Russell has a unique and effective system for heating his greenhouse. On sunny days, the system takes excess heat from the peak of the greenhouse that would normally just be vented outside and uses a water to air heat exchanger to transfer this this heat to a large water tank. The heat stored in the water tank provides heat to the greenhouse on cold nights and cold cloudy days. The same water to air heat exchanger that stores heat is used to distribute heat to the greenhouse.
In Russell's North Carolina climate, the system is doing quite well and is able to weather cold and cloudy days on stored heat.
The system is described in detail in a 12 page pdf (download below).
Thanks very much to Russell for providing this description!
The greenhouse is optimized for winter growing with steep glazing and with non glazed areas well insulated.
The fan pulls warm air from the peak through the heat exchanger (under the bench). The water side of the heat exchanger sends warmed water to the tank (behind the wall).
The heat storage tank is a 275 gallon IBC tote which is housed in the yellow extension to the greenhouse -- it is well insulated.
Download the detailed description of this efficient solar greenhouse...
Gary March 20, 2014