DIY Geothermal Greenhouse Part 3: Earth Battery Excavation
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- čas přidán 20. 08. 2024
- #112 After starting to build our EMT electrical metal conduit (1.25") greenhouse two years ago, we are finally back to completing this project. We're actually glad we didn't finish it then, as we would not have had the time to learn all that we have about greenhouses since that time. We would have regretted doing/not doing some of the things then, in light of what we'll be doing now.
In this video we are FINISHING 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) 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
David Mumford: "Wayfaring Stranger" goo.gl/ug2a95
Jason Shaw: "Landra's Dream" goo.gl/pi68XB
As a 40 year heavy equipment operator, you did a great job with that tractor which was working above it's capacity. You did a good job!
Thank you. We've had more than a few comments telling us what we should have used, but I think they missed that money was a constraint, and we own the tractor. So again, thank you for the kind words!
@@StIsidoresFarm One of the things that impressed me the most was how well you kept the bottom flat and level. That told me you have tractor experience. Did you shoot grade as you dug?
Fascinating video but I can't help thinking digging the pit before erecting the greenhouse frame would have been easier...
Ty
Looks like you are all doing a great job! Loved the drone shots! Keep up the great work!!!
Thanks! We'll pass on the kind words to our son about the drone shots. He's getting much better with it!
Nice JOB.. To maybe help you with your foam insulation decision. The highest % of heat loss is in the floor than the plastic. This is due to the wicking effect of the moister in the ground in your first 2- 3 feet of earth. All large greenhouses always put foam down first under their concert floor, THANKS.
That looks like some tough soil, but great job!
Thank you! Actually, it was perfect for this project - solid, densely packed red clay with NO ROCKS.
woow looks great! Fantastic camera-work & music, well done!
I have been studying climate battery greenhouses. I would fill the bottom with biochar which has to be charged by mixing it with an equal amount of compost and then drenched with water. Biochar is wood burned under reduced oxygen.It absorbs water and adsorbs electrical charges. It also provides a home for beneficial microbes. Above that I would want 3 feet of good earth and some compost and earthworm castings. To me the whole point of a climate battery is the temperature of the soil. Mycorrhizal fungi brings water and nutrients to your plant's roots. It requires a min temp of 12 degrees C (53.6 F). And earthworms do their best work at 18 degrees C (84.4 F).
The ancient Indians of the Amazon had terrible soil but made Terra Preta (Do a YT search) which means Dark Earth. They had 3 feet of top soil. Amazing soil. WalMart Brazil digs up the top 20 inches and sells it to gardeners. The local farmers then fill the top missing layer with compost and let the worms and microbes do their thing for 20 years so they can sell another top 2 feet to WalMart all over again.
We are entering another Grand Solar Minimum like the Maunder Minimum during which 25% of the world's population died from starvation and disease. I would expect severe and sudden weather shifts. If I had the money I would buy German Riga plastic for the outer layer so it can stand up to 120 mph winds and to hail. love your channel.
Wow, thank you for taking the time to share all of that information. Funny how we feel like we can research something for a long time, and still not hit all the information available on a subject. Unfortunately, we are on a super tight timeline on THIS greenhouse project, and won't be able to do all that we would want. The good news is that we have everything in place for a second, larger greenhouse. So we're looking at this one as an experiment. As to plastic, we're getting 6mil from Greenhouse Megastore (a four foot square section of it held 530 pounds before starting to tear: czcams.com/video/Uhp6cKqM8fM/video.html).
Hey Horse237.... yes, we have been following this too! We are more North so we are building an underground greenhouse like the Chinese greenhouses! Very interesting stuff!!!
Thanks glad it finally dried out for you
Yes, and when it did it only took two days to get it all excavated. Now for the exciting parts - building things!
Sweet! You guys rock!
Thank you!
3:20 that looks nice
Looks like its going to be a great pool ...kidding. .good job dude
Looking fantastic.
Thanks! It's one of those fun projects where you do a lot of work and at the end cover it all up to look like you didn't do anything!
Gettin' it done!
Thanks
Nice work. How many hours you estimate did it take to complete the dig?
Great presentations thank you.... what is the music.. it's great
First one is wayfaring stranger.
I know I'm a bit late but instead of using legs or other things for your tables if you make or find tanks to fill with water the heat from the sun will warm the water and you will have radiant heat from them
You're not late - we just didn't have the time or money left to get them. The reason the tables are as tall as they are, is to allow for black plastic barrels to fit under them. But short term, we wanted to get the table up to a height we could more comfortably work on. Thanks!
Hello guys
I moved (after 34 years) from Canada to Hungary (my home country) and I'm planning to start a hydroponic lettuce farm. I already purchased a Dutch made greenhouse 33'x100'
I'm also planning to do the same heat exchanger you did but before I will start to do it I would like to know how it works out for you. How does it work for cooling and for heating
Regards
Joseph
Maybe I missed it, but you never concluded the system kept it warm in the winter and cool in the summer?? I would love to know the temperature in the middle of the greenhose in winter and summer and compare it, of course, to the outside temps. I watched 10 of your vids and only saw a measurement next to the intake and output....but what about the middle of the greenhouse....not to repeat myself here. Also, in #10 I saw you had to put a fan at the door...that indicates to me it did not cool enough in summer?? Thanks...great work!
Spray hempcrete walls. Black.
without the insulation around 5 sides, you will be dumping heat into an area that will migrate away from the area you are trying to heat. Insulation is a necessary evil in a type of project like this. Without insulation, to raise the greenhouse floor temp 1 degree, you have to raise the surrounding area also one degree, ad so forth going down and around the heated area.
I sure hope you don't fill that hole in with dirt...keep that level that you've got and put a berm of dirt on one side to act as a heat battery.
guy digs a hole. lol not what I was expecting
What were you expecting?
was looking for the installation of the tubes. Found it on your next video thanks!
Excellent. Thanks for watching!
you could also keep it like this and you wil have the same if not more benefit controling temp
Ha! We thought about that!
It's looking good.
Too bad you can't go down another 2 ft and leave a 2 ft sunken floor to get more headroom for vines and cooler temps. It looks like it would just flood with any rain.
Thanks! Funny, we were thinking the same thing about going down further. But you're right - it would flood. Other issue is that we are up against time on this project. Not sure if you've followed the other videos, but our son received and FFA grant for part of this project, so we have to get it finished pretty soon. Four feet is going to be as far as we go.
I hate to be an arm chair cowboy but if you already had the roof frame assembled, why didn't you throw a tarp over it to prevent water from going in? That would have protected your progress.
how deep is the hole and what zone are you in
Hi, ok so i don't fully understand your design. Many geotheral houses have the floor below grade internationally to draw geothermal heat naturally from surrounding soil.
At just 4' depth, with thermal gain from the house on sunny days, the soil will maintain temps that average around 50 degrees all year. (Depends on your location).
Thats pretty good to keep certain plants alive and growing all winter. Call it a natural thermal bank.
If you bury some pipes in the surrounding ground at just 6-8 feet, and run a blower, that 50 plus temp can be had all night for most if winter and acts as cooling in summer.
Although i have not directly compared both of these, unless your using somthing like concrete as your thermal mass storage(can be waste chunks, stones, gravels), then the other may be better. Need to compare the heat capacity of the different substrates.
My point is that naturally, without even adding any thermal mass, your going to get good heat from the subsurface with no cost for insulation pipes etc.
Many use black barrels full of water as water is one of best for heat storage.
Insulating will block the natural heat flow from the floor. Yes, its necessary if you are using a thermal mass but if your thermal mass is not one with close to the best heat capacity, you might want to look at other options.
Not sure your goals in temps inside the house but make sure you review different designs in case you have not.
Look up on youtube the guy who grows oranges in midwest in a geo greenhouse. Note its partial subsurface design. All part of its effectiveness. Maybe do a hybrid design with only half a thermal mass or a smaller one that takes less materiala and work.
His design does pipe the hot air from peak during day under the floor but i do not believe he use somthing w high thermal capacity like concrete or water etc.
Good stuff. Have fun!
Its easy to make wrong decisions if you dont fully understand the processes involved, Water has a better specific heat capacity but it may not be the best medium to use in every situation. Water barrels are popular, the downside is they reduce reflected lght, take up valuable space, and need to be in direct sun As soon as the the barrel temp rises above the greenhouse temp they begin to release heat , they will also radiate heat to anything cooler thats in line of sight, including the sky ;). Most greenhouses begin to cool rapidly when the sun disappears so the barrels will lose a considerable percentage of the heat gained in the day long before its needed at 2am.
Most folks lose sight of the fact its a greenhouse to grow plants, relegating plants to the shade so a black barrel can have the sun is counter productive. If the plants cast shadow on the barrels the efficiency drops to the point its not worth losing the space.
there are slight better ways to do it go down 5 extra feet it will pay out over time deeper now the better
I want a tractor.
would this work in southern Ontario
Heck, I would have just put in a pool...
Hey I have a good question I built my geothermal and are used to heat from underneath the ground to make a long story short I dug out 6’5” and hit bedrock I cannot go any father can I still use the heat to heat up my greenhouse or do I need to go deeper
We only went 4' and 2'. 8' is better, but plenty of people seem to go with four.
What about radon?
Where are you guys located?
How much fuel did it take to dig out? To Fill?
Great question. Only about twelve gallons of diesel.
ok....what ya gunna do with the big lot of dirt you dug out..??...lol
Ha! Well, most of it goes right back in the hole. What doesn't is going to be used in various places around the farm where we need some fill dirt.
Say, is that a Branson tractor?
Holder and Sons in Durham.
Where can I get teh music from David Mumford?
Free Music Archive
10 hours digging on the first take. Do you have teeth on that bucket?