On Mon, 12 Nov 2007 15:06:41 -0600, "Mark_OK" wrote:

My thought was a recirculating system. Say an inlet at the top of the
greenhouse and an outlet at the bottom of the greenhouse, at opposite ends
of the greenhouse. A fan or fans would have to be used to force the air
through the duct work. I have a feeling that the amount of underground duct
work needed to even make a slight difference will be substantial. It
probably would be just as effective if you just sunk the greenhouse into the
ground a few feet.



We sunk the support walls on the lean-to greenhouse - wall is depth of
house wall (basement). Filled the gh with cobbles ( football sized
rock) then topped with gravel for a level floor. We put pipes in the
cobbles - planned to force ceiling height air down thru the pipes and
let it drift up thru the cobbles to create humidity. Never did find a
way to use a fan to do this. The vertical is now gone and since the
gh floor has settled I will bet the pipes collapsed under the cobbles
as well. But the 4 foot of rock in the gh floor is a mitigating
factor on heat and cold.

I thought the article was clay pipe with the clay walls pulling
humidity from the surrounding ground water and would need a reversible
fan to force hot air in to cool and pull warmed air out to mitigate
the cold. If a loop maybe the fan only goes one way and the effect is
different by the season.
SuE
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