Hello Morgan; from watching your video and concept I started the same design until I hit a very deep white sand layer that constantly caved in. So I had to adapt / compensate by enlarging my 9 foot deep, 4 ft wide by 8 ft length, pit/trench to 12 foot in length, and since I couldn't go deeper I coiled the 4 inch wide 130 foot long flex tube with a 4 inch layer of dirt for each coil. I coiled the hose 4 times at 9 foot and finishing at about the 8 foot mark then running exhaust back in creating a sealed system. I can't post exact stats like you but I have turned on my LED lights (4-300Wt)--- A/C --- dehumidifier-- circulation fans--- and so-on when shed was 102 degrees and outside was 104 degrees ; It took around 15 min to pull temp down 76 degrees- So I'm saying great info/video because it works great!!! Well if you wouldn't mind watching my video and tell me what you think of design th-cam.com/users/edit?video_id=U5tY6ved_ZY
I built one yesterday and our frost line is 18" in Vancouver Canada so my air draw is at 56f inches down and has 13.8c temp for cooling my citrus greenhouse. I used a vented Ikea basket as shoring a the 4 inch at bottom with drill 5" pot intake.
that's great. Yeah I think the geothermal systems are actually more effective for cooling! It's been awhile since I've had an active geothermal system in a greenhouse, but maybe next year.
This is awesome! There's a pop can solar heater video around where tubes of pop cans are painted black to absorb heat from the sun then transfer the air into the building. It would never supplement this system as the wells would actually cool the air that's heated by this, but it's interesting how the "Tubes" in the heater are constructed. they leave the bottoms on the pop cans but cut them in a way that makes the air spiral down the tube instead of going straight through. If you were to "Spiral" the inlet below the frost line, you would increase the distance the air has to travel, thus giving the air more time to 'soak up' the heat (or lack thereof). I'm not sure how much more efficiency you would gain, but would certainly help where space is limited.
Dwayne, thanks for your note. The design that I'm most interested in trying is a "U-shaped" system. i'll have to figure out a way to dig two holes very closely together. I'll probably buy an 8-foot section of 6" PVC, cut it in half, and make a side-by-side template. The advantage of the U-shaped system is that I can simply pump the air through the U, which is far more efficient than the system I show here. Also, because I have air circulating over open hole, I add a lot of unwanted humidity into my greenhouse in the winter. The U-shaped system won't touch the wet soil underground.
Wasn't expecting a reply after 2 years, wow! We bought some land and I'm hoping to build one of these in the spring! Going to try some experiments and see what works best. Was also thinking of the actual Solar heater and well combination with sensors and programming. Depending on the temps in the well and the solar output, I could have software switch between the two 'technologies' to help stabilize the temps.
now i want to dig holes all over my house !!! looking now for a seymour post hole digger and a galvanized steel pole is a 3/4 threaded steel pole good for the seymour ?
The Seymour digger is excellent. Yes, I used 3/4 inch threaded black pipe and coupling to extend the length of the digger. Make sure you lube the fittings, because they get pretty tight after a lot of digging!
Thanks for a very detailed video. Really appreciated the formulae as well as the graphs. Data fit perfectly into linear function! Now to drum up materials for a test.
You are welcome. I'm preparing to rebuild my geothermal system with the goal of improving airflow into the holes. I'll report on that when I can! I've been more fixated on compost heating recently - check out my most recent videos on that subject
I first noticed the greenhouse in the snow geo air system...I want to combine ICF concrete construction including a concrete roof (extraordinary thermal mass of concrete) with geo air and solar panels including a couple of banks of lithium diode batteries, LED lights and induction stove. I believe I can make a home that is a net electricity producer. Hope to try it in the next 2 or 3 years.
Yes you could, though I would recommend using a closed system (no air flowing past open hole), due mainly to the humidity that it would add. Take a look at my newest geothermal system (th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html) for one idea. You'd probably want to use a larger system than I implemented, with a powerful blower. The water vapor in the warm air will condense when it goes underground, so make sure that you add weep holes at the low point of your geothermal. These types of systems actually work FAR BETTER for cooling than they do for heating! Good luck.
Great presentation, chock full of useful information. Thank you very much for making it! No concerns about blowing microbes into the greenhouse (could be avoided with a double tube system I suppose)?
Thanks, I sure appreciate it. I think your concern about microbes is a valid one. Another concern is the increase in humidity from the ground. As a result, I went to a U-shaped configuration last year (th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html) and actually simplified to a more conventional horizontal system this year (th-cam.com/video/A2TQJl9WjLc/w-d-xo.html). I'm more focused on compost heating for my greenhouse now. If you have enough space, however, the geothermal concept is excellent.
Do you have any advice about Radon? If I dig a hole and lower a test kit, will it give me an accurate reading? Will this system cool a greenhouse in the Arizona desert?
Radon could be a problem with this system (hole open to the surrounding dirt). Especially if you have clay soil. If you vent the greenhouse, as I'm sure you'd do anyway, Radon probably not an issue. However, my 2018-19 and 2019-20 geothermal systems are all completely closed (go to my channel page). Most people utilize a horizontal, closed system. Horizontal is typically more efficient for full greenhouse heating/cooling applications for the simple reason that you can get more pipe underground than with a vertical system. Of course, those people typically have large acreage. If you are a) space-constrained, b) have a low water table, and c) can easily drill to 20 ft, then the vertical system has real merit. The deeper you drill, the more stable the temperature (say 55 deg F). If you leave the outside of the hole open to the ground like I did in this video, then you will increase humidity in the greenhouse. In Arizona, maybe this isn't a problem. If you have any more questions let me know. Good luck!
I'm sure you could test for radon by simply putting a test kit in the greenhouse. I am not sure if this geothermal implementation would cause the greenhouse to have more radon than it would without geothermal. In any event, I've gotten away from this implementation for the last 2 years. I'm now using a closed system (no down-hole soil exposed to air)
No greenhouse as yet. I wanted to dig a vent and test it before commitig to the system. I'm planning on building a house too with the same system. As long as I'm not getting radon. I'll dig a hole and lower a test into it.
@@taylorphillips5118 Ah, I understand. Yes, if it was my house, I would definitely want to ensure that radon wasn't a problem. Last year, I drilled two adjacent holes and used a U-shaped tube (th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html). That could be a good answer if you want to use this for household purposes. This year, I simply dug a pit and buried 25 feet of tubing (th-cam.com/video/A2TQJl9WjLc/w-d-xo.html). If you plan on using the geothermal system for cooling (probably most useful for household), make sure you put a weep hole at the lowest point of the system and bury gravel to keep condensation out of the pipe.
@Moaz Qadri - Geothermal is very effective for cooling, because as the hot, humid air goes underground, water vapor will condense. This cools the air AND reduces the humidity. However, you must take great care to allow the condensation to drain away from the geothermal system. For this reason, I prefer "closed" geothermal systems (th-cam.com/video/A2TQJl9WjLc/w-d-xo.html or th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html). You will need to install drainage holes in the geothermal pipe and ensure that condensation drains away from the pipe. If the pipe fills with water, then your system won't work!
Morgan, we'd like to build an earthtube to help cool our second floor. We also live in Denver (Golden) on 2 acres. Could you help us find someone to build it or could we hire your to build it? We don't need heating, and just cooling on the 800 sq foot second floor story.
I'm flattered! Unfortunately I do have a day job, so I wouldn't be able to actually do it for you. However, I can definitely give some words of "wisdom" (or maybe lessons learned from failure). For a 800 sq ft space, you will need a bigger system than I show here. However, you have a nice big lot, so you have flexibility. I would aim for a "horizontal earth battery" system, rather than the vertical system that I show here. I'd recommend hiring a backhoe to dig a fairly large area as deep as possible. Just pulling numbers out of the air, but I think you want to aim to have about 500 ft of drain pipe underground. Since the air will be going directly into your home, you will want to have a fully sealed system, unlike what I showed here. Air flows over the moist annulus of the well, pulling humidity out of the soil (and into your room), and posing a radon risk. When you cool hot air, moisture will condense out of it and fill the pipe. You'll also want to have the pipes slightly angled down in one direction, with weep holes and gravel pack, to keep water from filling the pipe. I would also look into a filter on the outlet pipe to protect against any microbes that could be growing in the pipe. I'm definitely happy to provide my opinions, but I'm no professional! There's a company in Boulder called Ceres Greenhouse Solutions which builds greenhouses using this geothermal heating & cooling. They could provide you with some advice, but they'd likely be pretty expensive and they might balk at doing a project like this.
Humidity was my concern. I was thinking of a three staged closed duct loop. It would have a blower forcing return air from the house through horizontal air tubes first, sloped away from the house with a small constant drain. Then the air will go into vertical wells like your system. A long slope up to the house and through a radiator with s closed loop of geothermal cooled water from the bottom of my pond. Any condensate from the radiator can drain down into the vertical wells. What do you think? I know it sounds elaborate but it could be ran with a 12 Vdc fan and pump. We are looking into options for an off grid earthberm home.
+Chris Daughtry Sorry, I failed to respond in a timely manner! I like your drainage idea. In the hot months, I bet that the water vapor in the cool return air would condense as it heats up, if you engineer it correctly. In the cool months, maybe you want the extra humidity? (In Colorado we don't mind it!). One worry we do have here is radon -- the clay bearing soils are known to have high radon. Not sure how you engineer around that one, but it's probably worth thinking about.
could you use an inverted V and intersect the the borings ????? no backhoe and yet you have more surface area per unit and less back pressure if you did it right you could lower some 6" pipe cut at angles to stop collapsing dirt.. or could you line the holes with cement?
Not a bad idea to improve airflow into the system. Personally, I am lucky as my soil is easily diggable, yet dry and very stable, so I don't require any casing to improve hole stability. Many other people who have posted comments do have a problem with hole stability, and yes, I recommend casing the hole with 6-inch pipe. My next geothermal system is actually going to be a big hole -- think root cellar -- with fans blowing air in and pulling it out. A decent sized hole would have as much volume as a buried system with 200 feet of pipe. We shall see!
Hi Morgan, we have this 32 foot old dug well we no longer use from our 1890's homestead, right next to our house. Currently it just has a heavy metal grate over it on stone about 20 inches above ground level. We would like to build a lean too greenhouse on this southern side of the house, with the well right smack in the center. I like you idea but wonder how we can utilize our well for heating our greenhouse. Wonder how to cover it and should we fill it in or leave some types of tubing go down and through the water? Any ideas would be greatly appreciated.
Michael TORLUCCIO , how wide is the well? If it's at least 6" wide, The easiest thing to do is just run 4" air tubing from surface to the water level and let the return air come up the annulus (outer ring) of the well. I'm assuming that the well has water in it? Some people worry about excess humidity with a water filled well. I'm not sure it's a big problem, honestly. However, if the water table is shallow, you'll have to think about running casing from the surface to the base, pumping out the water, then plugging the base of the well, probably with cement. Another thought: if the well is quite wide, you could simply bend the 4" flexible tubing into a U shape and drop it down the well. That way, the pipe could be submerged, yet it would be airtight.
Great videos. Thanks. I have three questions: what if the soil is loose. Can you line the holes or does that defeat the purpose? What if water gets in the hole does that negate the value? I notice you cover the holes so aren't you blocking the outflow of warm air? I'm assuming these holes need to be inside the greenhouse, correct? Sorry, four questions.
Hi George. You hit all the good questions. Loose soil is a blessing and a curse. Good because it's easy to dig, bad because of the cave ins! You can definitely line the tubes and in fact I'd recommend it to keep humidity and radon at bay. Last year I came up with a way to dig two parallel holes and run a u-shaped length of drain pipe in the hole. This suppresses humidity and enhances airflow, but it's tricky to implement. Water is an omnipresent problem. You don't want water. As long as you live in a dry climate and don't use the pipes for cooling, you shouldn't have condensation in the bottom of the holes. Condensation would destroy the u-shaped airflow. If condensation is a problem, I'd recommend opening small weep holes in the drain pipe and filling the bottom of the hole with gravel prior to inserting the drain pipe. This year I abandoned the vertical earth tubes and just went with a small horizontal system.
Thanks for the quick reply. Unfortunately for me I have a spring that feeds a pond and the spring is some twenty feet away from where I was hoping to put this system. By "lining the hole" I meant putting in a pipe with a cap on the end so water could not enter the pipe but it sounds like an opening in the bottom of the pipe is essential so, I'm out but thanks again!
I have a fairly deep lake in my back yard. The water temperature at 10' down rarely gets below 60 F. I would like to pump water from that depth and run it through a radiator in my greenhouse. I will return the water below the surface and won't be wasting energy due to lift. The resistance to flow and the power to the fan will be my only energy loss. The specific heat of water is very high and represents hundreds of watts of free energy.
Jim, I wish I had one in my back yard! ;-) Smart of you to keep the water in a closed system, as it'll help control humidity. Another (lower-tech) option: just pump into a 55-gallon drum with an overflow pipe running back to your lake. The thermal mass of the water barrel would act as an additional temperature stabilizer. Or, you could pump into the drum AND run your radiator to get the benefits of the thermal mass AND rapid heat transfer.
One of the reasons I bought the house was because of its proximity to the lake. It represents millions of BTUs of almost free energy for both hearing and cooling. I like your thermal mass idea.
Jim Ferguson yeah, my in laws live on a lake in Florida. Not as deep as yours, I’m sure, but they have a geothermal heat pump system utilizing the lake. Great bang for the buck. My dad in western Colorado also has geothermal heat pump, but he had to drill about 250 ft...that wasn’t cheap!
In our area the water table is at about 4' in the summer and as little as 1' (or less) during the wet seasons. We could put in a casing with a closed bottom to keep the water out, but PVC would be the affordable material. Do you think the PVC would have an acceptable heat transfer?
Wow, you must live somewhere that gets a lot of rain! I wonder if it might be more effective to just pump water to the surface and run a heat exchanger? What's the water temperature?
We're in Glenoma, WA. It rarely stays below freezing for an entire day. Maybe we should pump water into barrels painted black and then circulate the water in pipes under the soil for the night? My husband was thinking that it would be hard to keep a dry casing buried for a geothermal here because it would want to float. We'd have to give the casing a substantial collar with weight equivalent to the water being displaced.
yeah, I agree with him! Perhaps you could create a concrete "plug" - essentially you would pour a concrete deck footer, then attach it to the casing and drop the concrete into the hole. Essentially, it's a collar, it's just buried. I'm no expert on water wells, so take this with a grain of salt! I like your idea to pump the water up into a rain barrel. To give you some perspective, I had a rain barrel in my old greenhouse. In the winter (and it is cold in Colorado), I had a 300 W fish tank heater running all day long just to keep the water at 60 deg F. Let's say that the buried water is 60 deg F year around - if you could get it to the surface with a 20 W submersible pump, you'd be well ahead of the game! Since the cold water should sink, you could drain water from the bottom of the barrel back into the well.
Luis, thanks! I have just built a new greenhouse and I have a 5-hole geothermal system with 50 feet of holes. I am hoping to get this running tomorrow and will put up a video soon. Stay tuned!
What size is your greenhouse? I'm wondering how many wells we would need for a 13,000 sq foot greenhouse in southern AZ. We are interested in heating and cooling.
Sorry, I just saw your comment now. It really depends on how many wells you drill. I found that for heating, I could heat a ~20 cubic foot volume by 4 degrees with 4 wells drilled to about 8 feet. For a 13000 sqft GH, you'd need a lot of wells...unless, perhaps, if they were very deep. For a GH of that size, I'd recommend the horizontal earth tube. You excavate with a backhoe and lay hundreds of feet of tubing. I'd also recommend excavating directly below the footprint of your GH, if that's feasible.
Disclaimer: I've never tested radon in this system and don't really care because I'm not inside the structure often. If you have a problem with radon, you'd probably want to line the hole with PVC (pricy) or drill two holes next to one another and run a u shaped tube. I will take the latter approach this week when I redrill my geothermal system
@@rblibit Check out greenhouse 2.0 ( th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html ). I was able to drill two adjacent holes, then run the drain pipe in a closed, U-shaped configuration. Will post the results soon
Have you noticed if there is an oder in the greenhouse that resembles a basement. I've considered similar system for my house but I have concerns of the damp smell that can be present in some basements.
I don't think that my geothermal system causes an odor. But, consider that the ground where i live is very dry (bottom of hole is well above water table). if you have a lot of water in the bottom of the hole, I would recommend casing (sealing) the hole in PVC pipe. Also, radon is a worry, and it is present in clay soils. If I was using such a system to cool a house, I would definitely use casing. You will need a lot of holes and a strong pump to cool a house. My greenhouse is very small.
Thanks for your input. I live in Florida and we have sandy loom soil and A LOT of humidity. The proposed spot for my new house is 42 feet above the water table (rare for this state) but I am thinking of a near horizontal system at a depth of 15 feet. We don't have a big radon problem here but I wouldn't know how to remove radon from a system such as this any way. I would simply have to rely on my smoke/CO2/Radon detectors to warn me of this buildup. I was also considering using my well to cool my house because the water stays a constant 72 degrees (have you experimented with this at all?
Michael S Florida should be interesting. Yeah, you'll definitely want to case your holes! But the digging should be easy, right? I am limited to 12 feet (bedrock), but I was planning to dig to 20 ft. Many closed systems will have weep holes at the bottom to handle condensation. A horizontal system might be best for you to handle a large volume of air, but I'm not sure how you'd dig so deep - backhoes are usually limited to 8 ft, right? The water idea is interesting. Rather than an air based geothermal, you could get a strong water pump, dig a hole, and build a closed loop system. Coils of copper tubing at the surface and in the ground to transfer the heat. Just blow a fan across the surface loop and collect the condensation. At 42 feet I would suspect that the ground temp is lower than 72, but what do I know?
Morgan, it's nice to chat with someone who has fresh memories of his experiment(s). My well water temperature at the tap immediately after the casing is 72 degrees. The static water level is 42 feet but the pump is at a depth of 92 feet (for drought purposes) but the casing is 212 feet down, this gets me below most of the surface contaminants. I've done some limited research on ground temps in my state and my water temp falls right where the data says it should. Using the same well that will be supplying my house allows for the warmed water (caused from the heat exchange) to be replaced with cooler water every time the house pump comes on. I own a small backhoe so I can dig a hole at my leisure to any depth I desire (with in reason of course) using the front loader. I have also looked at a closed loop system whereas you bury coiled tubing at depth and pump water through it and across an evaporator (collecting the condensate below the evaporator) but at this point I'm looking at all option because unlike you, I have a bigger need to cool rather than heat. :) We have 9 month summers here and fall like winters.
Michael, yeah, I guess your Florida aquifer is at a constant temperature - my in-laws live in Sarasota and I have good memories of swimming in the spring-fed rivers. We wore wetsuits on the Crystal River - I think it was 67 degrees(?), with unbelievably robust flow. The simplicity of the air-driven systems make them worthy of consideration, even if they're less efficient than a water-circulation system. Honestly, I think the key to success relates to maximizing airflow. I've had discussions with a couple other guys with air-driven geothermal (horizontal) and they are using high capacity fans which draw ~300 W. I'm using small fans that draw only 12 W apiece, and I'm not getting enough airflow into the greenhouse. Once my broken leg allows me to walk again(!!!), I plan to revamp my air circulation to reduce the amount of air resistance when traveling through long, circuitous tubing. I will post a video at that time.
If I'm making an earth tube to cool a desert cabin is it better to have a blower on the inside sucking the air in or should I put a blower on the outside that pushes the air into the house? Which way is more efficient?
I wish I could give you a definitive answer. I suspect that pulling would be slightly more efficient, as the zone of turbulence in front of the fan would be dispersed into your cabin. Right now I am running a heat exchanger in my compost heating system and have fans on BOTH ends!
In my case, the soil is fairly competent, and doesn't collapse. If you have a sandy soil, and/or shallow groundwater, that could be a problem. My water table is deep.
Would this system still work as well, if the outer hole was lined using 6"d. pipe? I'd love to use this to temper air for a house...but here, the air must recirculate....would the dirt of the hole carry mold into the house, if left unlined?
Yes, but efficiency would drop and expense would increase. I've recommended "casing" the outer hole for people who live in areas with unstable soil. I live in a dry climate, and have noticed no issues with mold. Can't vouch for best practices for direct house cooling/heating. Honestly, I'd probably use a heat exchanger rather than direct airflow into the home.
@@MorganBrown I need a cooling system for my permanently parked RV/home in West Texas & am about to put the work in to make horizontal tubes but am hesitant. How much length under how far would I need? I've seen earth ships using 40'×10" tubes, so I was under the impression I'd need 40' under the frost line & since I'm in a smaller structure I could size down the diameter. I saw a post making the argument that only 20' is necessary as x - y = I don't know, my brain is not geared for this. Could you please let me know before I go all in, which will be shortly? It's getting hot again & I can't do summer like last year, nearly killed me. As I don't know how comments are seen if in older video I'm going to repost this query in your latest one. Thanks for your time and effort, I appreciate it.
M. Waters I wish I could give you more hard numbers. I don’t think frost line is relevant for you in west TX. Good thing about your area is low humidity and deep water table. You will want your system to be sloped down with weep holes and gravel at the low point to address any condensation. I’m pulling numbers out of the air but for an RV would guess that you can get away with maybe 100 feet of tube buried at 3 feet or lower. If you have caliche at the surface you may try just laying the pipe at the surface and covering with dirt. Post a reply if you have lingering doubts and I’ll do my best to comment
M. Waters look below for a reply from Scott Hiebert. He has a grow shed in Bakersfield and he did a horizontal system which was effective. Similar sized structure, similar climate. He made videos
I live in the SW, local frost line is at 5-10". Does this mean that I Would only have to sink the vertical pipes to depths of only 1foot to acquire the geothermal benefits?
The deeper you go, the closer temperature gets to a stable background. That’s probably 10 feet in any environment. Another reason to go deeper is to maximize the volume of air cooled or heated.
Correct, just simple open holes. Have thought about home heating and cooling applications. Biggest concern would be high humidity of the output air. You could "case" the well with large diameter tubing (like a water well), but it would add to cost. I've heard of some people just circulating into a crawl space, where you might be less worried about humidity. Not sure I've answered your question, so shoot back if not.
+Jeff Cassman - thanks much. I like the black drainage pipe because a) it's cheaper than corresponding 4" PVC, and b) its flexible nature makes it easy to bend around without extra fittings. I taped a "pipe" made of aluminum cans (th-cam.com/video/ghmvI9U1KQI/w-d-xo.html) to extend from the 4-8 ft depth range. My rationale there was that I'd get improved heat transfer at the bottom of the well, and the temperature data bore that out. Regarding cave-ins, luckily, no, I didn't have that problem. But our soil here in Colorado is pretty competent and we haven't had the rainy season yet. I also had a pretty good "sandbag" and cover to keep dirt and water out of the open holes. Unfortunately had to tear down my greenhouse, but I'm up and running in another location in the backyard and will try to rebuild the system at a greater scale in the new greenhouse.
Morgan Brown thanks for the reply. Have you given much thought to the optimal scale relative to cubic feet? I know that LDS Prepper estimates a 10% figure with the traditional horizontal geothermal pipes. That would involve lots of holes with this method.
+Jeff Cassman Heheh, I've had my share of skeptics (myself included). A guy who posted on the other video was pretty skeptical. What I hope for with this method is a couple of efficiency advantages. First, I should be able to drill holes with this rig to 20 ft (assuming I don't hit bedrock). If you look at the temperature vs depth (Indiana: igs.indiana.edu/images/Geothermal/fig2.png) note that going from 5 ft depth to 12 ft depth and deeper, you get a huge temperature differential, especially in the coldest and warmest months of the year. The horizontal earth tubes are usually ~5 ft deep. I should be much more efficient at 12 ft and lower. Second, because I don't have to fill in my hole, I can keep the air flowing past the open dirt. I assume that this increases heat flow, relative to a buried plastic pipe. In any event, you are right to be skeptical! ;-) Only way to find out is to dig some holes and see what I can do. Amount of air flow needed is another issue I haven't researched. I'd ideally like to run this from solar, so I'm hoping that the small 12V fans suffice. The other skeptic didn't think my 90 cubic ft/min fan was sufficient.
+Morgan Brown I didn't realize I was a skeptic! Maybe just a slow learner? I'm struggling with the volume of air the fan moves relative to the volume of air at depth and the speed of cooling given the short duration at depth. Does that make sense?
+Jeff Cassman if you read comments on my other video, a guy named John Guest says he aims for 20 complete air changes per hour through a horizontal system. I computed only 4.3 air changes per hour with mine. My coefficient of performance is high, but I'm not sure how much I was heating the greenhouse. My hope is that a more efficient system would require fewer air changes per hour to transfer the same amount of heat.
Thanks for your video, my thoughts are isn't 52 F still quite cold? If you kept your home at 68 F you would still be shy some 16 F. Or am I missing something?
Ha, no you're not missing anything! I'm using this to warm my greenhouse, so 52 F is perfect! It would be much more challenging for a house. You could probably cool a house. Heating is much harder.
吳瓊錚 yes, the humidity inside the greenhouse definitely increases with this system. However, the air where I live has very low humidity, especially in the winter, so I have not attempted to mitigate.
Yes, I understand that most climates have higher humidity than Colorado, USA! Unfortunately, I think in more humid climates, you may need to either install a dehumidification system inside the greenhouse or add underground drainage to the earth tube...
Hi Morgan, I’m currently fabricating a greenhouse and I like the system you have in place. If you can contact me I would like to know more about your geothermal conservation of energy. We are a company and we are starting up the fabrication of greenhouses and I would like some more information, thank you.
12 watt inline duct fan. I'm running it off of AC, but it is a low enough wattage that you could easily run it off a solar installation, but I've not tried it.
joseph telese thanks for your question. I have a new greenhouse which is a bit smaller than yours. Check the link in the description. I have five holes and three small fans, and it produced a noticeable heating effect. However, I think it has better potential and I think the biggest problem is the drainage pipe that I use for air circulation. Too much friction. I hope to redesign the air distribution to improve airflow. Done over again, I would put the holes UNDER the greenhouse, instead of OUTSIDE the greenhouse.
Any thoughts into using 4" Marine bilge exhaust fans instead? They are 12volt, cheaper, have a higher cfm and may hold up better the weather. With the 12volt motors they can possibly be powered with solar power...just a thought.
Morgan Brown jet.com/product/detail/7770d82a6631446eaf62b1ad1f6197e2?jcmp=pla:ggl:JD_dur_Gen_Sporting_Goods_a3:Sporting_Goods_Boating_Boat_Parts_Accessories_a3:na:PLA_783891022_42653192818_aud-318763390747:pla-314603173676:na:na:na:2&code=PLA15&pid=kenshoo_int&c=783891022&is_retargeting=true&clickid=58e01dad-8816-45de-936a-021bdd156d65
one more question. after boring the 6" hole I would feel better sleeving the hole, with maybe thin wall 6" PVC pipe. Do you think this having the hole sleeved would decrease the performance of this system?
A Nebraska greenhouse that used this system: www.starherald.com/news/local_news/alliance-greenhouse-uses-geothermal-heat-to-produce-all-yearlong/article_0184cb18-f081-5329-8b54-0e767472216e.html www.citrusinthesnow.com/geothermal-energy.html
Hello Morgan; from watching your video and concept I started the same design until I hit a very deep white sand layer that constantly caved in. So I had to adapt / compensate by enlarging my 9 foot deep, 4 ft wide by 8 ft length, pit/trench to 12 foot in length, and since I couldn't go deeper I coiled the 4 inch wide 130 foot long flex tube with a 4 inch layer of dirt for each coil. I coiled the hose 4 times at 9 foot and finishing at about the 8 foot mark then running exhaust back in creating a sealed system. I can't post exact stats like you but I have turned on my LED lights (4-300Wt)--- A/C --- dehumidifier-- circulation fans--- and so-on when shed was 102 degrees and outside was 104 degrees ; It took around 15 min to pull temp down 76 degrees- So I'm saying great info/video because it works great!!! Well if you wouldn't mind watching my video and tell me what you think of design
th-cam.com/users/edit?video_id=U5tY6ved_ZY
Scott hiebert awesome! Thanks!
Scott hiebert was
link not working
I built one yesterday and our frost line is 18" in Vancouver Canada so my air draw is at 56f inches down and has 13.8c temp for cooling my citrus greenhouse. I used a vented Ikea basket as shoring a the 4 inch at bottom with drill 5" pot intake.
that's great. Yeah I think the geothermal systems are actually more effective for cooling! It's been awhile since I've had an active geothermal system in a greenhouse, but maybe next year.
This is awesome! There's a pop can solar heater video around where tubes of pop cans are painted black to absorb heat from the sun then transfer the air into the building. It would never supplement this system as the wells would actually cool the air that's heated by this, but it's interesting how the "Tubes" in the heater are constructed. they leave the bottoms on the pop cans but cut them in a way that makes the air spiral down the tube instead of going straight through. If you were to "Spiral" the inlet below the frost line, you would increase the distance the air has to travel, thus giving the air more time to 'soak up' the heat (or lack thereof). I'm not sure how much more efficiency you would gain, but would certainly help where space is limited.
Dwayne, thanks for your note. The design that I'm most interested in trying is a "U-shaped" system. i'll have to figure out a way to dig two holes very closely together. I'll probably buy an 8-foot section of 6" PVC, cut it in half, and make a side-by-side template. The advantage of the U-shaped system is that I can simply pump the air through the U, which is far more efficient than the system I show here. Also, because I have air circulating over open hole, I add a lot of unwanted humidity into my greenhouse in the winter. The U-shaped system won't touch the wet soil underground.
Wasn't expecting a reply after 2 years, wow!
We bought some land and I'm hoping to build one of these in the spring! Going to try some experiments and see what works best. Was also thinking of the actual Solar heater and well combination with sensors and programming. Depending on the temps in the well and the solar output, I could have software switch between the two 'technologies' to help stabilize the temps.
now i want to dig holes all over my house !!!
looking now for a seymour post hole digger and a galvanized steel pole
is a 3/4 threaded steel pole good for the seymour ?
The Seymour digger is excellent. Yes, I used 3/4 inch threaded black pipe and coupling to extend the length of the digger. Make sure you lube the fittings, because they get pretty tight after a lot of digging!
Thanks for a very detailed video. Really appreciated the formulae as well as the graphs. Data fit perfectly into linear function! Now to drum up materials for a test.
You are welcome. I'm preparing to rebuild my geothermal system with the goal of improving airflow into the holes. I'll report on that when I can! I've been more fixated on compost heating recently - check out my most recent videos on that subject
I first noticed the greenhouse in the snow geo air system...I want to combine ICF concrete construction including a concrete roof (extraordinary thermal mass of concrete) with geo air and solar panels including a couple of banks of lithium diode batteries, LED lights and induction stove. I believe I can make a home that is a net electricity producer. Hope to try it in the next 2 or 3 years.
I was just wondering if you could cool your house this way.
Yes you could, though I would recommend using a closed system (no air flowing past open hole), due mainly to the humidity that it would add. Take a look at my newest geothermal system (th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html) for one idea. You'd probably want to use a larger system than I implemented, with a powerful blower. The water vapor in the warm air will condense when it goes underground, so make sure that you add weep holes at the low point of your geothermal. These types of systems actually work FAR BETTER for cooling than they do for heating! Good luck.
@@MorganBrown the link above is broken
@@moazqadri5324 th-cam.com/video/A2TQJl9WjLc/w-d-xo.html or th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html
Great presentation, chock full of useful information. Thank you very much for making it! No concerns about blowing microbes into the greenhouse (could be avoided with a double tube system I suppose)?
Thanks, I sure appreciate it. I think your concern about microbes is a valid one. Another concern is the increase in humidity from the ground. As a result, I went to a U-shaped configuration last year (th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html) and actually simplified to a more conventional horizontal system this year (th-cam.com/video/A2TQJl9WjLc/w-d-xo.html). I'm more focused on compost heating for my greenhouse now. If you have enough space, however, the geothermal concept is excellent.
Do you have any advice about Radon?
If I dig a hole and lower a test kit, will it give me an accurate reading?
Will this system cool a greenhouse in the Arizona desert?
Radon could be a problem with this system (hole open to the surrounding dirt). Especially if you have clay soil. If you vent the greenhouse, as I'm sure you'd do anyway, Radon probably not an issue. However, my 2018-19 and 2019-20 geothermal systems are all completely closed (go to my channel page). Most people utilize a horizontal, closed system. Horizontal is typically more efficient for full greenhouse heating/cooling applications for the simple reason that you can get more pipe underground than with a vertical system. Of course, those people typically have large acreage. If you are a) space-constrained, b) have a low water table, and c) can easily drill to 20 ft, then the vertical system has real merit. The deeper you drill, the more stable the temperature (say 55 deg F). If you leave the outside of the hole open to the ground like I did in this video, then you will increase humidity in the greenhouse. In Arizona, maybe this isn't a problem. If you have any more questions let me know. Good luck!
Is it possible to test the system for radon?
I'm sure you could test for radon by simply putting a test kit in the greenhouse. I am not sure if this geothermal implementation would cause the greenhouse to have more radon than it would without geothermal. In any event, I've gotten away from this implementation for the last 2 years. I'm now using a closed system (no down-hole soil exposed to air)
No greenhouse as yet. I wanted to dig a vent and test it before commitig to the system. I'm planning on building a house too with the same system. As long as I'm not getting radon. I'll dig a hole and lower a test into it.
@@taylorphillips5118 Ah, I understand. Yes, if it was my house, I would definitely want to ensure that radon wasn't a problem. Last year, I drilled two adjacent holes and used a U-shaped tube (th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html). That could be a good answer if you want to use this for household purposes. This year, I simply dug a pit and buried 25 feet of tubing (th-cam.com/video/A2TQJl9WjLc/w-d-xo.html). If you plan on using the geothermal system for cooling (probably most useful for household), make sure you put a weep hole at the lowest point of the system and bury gravel to keep condensation out of the pipe.
Have been trying to find quality content and experimentation on this. Found you
could you recommend a system design for a tropical climate ?
@Moaz Qadri - Geothermal is very effective for cooling, because as the hot, humid air goes underground, water vapor will condense. This cools the air AND reduces the humidity. However, you must take great care to allow the condensation to drain away from the geothermal system. For this reason, I prefer "closed" geothermal systems (th-cam.com/video/A2TQJl9WjLc/w-d-xo.html or th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html). You will need to install drainage holes in the geothermal pipe and ensure that condensation drains away from the pipe. If the pipe fills with water, then your system won't work!
Morgan, we'd like to build an earthtube to help cool our second floor. We also live in Denver (Golden) on 2 acres. Could you help us find someone to build it or could we hire your to build it? We don't need heating, and just cooling on the 800 sq foot second floor story.
I'm flattered! Unfortunately I do have a day job, so I wouldn't be able to actually do it for you. However, I can definitely give some words of "wisdom" (or maybe lessons learned from failure). For a 800 sq ft space, you will need a bigger system than I show here. However, you have a nice big lot, so you have flexibility. I would aim for a "horizontal earth battery" system, rather than the vertical system that I show here. I'd recommend hiring a backhoe to dig a fairly large area as deep as possible. Just pulling numbers out of the air, but I think you want to aim to have about 500 ft of drain pipe underground.
Since the air will be going directly into your home, you will want to have a fully sealed system, unlike what I showed here. Air flows over the moist annulus of the well, pulling humidity out of the soil (and into your room), and posing a radon risk.
When you cool hot air, moisture will condense out of it and fill the pipe. You'll also want to have the pipes slightly angled down in one direction, with weep holes and gravel pack, to keep water from filling the pipe. I would also look into a filter on the outlet pipe to protect against any microbes that could be growing in the pipe.
I'm definitely happy to provide my opinions, but I'm no professional! There's a company in Boulder called Ceres Greenhouse Solutions which builds greenhouses using this geothermal heating & cooling. They could provide you with some advice, but they'd likely be pretty expensive and they might balk at doing a project like this.
Very informative video.It is hard to interpret because of Fahrenheit but still managed to interpret. Thank you.
heheh, sorry! I will try to provide temperatures in celsius as well, on future videos.
Humidity was my concern. I was thinking of a three staged closed duct loop. It would have a blower forcing return air from the house through horizontal air tubes first, sloped away from the house with a small constant drain. Then the air will go into vertical wells like your system. A long slope up to the house and through a radiator with s closed loop of geothermal cooled water from the bottom of my pond. Any condensate from the radiator can drain down into the vertical wells. What do you think? I know it sounds elaborate but it could be ran with a 12 Vdc fan and pump. We are looking into options for an off grid earthberm home.
+Chris Daughtry Sorry, I failed to respond in a timely manner! I like your drainage idea. In the hot months, I bet that the water vapor in the cool return air would condense as it heats up, if you engineer it correctly. In the cool months, maybe you want the extra humidity? (In Colorado we don't mind it!). One worry we do have here is radon -- the clay bearing soils are known to have high radon. Not sure how you engineer around that one, but it's probably worth thinking about.
could you use an inverted V and intersect the the borings ????? no backhoe and yet you have more surface area per unit and less back pressure if you did it right you could lower some 6" pipe cut at angles to stop collapsing dirt.. or could you line the holes with cement?
Not a bad idea to improve airflow into the system. Personally, I am lucky as my soil is easily diggable, yet dry and very stable, so I don't require any casing to improve hole stability. Many other people who have posted comments do have a problem with hole stability, and yes, I recommend casing the hole with 6-inch pipe. My next geothermal system is actually going to be a big hole -- think root cellar -- with fans blowing air in and pulling it out. A decent sized hole would have as much volume as a buried system with 200 feet of pipe. We shall see!
Really cool little experiment. Very insightful.
thanks much. hoping to get a beefier system up and running this winter, once I get my new greenhouse built.
from the heart
thank you very much!
Hi Morgan, we have this 32 foot old dug well we no longer use from our 1890's homestead, right next to our house. Currently it just has a heavy metal grate over it on stone about 20 inches above ground level. We would like to build a lean too greenhouse on this southern side of the house, with the well right smack in the center. I like you idea but wonder how we can utilize our well for heating our greenhouse. Wonder how to cover it and should we fill it in or leave some types of tubing go down and through the water? Any ideas would be greatly appreciated.
Michael TORLUCCIO , how wide is the well? If it's at least 6" wide, The easiest thing to do is just run 4" air tubing from surface to the water level and let the return air come up the annulus (outer ring) of the well.
I'm assuming that the well has water in it? Some people worry about excess humidity with a water filled well. I'm not sure it's a big problem, honestly.
However, if the water table is shallow, you'll have to think about running casing from the surface to the base, pumping out the water, then plugging the base of the well, probably with cement.
Another thought: if the well is quite wide, you could simply bend the 4" flexible tubing into a U shape and drop it down the well. That way, the pipe could be submerged, yet it would be airtight.
Great videos. Thanks. I have three questions: what if the soil is loose. Can you line the holes or does that defeat the purpose? What if water gets in the hole does that negate the value? I notice you cover the holes so aren't you blocking the outflow of warm air? I'm assuming these holes need to be inside the greenhouse, correct? Sorry, four questions.
Hi George. You hit all the good questions. Loose soil is a blessing and a curse. Good because it's easy to dig, bad because of the cave ins! You can definitely line the tubes and in fact I'd recommend it to keep humidity and radon at bay. Last year I came up with a way to dig two parallel holes and run a u-shaped length of drain pipe in the hole. This suppresses humidity and enhances airflow, but it's tricky to implement. Water is an omnipresent problem. You don't want water. As long as you live in a dry climate and don't use the pipes for cooling, you shouldn't have condensation in the bottom of the holes. Condensation would destroy the u-shaped airflow. If condensation is a problem, I'd recommend opening small weep holes in the drain pipe and filling the bottom of the hole with gravel prior to inserting the drain pipe. This year I abandoned the vertical earth tubes and just went with a small horizontal system.
Thanks for the quick reply. Unfortunately for me I have a spring that feeds a pond and the spring is some twenty feet away from where I was hoping to put this system. By "lining the hole" I meant putting in a pipe with a cap on the end so water could not enter the pipe but it sounds like an opening in the bottom of the pipe is essential so, I'm out but thanks again!
I have a fairly deep lake in my back yard. The water temperature at 10' down rarely gets below 60 F. I would like to pump water from that depth and run it through a radiator in my greenhouse. I will return the water below the surface and won't be wasting energy due to lift. The resistance to flow and the power to the fan will be my only energy loss. The specific heat of water is very high and represents hundreds of watts of free energy.
Jim, I wish I had one in my back yard! ;-) Smart of you to keep the water in a closed system, as it'll help control humidity. Another (lower-tech) option: just pump into a 55-gallon drum with an overflow pipe running back to your lake. The thermal mass of the water barrel would act as an additional temperature stabilizer. Or, you could pump into the drum AND run your radiator to get the benefits of the thermal mass AND rapid heat transfer.
One of the reasons I bought the house was because of its proximity to the lake. It represents millions of BTUs of almost free energy for both hearing and cooling. I like your thermal mass idea.
Jim Ferguson yeah, my in laws live on a lake in Florida. Not as deep as yours, I’m sure, but they have a geothermal heat pump system utilizing the lake. Great bang for the buck. My dad in western Colorado also has geothermal heat pump, but he had to drill about 250 ft...that wasn’t cheap!
In our area the water table is at about 4' in the summer and as little as 1' (or less) during the wet seasons. We could put in a casing with a closed bottom to keep the water out, but PVC would be the affordable material. Do you think the PVC would have an acceptable heat transfer?
Wow, you must live somewhere that gets a lot of rain! I wonder if it might be more effective to just pump water to the surface and run a heat exchanger? What's the water temperature?
To answer your question, I think PVC *will* degrade the heat transfer, but I don't have numbers.
We're in Glenoma, WA. It rarely stays below freezing for an entire day. Maybe we should pump water into barrels painted black and then circulate the water in pipes under the soil for the night? My husband was thinking that it would be hard to keep a dry casing buried for a geothermal here because it would want to float. We'd have to give the casing a substantial collar with weight equivalent to the water being displaced.
yeah, I agree with him! Perhaps you could create a concrete "plug" - essentially you would pour a concrete deck footer, then attach it to the casing and drop the concrete into the hole. Essentially, it's a collar, it's just buried. I'm no expert on water wells, so take this with a grain of salt! I like your idea to pump the water up into a rain barrel. To give you some perspective, I had a rain barrel in my old greenhouse. In the winter (and it is cold in Colorado), I had a 300 W fish tank heater running all day long just to keep the water at 60 deg F. Let's say that the buried water is 60 deg F year around - if you could get it to the surface with a 20 W submersible pump, you'd be well ahead of the game! Since the cold water should sink, you could drain water from the bottom of the barrel back into the well.
Awesome, thanks to share your project! I hope the world must see...
Luis, thanks! I have just built a new greenhouse and I have a 5-hole geothermal system with 50 feet of holes. I am hoping to get this running tomorrow and will put up a video soon. Stay tuned!
Do you get a smell moldy or radon gas methane when you do this
none that I'm aware of, but I recommend a "closed" system if possible. Excessive moisture is my bigger concern with open hole geothermal
What size is your greenhouse? I'm wondering how many wells we would need for a 13,000 sq foot greenhouse in southern AZ. We are interested in heating and cooling.
Sorry, I just saw your comment now. It really depends on how many wells you drill. I found that for heating, I could heat a ~20 cubic foot volume by 4 degrees with 4 wells drilled to about 8 feet. For a 13000 sqft GH, you'd need a lot of wells...unless, perhaps, if they were very deep. For a GH of that size, I'd recommend the horizontal earth tube. You excavate with a backhoe and lay hundreds of feet of tubing. I'd also recommend excavating directly below the footprint of your GH, if that's feasible.
Will this cause more radon to come up from the ground? This is my main concern.
Bob Sapp yes,I think it would. Check out my greenhouse 2.0 video (link on my main channel page). I’m using a fully enclosed vertical system
How do you deal with radon gas emitting from the earth into your perforated tubes?
Disclaimer: I've never tested radon in this system and don't really care because I'm not inside the structure often. If you have a problem with radon, you'd probably want to line the hole with PVC (pricy) or drill two holes next to one another and run a u shaped tube. I will take the latter approach this week when I redrill my geothermal system
Also, FWIW, these tubes aren't perforated
I was going to say that the pipe should not be open or perforated but he beat me to it. That certainly solves the problem.
@@rblibit Check out greenhouse 2.0 ( th-cam.com/video/Ze0nXN6Vvic/w-d-xo.html ). I was able to drill two adjacent holes, then run the drain pipe in a closed, U-shaped configuration. Will post the results soon
Hello , tried to follow your TH-cam link . I believe you have the last symbol included in your link . That makes not able to follow .
Have you noticed if there is an oder in the greenhouse that resembles a basement. I've considered similar system for my house but I have concerns of the damp smell that can be present in some basements.
I don't think that my geothermal system causes an odor. But, consider that the ground where i live is very dry (bottom of hole is well above water table). if you have a lot of water in the bottom of the hole, I would recommend casing (sealing) the hole in PVC pipe. Also, radon is a worry, and it is present in clay soils. If I was using such a system to cool a house, I would definitely use casing. You will need a lot of holes and a strong pump to cool a house. My greenhouse is very small.
Thanks for your input. I live in Florida and we have sandy loom soil and A LOT of humidity. The proposed spot for my new house is 42 feet above the water table (rare for this state) but I am thinking of a near horizontal system at a depth of 15 feet. We don't have a big radon problem here but I wouldn't know how to remove radon from a system such as this any way. I would simply have to rely on my smoke/CO2/Radon detectors to warn me of this buildup. I was also considering using my well to cool my house because the water stays a constant 72 degrees (have you experimented with this at all?
Michael S Florida should be interesting. Yeah, you'll definitely want to case your holes! But the digging should be easy, right? I am limited to 12 feet (bedrock), but I was planning to dig to 20 ft. Many closed systems will have weep holes at the bottom to handle condensation. A horizontal system might be best for you to handle a large volume of air, but I'm not sure how you'd dig so deep - backhoes are usually limited to 8 ft, right? The water idea is interesting. Rather than an air based geothermal, you could get a strong water pump, dig a hole, and build a closed loop system. Coils of copper tubing at the surface and in the ground to transfer the heat. Just blow a fan across the surface loop and collect the condensation. At 42 feet I would suspect that the ground temp is lower than 72, but what do I know?
Morgan, it's nice to chat with someone who has fresh memories of his experiment(s). My well water temperature at the tap immediately after the casing is 72 degrees. The static water level is 42 feet but the pump is at a depth of 92 feet (for drought purposes) but the casing is 212 feet down, this gets me below most of the surface contaminants. I've done some limited research on ground temps in my state and my water temp falls right where the data says it should. Using the same well that will be supplying my house allows for the warmed water (caused from the heat exchange) to be replaced with cooler water every time the house pump comes on.
I own a small backhoe so I can dig a hole at my leisure to any depth I desire (with in reason of course) using the front loader. I have also looked at a closed loop system whereas you bury coiled tubing at depth and pump water through it and across an evaporator (collecting the condensate below the evaporator) but at this point I'm looking at all option because unlike you, I have a bigger need to cool rather than heat. :) We have 9 month summers here and fall like winters.
Michael, yeah, I guess your Florida aquifer is at a constant temperature - my in-laws live in Sarasota and I have good memories of swimming in the spring-fed rivers. We wore wetsuits on the Crystal River - I think it was 67 degrees(?), with unbelievably robust flow. The simplicity of the air-driven systems make them worthy of consideration, even if they're less efficient than a water-circulation system. Honestly, I think the key to success relates to maximizing airflow. I've had discussions with a couple other guys with air-driven geothermal (horizontal) and they are using high capacity fans which draw ~300 W. I'm using small fans that draw only 12 W apiece, and I'm not getting enough airflow into the greenhouse. Once my broken leg allows me to walk again(!!!), I plan to revamp my air circulation to reduce the amount of air resistance when traveling through long, circuitous tubing. I will post a video at that time.
If I'm making an earth tube to cool a desert cabin is it better to have a blower on the inside sucking the air in or should I put a blower on the outside that pushes the air into the house? Which way is more efficient?
I wish I could give you a definitive answer. I suspect that pulling would be slightly more efficient, as the zone of turbulence in front of the fan would be dispersed into your cabin. Right now I am running a heat exchanger in my compost heating system and have fans on BOTH ends!
What's keeping the holes from collapsing?
In my case, the soil is fairly competent, and doesn't collapse. If you have a sandy soil, and/or shallow groundwater, that could be a problem. My water table is deep.
Would this system still work as well, if the outer hole was lined using 6"d. pipe? I'd love to use this to temper air for a house...but here, the air must recirculate....would the dirt of the hole carry mold into the house, if left unlined?
Yes, but efficiency would drop and expense would increase. I've recommended "casing" the outer hole for people who live in areas with unstable soil. I live in a dry climate, and have noticed no issues with mold. Can't vouch for best practices for direct house cooling/heating. Honestly, I'd probably use a heat exchanger rather than direct airflow into the home.
@@MorganBrown
I need a cooling system for my permanently parked RV/home in West Texas & am about to put the work in to make horizontal tubes but am hesitant.
How much length under how far would I need?
I've seen earth ships using 40'×10" tubes, so I was under the impression I'd need 40' under the frost line & since I'm in a smaller structure I could size down the diameter.
I saw a post making the argument that only 20' is necessary as x - y = I don't know, my brain is not geared for this. Could you please let me know before I go all in, which will be shortly?
It's getting hot again & I can't do summer like last year, nearly killed me.
As I don't know how comments are seen if in older video I'm going to repost this query in your latest one.
Thanks for your time and effort, I appreciate it.
M. Waters I wish I could give you more hard numbers. I don’t think frost line is relevant for you in west TX. Good thing about your area is low humidity and deep water table. You will want your system to be sloped down with weep holes and gravel at the low point to address any condensation. I’m pulling numbers out of the air but for an RV would guess that you can get away with maybe 100 feet of tube buried at 3 feet or lower. If you have caliche at the surface you may try just laying the pipe at the surface and covering with dirt. Post a reply if you have lingering doubts and I’ll do my best to comment
M. Waters look below for a reply from Scott Hiebert. He has a grow shed in Bakersfield and he did a horizontal system which was effective. Similar sized structure, similar climate. He made videos
I live in the SW, local frost line is at 5-10". Does this mean that I Would only have to sink the vertical pipes to depths of only 1foot to acquire the geothermal benefits?
The deeper you go, the closer temperature gets to a stable background. That’s probably 10 feet in any environment. Another reason to go deeper is to maximize the volume of air cooled or heated.
Thank you so much for clarifying that for me.
The vertical wells are open ended - correct? Do you think this would work close looped and for a home?
Correct, just simple open holes. Have thought about home heating and cooling applications. Biggest concern would be high humidity of the output air. You could "case" the well with large diameter tubing (like a water well), but it would add to cost. I've heard of some people just circulating into a crawl space, where you might be less worried about humidity. Not sure I've answered your question, so shoot back if not.
Morgan, great idea. Why did you choose the drainage pipe as opposed to say, PVC pipe? Did you have any problem with the non-cased well caving in?
+Jeff Cassman - thanks much. I like the black drainage pipe because a) it's cheaper than corresponding 4" PVC, and b) its flexible nature makes it easy to bend around without extra fittings. I taped a "pipe" made of aluminum cans (th-cam.com/video/ghmvI9U1KQI/w-d-xo.html) to extend from the 4-8 ft depth range. My rationale there was that I'd get improved heat transfer at the bottom of the well, and the temperature data bore that out. Regarding cave-ins, luckily, no, I didn't have that problem. But our soil here in Colorado is pretty competent and we haven't had the rainy season yet. I also had a pretty good "sandbag" and cover to keep dirt and water out of the open holes. Unfortunately had to tear down my greenhouse, but I'm up and running in another location in the backyard and will try to rebuild the system at a greater scale in the new greenhouse.
Morgan Brown thanks for the reply. Have you given much thought to the optimal scale relative to cubic feet? I know that LDS Prepper estimates a 10% figure with the traditional horizontal geothermal pipes. That would involve lots of holes with this method.
+Jeff Cassman Heheh, I've had my share of skeptics (myself included). A guy who posted on the other video was pretty skeptical. What I hope for with this method is a couple of efficiency advantages. First, I should be able to drill holes with this rig to 20 ft (assuming I don't hit bedrock). If you look at the temperature vs depth (Indiana: igs.indiana.edu/images/Geothermal/fig2.png) note that going from 5 ft depth to 12 ft depth and deeper, you get a huge temperature differential, especially in the coldest and warmest months of the year. The horizontal earth tubes are usually ~5 ft deep. I should be much more efficient at 12 ft and lower. Second, because I don't have to fill in my hole, I can keep the air flowing past the open dirt. I assume that this increases heat flow, relative to a buried plastic pipe.
In any event, you are right to be skeptical! ;-) Only way to find out is to dig some holes and see what I can do. Amount of air flow needed is another issue I haven't researched. I'd ideally like to run this from solar, so I'm hoping that the small 12V fans suffice. The other skeptic didn't think my 90 cubic ft/min fan was sufficient.
+Morgan Brown I didn't realize I was a skeptic! Maybe just a slow learner? I'm struggling with the volume of air the fan moves relative to the volume of air at depth and the speed of cooling given the short duration at depth. Does that make sense?
+Jeff Cassman if you read comments on my other video, a guy named John Guest says he aims for 20 complete air changes per hour through a horizontal system. I computed only 4.3 air changes per hour with mine. My coefficient of performance is high, but I'm not sure how much I was heating the greenhouse. My hope is that a more efficient system would require fewer air changes per hour to transfer the same amount of heat.
Thanks for your video, my thoughts are isn't 52 F still quite cold? If you kept your home at 68 F you would still be shy some 16 F. Or am I missing something?
Ha, no you're not missing anything! I'm using this to warm my greenhouse, so 52 F is perfect! It would be much more challenging for a house. You could probably cool a house. Heating is much harder.
But in colder climates, isn't 52 F still warmer than the outside temps, so presumably the house wouldn't need as much energy to heat it in the winter?
In case of closed loop, you have taken into account the condensation discharge, right?
吳瓊錚 yes, the humidity inside the greenhouse definitely increases with this system. However, the air where I live has very low humidity, especially in the winter, so I have not attempted to mitigate.
Oh, I didn't realize your situation. I just thought of the climate I stay. Thank you for your prompt answer!
I like your simple solution.
Yes, I understand that most climates have higher humidity than Colorado, USA! Unfortunately, I think in more humid climates, you may need to either install a dehumidification system inside the greenhouse or add underground drainage to the earth tube...
Hi Morgan, I’m currently fabricating a greenhouse and I like the system you have in place. If you can contact me I would like to know more about your geothermal conservation of energy. We are a company and we are starting up the fabrication of greenhouses and I would like some more information, thank you.
Mark Mekhuri drop me an email at morganpbrown “at” gmail.com and we can connect
Morgan Brown thanks for replying back to me, I will get back to you as soon as possible with my greenhouse fabrication ideas
So what powers the blower ?
12 watt inline duct fan. I'm running it off of AC, but it is a low enough wattage that you could easily run it off a solar installation, but I've not tried it.
How do you go about sizing these systems? I want to put up a relatively small green house (6'x8'x8'). How many 12' deep penetrations would I need?
joseph telese thanks for your question. I have a new greenhouse which is a bit smaller than yours. Check the link in the description. I have five holes and three small fans, and it produced a noticeable heating effect. However, I think it has better potential and I think the biggest problem is the drainage pipe that I use for air circulation. Too much friction. I hope to redesign the air distribution to improve airflow. Done over again, I would put the holes UNDER the greenhouse, instead of OUTSIDE the greenhouse.
Any thoughts into using 4" Marine bilge exhaust fans instead? They are 12volt, cheaper, have a higher cfm and may hold up better the weather.
With the 12volt motors they can possibly be powered with solar power...just a thought.
joseph telese sure, go for it! Do you have a link? I might want to convert to a 12-volt off the grid system at some point! ;-)
Morgan Brown jet.com/product/detail/7770d82a6631446eaf62b1ad1f6197e2?jcmp=pla:ggl:JD_dur_Gen_Sporting_Goods_a3:Sporting_Goods_Boating_Boat_Parts_Accessories_a3:na:PLA_783891022_42653192818_aud-318763390747:pla-314603173676:na:na:na:2&code=PLA15&pid=kenshoo_int&c=783891022&is_retargeting=true&clickid=58e01dad-8816-45de-936a-021bdd156d65
one more question. after boring the 6" hole I would feel better sleeving the hole, with maybe thin wall 6" PVC pipe. Do you think this having the hole sleeved would decrease the performance of this system?
A Nebraska greenhouse that used this system:
www.starherald.com/news/local_news/alliance-greenhouse-uses-geothermal-heat-to-produce-all-yearlong/article_0184cb18-f081-5329-8b54-0e767472216e.html
www.citrusinthesnow.com/geothermal-energy.html