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Post by johnsgard on Jul 4, 2020 8:55:16 GMT -5
Pdxian. I’d like to get an update on how your greenhouse performed this past winter (min. temp, plant health, etc.). I live in SE Texas now, but may be moving back to Nebraska in the next few years and dread giving up my whole collection on citrus (about 100 varieties) and other sub-tropical plants. I ran across a website of a man in western Nebraska with an earth-sheltered greenhouse that is heated/cooled with an earth battery (https://greenhouseinthesnow.com/about-us) and he grows (and fruits!) quite a few citrus very successfully. I now have some encouragement that it may actually be possible to grow citrus “up north” after all (admittedly at quite some expense). Let me know your verdict. Thanks, Scott
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Post by artie10 on Nov 9, 2020 13:04:58 GMT -5
Hi so you have 10,000 of pipe under ground, what's the size of your double skinned polytunnel, looking to do something like this in Southampton UK..
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Post by mikkel on Nov 10, 2020 2:16:06 GMT -5
Do you have a humidity control in your greenhouse?
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Post by Sylvain on Nov 11, 2020 5:57:58 GMT -5
There are reports that say there is an issue from water clogging in the tubes coming from condensation. Have you planned something against that, like pumping water to the lowest point?
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Post by mikkel on Nov 11, 2020 7:36:19 GMT -5
In Nebraska it is working for almost 30 years without this problem
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Post by loneroc1 on Dec 4, 2020 8:44:37 GMT -5
Howdy all,
I have a similar underground "heating" system in a zone 3 16'x 32'. In the literature I've seen my system described as SHCS, subterranean heating and cooling system. (Google "Sunny John SHCS") It is utterly worthless in my cold climate for heating. Worse than worthless even. It doesn't collect enough heat over the warm season to be of much help in the cold. Even with a heavily insulated greenhouse (and foundation) the soil "battery" stays at an even 40°F from December through March, no matter how much hot air blows through the system.
Moreover, I needed to provide extra (propane) heat to keep greenhouse air temps above freezing. The system sucked the heated air underground and chilled it. I can maintain a temp of 60F when when it's -40 C/F outside with 25000 BTUs/hour I decided it wasn't worth the wasted heat to try to quantify exactly how much heat I was losing with the underground system.
I do find the system to be worthwhile in the summer. It blows out cooled and humidified air, and while you still need to vent on sunny days it's refreshing to sit in front of the air outlet. I aim the cool air at orchids and other plants that are sensitive to the heat. By the way, a properly constructed SHCS should never have water condensation blockage. If you have impermeable clay soil you're supposed to replace it with sand or gravel instead.
Good luck with your Portland project. You should be able to extract enough heat to ward off your paltry few days of frost. 😁
Steve Herje SW WI USA, USDA zone 3 with an all-time low of-53F. But it's only gotten to -48F since I've lived here.
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Post by poncirusguy on Dec 4, 2020 12:19:34 GMT -5
I live in zone 6a just 600 feet from zone 6b in a micro climate that pushes me up to Z6b. I use 4 layers of glass on my Greenhouse and I still need to use some heat input. The north wall is my house so all of my glass surfaces face the sun at some part of the day including the south sloping roof. It would cost far more to Thermal-Climate battery my green house than to heat with an open window from my gas heated house.
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Post by xmpraedicta on Jan 12, 2021 13:37:38 GMT -5
Howdy all, I have a similar underground "heating" system in a zone 3 16'x 32'. In the literature Hi Steve, New here but saw your post that’s relatively recent so wanted to pick your brain a bit. In the process of designing a 4 season greenhouse in zone 3 as well, for some citrus but primarily intermediate temperature orchids (55-70 winters, 70-85 summers, 70-90% RHS year around). Was originally considering a passive underground system (SHCS) but now rethinking it after your post. Was also considering radiant in-floor heating with a gas burner backup, but can’t find much information on this. Wondering what you would do differently if you were to redo your heating/cooling system. Would you still consider a passive system for cooling? Any thoughts on radiant in floor heating? (My greenhouse will not be a dirt floor - will likely be concrete or some other material upon which benches are placed)
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Post by Sylvain on Jan 13, 2021 7:35:29 GMT -5
Very interesting.
I agree about the geo-thermal definition.
As you are in a 8a/8b zone, yuzu could have been planted outside. You could try with one as a test.
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