Longer pipe, not larger diameter, longer pipe will allow more time to cool, bigger diameter pipe won't change how much it cools without making it longer
@@shawnd567 surface area is important , but think about it like this, a longer smaller pipe allows more air contact with the pipe allowing the heat transfer and the length gives it more time to transfer where a larger pipe will allow more air thru but leaves more air not contacting the pipe to come thru and does not allow the time needed to transfer the heat , yes there is more surface area with a larger pipe but there is a lot of air in the middle of that pipe that isn't making as efficient contact with the pipe so it's not getting cooled or heated as with a smaller tube, same reasons a radiator uses small tubes that run back and fourth inside instead of a lage pipe with some fins, a larger pipe with a significant longer run can increase efficiency. Another example, run water thru a 55 gallon barrel one end to the other with a torch on the side of it and you won't notice much difference but take 50' of 1" tube with the same amount of water going thru it and put a torch on it and it's going to come out hot. Not to mention the slower the water goes the hotter it will get
@@raducumilea-is2yi depth it important for constant temperature, too shallow and it will be effected by weather like snow or hot sunny days, from what Ive read at 8'-10' in most soil types is very consistent
Great idea, Dave. I have seen this method multiple times. There is an old man in Nebraska that has done this method for greenhouse and he is very successful. He has several greenhouses running this way. I have few suggestions: make it longer. Also use multiple smaller the pipes. The smaller the pipe the more surface area in contact to the cool earth. So instead of going with a larger diameter pipe, use maybe 4 smaller diameter pipes, maybe 4 or 5 inches. The theory behind this: suppose you have a cube that is 1x1x1 feet. So you have 6 square feet surface area. If you cut the cube in half, you end up with 8 square feet from the same cube. And if you cut it once again you will end up with 10 sq ft, and etc.
You can use smaller pipes, but then you need a lot more of them to get the same amount of air movement, and that drives up the price. As a result, we usually see people using one or two larger tubes... In situations where people really want to use smaller pipes, they tend to use water instead of air, which is also effective but requires some expensive machinery.
@@dtc989iirc the “Oranges in Nebraska” video (I think) shows 6-8 pipes run together, with ~150 of trench run out then looped back. Velocity through the pipe matters too, slowing it down a bit helps. In a high humidity environment (I’m in Kentucky) I’d be c
The biggest issue that you have is that the feed and return are on the same wall and at the same level. The air comes in the feed and then flows right back out without circulating the room. The feed should come in low on one side of the room because heat rises, then exit the room high to let the heat return back into the system on the other side of the room. This will give a much better cooling effect because heat gathers at the top where it is easier to allow all that hot air to exit. Returning the heat back into the system will still need to be insulated on the outside of the home, not to let outside temps heat the return pipe too much, but it will cool back down in your trench and come back to your home cooled down again. It's always smart to open the doors and windows in the AM to get the home cooled down, then try and maintain the temp. Also, the pipes used should be 100% sealed without perforations to keep the inside of the conduit completely dry. Most folks backfill the trenches with large rocks in their fill which will only crack or break holes in the pipe. If there is moisture in the pipes, you will end up with mold from the moisture.
One up high, one down low. Make sure the fans can run in both directions. Then you can use it one direction for cooling, pushing hot air up top out and the other for heating, pulling the hot air up top in. Does that all sound legit ?
Exactly what I was thinking. Outflow should be at the highest point and inflow at the lowest. You'd have to do some finagling with the pipe, but it would probably make a noticeable difference.
So I've lived with geo thermal air systems for yrs. My daddy and granddaddy taught Me by making me do the shovel work building theirs 😅. First...ya need a living fish pond small, not very deep but enough to keep water and hence buried pipes being around (not underneath) plus move the intake down lower and the exhaust higher .. I would do that whole place if it was me, up and down stairs. Also ... solar powered fans so you never need to turn air system off. And last .. be alittle creative when Burying the pipe system be sure to work with your environment... shades etc... truly makes difference. Installing insulation and building your roof as living roof (meaning growing something/grass/flowers etc ) will also tremendously help the combination of controlling the air temp. **** and small woodfire burner and or rocket Heater would be plenty to both keep warmth and combat humidity hence mold and mildew just by burning few times off and on if need be. It's not rocket science just got to seriously use some intelligence and listen.... the whole point is to help the earth and co exist living comfortably so paying for ac unit that technology has deamed easy to use but costs out the ass to own run replace then cost of environmental is beyond mentioning.... So A for effort here brother keep at it I got complete confidence you'll get the kinks worked out and there is no one way remember that be creative... like adjusting vent tube's hidden by garden stautes allows for more openings to allow air flow down into the pipping area to either release heat and or draw the cool night air down. Use your Free Will and Forgive and unconditionally love ✌️🫶♾️
Good point with the pond... water has a much higher specific heat capacity, meaning it will hold more heat (or cold) for it's volume than earth. Obviously gets a bit more complex when integrating underground water containers, but there are a number of places that use this method for seasonal cooling/heating. 👍👍
I’ve got a 40x60x16’ metal shop that I’m going to insulate. I live in TN… thinking of running multiple of these… I’m going to have a 2 acre pond out front, so would be easy to run it at the bottom of the pond instead of digging a ton… From your experience… do you think it would be worth it? Or would it not make much difference? Thanks for the videos!
@@MrBudcampoI’d just consider getting a heat pump and just laying coils of pipe at the bottom of the pond after it’s excavated. You’d have heat and aircon in an engineered box with a warranty and save a ton of electric. 😊
Howdy, When I was a kid in the late '50's, our house on the gulf coast of Texas had an attic fan in the central hallway. You opened all the windows in the house, and when you turned on the fan, it sucked outside air in through the windows, and exhausted it through the attic. The hot air which had been trapped in the attic and various interior rooms left the home, and the cooler air from under our shade trees came in. It made things livable, if not comfortable.. The whole idea is to exhaust the hot air, or to exchange the heat in that air outwards. Even my current central air unit takes the heat of our air and exhausts it outside via various steps, in what amounts to a radiator. You cool things through removing heat, not pumping in cool. (cold is the absence of heat, not a force of it's own) Your system merely recirculates the hot air without much thermal exchange.. You might want to consider placing a pair of valves on your exhaust side, on the outside of the building, to make your system an "on demand" open or closed system. The first valve, would be to exhaust the hot air when you want, and the second valve, to intake cooler outside air to go through your pipe, presumably 100 ft. out, and 100 ft. back to replace the exhausted air. Once you get the hot air out and start to draw the heat out of the walls of the interior, you can return to a closed system by returning the valves to their closed positions.. Also, you must move your exhaust as high up as you can get it, and your intake should be fairly low on the wall. Anything else is inefficient. Further, you should have a fan to exhaust the heat and a fan to suck in the air in your underground pipe. This is vital for the "open system" stage of the described dual system. I think that the valves and an extra fan would be much cheaper than re-digging. Lastly, shade, shade, shade. If I had the money, I would build a second roof on my house, maybe a couple of feet above my existing roof, and open on all sides to keep the sun's heat out of my house, so I wouldn't have to exhaust that solar heat in the first place. Just the ramblings of an old man with no more than a high school diploma from five decades ago. My ramblings are probably worth exactly what you paid for them. GRIN Y'all have a great day. Bob
moisture from the humidity is the major issue people don't do this. to do it they make sure there is a way to address the mold issue from condensation, which occurs and you don't even know it. dehumidify inlet with desiccant (not at outlet because somewhere in the middle is where condensation/mold begins), provide slope for maintenance, slope for outlet, good ventilation(a fan) in front of the outlet, and a solar chimney to increase air flow.
@@xungngo I'm from Texas but live in N.C. now, also very humid. The thing that is stumping me is setting up some sort of condensation removal system when the pipes are eight feet underground. Here my water table sems to be around four feet according to the critter grabes I've dig but even at fur, any sort of condensation cleanout seems problematic.
Try this: Build an underground chamber that pulls cool air into your place near the floor and put a dome ceiling with a fan that exhausts hot air out the top of your home. I noticed our basement was always cool year round, so we put fanned vents between the first floor and basement that pulled that cool air up from the basement, then vented the ceiling to draw the hot air out and our cooling bill plummeted. We reverse the fans in the floor in the cold months to warm the basement.
I think one of your issues is the even input and output. you need to have a vent at the top of a wall and one at the bottom somewhere else. you are just creating a loop with your current setup where the other way would circulate the air and use its own hot/cold physics to help move it. another thought is to have the hot going in on one side of the room and the cold on the opposite so that the air has to travel through more of the room therefore transferring more heat and maybe reducing draft? there are several insulating options that may help as well for transference of the pipe outside. you could also use a water loop as water transfers heat energy much much better than air. with water you could also use radiators to effectively dump the cold somewhere. an extension on that thought, have a radiator at the bottom of a wall and another at the top to collect heat better. as far as where to get radiators if you really want something cheap you could probably go to a junk yard and get a bunch from cars, the caveat being that you would have to find a way to connect them all. the huge downside of water is the chance to freeze so it would possibly have to go deeper which will cost more but water pipes are cheapers usually so the cost/effectiveness may or may not even out. if you used a solar heater for water that could help with heat and circulation during winter though I guess you could do this with air as well by making a big black box on your roof to collect the sun.
I live in Arizona and honestly, maintaining temperature on 1/10th of an amp sounds damn good to me. Our household AC unit struggles to even do that when it's crazy hot in the summer. And we're paying $400 a month for it to try. smh
well the A/C fights the heat while the ground just evens it out so if youre in arizona I would suggest doing this. all you need is some pipe and a shovel. you can also use water, but that can freeze.
Great work, inspiring to see. If you keep consistent airflow, I think that should reduce mold spores from settling. I'm not sure about mildew, maybe if there's a lot of humidity and it condenses and settles in the tubes.
8 ft depth minimum for pipe. Even at 100f outside it can keep it at around 72f inside if the pipe is long enough. Those earth houses in new Mexico use this. Also some greenhouse. You still need a way to force airflow though.
Uncle Daves Frontier: Hey, Dave! I think that if I left the cabin in the early morning while it was cool and came back mid-to- late morning after a walk, I'd be happy with it maintaining my earlier cool temperature. I managed to get a 1 degree drop in temperature with four-inch pipe by running it into and out of an empty 5-gallon water bottle. The air gets stalled momentarily while a small vent hole at the top of the bottle allows heat to rise out of my system. The rest of the air passes on along the run. That was a one degree drop using only one water bottle and about ten feet of 4-inch pipe. I had planned on using a narrow tube at the top of the 5-gallon bottle to get that heat out to the surface straight up. My test was not buried on a finished system either, so the results could be a little better or variable to say the least.
Plant trees Install deep awnings Use insulated drapes in hottest times Don’t insulate basement or first floor floors - n leave door open too. It helps a bit too n u can escape down there where it’s 65* when it’s 90* on first floor at 8pm or 7am!
Two suggestions. One option is increase the surface area of your pipe. The more surface area the more efficient. This can be achieved by increasing length and increasing your cfm. The other option is run with a pex type pipe and reservoir. The fluid circulatef via pump through the pipe carries a lot more thermal mass. Inside your home attatch to literal radiators with a small fan. The radiator of course has an incredible amount of surface area to radiate heat from. Ive thought about doing something such as this myself. I have a greenhouse, polebarn and of course home. I dug a 3/4 acre pond this year and this idea can be adapted using your pond as the the thermal mass and reservoir. My home has a very high water table which works to my benefit. If i go below four feet im around 55 degrees but because that constant water comes in contact with the pipe i should get more efficient exchange and a constant temp. It really amazes me this isnt as well known or put into use. We have this transition to a green world and the reality is all the tech is as far from green as possible. In theory every home in the world has access to all the energy it needs under the footprint of the property. I appreciate your short videos and keeping it simple. So many people go on and on. PS what would happen if you took say a 12 or 15 inch pipe at the inlet and underground go into a manifold that say branches four 6 inch holes. Then run 600-800 feet. After the loop go back into a manifold and your outlet re enter with a 12 or 15. The reality is this massively increases surface area and lengthening means a longer distance to exchange energy or force more air through the system . The result would allow you to overcome and actually lower vs keep a constant temp. The other option might be after your manifold to push your air to variaous vent ducts instead of a singular. You're getting close. I love figuring out this stuff and love trying to cheat the system for as cheap as possible 😂
I've always wondered about Mold growing in the pipes with these types of geothermal cooling. I guess flooding it with ozone from time to time could keep it clean. Just have to make sure not to breathe the gas.......
The key is the length of the pipe, not the diameter. I’m sure the diameter would help somewhat but the bigger difference happens with the length of pipe.
I feel like your problem is not size but conductance. Smaller pipe in longer distance would probably give you better results. But corrugated or solid pvc, neither is anywhere near conductive enough. Copper tubing would be great if you could go from a larger size into multiple smaller tubes over long distances. I've seen "earth ship" homes in the desert that have a long pipe come out the back that flows through large buried hillsides, but its metal corrugated pipe, not plastic. The conductivity is so much greater with metal.
Maybe just use more than one 6" and place the intake hose higher up and the exhaust hose lower to the ground. That way it gets the hottest air at the top of the room to mix with the cold in the pipe. I think it would be cool if you got a fan that can move more air too. It might not be worth it with a 6" pipe but I'm curious if a much larger fan could make a 99° room comfortable in a 20-30 min timeframe.
Nice work and thanks for sharing. I've got this idea I am wondering about... In some off grid land i own in Central florida. The soil is white sugar sand and the water table is very high.. so high that I was able to dig a well by hand for washing, irrigation and making cement. I cleared a patch under the trees where I park a van I camp, sleep and work in. Florida is very hot and humid, but around midnight it seems to cool down a lot where I'm at because of our higher elevation and sandy soil. My living space in the van is tiny 3' x 6'x 5' and I just want to cool it down to where I'm not sweating really. I have a 7' x 12' hole I am planning to build a pond in 20' away. I have this untested idea of coiling some 6" drainage pipe under and around the pond and then backfilling before I line it.. then pulling air from under the trees, under and around the pond 100' and into my van intake fan. It wont be a closed loop system, but I figure the air will be a lot cooler than what my van pulls. Is 100' x6" enough to make a difference?
If I try this, I'll use the thinnest-walled pipe possible and take air from ceiling level and bring it back in at floor level so probably under my computer desk.
OK I was going to suggest a manifold, but I see others got there before me. Make sure the volume of air in the manifold is several times larger than the source pipe. This will cause the air to contact the cooling surface for longer and improve efficiency. Also, put the fan outside and blow into the system. This will reduce the noise some, inside the cabin.
I would go 10" from wall down underground then branch off with 2 or 3 6 inch underground and come back together to be a 10" from underground to wall and I would insulate the part from the wall going down to the point where it split on both ends. This would multiply the surface area for heat exchange and slow down the airflow slightly giving a longer time underground for the heat exchange while keeping the greater flow inside the building. That should increase the efficiency greatly while not using any more electricity.
Several things. I would wouldn't have the vents at the same height. I would have one down low and one up high. To cool the place I would suck the air from up high and push it out down low. I would use a larger fan that is downsizes to the pipe size. A larger fan can run slower and thereby be quieter. Add extra pipes to get more contact with ground - longer pipes would require the fan to push harder. This will allow the pipe to actually cool the building instead of just maintaining the temperature, when turned on.
Move the air slowly. If air goes through the pipes too fast it cannot absorb the coolness from the ground. Use a low speed, USB 4" fan on an 8" pipe. 👌
I think you have it backwards. Surface area to volume ratio should be maximized to get better heat or cool transfer. I woul use 4 inch or 3 inch pipe. Small beans cook quicker and with less energy than large beans because of this ratio. Am I wrong here???
I suggest consult an expert which I am not but fan X is only going to exchange Y amount of air. BIgger pipe will not increase the amount of air exchanged thus the cooling would not change.
Still going good. I'd do a 8 or 10 inch pipe if I had to do it again. I have another build I'm going to start this summer and I'll use this same design but use a bigger pipe. Been too much rain this year so I'm still waiting on some areas to dry out
A couple of questions is the fan pulling the air trough the pipe or is pushing it? I ask this because I remember watching a video posted by someone that had built a earth battery system to heat/coll a greenhouse and he experimented with the direction of the fan and he stated that he had better results by pulling the air trough the pipe rather than pushing it trough. The other question? could you insulate the part of the pipe exposed to the ambient temperature? it might make a difference. Just my two cents.
What if instead of using the small fan to push air through and worry about potential of mildew, use a dehumidifier, have it drain itself outside also. Larger fan pushes more air.
I understand that you wanted to use a continuous pipe roll, so that means some sort of plastic pipe, but wouldn't any type of metal pipe have been a much better conductor of heat?
Better to use a 1000 feet of water filled 1" tube looped about 20' down pumped throw a radiator and fan set up. Air is not the best heat exchange medium.
Cost wife go with 2x 6 inch to acheave same circumference of ciotact in total.? Maybe cost wise and ease of install is to consider. Run the material cost number.
Could you get a "Y" connector and run 2 runs of 6 inch pipe still with a 6" fan? Might there be some metal pipe, like thin aluminum, that would transfer heat better than plastic?
Ya got it all wrong bro. Smaller lines fanned out = more surface area of dissipation. Think like a radiator to a vehicle. Also think of other mediums that have lower S.G. like running creek water or air. Or both air and water to devise an evaporated system as your primary cooling, have multiple systems on a low select switch for a small micro controller to choose the best of the 3 for optimal conditions. Then a small servo to close main flow to each that do not have best air temp. Further servo can be used as blender for facilitating true real time control without additional energy. For heating during the winter used small black corigated pipe about 1/2", place in a spiral on plywood and strap it down cover with plexiglass to hold heat. Basically a hydro solar system. Take 1/2" air tube and wrap it under the water pipe and when the sun goes down the water will hold until really late.
Maybe more pipe in the ground is better 2,,300 foot.biger pipe,ok I'm trying to think there should be a way to clean the inside of it.easly. so.if you had a pipe you could crawl through, that's a big pipe,8 foot in ground 200 feet long.fans pushing air . easier to clean inspect.? accompanied by a swamp cooler on the other side of the building?
Why not use multiple tubes? And add more distance underground? You failed to show the tempreture of the air coming inside the cabin. Would not a pusher fan on the tube going out not help with the air circulation? Record all results and they will help you in designing your next project.
I can't believe I haven't seen this before but.... is the extraction fan pulling air out of the space and trying to push it through the ground? That's certainly what it looks like. If so this is a major facepalm and the whole system could be fixed so it actually works. All you have to do is reverse the fan direction. You should be pulling air from the ground not pushing it into the ground. Hot air rises so it's nearly impossible for that small bathroom fan to push thousands of BTUs 4 feet down into the cold earth. If you pull the cold air into your space the heat will naturally removed via equilibrium. Your little fan will then do the impossible and bring ambient down to ~65, providing you have enough surface area in the earth to offset the BTUs you need to remove.
Maybe you are moving the air too fast. The ones in NM use natural convection. The Earthships use those vents in their sun rooms to help with the exhaust of the warm air.
That would work with a open pipe outside. It would have natural draw. But with this being a closed loop system, gotta move the air somehow. But it's all trial and error.
@uncledavesfrontier6846 I've a friend in north Texas that put in heat pipes as well. He used a lot of 4-inch drain pipe. He said that they worked marginally for him. I live in a smaller town and there really isn't enough room to use them. Keep us informed on your progress. God bless
@1timby I'm in northeast Texss. I have some other ideas I'm gonna try on the next build. Just been waiting for this God awful Texas summer to be over with so I can get back on my projects. If the fall isn't too bad, I'm gonna get started on the hobbit house where I will incorporate tubes again.
At what depth are your pipes at? And what is the sub-surface temperature at that depth? I live in east Texas near Tyler and want to know if it will work here. How well does it work in 95+ degree temperature?
I live in Longview. What i did was drill down first to 8 foot and checked with temp probs before ever digging. But those temps pretty much hold true everywhere here in east Texas.
@@draaks1 The info I read pertained to earth-air exchange systems. I imagine eater systems would be more efficient due to water’s energy storage capacity.
It would cool better if your air that entered came from outside, and the air that exits goes out the highest part of your roof that you can put a pipe or PVC exit. Your pipes come in at only half the height of the cabin. Cool air goes down, hot air rises. Both tubes are at the same height, so the actual heat is still in the cabin from Midway and up. You can't cool captured heat that stays high. Also the cool air should come in at the lowest point, heat exhaust at the highest point, creating a convection pull to naturally suck the air out. Hope this helps. I've done it on my house. It cools 10 to 15 degrees cooler. I only have 1 entrance pipe, 5 ft buried, and 30 ft long. I plan on adding more just for more comfort.
A couple of people have touched on it, but a higher ratio of surface area to volume will mean better heat transfer. Four 4" pipes side by side will cool more than one 10" pipe even though they have less volume (even combined) because they have more surface area. The surface of the pipe is where heat gets dumped into the dirt. Also, a smooth metal pipe would transfer a lot more heat. If you used 3.25" x 10" stack duct (I make no promises of its suitability, and permanently sealing it would be some work), it would be much more efficient at dumping heat. That's why commercial heat exchangers use a long run of very small conduit. If you have a stream on your property, or a similar consistent water source, creating an overflow reservoir big enough for a heat exchanger can work awfully well, too.
Don't bury that galvanized stack pipe, conductor pipe or any other sheet metal ducting! It will rust and cave in or disintegrate in less than 7-14 years! Also recheck your 'Pie" formula for figuring circumference, cubic feet per minute etc. Might be off a little.........ha, lol !
I was just checking on this an i found something interesting. For it too work at maximum potential, it needs to move 5 times the amount of air that is in the room per hour. Hope that helps.
A 6" pipe has approx 18.8" circumference. (Diameter x Pi, 3.1415) Two pipes would give you 37.7" total cold dirt surface. (1) 10" pipe will have only 31.4" circumference touching dirt and be danged expensive. To eliminate any possibility of mold in the pipes or water seeping in, just run the pipe out with pex tubing inside. Flood with water, pull water in through the pex tubing, through a couple car radiators, backflow into the corrugated flex pipe. Blow air through the radiators. If you keep the water, level with the radiators, the pump will just be moving the water, not lifting it...more efficient. Get the air intake as far from the exhaust as possible. Insulate the cabin 8" or 12" thick. White EPS styrofoam packing can be salvaged from many a dumpster, shredded in a 55-gallon drum-lawnmower-blender, mixed with a tiny bit of cement and packed into the walls/ roof for insulation. Put some 1/4" foam then stringers on your metal roof, then a second metal roof with eave and (large) peak venting. Or anything to shade the roof and keep the sun from baking you to death.
Amazing! Thank you for sharing this follow-up video. I would suggest that you try a longer run pipes under-ground with one end into a small shelter from the elements, bugs, mosquitos, critters & snakes etc but ensure free flow of air and use charcoal or activated charcoal as filters in series with the air system when air is re-circulated back into your home. In your home you should consider a passive or active system to drawn hot air within the building to above the roof of the building & if done correctly you may not need an active exhaust air pumping to above the roof of the building. Keep in mind that the height of the small shelter where the intake air comes in should be much, much, much lower then the hot air vent above the roof of the building. In-fact you may consider using solar powered exhaust fans if you like. I would also suggest you consider some indoor pot plants & flowers to assist with filtering & fresh oxygen within your home. Greetings from Madang, Papua New Guinea!
If you look up a PAHS (Passive Annual Heat Storage) system, they go with a smaller diameter (4”) for a longer run (minimum 200’). A larger diameter will decrease energy transfer for the same energy input. The surface area increases but the internal airflow transfers nothing and wastes energy. A PAHS is a different system altogether but their design seems more sound.
You're 100% correct about the volume to surface area ratio. Also, the intake should be higher in the room, as warmer air will be nearest the ceiling... Thermodynamics 101. He'd get a lot better cooling than just "maintaining" that way - but still, he's got the right idea. Two-story structures? That a different taco to tackle, but doable. ~edit - You're also correct about the length of run... longer = more time for heat transfer.
How about garden hose? Seems a few hundred feet of that means a lot more surface area exposure, the flexibility of the hose means easy to place, and -probably more crush resistant.
@@jksuzuki9350 A Garden Hose would be too small in diameter, and too well insulated as well, for it's diameter/volume ratio... you'd have to run hundreds of feet just to get any significant effect. But you're thinking on the right path.
Air is not the best conductor of thermal energy.. which is why liquids are used.. You could have buried a few coils of 1” pipe and put a couple recycled hot water radiators in series and gotten a much better return on your work. (Needs a solar pump and drain pans under the radiators.. makes nice clean condensate).. in your design, Condensation in that buried pipe can collect in the corrugations and grow pretty toxic molds.. ideally a pipe which has a smooth inner bore, but also metallic spikes through it to engage the thermal mass of the earth and transfer that heat into the passing air.. I melted large landscape nails into 4” PVC which worked well (if you look in a gas home furnace, it uses a similar concept to heat air).. and it requires a condensate drain as well.. which you can add with some second hand goretex from Goodwill and a little gravel. Larger diameter pipe mean you need a larger blower and corrugated pipe is really restrictive The systems like you have built work in the Southwest because the humidity is so low and the overnight temp usually drops dramatically … This is just information that may help anyone going forward.. Your videos on this have been great. This is not a criticism at all of what you have done.. making good content. 👏👏👏👍
Thanx for the whole rundown. We are building a tiny cabin/house and have been considering a similar set up. May have to go bigger or back to the drawing board to find an inexpensive solution. Be Safe!!
@ TimelessNews3 … what is theoretical the best location for a drain and where could it be fit in here in this actual situation ? I would expect lower points to be a problem but how to drain those in the actual situation ?
For a cooling system, this is what I see working for others: - 4 inch pipe works fine, makes turns easily, and you lay it out as a grid in a tight area, instead of one long strand like yours. - 100ft of this 4" pipe should work well for a small bulding. - Make the intake at the highest point and the outlet towards the bottom, shooting upwards at an angle across the room. Helps circulate the cold air and push the hotest up to the intake. - In warmer climates, you lay a second pipe a foot above the first one. This second pipe system has both ends outside and is used during the night / winter (as long as night temp is below your ground temp) to pump outside air into the ground and cooling it further than it could on its own. As cold sinks, the first pipe gets colder and your AC system becomes more efficient. - Make sure to have some holes at the bottom of the pipe section underground to allow condensation to leach into the soil, thus reducing moisture returning to the cabin. It's not about the size of the pipe, but rather the surface area for temp exchange, coupled with making a tighter system for better temperature "storage". Hope this helps.
I was mostly with you however, hot air rises because it is lighter than cooler air. "Cold AIR" sinks, not "cold." Cold is the absence of heat in any substance.. I repeat, in any substance be it air or dirt. Empty outer space has NO temperature at all since it has no substance. The absence of heat, in and of itself, does not sink. Again cold AIR sinks, and hot AIR rises. The air in the lower pipe exchanges it's heat into the ground around it, thus heating the dirt by some small amount. The air in the pipe loses heat and becomes cooler. The second pipe might possibly be a heat sink for the ground around it and cooling that dirt, but don't think it would to much for the lower pipe with a foot of dirt between it and the lower pipe. Now a smaller pipe in direct contact with the larger pipe, with an intake for the atmosphere, and a forces exhaust MIGHT do some good in exchanging heat, but probably not much. Sorry, I just can't see the two pipe system working very efficiently.
@Grynslvr2 interesting point, but I think you're hung up on the terminology of thermal physics. It is in regular terms for all to grasp the simple concept of pre-cooling the soil before summer heat returns. Soil is a great thermal sink (or void) for such usage and others like mud ovens and rocket stoves, earth ship houses etc. And of course I get the concept of measuring / transfering heat, not the absence of it lol
@@thatguychris5654 Howdy. I am starting to think that maybe it is my preconceived notions, based on where I live. I live on an island off the coast of Texas, an overgrown sandbar really. No rocks, no clay, and when I dig a hole in the ground, water weeps into it slowly at about 18 inches, even though I am at 11 feet above sea level. It snows regularly here - about once every 10 or 11 years. As far as I can tell, our two or three months of cool to cold weather, doesn't suck much heat from the ground beyond the first few inches. My water pipes run about 18 inches deep from the city supply line, and they have never frozen since being installed in 1949. All that being said, I am predisposed to think in terms of evacuating heat from air and thereby from buildings. That may work differently in other places. Here the ground is always around 65 degrees or so. I am just looking for ways to reduce my energy bills. Thanks for the friendly reply. Many folks jump down my throat, so it is very much appreciated.
@@Grynslvr2 no problem, I love friendly chats regarding science that we can actually do ourselves 😁 Indeed your location is unique. Having water so close to the surface changes things a lot, as does the soil content (all sand). But this could be a good thing if you were to use water instead of air. If the water temp and flow is pretty consistent, perhaps pumping water into a type of radiator, and having a fan on it, would cool enough. If your area has air that is dry enough, even a swamp cooler would be awesome. I even wonder if using a passive cooling system tower with wind, like they do in the desert, would work with you ocean breezes. But you are 100% right, your winters couldn't be used to rob the soil of its heat. I guess I'm biased in that way living in central VA with lots of clay around and decent seasonal temp swings.
@@thatguychris5654 Thanks for the response. Sadly our relative humidity runs from a low in winter of about 40% to a high in summer (on days with no rain) in the mid 90% range. I was hoping there was something here for me, but with only a 1/10 th of an acre lot, I just don't see a way to use this really "cool" technology. Sorry, I couldn't resist. Maybe with a bit more room for ground cooling, I could do some good. Oh well, it was in interesting mental exercise. Thanks for playing along.
A suggestion, if you want to hear it, (and i'll piss off if it's none of my business, you seem to be doing fine without my nosiness), but you might be able to heat/cool even more effectively if you throw a solar chimney into the mix. you take a pretty standard fireplace setup and on one of the outside walls you put in some glass to warm the air inside (if you don't intend to use it as a normal fireplace), or just paint the stones black to absorb heat. also a big point is that the flue lever should vent out at the top, not be at the ground level. Mechanically what this does is create a current of air that constantly pulls the hot air up and out the top of the chimney, and the cool air into the rest of the house. If you put some venting between the first and second floors, and put the solar chimney on the second floor, you could near-passively regulate the entire houses' temps, especially if you put in another earth tube to the outside to bring in more fresh air and avoid making a vacuum. Anyway, great stuff, and hope you're doing well!
I get a lot of what your saying. I found very little research on this prior to building. So it was trial and error. Mostly to see what works and doesnt work for the next cabin im gonna build. It will be a full size hobbit house and i will incorporate a lot of what your saying as far as the stone and fireplace. Ill do a series when i start the hobbit house. Kinda been preoccupied building my food truck. Its almost done and then i can get back to my cabin projects. I have lots of cool builds coming up. I appreciate the feed back and always welcome suggestions.
@@uncledavesfrontier6846 ua-cam.com/video/UsZgCz3PQks/v-deo.html Worth a watch. (for the price of large tubes right now, it would be less expensive to get solar panels, a battery and an efficient air conditioner for better performance) I think you need a lot more air flow and a lot more surface area. I've always liked this idea for its simplicity, but there needs to be a better, less expensive way to tunnel air under ground. Thanks for sharing and following up.
@@orangezeroalpha my cabin is solar powered and i do have ac units. I gave this a try to see what the results would be. I enjoy experimenting hoping to find better ways of being off grid. Ultimately i think the best design is an above ground cabin thats buried. Im gonna incorporate a lot of different things on the hobbit house im gonna build.
I think if you moved your intake/suction side higher, perhaps 7ft high, your air into the house at 4ft high you may see better performance. Im thinking your are recycling your cool air rather than removing you hot air.
Great follow up! I think that you can use a 10" 12v DC only radiator fan and save even more energy. Check the CFM ratings (cubic feet per minute). I didn't realize that your cabin was 2 stories tall, that's a very large airspace for only 100' of tube. Great work. I look forward to seeing the next build! (my dad lives not far from you and we talked about this for his wine cellar)
For a wine cellar, this would definitely work great. Another thing i forgot to mention is my cabin outside is metal. So that plays a big difference. Even though my cabin is completely shaded, the metal still adds a lot of heat. But i plan to go over the outside in stone and add some insulation between that. I appreciate you watching.
@@uncledavesfrontier6846 I think that instead of going to a larger pipe, you should have more length. That way the air has more 'time' to lose it's heat. 200-300ft.
@uncledavesfrontier6846, if there is a granite slab showroom near you, or an installer, you could ask if the stuff they throw away is available. Marble or granite may be helpful as a heat sink (if you can crumble that material) above the pipes ☺
Because you have a very low Delta tea, you’re not going to condensate too much but overtime. The pipes will get moldy. It’ll be impossible to clean them out unless if you can run a small amount of ozone through there consistently. To be honest for the time and money, you were going to get much more bang for your buck by installing a radiant barrier on the exterior of your roof
If the cabin is 95 degrees, of course it's not going to cool it down, because you are blowing hot air through your tubing and it's just recirculating the hot air. Now if you were near a creek or a large spring, you could run your tubing through that and you would get a cooling effect.
Pipes out of the ground are insulated now and have cement over em. I thought about metal pipe but it doesn't last long. I put one stick in once for a culvert and it literally rusted away in 3 years
I would suggest a 8 inch pipe running out to a dead end(capped) and another 8 inch running back in that dead ends, parallel in the ground , then run many 2 inch pipes between them so you break the air into smaller pipes increasing its contact (surface area)to the cool pipe walls before returning. like a radiator shape under ground. ribbed pipe would also bring more cool earth into contact with the pipe and air better than smooth walled pipe. Also i would suggest the outgoing vent placed up near the ceiling to pull hottest air out and the incoming vent on opposite wall at mid level to reduce the air being just circled from incoming to outgoing vents without circulating in the entire room. baffles inside the pipe would work good to force the air to linger in the pipe longer as well but it's not easy to do. you could slow the fan also to allow the air to radiate as much heat out as possible before returning.😎
You'll get better heat exchange by multiple smaller pipes, as opposed to one larger pipe. Smaller pipes have more surface area (per air volume) to exchange heat from the air to the ground around it.
Is it easier to push a cooked spaghetti noodles or is it easier to pull that noodle? Put a fan on there sucking the cool air into the room instead of trying to push 100 feet of air through a six inch pipe. Also, put the air going out of the cabin 12 inches above the floor. The air coming in can be at face hight. Like you said, do not put a 90 degree bend in your pipe right out side the wall. Hope this helps.
12” No 12’ if possible Make ur ceilings high like all southern homes used to be with the transom windows over the doors Pull hot out high There’s no hot air on or near floor Blow cold in high and it will fall down, cooling as it goes
Heat rises so the air at the ceiling is 50% hotter than where you have the air inlet located on the wall. Insulation in the walls ceiling and floor are major factors.
I've heard performance is better with 4" because the air flow hits the ribs more collecting more btu 10" air flows thru center not really absorbing the btu a thought? Made sense?
I have a dehumidifier in the room. It's never humid in my cabin. If you didn't want to go that route, use the pipe with holes in it and lay it on gravel before you bury it. But I've had no issues with any of that. No smell, no mold, no mustiness.
Do two tens, one for up stairs and downstairs. Also, run a duct across the ceiling and wall with two 5 inch outlets for each to even out the flow. It will cool, you just need to get the airflow and air dispersion even and strong enough to move the air.
Consider multiple six inch pipes. More resistance for the air flow, but also more surface area. So the heat exchange should be improved. I know there is a mathematical way of comparing those differences, but it's not something I know. Also, space the pipes apart, and the heat will transfer more efficiently. As the summer goes on, does the temperature differential between In going and out going air remain about the same?
Longer pipe, not larger diameter, longer pipe will allow more time to cool, bigger diameter pipe won't change how much it cools without making it longer
Not true. You just need to calculate surface area. Larger short pipe could have the same surface area and performance of smaller long pipe.
@@shawnd567 surface area is important , but think about it like this, a longer smaller pipe allows more air contact with the pipe allowing the heat transfer and the length gives it more time to transfer where a larger pipe will allow more air thru but leaves more air not contacting the pipe to come thru and does not allow the time needed to transfer the heat , yes there is more surface area with a larger pipe but there is a lot of air in the middle of that pipe that isn't making as efficient contact with the pipe so it's not getting cooled or heated as with a smaller tube, same reasons a radiator uses small tubes that run back and fourth inside instead of a lage pipe with some fins, a larger pipe with a significant longer run can increase efficiency. Another example, run water thru a 55 gallon barrel one end to the other with a torch on the side of it and you won't notice much difference but take 50' of 1" tube with the same amount of water going thru it and put a torch on it and it's going to come out hot. Not to mention the slower the water goes the hotter it will get
@@Cornfed_Off-roadyeahhh! It depends the lenth, the diameter and deepest is better. 😉
@@raducumilea-is2yi depth it important for constant temperature, too shallow and it will be effected by weather like snow or hot sunny days, from what Ive read at 8'-10' in most soil types is very consistent
@@Cornfed_Off-roadbut i was saying the same thing...
Great idea, Dave. I have seen this method multiple times. There is an old man in Nebraska that has done this method for greenhouse and he is very successful. He has several greenhouses running this way.
I have few suggestions: make it longer. Also use multiple smaller the pipes. The smaller the pipe the more surface area in contact to the cool earth.
So instead of going with a larger diameter pipe, use maybe 4 smaller diameter pipes, maybe 4 or 5 inches.
The theory behind this: suppose you have a cube that is 1x1x1 feet. So you have 6 square feet surface area.
If you cut the cube in half, you end up with 8 square feet from the same cube. And if you cut it once again you will end up with 10 sq ft, and etc.
Nebraska greenhouse guy also buried 1100 feet of pipe buried 8 feet deep...6 inch pipes. It's in one of his videos.
You can use smaller pipes, but then you need a lot more of them to get the same amount of air movement, and that drives up the price. As a result, we usually see people using one or two larger tubes... In situations where people really want to use smaller pipes, they tend to use water instead of air, which is also effective but requires some expensive machinery.
A 12” pipe will have the surface area of three four inch pipes.
@@dtc989iirc the “Oranges in Nebraska” video (I think) shows 6-8 pipes run together, with ~150 of trench run out then looped back.
Velocity through the pipe matters too, slowing it down a bit helps.
In a high humidity environment (I’m in Kentucky) I’d be c
The biggest issue that you have is that the feed and return are on the same wall and at the same level. The air comes in the feed and then flows right back out without circulating the room. The feed should come in low on one side of the room because heat rises, then exit the room high to let the heat return back into the system on the other side of the room. This will give a much better cooling effect because heat gathers at the top where it is easier to allow all that hot air to exit. Returning the heat back into the system will still need to be insulated on the outside of the home, not to let outside temps heat the return pipe too much, but it will cool back down in your trench and come back to your home cooled down again. It's always smart to open the doors and windows in the AM to get the home cooled down, then try and maintain the temp. Also, the pipes used should be 100% sealed without perforations to keep the inside of the conduit completely dry. Most folks backfill the trenches with large rocks in their fill which will only crack or break holes in the pipe. If there is moisture in the pipes, you will end up with mold from the moisture.
It seems like you should put the intake up at the highest point of the interior so it sucks all the hot air that rises into the cooling system.
He might have made it that way to get more comments, He sounds technical enough to not know that
One up high, one down low. Make sure the fans can run in both directions.
Then you can use it one direction for cooling, pushing hot air up top out and the other for heating, pulling the hot air up top in.
Does that all sound legit ?
Exactly what I was thinking. Outflow should be at the highest point and inflow at the lowest.
You'd have to do some finagling with the pipe, but it would probably make a noticeable difference.
Your goal is to make a person comfortable, not heat up the ground, so it makes sense to cool the air where the person is, and not the ceiling.
@@hottractor1999 3:30 he said it didnt work
So I've lived with geo thermal air systems for yrs. My daddy and granddaddy taught Me by making me do the shovel work building theirs 😅. First...ya need a living fish pond small, not very deep but enough to keep water and hence buried pipes being around (not underneath) plus move the intake down lower and the exhaust higher .. I would do that whole place if it was me, up and down stairs. Also ... solar powered fans so you never need to turn air system off. And last .. be alittle creative when Burying the pipe system be sure to work with your environment... shades etc... truly makes difference.
Installing insulation and building your roof as living roof (meaning growing something/grass/flowers etc ) will also tremendously help the combination of controlling the air temp. **** and small woodfire burner and or rocket Heater would be plenty to both keep warmth and combat humidity hence mold and mildew just by burning few times off and on if need be. It's not rocket science just got to seriously use some intelligence and listen.... the whole point is to help the earth and co exist living comfortably so paying for ac unit that technology has deamed easy to use but costs out the ass to own run replace then cost of environmental is beyond mentioning....
So A for effort here brother keep at it I got complete confidence you'll get the kinks worked out and there is no one way remember that be creative... like adjusting vent tube's hidden by garden stautes allows for more openings to allow air flow down into the pipping area to either release heat and or draw the cool night air down.
Use your Free Will and
Forgive and unconditionally love
✌️🫶♾️
Great tips!
Good point with the pond... water has a much higher specific heat capacity, meaning it will hold more heat (or cold) for it's volume than earth. Obviously gets a bit more complex when integrating underground water containers, but there are a number of places that use this method for seasonal cooling/heating. 👍👍
You could also have run 3 or 4 of the 6-inch pipes into a mainfold setup.
I had thought about that as well.
@@uncledavesfrontier6846, maybe run the fan as a draw into the cabin instead of the pushing it into the ground.
@@uncledavesfrontier6846 fyi smaller diameter pipe has greater surface area to volume ratio so will work as better heat exchange.
I’ve got a 40x60x16’ metal shop that I’m going to insulate. I live in TN… thinking of running multiple of these… I’m going to have a 2 acre pond out front, so would be easy to run it at the bottom of the pond instead of digging a ton…
From your experience… do you think it would be worth it? Or would it not make much difference?
Thanks for the videos!
@@MrBudcampoI’d just consider getting a heat pump and just laying coils of pipe at the bottom of the pond after it’s excavated. You’d have heat and aircon in an engineered box with a warranty and save a ton of electric. 😊
Howdy,
When I was a kid in the late '50's, our house on the gulf coast of Texas had an attic fan in the central hallway. You opened all the windows in the house, and when you turned on the fan, it sucked outside air in through the windows, and exhausted it through the attic. The hot air which had been trapped in the attic and various interior rooms left the home, and the cooler air from under our shade trees came in. It made things livable, if not comfortable..
The whole idea is to exhaust the hot air, or to exchange the heat in that air outwards. Even my current central air unit takes the heat of our air and exhausts it outside via various steps, in what amounts to a radiator. You cool things through removing heat, not pumping in cool. (cold is the absence of heat, not a force of it's own) Your system merely recirculates the hot air without much thermal exchange..
You might want to consider placing a pair of valves on your exhaust side, on the outside of the building, to make your system an "on demand" open or closed system. The first valve, would be to exhaust the hot air when you want, and the second valve, to intake cooler outside air to go through your pipe, presumably 100 ft. out, and 100 ft. back to replace the exhausted air. Once you get the hot air out and start to draw the heat out of the walls of the interior, you can return to a closed system by returning the valves to their closed positions..
Also, you must move your exhaust as high up as you can get it, and your intake should be fairly low on the wall. Anything else is inefficient. Further, you should have a fan to exhaust the heat and a fan to suck in the air in your underground pipe. This is vital for the "open system" stage of the described dual system. I think that the valves and an extra fan would be much cheaper than re-digging.
Lastly, shade, shade, shade. If I had the money, I would build a second roof on my house, maybe a couple of feet above my existing roof, and open on all sides to keep the sun's heat out of my house, so I wouldn't have to exhaust that solar heat in the first place.
Just the ramblings of an old man with no more than a high school diploma from five decades ago. My ramblings are probably worth exactly what you paid for them. GRIN
Y'all have a great day. Bob
Nice follow up. Mildew should never be a problem as long as pipes are sealed. It doesn’t produce moisture, and it’s drawing air from inside.
Moisture would come from the air condensing as it is cooled inside the buried pipe.
Not true. This man lives in Texas which has damned near 100% humidity all year round.
moisture from the humidity is the major issue people don't do this. to do it they make sure there is a way to address the mold issue from condensation, which occurs and you don't even know it. dehumidify inlet with desiccant (not at outlet because somewhere in the middle is where condensation/mold begins), provide slope for maintenance, slope for outlet, good ventilation(a fan) in front of the outlet, and a solar chimney to increase air flow.
@@xungngo I'm from Texas but live in N.C. now, also very humid. The thing that is stumping me is setting up some sort of condensation removal system when the pipes are eight feet underground. Here my water table sems to be around four feet according to the critter grabes I've dig but even at fur, any sort of condensation cleanout seems problematic.
Try this: Build an underground chamber that pulls cool air into your place near the floor and put a dome ceiling with a fan that exhausts hot air out the top of your home. I noticed our basement was always cool year round, so we put fanned vents between the first floor and basement that pulled that cool air up from the basement, then vented the ceiling to draw the hot air out and our cooling bill plummeted. We reverse the fans in the floor in the cold months to warm the basement.
10" return 6" supply graded and connected to a drum to collect water and use with check valve pump
I think one of your issues is the even input and output. you need to have a vent at the top of a wall and one at the bottom somewhere else. you are just creating a loop with your current setup where the other way would circulate the air and use its own hot/cold physics to help move it. another thought is to have the hot going in on one side of the room and the cold on the opposite so that the air has to travel through more of the room therefore transferring more heat and maybe reducing draft?
there are several insulating options that may help as well for transference of the pipe outside.
you could also use a water loop as water transfers heat energy much much better than air. with water you could also use radiators to effectively dump the cold somewhere. an extension on that thought, have a radiator at the bottom of a wall and another at the top to collect heat better. as far as where to get radiators if you really want something cheap you could probably go to a junk yard and get a bunch from cars, the caveat being that you would have to find a way to connect them all. the huge downside of water is the chance to freeze so it would possibly have to go deeper which will cost more but water pipes are cheapers usually so the cost/effectiveness may or may not even out. if you used a solar heater for water that could help with heat and circulation during winter though I guess you could do this with air as well by making a big black box on your roof to collect the sun.
I live in Arizona and honestly, maintaining temperature on 1/10th of an amp sounds damn good to me. Our household AC unit struggles to even do that when it's crazy hot in the summer. And we're paying $400 a month for it to try. smh
well the A/C fights the heat while the ground just evens it out so if youre in arizona I would suggest doing this. all you need is some pipe and a shovel. you can also use water, but that can freeze.
Had a Swamp Cooler in Sedona [[Not feasible here in NC die to humidity]] Kept the place liveable during the day and darn cold at night.
Great work, inspiring to see. If you keep consistent airflow, I think that should reduce mold spores from settling. I'm not sure about mildew, maybe if there's a lot of humidity and it condenses and settles in the tubes.
I run a dehumidifier in my cabin.
8 ft depth minimum for pipe. Even at 100f outside it can keep it at around 72f inside if the pipe is long enough. Those earth houses in new Mexico use this. Also some greenhouse. You still need a way to force airflow though.
Uncle Daves Frontier: Hey, Dave! I think that if I left the cabin in the early morning while it was cool and came back mid-to- late morning after a walk, I'd be happy with it maintaining my earlier cool temperature.
I managed to get a 1 degree drop in temperature with four-inch pipe by running it into and out of an empty 5-gallon water bottle. The air gets stalled momentarily while a small vent hole at the top of the bottle allows heat to rise out of my system. The rest of the air passes on along the run. That was a one degree drop using only one water bottle and about ten feet of 4-inch pipe. I had planned on using a narrow tube at the top of the 5-gallon bottle to get that heat out to the surface straight up. My test was not buried on a finished system either, so the results could be a little better or variable to say the least.
Build a insulated box around the pipe where it is piped into the cabin
could you run 2 / 6"pipe side by side? Hot air rises have in intake fan in the ceiling and the cold air return in the floor. Love your video. Kevin
Good idea
You need your inlet low on the wall and your outlet high up where the warm air is.
Have you considered a passive evaporation cooler.
Low humidity, high heat....
The temperature deferential will drive the exchange....
I’ve thought of putting a 2 x 4 foot aluminium box under ground where the tubing runs in and out of
Also move the intake across the room. So it moves more air around.
Plant trees
Install deep awnings
Use insulated drapes in hottest times
Don’t insulate basement or first floor floors - n leave door open too. It helps a bit too n u can escape down there where it’s 65* when it’s 90* on first floor at 8pm or 7am!
Two suggestions. One option is increase the surface area of your pipe. The more surface area the more efficient. This can be achieved by increasing length and increasing your cfm. The other option is run with a pex type pipe and reservoir. The fluid circulatef via pump through the pipe carries a lot more thermal mass. Inside your home attatch to literal radiators with a small fan. The radiator of course has an incredible amount of surface area to radiate heat from. Ive thought about doing something such as this myself. I have a greenhouse, polebarn and of course home. I dug a 3/4 acre pond this year and this idea can be adapted using your pond as the the thermal mass and reservoir. My home has a very high water table which works to my benefit. If i go below four feet im around 55 degrees but because that constant water comes in contact with the pipe i should get more efficient exchange and a constant temp. It really amazes me this isnt as well known or put into use. We have this transition to a green world and the reality is all the tech is as far from green as possible. In theory every home in the world has access to all the energy it needs under the footprint of the property. I appreciate your short videos and keeping it simple. So many people go on and on. PS what would happen if you took say a 12 or 15 inch pipe at the inlet and underground go into a manifold that say branches four 6 inch holes. Then run 600-800 feet. After the loop go back into a manifold and your outlet re enter with a 12 or 15. The reality is this massively increases surface area and lengthening means a longer distance to exchange energy or force more air through the system . The result would allow you to overcome and actually lower vs keep a constant temp. The other option might be after your manifold to push your air to variaous vent ducts instead of a singular. You're getting close. I love figuring out this stuff and love trying to cheat the system for as cheap as possible 😂
I have some other ideas I'm gonna try. I appreciate the feedback.
You only need to be 30 inches down... And 55-gallon drums... Daisy chained.
You need longer pipe runs. Simple as that. But you did it correctly, you just need more.
I've always wondered about Mold growing in the pipes with these types of geothermal cooling. I guess flooding it with ozone from time to time could keep it clean. Just have to make sure not to breathe the gas.......
The key is the length of the pipe, not the diameter. I’m sure the diameter would help somewhat but the bigger difference happens with the length of pipe.
I feel like your problem is not size but conductance. Smaller pipe in longer distance would probably give you better results. But corrugated or solid pvc, neither is anywhere near conductive enough. Copper tubing would be great if you could go from a larger size into multiple smaller tubes over long distances. I've seen "earth ship" homes in the desert that have a long pipe come out the back that flows through large buried hillsides, but its metal corrugated pipe, not plastic. The conductivity is so much greater with metal.
Maybe just use more than one 6" and place the intake hose higher up and the exhaust hose lower to the ground. That way it gets the hottest air at the top of the room to mix with the cold in the pipe.
I think it would be cool if you got a fan that can move more air too. It might not be worth it with a 6" pipe but I'm curious if a much larger fan could make a 99° room comfortable in a 20-30 min timeframe.
Nice work and thanks for sharing.
I've got this idea I am wondering about... In some off grid land i own in Central florida. The soil is white sugar sand and the water table is very high.. so high that I was able to dig a well by hand for washing, irrigation and making cement. I cleared a patch under the trees where I park a van I camp, sleep and work in. Florida is very hot and humid, but around midnight it seems to cool down a lot where I'm at because of our higher elevation and sandy soil. My living space in the van is tiny 3' x 6'x 5' and I just want to cool it down to where I'm not sweating really. I have a 7' x 12' hole I am planning to build a pond in 20' away. I have this untested idea of coiling some 6" drainage pipe under and around the pond and then backfilling before I line it.. then pulling air from under the trees, under and around the pond 100' and into my van intake fan. It wont be a closed loop system, but I figure the air will be a lot cooler than what my van pulls. Is 100' x6" enough to make a difference?
@12vLife running it in a p9nd will work good. And according to your dimensions, it should work fine
If I try this, I'll use the thinnest-walled pipe possible and take air from ceiling level and bring it back in at floor level so probably under my computer desk.
OK I was going to suggest a manifold, but I see others got there before me.
Make sure the volume of air in the manifold is several times larger than the source pipe. This will cause the air to contact the cooling surface for longer and improve efficiency.
Also, put the fan outside and blow into the system. This will reduce the noise some, inside the cabin.
That's my fault. I had the mic sensitivity turned up too much. It's actually really quiet.
I think if you go with a four inch pipe and longer runs under ground of six to eight feet deep you will have better cooling than bigger pipes
I would go 10" from wall down underground then branch off with 2 or 3 6 inch underground and come back together to be a 10" from underground to wall and I would insulate the part from the wall going down to the point where it split on both ends. This would multiply the surface area for heat exchange and slow down the airflow slightly giving a longer time underground for the heat exchange while keeping the greater flow inside the building. That should increase the efficiency greatly while not using any more electricity.
Several things. I would wouldn't have the vents at the same height. I would have one down low and one up high. To cool the place I would suck the air from up high and push it out down low. I would use a larger fan that is downsizes to the pipe size. A larger fan can run slower and thereby be quieter. Add extra pipes to get more contact with ground - longer pipes would require the fan to push harder. This will allow the pipe to actually cool the building instead of just maintaining the temperature, when turned on.
Move the air slowly.
If air goes through the pipes too fast it cannot absorb the coolness from the ground.
Use a low speed, USB 4" fan on an 8" pipe. 👌
I think you have it backwards. Surface area to volume ratio should be maximized to get better heat or cool transfer. I woul use 4 inch or 3 inch pipe. Small beans cook quicker and with less energy than large beans because of this ratio. Am I wrong here???
I suggest consult an expert which I am not but fan X is only going to exchange Y amount of air. BIgger pipe will not increase the amount of air exchanged thus the cooling would not change.
Put a 6in pipe inside a 10 inch pipe and fill the 10 inch with water to maximize the cooling
I would love to know how this is working for you now. I'm seriously considering this for an, at least partial, off grid place in northeast Texas.
Still going good. I'd do a 8 or 10 inch pipe if I had to do it again.
I have another build I'm going to start this summer and I'll use this same design but use a bigger pipe.
Been too much rain this year so I'm still waiting on some areas to dry out
@uncledavesfrontier6846 yes we are swimming in it here. Have you considered a solar chimney to help with the exhaust?
A couple of questions is the fan pulling the air trough the pipe or is pushing it? I ask this because I remember watching a video posted by someone that had built a earth battery system to heat/coll a greenhouse and he experimented with the direction of the fan and he stated that he had better results by pulling the air trough the pipe rather than pushing it trough. The other question? could you insulate the part of the pipe exposed to the ambient temperature? it might make a difference.
Just my two cents.
I use an exhaust fan pulling the air. Pipes that are exposed are insulated. Didn't get a change to show it. Still had a cement job to do around it
What if instead of using the small fan to push air through and worry about potential of mildew, use a dehumidifier, have it drain itself outside also. Larger fan pushes more air.
@chips2458 I run a dehumidifier in my cabin. This doesn't drop below dew point. Doesn't build up moisture
I understand that you wanted to use a continuous pipe roll, so that means some sort of plastic pipe, but wouldn't any type of metal pipe have been a much better conductor of heat?
If costs aren't a factor then yes. Once you go metal, your prices go through the roof.
Better to use a 1000 feet of water filled 1" tube looped about 20' down pumped throw a radiator and fan set up. Air is not the best heat exchange medium.
Cost wife go with 2x 6 inch to acheave same circumference of ciotact in total.? Maybe cost wise and ease of install is to consider. Run the material cost number.
Metal pipe would give better heat transfer as well.
How about running 2 or 3 6 inch pipes instead of just one?
Could you get a "Y" connector and run 2 runs of 6 inch pipe still with a 6" fan? Might there be some metal pipe, like thin aluminum, that would transfer heat better than plastic?
Ya got it all wrong bro. Smaller lines fanned out = more surface area of dissipation. Think like a radiator to a vehicle. Also think of other mediums that have lower S.G. like running creek water or air. Or both air and water to devise an evaporated system as your primary cooling, have multiple systems on a low select switch for a small micro controller to choose the best of the 3 for optimal conditions. Then a small servo to close main flow to each that do not have best air temp. Further servo can be used as blender for facilitating true real time control without additional energy. For heating during the winter used small black corigated pipe about 1/2", place in a spiral on plywood and strap it down cover with plexiglass to hold heat. Basically a hydro solar system. Take 1/2" air tube and wrap it under the water pipe and when the sun goes down the water will hold until really late.
Do water line to a radiator with fan.
ITS GREAT START................
Recommend 12in pipe for this.
Maybe more pipe in the ground is better 2,,300 foot.biger pipe,ok I'm trying to think there should be a way to clean the inside of it.easly. so.if you had a pipe you could crawl through, that's a big pipe,8 foot in ground 200 feet long.fans pushing air . easier to clean inspect.? accompanied by a swamp cooler on the other side of the building?
Why don’t you use two pipes?
Why not use multiple tubes? And add more distance underground? You failed to show the tempreture of the air coming inside the cabin. Would not a pusher fan on the tube going out not help with the air circulation? Record all results and they will help you in designing your next project.
I can't believe I haven't seen this before but.... is the extraction fan pulling air out of the space and trying to push it through the ground? That's certainly what it looks like. If so this is a major facepalm and the whole system could be fixed so it actually works. All you have to do is reverse the fan direction. You should be pulling air from the ground not pushing it into the ground. Hot air rises so it's nearly impossible for that small bathroom fan to push thousands of BTUs 4 feet down into the cold earth. If you pull the cold air into your space the heat will naturally removed via equilibrium. Your little fan will then do the impossible and bring ambient down to ~65, providing you have enough surface area in the earth to offset the BTUs you need to remove.
How do you keep moisture from condensing in the pipes?
I run a dehumidifier in my cabin. Haven't had any issues
do you know the temp. of the air coming in from the pipe ?
Bout 58 in my area
Why don’t you try 2 six inch pipes.
And hopefully by the time you actually do smell mold. It isn't too late for u
Did you drill holes in the pipe? Did you insulate the pipe? If so how did you insulate it?
Just buried it 8 foot deep
I insulted the pipe coming out of ground.
Maybe you are moving the air too fast. The ones in NM use natural convection. The Earthships use those vents in their sun rooms to help with the exhaust of the warm air.
That would work with a open pipe outside. It would have natural draw. But with this being a closed loop system, gotta move the air somehow. But it's all trial and error.
@uncledavesfrontier6846 I've a friend in north Texas that put in heat pipes as well. He used a lot of 4-inch drain pipe. He said that they worked marginally for him. I live in a smaller town and there really isn't enough room to use them. Keep us informed on your progress. God bless
@1timby I'm in northeast Texss. I have some other ideas I'm gonna try on the next build. Just been waiting for this God awful Texas summer to be over with so I can get back on my projects. If the fall isn't too bad, I'm gonna get started on the hobbit house where I will incorporate tubes again.
NEED TO INSULATE PIPE 4 FT DOWN TO THE TOP GOING INTO THE CABIN
At what depth are your pipes at? And what is the sub-surface temperature at that depth? I live in east Texas near Tyler and want to know if it will work here.
How well does it work in 95+ degree temperature?
This is in new boston. I buried the lines about 8 ft deep. The temp at that depth is about low 50s
I live in Longview. What i did was drill down first to 8 foot and checked with temp probs before ever digging. But those temps pretty much hold true everywhere here in east Texas.
hello how can I contac you for your help maybe with somne queestions about the system, we want to use this in Honduras
Regards
You can email me at bossgamecalls@gmail.com
I am intered in this. I want to try it on my shop. I am i. East TX near Terrell. Whatnpart are you in. Could you use the 10bin culvert type pipe?
My cabin is in northeast Texas. Up close to Texarkana. When I do it again, I'm gonna use the 10 inch. And go a bit deeper. Probably 10 feet deep.
Concrete pipes
What about a metal/aluminum corrugated pipe? I dont see plastic as a good heat exchanger
Metal in my area doesn't last long buried.
From what I’ve read about these is you need about 1ft of length per square foot of space. All in all, good job. These experiments are very useful.
interesting any sources for that? Trying to plan out a water based system for approx 7500 to 9750 sq ft barn.
@@draaks1 The info I read pertained to earth-air exchange systems. I imagine eater systems would be more efficient due to water’s energy storage capacity.
Thanks for sharing your experience. Others can pick up where you left off and make adjustments and save a lot of money and time because of you.
It would cool better if your air that entered came from outside, and the air that exits goes out the highest part of your roof that you can put a pipe or PVC exit. Your pipes come in at only half the height of the cabin. Cool air goes down, hot air rises. Both tubes are at the same height, so the actual heat is still in the cabin from Midway and up. You can't cool captured heat that stays high. Also the cool air should come in at the lowest point, heat exhaust at the highest point, creating a convection pull to naturally suck the air out. Hope this helps. I've done it on my house. It cools 10 to 15 degrees cooler. I only have 1 entrance pipe, 5 ft buried, and 30 ft long. I plan on adding more just for more comfort.
A couple of people have touched on it, but a higher ratio of surface area to volume will mean better heat transfer. Four 4" pipes side by side will cool more than one 10" pipe even though they have less volume (even combined) because they have more surface area. The surface of the pipe is where heat gets dumped into the dirt.
Also, a smooth metal pipe would transfer a lot more heat. If you used 3.25" x 10" stack duct (I make no promises of its suitability, and permanently sealing it would be some work), it would be much more efficient at dumping heat. That's why commercial heat exchangers use a long run of very small conduit.
If you have a stream on your property, or a similar consistent water source, creating an overflow reservoir big enough for a heat exchanger can work awfully well, too.
Don't bury that galvanized stack pipe, conductor pipe or any other sheet metal ducting! It will rust and cave in or disintegrate in less than 7-14 years! Also recheck your 'Pie" formula for figuring circumference, cubic feet per minute etc. Might be off a little.........ha, lol !
Like the radiator or if you have a turbo a after cooler in your car, it’s made up almost flat pipes with fins to increase surface area.
I was just checking on this an i found something interesting. For it too work at maximum potential, it needs to move 5 times the amount of air that is in the room per hour. Hope that helps.
I appreciate that
A 6" pipe has approx 18.8" circumference. (Diameter x Pi, 3.1415) Two pipes would give you 37.7" total cold dirt surface. (1) 10" pipe will have only 31.4" circumference touching dirt and be danged expensive.
To eliminate any possibility of mold in the pipes or water seeping in, just run the pipe out with pex tubing inside. Flood with water, pull water in through the pex tubing, through a couple car radiators, backflow into the corrugated flex pipe. Blow air through the radiators. If you keep the water, level with the radiators, the pump will just be moving the water, not lifting it...more efficient.
Get the air intake as far from the exhaust as possible. Insulate the cabin 8" or 12" thick. White EPS styrofoam packing can be salvaged from many a dumpster, shredded in a 55-gallon drum-lawnmower-blender, mixed with a tiny bit of cement and packed into the walls/ roof for insulation.
Put some 1/4" foam then stringers on your metal roof, then a second metal roof with eave and (large) peak venting. Or anything to shade the roof and keep the sun from baking you to death.
Your advice is worth its weight in gold!
Shade the roof with solar panels
Kudos for making a follow-up video, when things don't quite go as planned.
I cant find the first video
@@chrischtis2082it’s 2 years ago
Amazing! Thank you for sharing this follow-up video. I would suggest that you try a longer run pipes under-ground with one end into a small shelter from the elements, bugs, mosquitos, critters & snakes etc but ensure free flow of air and use charcoal or activated charcoal as filters in series with the air system when air is re-circulated back into your home. In your home you should consider a passive or active system to drawn hot air within the building to above the roof of the building & if done correctly you may not need an active exhaust air pumping to above the roof of the building. Keep in mind that the height of the small shelter where the intake air comes in should be much, much, much lower then the hot air vent above the roof of the building. In-fact you may consider using solar powered exhaust fans if you like. I would also suggest you consider some indoor pot plants & flowers to assist with filtering & fresh oxygen within your home. Greetings from Madang, Papua New Guinea!
If you look up a PAHS (Passive Annual Heat Storage) system, they go with a smaller diameter (4”) for a longer run (minimum 200’). A larger diameter will decrease energy transfer for the same energy input. The surface area increases but the internal airflow transfers nothing and wastes energy. A PAHS is a different system altogether but their design seems more sound.
You're 100% correct about the volume to surface area ratio.
Also, the intake should be higher in the room, as warmer air will be nearest the ceiling... Thermodynamics 101.
He'd get a lot better cooling than just "maintaining" that way - but still, he's got the right idea.
Two-story structures? That a different taco to tackle, but doable.
~edit - You're also correct about the length of run... longer = more time for heat transfer.
How about garden hose? Seems a few hundred feet of that means a lot more surface area exposure, the flexibility of the hose means easy to place, and -probably more crush resistant.
@@jksuzuki9350
A Garden Hose would be too small in diameter, and too well insulated as well, for it's diameter/volume ratio... you'd have to run hundreds of feet just to get any significant effect.
But you're thinking on the right path.
Air is not the best conductor of thermal energy.. which is why liquids are used.. You could have buried a few coils of 1” pipe and put a couple recycled hot water radiators in series and gotten a much better return on your work. (Needs a solar pump and drain pans under the radiators.. makes nice clean condensate).. in your design, Condensation in that buried pipe can collect in the corrugations and grow pretty toxic molds.. ideally a pipe which has a smooth inner bore, but also metallic spikes through it to engage the thermal mass of the earth and transfer that heat into the passing air.. I melted large landscape nails into 4” PVC which worked well (if you look in a gas home furnace, it uses a similar concept to heat air).. and it requires a condensate drain as well.. which you can add with some second hand goretex from Goodwill and a little gravel. Larger diameter pipe mean you need a larger blower and corrugated pipe is really restrictive
The systems like you have built work in the Southwest because the humidity is so low and the overnight temp usually drops dramatically …
This is just information that may help anyone going forward.. Your videos on this have been great. This is not a criticism at all of what you have done.. making good content. 👏👏👏👍
Ahhhhh
SW only
Deep South would have mildew probs for sure!
My books in outside storage waterproof unit are mildewing 😳
Thanx for the whole rundown. We are building a tiny cabin/house and have been considering a similar set up. May have to go bigger or back to the drawing board to find an inexpensive solution. Be Safe!!
A setup I saw they used 400 feet with several separate loops.
Also, others recommend drainage pipe to drain any accumulated water
@ TimelessNews3 … what is theoretical the best location for a drain and where could it be fit in here in this actual situation ?
I would expect lower points to be a problem but how to drain those in the actual situation ?
For a cooling system, this is what I see working for others:
- 4 inch pipe works fine, makes turns easily, and you lay it out as a grid in a tight area, instead of one long strand like yours.
- 100ft of this 4" pipe should work well for a small bulding.
- Make the intake at the highest point and the outlet towards the bottom, shooting upwards at an angle across the room. Helps circulate the cold air and push the hotest up to the intake.
- In warmer climates, you lay a second pipe a foot above the first one. This second pipe system has both ends outside and is used during the night / winter (as long as night temp is below your ground temp) to pump outside air into the ground and cooling it further than it could on its own. As cold sinks, the first pipe gets colder and your AC system becomes more efficient.
- Make sure to have some holes at the bottom of the pipe section underground to allow condensation to leach into the soil, thus reducing moisture returning to the cabin.
It's not about the size of the pipe, but rather the surface area for temp exchange, coupled with making a tighter system for better temperature "storage". Hope this helps.
I was mostly with you however, hot air rises because it is lighter than cooler air. "Cold AIR" sinks, not "cold." Cold is the absence of heat in any substance.. I repeat, in any substance be it air or dirt. Empty outer space has NO temperature at all since it has no substance.
The absence of heat, in and of itself, does not sink. Again cold AIR sinks, and hot AIR rises. The air in the lower pipe exchanges it's heat into the ground around it, thus heating the dirt by some small amount. The air in the pipe loses heat and becomes cooler. The second pipe might possibly be a heat sink for the ground around it and cooling that dirt, but don't think it would to much for the lower pipe with a foot of dirt between it and the lower pipe. Now a smaller pipe in direct contact with the larger pipe, with an intake for the atmosphere, and a forces exhaust MIGHT do some good in exchanging heat, but probably not much. Sorry, I just can't see the two pipe system working very efficiently.
@Grynslvr2 interesting point, but I think you're hung up on the terminology of thermal physics. It is in regular terms for all to grasp the simple concept of pre-cooling the soil before summer heat returns. Soil is a great thermal sink (or void) for such usage and others like mud ovens and rocket stoves, earth ship houses etc.
And of course I get the concept of measuring / transfering heat, not the absence of it lol
@@thatguychris5654 Howdy. I am starting to think that maybe it is my preconceived notions, based on where I live. I live on an island off the coast of Texas, an overgrown sandbar really. No rocks, no clay, and when I dig a hole in the ground, water weeps into it slowly at about 18 inches, even though I am at 11 feet above sea level. It snows regularly here - about once every 10 or 11 years. As far as I can tell, our two or three months of cool to cold weather, doesn't suck much heat from the ground beyond the first few inches. My water pipes run about 18 inches deep from the city supply line, and they have never frozen since being installed in 1949. All that being said, I am predisposed to think in terms of evacuating heat from air and thereby from buildings. That may work differently in other places. Here the ground is always around 65 degrees or so. I am just looking for ways to reduce my energy bills. Thanks for the friendly reply. Many folks jump down my throat, so it is very much appreciated.
@@Grynslvr2 no problem, I love friendly chats regarding science that we can actually do ourselves 😁
Indeed your location is unique. Having water so close to the surface changes things a lot, as does the soil content (all sand). But this could be a good thing if you were to use water instead of air. If the water temp and flow is pretty consistent, perhaps pumping water into a type of radiator, and having a fan on it, would cool enough. If your area has air that is dry enough, even a swamp cooler would be awesome. I even wonder if using a passive cooling system tower with wind, like they do in the desert, would work with you ocean breezes. But you are 100% right, your winters couldn't be used to rob the soil of its heat. I guess I'm biased in that way living in central VA with lots of clay around and decent seasonal temp swings.
@@thatguychris5654 Thanks for the response. Sadly our relative humidity runs from a low in winter of about 40% to a high in summer (on days with no rain) in the mid 90% range. I was hoping there was something here for me, but with only a 1/10 th of an acre lot, I just don't see a way to use this really "cool" technology. Sorry, I couldn't resist. Maybe with a bit more room for ground cooling, I could do some good. Oh well, it was in interesting mental exercise. Thanks for playing along.
A suggestion, if you want to hear it, (and i'll piss off if it's none of my business, you seem to be doing fine without my nosiness), but you might be able to heat/cool even more effectively if you throw a solar chimney into the mix. you take a pretty standard fireplace setup and on one of the outside walls you put in some glass to warm the air inside (if you don't intend to use it as a normal fireplace), or just paint the stones black to absorb heat. also a big point is that the flue lever should vent out at the top, not be at the ground level. Mechanically what this does is create a current of air that constantly pulls the hot air up and out the top of the chimney, and the cool air into the rest of the house. If you put some venting between the first and second floors, and put the solar chimney on the second floor, you could near-passively regulate the entire houses' temps, especially if you put in another earth tube to the outside to bring in more fresh air and avoid making a vacuum.
Anyway, great stuff, and hope you're doing well!
I get a lot of what your saying. I found very little research on this prior to building. So it was trial and error. Mostly to see what works and doesnt work for the next cabin im gonna build. It will be a full size hobbit house and i will incorporate a lot of what your saying as far as the stone and fireplace. Ill do a series when i start the hobbit house.
Kinda been preoccupied building my food truck. Its almost done and then i can get back to my cabin projects. I have lots of cool builds coming up.
I appreciate the feed back and always welcome suggestions.
@@uncledavesfrontier6846 ua-cam.com/video/UsZgCz3PQks/v-deo.html Worth a watch. (for the price of large tubes right now, it would be less expensive to get solar panels, a battery and an efficient air conditioner for better performance) I think you need a lot more air flow and a lot more surface area. I've always liked this idea for its simplicity, but there needs to be a better, less expensive way to tunnel air under ground. Thanks for sharing and following up.
@@orangezeroalpha my cabin is solar powered and i do have ac units. I gave this a try to see what the results would be. I enjoy experimenting hoping to find better ways of being off grid.
Ultimately i think the best design is an above ground cabin thats buried. Im gonna incorporate a lot of different things on the hobbit house im gonna build.
I think if you moved your intake/suction side higher, perhaps 7ft high, your air into the house at 4ft high you may see better performance. Im thinking your are recycling your cool air rather than removing you hot air.
Great follow up! I think that you can use a 10" 12v DC only radiator fan and save even more energy. Check the CFM ratings (cubic feet per minute). I didn't realize that your cabin was 2 stories tall, that's a very large airspace for only 100' of tube. Great work. I look forward to seeing the next build! (my dad lives not far from you and we talked about this for his wine cellar)
For a wine cellar, this would definitely work great.
Another thing i forgot to mention is my cabin outside is metal. So that plays a big difference. Even though my cabin is completely shaded, the metal still adds a lot of heat. But i plan to go over the outside in stone and add some insulation between that. I appreciate you watching.
@@uncledavesfrontier6846 I think that instead of going to a larger pipe, you should have more length. That way the air has more 'time' to lose it's heat. 200-300ft.
@@scottbradford192 I'm thinking of lots of different things to do on the next build. Longer pipe may be a way I go.
@uncledavesfrontier6846, if there is a granite slab showroom near you, or an installer, you could ask if the stuff they throw away is available.
Marble or granite may be helpful as a heat sink (if you can crumble that material) above the pipes ☺
Because you have a very low Delta tea, you’re not going to condensate too much but overtime. The pipes will get moldy. It’ll be impossible to clean them out unless if you can run a small amount of ozone through there consistently.
To be honest for the time and money, you were going to get much more bang for your buck by installing a radiant barrier on the exterior of your roof
If the cabin is 95 degrees, of course it's not going to cool it down, because you are blowing hot air through your tubing and it's just recirculating the hot air. Now if you were near a creek or a large spring, you could run your tubing through that and you would get a cooling effect.
have one blower on the intake and one blower on the exhaust , make one with a 12 volt fan and run it on a solar panel all day .
Awesome stuff brother, watching from Australia! This stuffs great for our climate and off grid
You should use metal pipe in the ground for better heat transfer & insulate the pipes on the outside where they go out & come back in.
Pipes out of the ground are insulated now and have cement over em. I thought about metal pipe but it doesn't last long. I put one stick in once for a culvert and it literally rusted away in 3 years
This really is genius. Thanks for the update
Thanks buddy
I would suggest a 8 inch pipe running out to a dead end(capped) and another 8 inch running back in that dead ends, parallel in the ground , then run many 2 inch pipes between them so you break the air into smaller pipes increasing its contact (surface area)to the cool pipe walls before returning. like a radiator shape under ground. ribbed pipe would also bring more cool earth into contact with the pipe and air better than smooth walled pipe.
Also i would suggest the outgoing vent placed up near the ceiling to pull hottest air out and the incoming vent on opposite wall at mid level to reduce the air being just circled from incoming to outgoing vents without circulating in the entire room.
baffles inside the pipe would work good to force the air to linger in the pipe longer as well but it's not easy to do. you could slow the fan also to allow the air to radiate as much heat out as possible before returning.😎
Definitely a great idea. Have you considered using a fan on both holes? (One hole blows air in and the other blows it out).
my first thought
You'll get better heat exchange by multiple smaller pipes, as opposed to one larger pipe. Smaller pipes have more surface area (per air volume) to exchange heat from the air to the ground around it.
Is it easier to push a cooked spaghetti noodles or is it easier to pull that noodle? Put a fan on there sucking the cool air into the room instead of trying to push 100 feet of air through a six inch pipe. Also, put the air going out of the cabin 12 inches above the floor. The air coming in can be at face hight. Like you said, do not put a 90 degree bend in your pipe right out side the wall. Hope this helps.
Seems to me that hot air rises so the exhaust should be high.
12”
No 12’ if possible
Make ur ceilings high like all southern homes used to be with the transom windows over the doors
Pull hot out high
There’s no hot air on or near floor
Blow cold in high and it will fall down, cooling as it goes
About the mildew I guess the real problem is inside the pipe condensation will condense and no way to get it out
Heat rises so the air at the ceiling is 50% hotter than where you have the air inlet located on the wall. Insulation in the walls ceiling and floor are major factors.
I've heard performance is better with 4" because the air flow hits the ribs more collecting more btu 10" air flows thru center not really absorbing the btu a thought? Made sense?
I have several different things I'm trying before I commit to one on the next project.
How do you get rid of the condensate in the pipe? also, can you put a temp gun at the exhaust and see the actual air temperature?
I have a dehumidifier in the room. It's never humid in my cabin.
If you didn't want to go that route, use the pipe with holes in it and lay it on gravel before you bury it.
But I've had no issues with any of that. No smell, no mold, no mustiness.
Do two tens, one for up stairs and downstairs. Also, run a duct across the ceiling and wall with two 5 inch outlets for each to even out the flow. It will cool, you just need to get the airflow and air dispersion even and strong enough to move the air.
With bigger fans, there will be less time to transfer heat. You might need significantly more pipe.
Consider multiple six inch pipes. More resistance for the air flow, but also more surface area. So the heat exchange should be improved. I know there is a mathematical way of comparing those differences, but it's not something I know. Also, space the pipes apart, and the heat will transfer more efficiently. As the summer goes on, does the temperature differential between In going and out going air remain about the same?