heat and cool a dome naturally

I live in Zone 3-5ish where it snows a bunch in the winter and has 100 degree days in the summer. I built a 29' diameter Geodesic Dome that will soon be 3-4' deep in the earth. Now I am thinking I can have ice stored (In a rubber pond liner with a roof and insulation to keep frozen throughout the summer) above the dome elevation to cool in the summer ( Maybe using a subterranean heating and cooling type setup, with 55 gal blue plastic barrel on top of the ice with the piping going from the barrel to the dome where there would be another barrel, a fan would move the cold air?). Also, I am hoping to heat with a rocket mass heater and a makeshift geothermal type heating, with the ground. Would this work as I have it drawn out? (Scale is inaccurate as of now) Thanks!

Not sure how you are planning to store the ice, or move the colder temp into the dome, but I don't think you would need to bother with it.  I would just use earth tubes like the ones you show going downhill.  If you keep that angle and open windows near the top of the dome, the 45-55 degree cool air will be pulled thru passively on warm days.

I would like to see the dome if you have pictures, in particular the material you used to cover the triangles, and how you sealed it to prevent leaks.

Todd Parr wrote:Not sure how you are planning to store the ice, or move the colder temp into the dome, but I don't think you would need to bother with it.  I would just use earth tubes like the ones you show going downhill.  If you keep that angle and open windows near the top of the dome, the 45-55 degree cool air will be pulled thru passively on warm days.

I would like to see the dome if you have pictures, in particular the material you used to cover the triangles, and how you sealed it to prevent leaks.

Thanks ,Todd! ( I am new to Permies and not sure I am responding in the correct fashion) I responded to your ice storage question with a simple edit (on pond liner with a roof and insulation) I wasn't sure if convection would draw down the cold air naturally or not. I am not well educated on physics and thermodynamics... yet. There are pictures of the dome at www.sacredacres.info or follow sacred acres on instagram/facebook. As of now, the triangles are covered with a thick fire/tear/water proof vinyl and sealed with caulk and rubber paint. This summer I will be using wood, plastic, and earth as the new cover.

Bumping this thread because I'm attempting to try something like the deep pipe in the ground for convection air circulating: thermosyphon. Does anyone have any recommended reads for the concepts at work here? Would Scott's ideas have worked? Anyone have a good source for experimenting with thermodynamics?

Amy Gardener wrote:Bumping this thread because I'm attempting to try something like the deep pipe in the ground for convection air circulating: thermosyphon. Does anyone have any recommended reads for the concepts at work here? Would Scott's ideas have worked? Anyone have a good source for experimenting with thermodynamics?

Hi Amy, have you looked into Michael Reynolds Earthship designs by chance? The Earthships his team builds in Taos, NM utilize fresh air intake cooling tubes of 10 inches ID, in the range of 20 feet in length, buried approx 8-feet deep.  There's a diagram (drawing) on their website here: https://earthshipbiotecture.com/design-principles

The "cooling tubes" slant downhill away from the living space, to drain any condensate to the outdoors. From what I've read about the latest Earthship designs (Encounter & Global models) the indoor temperature stays 70° F all year round without supplemental heating or cooling.

Great idea Byron! I've watched the documentaries but never looked at the website. Looks like I'll be heading up to Taos for a stay. Thanks for writing.

Your most welcome. If Taos wasn't a 1000 mile drive, I'd show up for a tour of the Encounter model Earthship on the hottest day of the hottest month, armed with a pocket thermometer:o) I've heard summer temps get into the 90s' there just outside of Taos at the Greater-World Earthship community, high desert at 7000 feet. And that makes for a 20° or better temp. diff. with the Earthship staying close to 70° F in the living room.  

The Encounter is the basic but still does it all design, the affordable Chevy Nova of Earthships. Here's a neat video tour with some elaboration on the cooling tube system:  

Another good video worth watching is the tour given by Tom Duke, including his own early model Earthship he and his family have lived in for close to two decades now:  

There are lots of attractive interesting energy saving concepts of the Earthship design, I've been studying to eventually incorporate into my home.

Here's the video I was looking for, showing the rear (around back of the Encounter Earthship) view of the cooling tubes air entry areas:  

The Earthships take advantage of the earth's mass being banked up horizontally, at ground level. Dirt is heaped up. The convection occurs through the pipes above ground level that are covered with dirt. Really good ideas when you are building from scratch and can take a bull dozer and build a large mound of earth that air can pass through.
Where I live, the temperature is a consistent 61.5 degrees F straight down into the ground at 12'. Temperatures above ground go from the teens in winter to over 100 in summer. Scott's diagram shows a 12' long pipe reaching mostly down. How do we get that consistent 61.5 degree temp to go up into the living space (vertical airflow) instead of across (horizontal airflow)? The early inhabitants of this area built pit houses and subterranean buildings. Did they know something that we've forgotten?

There are other ways to "drive" the cooling tubes effect besides that really nice glass front built-in greenhouse:o) As far as the cooling tubes being sloped at a more aggressive angle, I have no idea if that is of concern or not. Only that cooling tubes that are sized in the range of 20 to 40 feet in length are commonly made to 10 inches in diameter (according the Earthship plans / drawings).

To cool a dome structure, the way Earthship Biotecture does it, is via an opening in the center of the top of the dome, and a short but large diameter pipe (chimney of sorts) fitted at that point and extending above the roof-line. Hot air inside the living space rises and flows out of the ceiling opening through that section of pipe. The sun heats up the pipe's rooftop located convection umbrella, raising the air temperature at that location, thus further driving the thermosyphon effect, and obviously pulling fresh cool air into living space from the buried cooling tubes.

Phil talks about this type of system at around 17 minutes (cooling tubes) and 30 minutes (convection umbrella) into this video:

This info is really helpful for summer airflow, Byron. With some strategic burrowing, ground level cooling tubes are possible in my situation and I will explore this more for summer cooling. In addition, I am especially intrigued by the convection umbrella. Currently, I have a skylight at the central peak of the dome. In summer, I could cover the skylight with black landscape fabric and put the domed skylight on a table-legged frame that will enable ventilation and draw the air from the cooling tubes and the ambient heat upward and out the roof. You really got me thinking and I thank you for these excellent ideas for cooling the space, Byron.

Now, what about the winter chill? Any ideas to passively move warm air into the living space, either from the sunny topside or the below-ground warmth?

Sorry, I'm of no help there as far a moving heat passively. Everything is on one floor level here, with a more or less centrally located, along one wall, RMH (6" batch-box + thermal mass bench) in 680 sq. ft. of open floor space, standard 8 ft. ceiling, in a small stick-frame house. Still grid-tied and using electric fans, to spread the warmth to the furthest back rooms. Would like to build an Earthship one day, but no dirt packed tires (steel reinforced MCUs instead, since I am a traditional builder at heart).

Amy Gardener wrote:Bumping this thread because I'm attempting to try something like the deep pipe in the ground for convection air circulating: thermosyphon. Does anyone have any recommended reads for the concepts at work here? Would Scott's ideas have worked? Anyone have a good source for experimenting with thermodynamics?

Maybe John Hait’s book on Passive Annual Heat Storage? There’s also threads about it. Exactly this method for circulation.

Correction on the 20 to 40 foot length cooling tubes. In the current production Earthships the pipe diameter for the cooling tubes is typically in the range or 15" to 16" in diameter.

I live 3 degrees North of the Equator, a former British colony. Before they demolished the government staff quarters, I went to look at the houses. This is way before the current global warming crisis. The two standout aspects of these terrace houses is the high ceiling and a CHIMNEY which reached down to the kitchen ceiling - not to a fireplace or above the stove.

I saw the bricks they used. Quality bricks. Well made. Tough and had an imprint of the name of the company. The two biggest faces were sunken on like a truncated pyramid.  By the time I thought of saving a memento, it was all boarded up.

Byron Campbell wrote:   There's a diagram (drawing) on their website here: https://earthshipbiotecture.com/design-principles

 

It's all gone. Not even found at the Wayback Machine. The internet is no longer immortal.

Buckminster Fuller had some observations about cooling domes.

https://www.stuartmcmillen.com/blog/chilling-domes-physics/

I've got a question. Would mold grow inside the pipes? We have a concrete dome and I've been thinking about burying around 80-100 ft of 4" PVC pipe, stubbing up one end above ground, and piping it into the basement and opening a skylight close to the top center of the dome, using natural convection.

The only thing that has prevented me from doing it is my concern about mold.

Jon R Anderson wrote:I've got a question. Would mold grow inside the pipes? We have a concrete dome and I've been thinking about burying around 80-100 ft of 4" PVC pipe, stubbing up one end above ground, and piping it into the basement and opening a skylight close to the top center of the dome, using natural convection.

The only thing that has prevented me from doing it is my concern about mold.

I think your concerns are valid.
My dad built a long 4 foot deep earth tube cooling system in Illinois back in the day, and the air coming out of those tubes smelled musty because mold could grow inside them. Who knows how much mold or how dangerous it was. I think to make them safe you need to periodically sterilize them, maybe with a back flush of bleach fog or something, but then the mold would return again. It feeds on dust which enters the tubes, so adding filters at the inlets might help but I think eventually mold would colonize the tubes regardless of the filters. Of course it all depends on how much earth gets into them through the drain holes, their depth, and other factors. Another issue you might have with plastic tubes is animals chewing through the pipes and getting in there.

The air coming out of underground tubes can be very humid depending on your climate and soil conditions. Drying the air with a dehumidifier and filtering it really well might improve the air considerably. Good luck!

Dave Pennington wrote:  I think to make them safe you need to periodically sterilize them, maybe with a back flush of bleach fog

Yikes!

I am NOT an expert on mould. But I read widely and come across stuff like :

"A lot of agencies recommend using a bleach solution to kill mold. As a consumer, you should NEVER use bleach on mold. Bleach will weaken the protein shell of a mold spore, and it will send out hyphal fragments and reproduce. By cleaning with bleach you will make your mold problem worse. "

This comes from:

which is worse

I always warn people about innoculation when planning on using biochar.

I always warn people about spontaneous fire when dealing with linseed oil.

I always warn people about using bleach or a combination of cleaners when treating mould. I don't know if I am right on this and await an expert to chime in. I read that vinegar is suitable. I don't know for sure.

Thanks Dave, I didn't think about critters getting chewing their way in, it's pretty humid here too. Might have to rethink this. Thanks Jon

Looks like someone decided to "improve" their website w/o getting my authorization :-D Similar diagrams and info appears to have been moved here: https://www.earthshipglobal.com/design-principles

And original info sighted is archived here: https://web.archive.org/web/20220524202731/https://earthshipbiotecture.com/design-principles/

Edward Lye wrote:

Byron Campbell wrote:   There's a diagram (drawing) on their website here: https://earthshipbiotecture.com/design-principles

 

It's all gone. Not even found at the Wayback Machine. The internet is no longer immortal.

Byron Campbell wrote:Looks like someone decided to "improve" their website w/o getting my authorization :-D Similar diagrams and info appears to have been moved here: https://www.earthshipglobal.com/design-principles

And original info sighted is archived here: https://web.archive.org/web/20220524202731/https://earthshipbiotecture.com/design-principles/

Thanks. I live in the tropics. High humidity. Mould.

So I just have an interest in Earthships. That they are feasible and we can draw inspiration from actual practice just like that famous double roof house in the Philippines.

But what bugged me most is this: "Every building has its own renewable “power plant” with photovoltaic panels, batteries, charge controller, and inverter. The key step in making these systems affordable for residential use is to “design down” the electrical requirements of the home before the solar system is sized. Super efficient lighting, pumps, and refrigeration help lower the load, as does the lack of any need for electric heat or air conditioning."

This requires a lot of electronics most of which are not evergreen like the 741 Operational Amplifier. Don't forget the supply chain problems around the world and chip shortages. Unless you have your own silicon foundry ...........

Edward Lye wrote:

Thanks. I live in the tropics. High humidity. Mould.

So I just have an interest in Earthships. That they are feasible and we can draw inspiration from actual practice just like that famous double roof house in the Philippines.

But what bugged me most is this: "Every building has its own renewable “power plant” with photovoltaic panels, batteries, charge controller, and inverter. The key step in making these systems affordable for residential use is to “design down” the electrical requirements of the home before the solar system is sized. Super efficient lighting, pumps, and refrigeration help lower the load, as does the lack of any need for electric heat or air conditioning."

This requires a lot of electronics most of which are not evergreen like the 741 Operational Amplifier. Don't forget the supply chain problems around the world and chip shortages. Unless you have your own silicon foundry ...........

Earthship Biotecture has an interesting Earthship design specifically for the tropics. Have you checked out their youtube channel? Especially of interest is their project in Haiti. I'll place the link here: https://www.youtube.com/c/earthship/videos

My own experience with mold, and preventing it, has to do with keeping indoor air moving, and fresh air flowing in the living space. Moisture combined with dead stagnant air, and a coarse substrate that holds moisture, dust and dirt, guarantees mold growth. The Haiti Earthships also have buried ventilation tubes, to keep the living space air refreshed etc. The DIY masonry roof design is appealing to me personally, to get away from using expensive materials like roofing "tin".

Edward Lye wrote:

Dave Pennington wrote:  I think to make them safe you need to periodically sterilize them, maybe with a back flush of bleach fog

Yikes!

I am NOT an expert on mould. But I read widely and come across stuff like :

"A lot of agencies recommend using a bleach solution to kill mold. As a consumer, you should NEVER use bleach on mold. Bleach will weaken the protein shell of a mold spore, and it will send out hyphal fragments and reproduce. By cleaning with bleach you will make your mold problem worse. "

This comes from:

which is worse

I always warn people about innoculation when planning on using biochar.

I always warn people about spontaneous fire when dealing with linseed oil.

I always warn people about using bleach or a combination of cleaners when treating mould. I don't know if I am right on this and await an expert to chime in. I read that vinegar is suitable. I don't know for sure.

Hydrogen peroxide might be a better solution.
Thanks for posting the info about bleach, I will study it.
In my experience people usually build underground to save on energy/insulation, and once you destroy the driving factor (the cost of good insulation) you can build above ground and properly air out your building, which solves the mold problem. The trick is to use a cheap structural insulation which is impervious to all the usual problems (EPIC).

I just stumbled across this:    Buckminster Fuller's Dymaxion Deployment Unit.

Like compressed air cars, Ragged Chutes 108m tall cold and DRY air compressor without moving parts,
Thomas Gaskell Allen's Hydrautomat water pump with one moving part, the Di Pietro Rotary
Air Engine which requires DRY compresssed air, Fuller's counter-intuitive accidental invention
deserves better.

It is worthy of a kickstarter.

DDU-1

DDU-2