Free garage heat -- just drink a lot of beer

[DrWebster]

Found this on Hack-a-Day, thought it was an interesting concept:

http://blog.hemmings.com/index.php/2010/06/22/soda-can-solar-heater-v2-completed/

 

[dmention7]

I'm a little lost on the concept... do the cans just provide surface area for collecting solar energy, or do you actually funnel air through them? I never would've thought you'd get enough heat out of such a system by heating the air directly.