Posted: 12/03/2013 at 22:23
Artjak the can furnace is basically a box of black painted cans behind glass Cold Air enters at the bottom and exits as very hot air at the top. Which is ducted where it is needed (eg heating a chicken coop) . Temperature went from 38 degrees F input to 130 degrees output. There are a number of idea's with a similar theme one i liked was done in 71 where a series of pipes was laid under slabs circulating water from an outdoor pool.
Heres a strange idea told to me by my local nursery that itis better and warmer for the plants if you open the vents when a frost is due, he reckons closing the vents actually makes the plants colder. yesterday he said it was 7 degrees warmer than the outside air! This I do not understand