I happen to have a load of cans, and a cold shop. Is it worth my effort to make the solar collector that uses aluminum cans as its heatsink? I have a south wall that is about 12 foot tall, and 30 foot long. I can use the entire wall if it makes a bunch of heat!

Check out the website:

www.fieldlines.com

http://www.fieldlines.com/story/2003/9/29/113052/340
http://www.fieldlines.com/story/2007/8/20/124818/249
http://www.fieldlines.com/story/2006/1/8/05158/92626
http://www.theworkshop.ca/energy/collector/collector.htm

And here

http://www.junkyardsolar.com/air.html

Great info! I have been on my toes, yelling at the guys to stop smashing thier cans...they think I am crazy.

I just scored a stack of used double pane sliding glass doors! I will keep looking for the rest of my parts. Anyone have a common cheap thermostat to turn fans on at 90 or 100F. I have one old thermostat from an attic fan, but want some cheaper sources. I just need it to turn on when hot, and turn back off when cooled.

quote:

Originally posted by Mysubrattles:
I just scored a stack of used double pane sliding glass doors! I will keep looking for the rest of my parts. Anyone have a common cheap thermostat to turn fans on at 90 or 100F. I have one old thermostat from an attic fan, but want some cheaper sources. I just need it to turn on when hot, and turn back off when cooled.

Use a thermostat from your home heating unit. You know the one in the hallway you use to set the temperature of the house.

I am ready to move on. I have 20 double pane, 32*78 glass doors, and plan on using them all in one giant collector. I think I have enough cans rounded up together to make it go. I will have to experiment with airflow, to keep optimum temps. I currently have one 4x8 on my garage roof, and it spits out 130F air all day, 9 am to about 5 pm. Free heat is good.

Mysubrattles,

I also am interested in building a large collector from about 10 - 12 glass panels. Would like to know how you made out building yours as your posting was Nov. 2005.

My wife saw something about the beer can solar heaters and has gotten me interested since I have the materials on hand..

SC

You need two thermostats in series. One that tells you when there is heat available in the panel. One that tells the fan that you want heat in the house. Use a household termostat like Rick suggested for the demand thermostat, or use a disc switch set at the max temp you want to see in the hou. Use a disc switch for the supply thermostat.

http://www.thermtrol.com/ntseries.htm

Pick around 75 deg F for the demand switch (how hot is too hot in the winter for free heat.) Pick 110 deg F or so for the supply heat (air blowing out of a vent at less than that may not feel very hot.) You actually want a fairly big dead band on the supply switch. 120 deg F with a 20 deg of deadband would be good. That way it would supply hot air once it hit 120F and would keep the fan running until the supplied hot air went down to 100F.

Even better would be a differential temperature controller for the supply controls, but you are looking at $150 for something like that.

This may sound silly,but, I'm wodering how much heat these heaters would put out in the summer months?

I suppose if you have a lot of free time and a lot of cans... but there are much easier, more effective ways to capture solar heat, and beer cans are worth more at the recycle depot. The easiest methods are called win-dows, and solar walls.

The designs I've seen are used to dry food in the summer/fall. They typically have two or more small computer fans on the air input with a solar panel providing electricity. The multiple fans are there as hot standby's in case one or more fails. The solar panel produces a current for the fans proportional to the solar radiation so it tends to keep a constant temperature. The simplest I've seen are made out of cardboard, and clear plastic sheeting.