Its ashame that most of the high heat in greenhouses even in the dead of winter is blown out the door! My solar greenhouse collects some heat in the water storage areas but only a small prcentage! When the temp goes to 90 or above we should be able to save some of this heat!
We need some good ideas here? Would a black hose or plastic black pipe collect more energy by being suspended in the air or pressed against a black metal insulated wall surface? Of course we need a pump to push water through the hose into a large water source!. This pump should kick off when the temp goes below 60 but kick back on when the temp goes blow 40!
Old radiators or base board copper tubing on the floors with water circulating will help.! There is no reason why any well insulated greenhouse can't stay above freezing all winter without any other heat except for solar right?