#113 After starting to build our DIY EMT electrical metal conduit (1.25″) greenhouse two years ago, we are finally completing the 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 YouTube (Don’t believe everything you see on the internet) to date and in line with our limited budget. Based on comments, 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 INSTALLING the passive solar geothermal earth battery system (or climate battery/thermal banking/ground to air heat transfer) after excavating 3,200 cubic feet of dirt from underneath the greenhouse with a Mahindra 3016 tractor. 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 150 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 – we HOPE.
Background on the project: Our farm 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.
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St. Isidore’s Farm
Foam not needed imo.
so, what happens in the HEAT of summer?
I really like this but am afraid that the air flows to the “path of least resistance” – the tubing should be one long path, forcing the air to flow all the way back and forth across the 6 lengths
That foam won’t decay or moist?
Apparently he missed all the videos that used a plastic 55g drum as the plenum for all the pipes and encloses the fan. Oops. This guy apparently disappeared 2 years ago. I don't upload many vids anymore but at least I answer comments on my channel👍😎👍
I am concerned about groundwater in those pipes. I am not an expert and not trying to point flaws in your work. I would love an update. We use buried pipe like that as a mock french drain to spread groundwater away from wet spots and move around the property. Wouldn't mold become an issue? The fans will dry it some, but wouldn't there be daily condensation? Thank you for running this experiment, how did it turn out?
Amazing… But shouldn't be posting stuff like this for the Gov to get there hand in your pocket…keep up the good work stay smart and safe
Good idea ! It will give u cool air when u need it.
Simple physics, gravel has far more mass than dirt, therefore will hold far more stored energy.
Seems like those pipes would fill with soil given a couple years.
How cold are your winters?
Do you expect enough heat gain in winter, to keep growing?
Or does this just lengthen the growing season.
I sure love this idea and hope it works. One worry is the distribution of air into the system. At low air velocities, I don't think it will be a big deal. But at higher velocities, there will be turbulence, raising the resistance. So the first split will see similar resistance in each direction, meaning volume will split roughly evenly between each side. But one side of the split connects to only one lateral run, while the other side goes to multiple. The heat/cold will be split asymmetrically.
Its just a worry. Let's see if it is a real world problem.
Black mold develops when air is Stagnant. Once started growth…youll have a deadly science project emitting Spores into anywhere air can go. High speed fans are your only savior. You need to Tamp that schitt as you go also. Dude educate yourself before attempting this. Its costly to your health & financially
Choke points in manifold are bad, all parallel better
Their seems to be allot of missing information like what climate zone they are in. Then it’s not clear if the objective is being able to create heat for winter growing or cooling for hot summer months or both. How can people make positive comments with all the missing information
I"m looking at doing something like this, but I live in a drained swamp and if I have perforated pipe it will fill with water likely to the point of restricting or preventing air flow. any suggestions on other piping to use?
LOL. 4:51 starts the silhouette making an appearance on the dirt mound
These are called GAHT systems, Ground to Air Heat Transfer. One thing I might add is that they have a high temp. and low temp. limit switches, that way your not using energy moving air when the temp. is just right in the green house….usually 50 F at the low and 75 F for the high….you save a bit on electricity, not as noisy all the time, blowers last longer and I'd like to add if your going to try this system out, go for it, they work great. Try and use 6 inch for your manifolds and solid 6 inch for the risers with 4 inch weeping pipe as shown here. Good job here and certainly worth it but could be improved on.
So he's heating the walls underground around the corrugated pipe but not underneath?? Can't heat escape there as well?
I'm confused, is the system cooling only or cooling and heating depending on the weather?
the foam does not make sense to me i dont understand why they all do it ?? doesnt it work against your purpose why do you want to insulate dont you want the heat to dissipate into the ground ?
Is 4ft down and 2 ft down deep enough? I know in Wisconsin I read we have to be down 6-8 feet to get that stable temperature
hello sir i am an engineer from australia am very interested in the idea but I cant understand the reason for the foam insulation as I believe this foam insulation will work against your purpose to exchange heat with the ground , for example in summer if you are cooling your greenhouse it means you are warming the cool ground underneath and these foams will stop the ground from being able to cool back down to keep supplying you with cold air
I found you Waldo!! 5:44
Amazing! Bob's Adventures hailing from Idaho
Please see this.https://archive.org/details/Electrical_Experimenter_1917_10/page/n23/mode/2up
if you do not plan to use the air for cooling your house, its hugely more efficient to use water to transfer thermic energy.
How do you keep the water seasonal water table from filling the pipes and restricting airflow?
Hey how's going? 🙂 1:03 did you do it on bigger GH? and any updates ? how the system works ? does it worth it? 🙂
Looks like a fine 🙂 project. You show offs.😜
An initial overview of the design and purpose of this structure would have made this a much more useful video.
I don’t understand why people aren’t just building on the idea from the guy in alliance nebraska – his system is proven to work – people she just continually improve on his design – he will tell you what he thinks should be added or changed
Suggestions in the capacity of a professional plumber .
Use pipe with a geo fabric covering to stop the silty clay from entering the pipe. If you don't have this in the USA you should still be able to buy I think geofab cut into strips and just wrap around the pipe.
If you want excellent all round penetration of the air into the clay I would use just a thin layer 3/4" of 1/4 pea gravel around your pipe. I think this would be much more efficient.
The site you have is very flat and although you are dealing with clay there's a possibility that rainfall off your greenhouse could penetrate the ground and end up filling your pipes with water and possibly ceiling the holes with fine clay. I would put a slight fall on your pipe work and at the lower end bring a Bend riser up that you could put a vacuum pipe to suck the water out,
All the best
Just in case.
I'm no scientist but I would locate my top layer of pipes about 12 inches from the surface as the heat doesn't have to penetrate so far to reach the pipes.
I'm certainly no expert just a keen gardener but I hope my comments may give you some considerations.
Did it work well or what?