It has been proposed that a Hugel-Bed as the north wall of a
Greenhouse will insulate, add moisture as it captures run off from
Greenhouse roof, increase growing
area, and as a thermal mass balance temperature swings !
For my dialog I will call the Hugel-Bed what it often is, and will be if used this way here ! Our Super Saturated
Hugel Sponge S.S.H.S., is a large mass that by being
saturated does not truly insulate the interior of the greenhouse, but actually cools it. ( I.M.H.O.!) As the Super Saturated Hugel Sponge S.S.H.S. tries to equalize its
water vapor pressure with the interior of the greenhouse, the movement of that vapor cools the S.S.H.S. as the result of the latent heat of evaporation . As the vapor
in the Greenhouse increases there will be more water vapor condensing against the interior skin of the green house- here most of that heat will be radiated out through
the outside wall of the Greenhouse!
The vaporization continues until the wet bulb temperature is reached and every surface in the green house is wet ! The S.S.H.S. has given up a lot of latent heat of
Evaporation to the interior of the green house that was then lost to the cooler skin of the Greenhouse and now cools the interior of the Greenhouse !
We now need to look at the Dangers of having a heated space at total water vapor saturation,leading to Smuts, Rusts, and molds - or requiring increased levels of Air
Exchanges With even more heat
energy lost plus the energy bill for moving/exchanging the air !
This does not mean that there would not be a place for the S.S.H.S. Greenhouse as an adjunct after your plants have hardened off ! We just need to be aware of the
hidden energy costs ! This is my attempt at a reasoned description of what I Believe will happen in a S.S.H.Sponge-Greenhouse. Y.M.M.V. - A. L.
For the future/good of the Craft ! Be safe, keep warm ! PYRO-Logical Big AL - As always, your comments / questions are solicited and are Welcome A. L.
