I found several videos of people making solar heaters out of aluminum and tin cans. A unit only a few feet in size can output air well over 100 °f. They can be made with soup or pop cans. The enclosure can be made out of most materials. The cover can be any clear material, plastic film, glass or plastic. At the bottom is a video on using milk jugs filled with waters will hold the head after the sun is down.
Enjoy the videos
A canadian man has made a business out of this
Using steel (tin) cans instead of aluminum
Milk Jug heat storage unit
