DIY Metal Conduit Greenhouse Pt 2: Passive Solar Geothermal Earth Battery

#110 After starting to build our EMT electrical metal conduit (1.25") greenhouse two years ago, we are finally back to completing this project.
We readily admit we are not experts at this (we are not engineers, greenhouse experts, or thermodynamic scientists), but a family doing our best to do it all ourselves and install based on all that we have read or watched on KZbin (Don't believe everything you see on the internet) to date and in line with our limited budget. Based on comments on future videos in this series, we already know some things should be done differently. Hopefully, it still works well enough, even if not optimally. We plan to share the results regardless.
In this video we are starting what we are calling, "The Big Dig" - excavating 3,200 cubic feet of dirt from underneath the greenhouse with a Mahindra 3016 tractor in order to install a passive solar earth battery (or climate battery, thermal banking, ground to air heat transfer, or geothermal) system. The idea is to use two high efficiency inline fans to pull hot air from the top of the greenhouse during the heat of the day down through a system of black corrugated drain pipes (600 linear feet) in the ground (300' buried at two feet and 300' at four feet) in order to heat the clay in the ground and return cooler air to the greenhouse. At night the process reverses, effectively warming the greenhouse for the cost of leaving a 75 watt light bulb on. In the summer, spring, and fall, this will help to keep the greenhouse cool(er) on hot days, and in the spring, fall, and winter it will help keep it warm(er) at night.
Background on the project: Our homestead came with metal pipes in the ground from a former 16' x 50' hoop house. It also had water lines run from the farm well (which also needed to be restored) and a 60 amp electric service. In the first video we installed the 1.25" EMT conduit that serves as the frame. In future videos we'll frame the end walls, run electric, and get the plastic cover on in time for winter.
Each rib or section of the greenhouse consists of three 10' pipes, no cutting. They are joined by stock EMT connectors. The two outer angles are 117.3. The ridge angle is 125.4. Sides are 6' tall. Just over 10' to the ridge. 16' wide.
Ultimately, this will be a double wall plastic film greenhouse.
+AMDG
Music
Jason Shaw: "Landra's Dream" goo.gl/pi68XB
Andy G. Cohen: "Bathed In Fine Dust" goo.gl/Smy2Am
#greenhouse
#passivesolar
#earthbattery
#thermalbanking
#geothermal

[@iamorganicgardening]

It is looking GREAT.. It reminded be when I had to dig a water main line 5 feet deep 300 feet and it rain . Used a old sump pump to pump out the water. If i did not, it stay their forever. Looking forward to the next one..

[@StIsidoresFarm]

Thanks, Mark! Unfortunately, efforts to go out now and get rid of the water would be in vain - we several more days of rain coming. I normally NEVER complain about rain or wish it away, but this is a moment where a week without would be perfect. Right now, I fear that our tractor would slide to the bottom of the hole and remain there.

[@GamingwithKandA]

How will you deal with the warm moist air, condensing in the pipes underground and starting mold/mildew growth etc?

[@JamesEndo1]

Interesting idea! How do you push the hot air into the pipes? What is expected temperature change? This is just for cooling? Seems like a venting system is better and cheaper? Will follow and thanks for sharing your project so we can all learn.

[@mobyindisguise]

Really interesting; great, simple explanation of how it all works, thanks.

[@thegardenfarmer]

Hello friends! Any update please? Did the pipes fill up with water ever?

[@surfinmurat]

I think, you needed the time from the first video to now, to work the plan out. but I think, it will be great!

[@chuckbailey6835]

Wouldnt the air move at night with out the fan by natural convection cold air gos down hot air comes up

[@artyberkhoff8878]

Wont those pipes become mouldy?

[@jeffreyatto2523]

Is this the same as the (Finch) Citrus In The Snow Greenhouse design?

[@joeowens8923]

Would this system be a good idea for a small house ?

[@bullseyek]

How do you deal with condensation buildup in the pipes as the hot air generated during the day is cooled?

[@deanlewis1650]

I would think.that if you have enough air flow the air will consume the moisture and bring it back up inside the greenhouse.

[@efrahaimrn]

Will it collect condensation overtime?

[@grasso7200]

Glad I found your channel. Great video liked and subbed :)

[@jimsgardensandrabbitry]

Very interesting and I will be following along. What are you going to do along the wall where you dug? Are you lining it with something to prevent it from falling in. What material are you going to put down on the floor once you install all the pipes? Thanks for sharing. Blessings, Jim

[@StIsidoresFarm]

Jim, great question. Actually, the walls all around will have 2" rigid foam insulation lining the hole before pipe installation and back filling. The first course of pipes will go in at four feet down, then we will back fill and tamp around the pipes up to two feet. Then we install the second course of pipes, before filling the hole back in completely. The rigid foam insulation will be like a giant ground thermos/cooler helping to keep the heat energy contained under the greenhouse and not bleed into surrounding clay. We're going to put greenhouse tables along the walls and raised beds in the middle. Gravel will go down where we walk and under the tables.

[@spex357]

Rather than take the whole floor out a back hoe can dig trenches maybe 6ft deep, then you could have more separation between the layers and less of a mound of soil.

[@danl.909]

Evaporative cooling? Do you perhaps mean "convective cooling?"

[@xpeeriments6452]

no. evaporative

[@Z71Ranger]

LOL... 50.00 to fix that... Amazon is NOT always the cheapest place to buy...

[@gufredd9675]

It's hardly ever the cheapest place to buy something. It's the convenience that we pay for, I guess.