Greenhouse heater size? calculation vs. table

[Subrosa]

Originally Posted by tropterrarium

Big water body or having GH lowered into ground are certainly theoretical options. For underground pond or storage tank you would also need some sort of circulation system. Passive radiation is most likely too slow. Haven't seen any calculations for that.

For my purposes I plan to run a closed system with a heat exchanger submerged in the storage vessel circulating an antifreeze mix. When the circulation pump runs a powerhead of the type used for reef aquaria will move water through the heat exchanger in the tank. I really think that passively sitting the whole works above some 50 some degree water will prevent freezes in your situation. I do agree that to get any significant cooling you would need to actively move the heat around.

[Ray]

Now that I live on 1/5 acre at the beach, I'll never get to do it, but I always wanted to replicate something I saw in an AOS bulletins years ago:


Some guy dug a 6' deep x 500 yard ditch in his yard. He laid in 18" diameter, unglazed, clay sewer pipe. One end opened into the greenhouse, the other into the open air above ground, protected by a small shelter and air filter. He ran exhaust fans 24/7, pulling air through that pipe into the greenhouse.

In winter, the dry, frigid air was warmed by the earth to the low-60's, so provided heat. Water in the soil permeated the porous pipe, so humidified the otherwise arid air.

In the summer, the hot, humid, outside air was cooled, which also served to drop out the excess moisture, to an absorbed by the clay and put into the soil.

Fantastic, reliable, climate control, at little cost.

[tropterrarium]

Thanks for this very detailed account. With plastic/metal barrels, I have no problem seeing the heat transfer. The build structure on top of pond/reservoir is where I see more issues, namely how radiation gets through a concrete floor.

Water tanks may be a stage two addition for me as well. Currently I have about 32 x 3' benches in the plan, the rest is hanging racks to the floor. I could put water tanks under those benches and even if not perfect, it should make some difference. I also plan on an internal koi & water lily pond, something like 6x6x3 feet. That's another descent amount of water. Still tossing around ideas ...

[Subrosa]

Originally Posted by tropterrarium

Thanks for this very detailed account. With plastic/metal barrels, I have no problem seeing the heat transfer. The build structure on top of pond/reservoir is where I see more issues, namely how radiation gets through a concrete floor.

Water tanks may be a stage two addition for me as well. Currently I have about 32 x 3' benches in the plan, the rest is hanging racks to the floor. I could put water tanks under those benches and even if not perfect, it should make some difference. I also plan on an internal koi & water lily pond, something like 6x6x3 feet. That's another descent amount of water. Still tossing around ideas ...

I plan on a concrete slab 3' below grade with a block structure rising up to a bit above grade. The last course of block will be laid to accommodate 2x8" floor joists. The joists and the entire storage tank will be sealed with epoxy, and composite floor boards will be spaced to allow easy drainage into the tank beneath. An ornamental koi pond would certainly complicate things a bit.

[dounoharm]

great ideas here.....I will love hearing how ray's 'ditch' method works.....ray's last ditch? lol...geo-thermal heating....

[Ray]

Originally Posted by dounoharm

great ideas here.....I will love hearing how ray's 'ditch' method works.....ray's last ditch? lol...geo-thermal heating....

It was neither my idea, nor will I ever try it. However, my next door neighbor in PA was looking into geothermal heating of his home, and the same 500 yards by 6 feed deep trench was one option, although the rocks (boulders) in our yards mandated that he drill wells instead.

[dounoharm]

I always loved the old greenhouses/conservatories that used boilers....we had one that opened to the public at certain times....reynolda gardens....at times they have nice orchids, but in the past 20 years, it has sort of had a lack of maintainence....I learned a lot going thru there!