Hello, my name is Manuel and I'll build a barn in a 2,5 acres land without utilities.
I've thought about a masonry stove like those in :
http://www.geocities.com/RainForest/Vines/4095/masonry/
http://www.dnr.mo.gov/pubs/pub781.pdf
My idea is to put a radiator into it (surrounded with sand for heat transfer) and connect it to several 200 litres drums (I think they are similar to yours 55 gallon ones) for keeping a greenhouse attached to the barn above freeze.
Some idea to improve it or another way of getting frost free?
Thanks
Manuel