector would work for this.


The pictures below show a 20 minute try at making the fins from soda pop cans instead of sheet aluminum.


The soda pop cans are only about 0.005 inch thick walls, so it makes for a fairly thin fin, but the fact the the fins only turn out to be about 4 inches wide rather than the 6 inches we usually use should still make them quite efficient.

I think these would actually make a collector with an efficiency not much lower than a commercial collector.



Click on the pictures for full size


Flatten the cans using a sledge hammer -- pounding them down flat with a block of wood would probably also work.


I used the flat part of the sledge -- just holding the sledge above the can and dropping it down.

Note that in this picture you can see the jig fairly clearly -- its just two pieces of 5/8ths plywood screwed and glued to a wider base of plywood.  Its the slot between the two 5/8ths pieces that is used to form the groove that fits over the copper pipe.

For a better view of the jig, see the pages on the $1000 Solar Water Heating Collector



Place the flattened cans centered over the slot between the two pieces of plywood, and lay the

5/8ths solid steel rod over the can above the slot.

In the next step, you drive the steel rod down into the slot to form a groove in the cans that will fit over the copper pipe.



Smoosh the rod down with your foot first.



Drive the rod down into the slot by driving the flat part of the head of the sledge down -- keep the handle of the sledge vertical.



Take the steel rod out, and place the copper pipe into the groove that was formed by the steel rod.



Place a couple inch wide strip of plywood centered over the copper pipe.

Once you flip the thing over, the plywood provides a base to staple the aluminum fins to down, and to push them into good thermal contact with the copper tube.


Flip the whole thing over, and then take the slot tool off.

This leaves you with the aluminum cans above the copper tube, and plywood below.



Staple each aluminum can down to the plywood with a staple on each side -- 3/8ths staples work well.

Push the cans very tightly against the copper tube -- you want to maximize thermal contact with the copper.


A (sort of) finished assembly.

The fins end up being about 4 inches wide -- about the same as many commercial collectors use.


Flipped over to see the back side.


You would of course want to make the copper risers longer than this little test section.


I like to put a bead of silicone caulk in the groove aluminum fin before stapling to the plywood for all the reasons shown here...

I think this might be even more important for this can construction, as even if the staples loosen up over time, the silicone will glue everything in place.


The collector for the $1K solar water heater is quite similar to this, and the small panel tests show it to be about 96% as efficient as a commercial collector...  I don't see any reason why this pop can collector would be any worse.


This is just  first try, and you might be able to work out a better way to use the pop cans -- please let me know gary...


Some other ways to make pop can collectors:

Air heating collectors... , more in this section...


        From beer bottles and 2 liter plastic pop bottles...




Gary March 22, 2010