John wrote:
>No matter what the theory I fail to see how half submerged water
>barrels will transfer much heat into the ground.
True, it would be better with more ground contact and the hot water
would probably stay near the top. It should work a little better
in very cold periods when the air temperatures drops to around 33F
because the soil stays at close to 50F. This will pull some heat
out of the ground.
>The most ingenious greenhouse system I have ever read about is that of a
>Joseph Orr of Laramie , Wyoming, in May 78 Mother Earth News. His was a
>hot air collector that blew heat into wet earth heat storage below the
>greenhouse. It is an active system but the major components of the hot
>air collector , fans , foam insulation, pvc pipe , and the earth which was
>there to begin with were not overly exspensive considering the results;
>tomatoes and tropicals yearround in Laramie with no other heat.
I would like to avoid active systems and keep it simple. This
eliminates tomatoes and other tropical crops in the winter. Actually,
last year i lost tomatoes in the summer due to overheating so cooling
is a bigger factor for the tropicals.
>I plan a 14 by 20 shed greenhouse on the sw side of my living room.
>Presently the area is sloped but averages 5 feet below living room floor
>level so that construction would start with an insulated perimiter
>foundation and then infilling with planting beds, heat storage,
>watertanks, rockwork to bring it up to desired levels.
Sounds interesting, i would love to hear how it performs. Yesterday
i ordered some min-max thermometers to do testing here and plan to compare
a standard greenhouse to one full of barrels. This makes the numbers
easy to understand.
Dave wrote:
>We will be adding our dome greenhouse after we build our
>passive solar earthship in the CO mountains in a couple
>years.
That should be a great solar location. Our climate is
milder here but the clouds block the sun all winter and
this kill most greenhouse designs. After a week of no
sun the only heat around is underground. Another possible
heat source is animals. Some animal systems are used in
the third world countries for house heating but the idea
isn't popular as sophistication increases. Our tolerance
for manure is a little low <grin>.
>In the middle of
>the greenhouse is a 300 gallon water tank to raise aquatic
>plants and to be a thermal battery in winter and summer.
Aren't those water tanks pretty expensive?
jeff
