This content is amazingly useful for cold weather locations. Also, good to see someone say, "I've built something cool, here's how to make it", then admire others improvements :) Love this, good job!
Good info Dean, clay has far more surface area than sand so it makes sense that it would store energy. The nice thing about sand is that it has 100 percent compaction from a building point of veiw. Its good to note that we both used what we had available, you can't let perfection get in the way of excellence.
@@ArkopiaUA-cam hey, have you ever heard of PCM, phase change materiel, to store a huge amount of energy at a constant temperature, store in the latent heat of fusion. worth digging
New ways of thinking and applying new methods of heating large green houses! Clay vs sand! So interesting for our future homes and green houses! Really exciting, guys! I am an artist !I live in Maine and love these types of sharing with You Tube 👏❤️✅❤️👏🥰👏👏👏 Please keep up your great work to promote natural green houses in cold climates!!
In your skittled rant, you actually made sence. I appreciate the insight of could have, would have thought. That is why we all seek whatever information we can to improve our plans. Bottom line, your ultimate greenhouse build will inspire even better builds. Awesomeness is contagious 🤠
I think your current concrete setup is already fairly good at capturing heat. What your friend in Alberta did was slow down heat loss by putting insulation under his sand and concrete. I think you could do the same, but rather than dig it up, think about where you are losing your heat. There is a community in Alberta, (might be Drake Landing, I don't remember) where they rely on the ground to be a thermal mass just like you (but with vertical pipes installed), but what they did was install insulation two feet underground outside, to keep the heat from escaping upwards. My theory is that you aren't losing heat straight down, as that is "charging the battery" and eventually the heat gradient will slow the heat loss downwards. Rather, you are losing heat sideways and up through the ground. Near the edge of your greenhouse the path for heat to travel involves let's say going down 2 feet, out 2 feet, and back up 2 feet, so travelling a distance of 6 feet total. Imagine putting insulation horizontally in the ground around your greenhouse - now the heat has to travel down 2 feet, out 10 feet, and back up 2 feet, so 14 feet total. I remember watching a youtube video of low-energy mobile homes being built this way where they didn't insulate the bottom of the mobile home, but insulated the ground around the mobile home and turned the ground beneath the home into the battery - with good results. Your greenhouse is likely already sitting on clay, just with perhaps a foot or two of non-clay near the surface. Just some food for thought. Regardless of if I'm right or wrong, thanks for posting the video and giving us something to think about! Keep it up!
4 ft of verticle insulation around the perimeter, and 8-12 ft out of horizontal just under the surface around shop, greenhouse and house. That really helps.
@@bobboersema362The climate control worked well, though, which is what they're referring to. Shitty communities can always be a thing--people don't choose where to live based on the heating setup generally
7:37 “at night time ‘heat rises’ “…. It doesn’t rise it radiates but you are correct with your rigid insulation underneath. It can only radiate to the floor surface at which point the air in contact with the floorsurface increases in temperature. The air itself, then expands and is displaced by the denser colder air, i.e. creating impression that heat rises through the movement of warm air up. The heat in the floor it will be radiant heat but the insulation prevents the energy moving down …sorry I’ve just been pedantic. 🤓I absolutely love your videos. Well done they are fantastic. They give me a lot of knowledge as I intend to follow your example and build a passive solar greenhouse. this is one of the best channel out there. Thank you😊
Sand can be superheated to over 1000 degrees in a fully insulated container for long term storage of summer heat using parabolic mirrors. Then release it in the winter.
Oh boy have you got my little brain thinking! I need to go back and see if I've missed any of your videos or if I've just forgotten some details (it happens a lot these days with everything else going on) because I'm suddenly full of questions and more to research. I've been so impressed with your greenhouse since the first video you put out about it and I dream of being able to replicate it as much as I can, but our leaders seem to want to drain our bank accounts more than any of their other goals.
Valuable information. Thank you. I'm bookmarking this video for the time if and when I get my own property in the Pacific North West. I want to achieve "Tropical" (not sub-Tropical) green house with aquaponics Tilapia and Fresh water Prawns, and exotic Tropical fruit trees.
What you say about the heat moving down is 100% correct. If you have temperature sensors installed in and below the thermal mass at different depths its easy to see heat moves down in the summer and up in the winter. It takes a huge amount of heat to charge the deep ground, most of which you wont get back. If you have temperature sensors outside the greenhouse in virgin ground at the same depth, you can confirm the average temperature of the deep ground under the greenhouse steadily increases and eventually becomes stable at a new norm based on the in/out energy balance. In my case this took 5 seasons. Insulating below the sand will fix the amount of mass which isnt an issue with evacuated tubes, as they are able to charge the mass to higher temperatures. The downside is heat loss increases with temperature and you cant plant directly in the mass. The upside is the heat stored is 100% sensible. A sand bed without bottom insulation will have a higher moisture content which will increase its thermal capacity, conductivity and diffusivity compared to dry sand. Fwiw, you would increase the overall system efficiency by installing air tubes in the planting areas. The sand battery essentially only heats the air. You can transfer some of that heat ( oxygen and condensed water) directly to the root zone, resulting in increased productivity. The primary function of a greenhouse is to grow plants :)
Only use sand for this. Clay expands and contracts an insane amount with temperatures. Sand is little to no expansion. Your cement would heave and crack. Or lift
Love your insights!!! Thanks so much for sharing. It helps us all improve. I'm building a tropical 4 season dome greenhouse with solar heated radiant PEX along with radiator fans to heat the air. I'm on the plains and have almost exclusively clay so that will save the sand/gravel cost just using my local material. I also wanted to put the PEX below the entire greenhouse including the plant beds, with the intention of only heating the soil to 90F where tropical and other beneficial soil microbes max out. I plan to burry and insulate a 1000 gallon water tank, headed by thermal solar panels and use that for thermal storage, and supplement it on the cold cloudy days with a Liberator Pellet Stove in the greenhouse that I'll also use to heat water for the same radiant system.
02:15 it´s not "in theory", as Daimler-Benz did some research decades ago, and they accnowledged, that the thermal loss down to the ground is an absolute thermic sinkhole and so is absolutely endless. Admire your honesty though and the spirit, so absolutely: Thumbs up!
I have done some calculations based on the water thermal capacity. The easiest way to store a huge amount of thermal energy, cheap, is to dig a big 1/4 swimming pool size whole, lay down poly and insulate it with straw bales from the bottom and all sides, add more poly and add water and cover it with straw bales. Run the energy from solar thermal panels through that water battery for the entire summer. 1 cubic yard, water can store 52KWh at around 55C temperature. A 30x15x1.5 yard pool will store about 35.5 MWh (and that is a lot of thermal energy - 127.6GJ) at 55C temperature. Clearly, increasing the size of the thermal pool increases the temperature proportionately. With a layer ( horizontally placed) straw bales the energy loss is around 3-6% per month! Clearly depending on the ground temperature as in the summer that loss is drastically lower.
Yes, water is the best choice, the storage of that water brings significant challenges. Sand and clay don't have these problems. You cannot use straw bales in or near the ground as they will degrade and eventually decompose. Foamboard is outrageously expensive but dependable and durable.
@@paulmaxwell8851 of course straw can not be used directly in the ground, this is why I mentioned poly, below them ( and clearly above them), as the PE or PP (or generally) any plastic based molecules are extremely sable in the ground ( no sunlight ). The cost effectiveness of this method is extremely favorable.
Furthermore if one could use flax bale straw with a baler that packs insanely tight, that bale, encapsulated on a 20mil poly will not rot in anyone’s lifetime and more. This thread/line of thought is worth serious R&D investment.
Honestly the difference seems to be that Patrick has a basic understanding of science. What you have done is nice but the knowledge of why things work is the reason his system seem so much more effective. Good to see you pushing the boundaries and seeing what can work.
You also need to be very careful with using just water. Water freezes and expands if you allow it to freeze. That will destroy your piping or your storage tanks. That’s why glycol mixtures are used for heating buildings.
There are many different types of clay, and some get real wild as to expanding and contracting when wet vs. dry at a single given temperature. More variation over different temperatures. So before spending the money it is safest to check out your own local clay for its physical characteristics. A good thing to read up on is "mudjacking" or talking to a local mudjacker about what you can get away with using your local clay types. One way to protect yourself is to have an underground curtain of French drainage around the building, so soil moisture variability is kept in check.
If you want to regulate the temperature of the in-ground pipes, have it as a separate system by heating the ground loop through a heat exchanger from the heat source that is at a higher temperature. When you need to use lots of pipe in the ground, the cost of a heat exchanger could easily be offset by saving on the pipe.
*MY SYSTEM:* 4" gravel. 4" sand. 2" concrete floor. *Greenhouse uses compost heating all winter long, using passive rebar radiator along the entirety of the rear wall, and a solar backup fan (rarely used) for circulation of temperature zones. Plantings customized to temp and solar zones. *It's very cheap, and it works down to -25c around here. Plus we get awesome compost for the next growing season.*
Love it Dean, Once I sell my house and build my own greenhouse - I’ll have you out too. Around Prince Albert National Park area… also, water is THE BEST heat sink of all per unit of volume vs. Other materials - with 1 caveat. That stops at 100 Degrees C. If one has a way of superheating the battery beyond boiling temp using solar mirrors or something crazy, then the best way to store heat beyond the 100C barrier is a sand battery. Still going to recommend like I did in the last video that you pick up Anna Edey’s book Green Light at the end of the tunnel and look closely at her solar passive heat designs, it’s possible to direct heat air up to about 80C using a combination of metal roofing and polycarbonate air chambers, and to also run water lines along the back side of the metal. I just see so much wasted opportunity to use the summer heat to provide heat in the winter, and to also use the power of the sun to pull cool air through the ground for passive a/c and then to use that heated air for heat storage. I plan to dig the biggest hole possible (way beyond 4’ down) and install channels of 3/4” washed rock just big enough for hot air infusion, with very large clay batteries between the layers of gravel protecting the gravel with landscape fabric. Water lines placed directly into the clay, and I’d even be curious to have a serviceable pv direct heating elements embedded into the middle of the clay batteries as a way to possible superheat certain areas… so many ideas flowing out of these videos! I’ve never thought of the pv direct to heating elements before watching your videos - I would like to run a lot of experiments too - but of course have to utilize cash as efficiently as possible, and I think the PV direct might be too expensive to start. Another technology I’m interested in trying out would be to order solar cooking (oven) vacuum tubes off of Alibaba wholesale, and run copper lines through them vs. The expense of the water heating specific vacuum tubes (would like to do a cost comparable on that idea). Thanks for the great videos!
@@ArkopiaUA-cam Crikey! I just looked at the extortionist prices on Amazon! $350 USD??!! I bought mine direct from a different source in the US about 2 years ago and paid about 40-50… I need to see if the website still exists, if so, I’ll provide it here.
an issue that may arise is time delay i.e takes a while to warm up but more importantly takes time to cool down. I have electric storage heaters and the issue I have had is the temps outside can vary wildly so making storage inefficient.
One of the primary advantages of sand over clay is that it is easier to compact. Clay needs to be spread and packed in thinner layers. Even compaction is important to prevent settling and cracking in your concrete floor.
I don't have sand or clay but I sure have a ton of rocks ... of course that's why they call it Rocky mountains where I live Thank you for the very informative video!!!
Hey, really appreciate the content. I am going to copy a ton of your designs and save myself a ton of time and money. I got an offgrid greenhouse youtube video coming out next week that you would like. All passive, no electrical, Zone 6. earth tubes. Uses Finches and frogs to control bugs
I think one of those duvet style insulation blankets that they use on Chinese greenhouses would probably put you over the top. Anything that could reduce your heat loss out the big glazing side would make a huge difference.
You should look at parabolic heat put in front of your greenhouse and use oil and a small pump have a 4 foot sand battery box in front of your window. Cheap to do and just insulate it so it doesn’t give off to much heat. I believe you could heat it up to 300 F
You don’t need more water lines in layers to store more heat. That is the most expensive component of the system. You simply need to insulate your heat battery and make sure that it’s big enough to radiate for the length of time you needed to radiate. Adding heat to that system will last a long time because of the thermal mass. I wouldn’t recommend running well water or anything through those pipes. Keep it a closed loop and use a heat exchanger if you want to cool the loop because you don’t want a bunch of dirt or any kind of debris accumulating in that system. Keep it a closed loop so that you don’t have to dig it up and have massive issues with it.
I like the idea of warming up the ground instead of trying to store large amounts of hot water somewhere, seems a bit more realistic. Seems like there are lots of upsides to my soil being 95% sand.
yes that is when you can take advantage of the high temperature capabilities of material like sand even though they have far lower heat storage capabilities per degree x mass....(latent heat)...so with sand or rock or clay you can charge a smaller amount to very high temperatures (red hot, thousands of degrees. One issue with going for very high temps is the heat loss is grater because of the increased differential in temp that drives it.... In my case I place the 2000F mass inside the living space..that way any amount that "leaks" through the insulation is not wasted to the outside. Of course one needs to be careful with high temp rocks. In the UK they have been using similar "storage heaters" for a very long time as thermal batteries, they were very common, not as easy to find in the USA.
I think Dong Jianyi's chinese passive solar greenhouse in Alberta could give you perspective on using clay - I'm pretty sure he uses 1 meter wide wall on the north side, with a bunch of insulating materials. Dan bostan's passive greenhouse experiences in montreal/quebec is pretty genius too. He converted big barns into low-to no energy input for growing fruit trees. I hope these two folks can help you perfect your greenhouse! cheers.
One thing you could do to additionally insulate your greenhouse is build a “Frost Proof Shallow Foundation” around the outside. What that means is you can excavate around your building, install rigid foam around the outside perimeter, 16” under the soil, out to an area of around 3 feet around the building. Exact numbers would need to be calculated, but that’s a ballpark figure. What that does is move the frost line away from your foundation by slowing the heat loss from the soil during winter. This technique is generally used to prevent frost heave without digging a basement through the frost line, and it generally works even in completely unheated spaces like garages. Just a bit of food for thought on your next greenhouse build…
If you skipp the concreat and idé clay and strax for the surface it Will be easier to re do if necessary. Also it will cost les. The surface of the clay and straw use to be treated with linseeds oil and then become water resistant.
A few thoughts: Firstly, clay shrinks and expands with humidity - so be careful about having it support a layer of concrete if it is going to be seasonally heated. Secondly, I think your larger earthern battery could still out perform a smaller sand battery in the long run. The longer it takes to heat up the longer it will take to cool down and I think that a cooler heat source that can buffer tempertures seasonally is more usesful in your contex than a hotter heat source that can only buffer temperature for tens of weeks.
I don't know much about greenhouses but as a physicist my guess is Patrick's idea will work fine, and for your greenhouses its a good experiment, but you'll probably need moisture in the soil to use the earth effectively.
NO!!! This is a common misperception. Heat energy moves from an area of warm to cool, regardless of direction. It doesn't 'know' up from down. Heat loss through the bottom of an insulated cube will be exactly equal to the heat loss through the top, or any one side. Warm FLUIDS (air, water) do move upwards, but that's an entirely different matter.
To do this kind of thing without the complications of water, you can have underground tunnels full of 6-12" rock and blow hot air through it, including outdoor chambers pre-intake with glass underground roofs open to the sunlight to concentrate the solar heat before it is taken fully underground to heat the rocks. Minnesota DOT has used this to heat their highway rest stop buildings.
Maybe instead of burying water pipes in the sand or the clay, you could bury an electrical resistance as it can heat above 100°C and so transfer more energy. If it is well calculated it could work directly on a solar panels array.
In Eastern Europe where temperature reach -40C they made the house floors more than hundreds years ago from few layers of clay mixed with dried straws and cow manure. The thickness of the floor was 50cm build pn top of packed river stones The walls were built with bricks made with same combination of materials. Are still parts of England where they still houses where they used same technique. The house needs an exterior coating to keep the moisture away. The ticker the walls or floor, you get better insulation. Was a very common way
@@ArkopiaUA-cam Siberia and Yakutsk use wood for construction as the best resistance to heating and thawing cycles. That includes not washing laundry indoors, to avoid moisture getting into the walls and lousing things up. Which is why they have separate outdoor buildings for laundry and bathing (the banya). Trees figured out what works best millions of years ago, and the ones that didn't went extinct.
Both your project and Patrick's are very, very impressive. Sure, you could have done more to improve the performance of your greenhouse, but you're standing among tropicals while you point this out! I do like the idea of foamboard down deep, under the slab and a sand or clay bed. And I'd love to see some clever person do computer modeling on these ideas before we spend a lot of money on one of them. We have three evacuated-tube solar collectors on our home's roof to supply all our hot water needs. They work really well, but they do have some challenges, like the need to run glycol through a heat exchanger with an additional pump, which adds to the complexity. If I could do it over (and I might yet!) I'd have the collectors on a ground mount, because keeping them clear of snow is a bit of a chore. It means I need to use a very long-handled snow rake, followed by a brush. It's a daily ritual that could have been made simpler if the panels were closer to me. Keep up the good work! It's people like you, willing to take chances and spend hard-earned money on new ideas, who advance our knowledge of better building practices. Cheers from Williams Lake, B.C.
My panels are steep enough angle that snow doesn't really stay on them for long. Frost does but simple solar says it let's enough light through that it doesn't really limit the heat production.
5:06 ...Clay would be a very good material for a Thermal Battery (which is fully insulated from the outdoors), yet that Thermal conductivity makes it an heatsink when exposed to the rest of the ground. Your current setup is better, clay only makes the bill get higher.
Have you thought about putting the electric heating elements directly into the sand or clay and deleting the water part of the system? From the chart it looks like sand and clay both transfer heat better then water. If you spaced the elements evenly through the medium you might be able to eliminate a chunk of the complication and cost. Just a thought. Really like what you've done.
I would say a huge no to the insulation under the slab due to lack of drainage. I'm sure this is why Patrick has problems keeping the humidity down. He mentioned some issues getting the watering dialed in. I suspect lack of drainage is contributing. I would be concerned about the long term effects, like mold and fungi growth.
@@ArkopiaUA-cam Why not build an air space below? Not saying anybody needs a nuclear bunker, but would an air gap using some gird style support structure be interesting?
I think sand batteries are used in industrial situations because they can be heated to thousands of degrees and have no retained moisture. Clay would not compact well with zero moisture, and if you try to charge it with more than the boiling temperature of water, you would have issues.
Sounds like the back wall can have an integrated sand battery, that could be insulated to not allow the heat to dissipate in the summer. Then uncover the front wall to allow the heat to dissipate in the winter. Or buy a shipping container and create a sand battery, then have a heat exchanger integrated into the greenhouse/house.
So then the back wall of the greenhouse can be a shipping container filled with sand/clay...plus the shipping container is structurally sound to build a roof upon. Include a water tank to preheat water and then you can also have domestic hot water.
How about insulating the sand/clay bettery (also water proof) separate from the house or greenhouse and put a heat exchanger in between that and the house/greenhouse to keep the temp where you need it for in-cement PEX? Then you could store heat all summer and should be able to make it through the winter
Very interesting. Have you worked out the pay back period on the greenhouse? I'm curious about valuable grow space being used as mass, I've thought about solar water into 2X 300L HWC then use a DIY heat exchanger as a heater. Or run copper pipe around the base plate or option A and B
The other thing is, i dont think we can get away with not heating our greenhouse without a Chinese style blanket . On those -40 days the amount of heat loss through the windows is to great to be overcome by the sand/clay battery alone.
Dean, I was just wondering how easily you could add a role up blanket on the inside of your greenhouse to stop heat loss in the evenings. It seems to me that it would be very practical and functional to have a system like they use on the Chinese greenhouses. Just a thought I wanted to share. Keep up the good work.
Yet another great info video from Arkopia!! Thank you! Would you build your own water/solar panels? Could you not heat under your plants using a separate pump and water line circuit with a thermostat?
You don't want to heat under your plants , their roots don't like it. Some of my lemon trees that are planted close to the concrete don't do well because some of the heat migrates over to their roots
My concern would be when the heat dehydrates the clay it may shrink and form cracks that cause the plastic water line issues. Just something to think about. I would do a test of the clay in an oven before doing what you suggest.
@@ArkopiaUA-cam a proper concrete slab should handle the stress. Heaving is water expanding as it freezes in the soil, if anything the concrete should thank you for preventing freezing:) The worst outcome is probably a kinked hose or leak.
I like what you are saying but a couple questions come to mind. Clay doesn't pack well and it retains water. As the Clay gets hot it will drive off water causing it to shrink under your concrete. Should your floor be floating to prevent it from sinking and cracking?
actually, you do not want layers of water line. i built my first geo-greenhouse (like an earth home) in the 80's. the whole greenhouse is below grade. when you stand inside, you can just see outside horizontally. my thermal mass was 3m below floor where the insulation layer is, above which is 20cm of clay, then the tubing, then more clay up to floor level. i did not have concrete floor. i grew heat loving crops in summer and charge the thermal mass but i did not have evacuated tube heaters, just the old school solar water heaters. i hope to build another of my greenhouses here at my current food forest project site in a year or so. here in zone 7a, i am still going with old school solar heaters as i was able to get 3 used ones very cheap. if they end up not being enough, i may later change them to evacuated units. i doubt i will have to as i am not planning on having tropical plants in mine. that will be a different greenhouse which will be on the south side of my cabin which i am going to setup with evacuated collectors and radiant heating with wood backup. in my projects, i try to reuse materials as much as possible and keep the cost and environmental impact as low as i can. great channel 🙂
Great video. We have been thinking of a sand battery/earth battery and were especially impressed with the figures coming out of Finland for sand batteries' potential. The idea of using clay is quite appealing, as we too have it in abundance in Sweden. However, or headache is bedrock... We have it at varying levels under our structures. Can we use that as a heat battery or is it futile without insulation from below?
i love the idea the only concern I would have is should a line ever be punctured. I suppose one could just run many different zones and cut off any trunks that are damaged.
my brother always has his bedroom window open because his computer puts out probably near 1000w of heat. i've wondered if it would be worth building a pc that has all water cooling tubes that then feed out of the case and into a sand battery built under the bed in the room, so that it heats up during the day while he's using the computer, his room doesn't get hot, he doesn't have to waste all the heat out of the open window, and then the heat comes out steadily during the night. though i have no idea how to balance such a design, how to know how thick to make the insulation, how large to make the mass. i picture spending ages building it and it just cooks him during the night :P i think its an interesting idea though.
Question... have you ever done some core samples or testing to see what the ground temp is, permafrost or such...? to see what your absorption gradient would be... maybe auger out some 30 cm holes a meter deep, put in a temp probe and backfill with various media - sand, clay, concrete etc. to collect some data for your particular area and geological conditions... the drawback to the sand or clay batteries is probably the extra cost and time to excavate, backfill and then make it firm enough to support the concrete and structures on top... but that is a one time capital cost... perhaps you can try these ideas in the animal barn floor...
Heat does NOT travel down. It bleeds off through the top and sides. You will have a zone of heat near the surface of the floor. Once that heat in the concrete equalizes with the air above it, the transfer stops...upward. As the air in the greenhouse loses heat to the atmosphere, your heat in the ground will equalize with the air in the greenhouse until all three are the same temperature. Heat will also radiate out the sides at the same time it is radiating into the greenhouse. It's best to have a "bathtub" of insulation below and around the foundation so that you can store more heat and focus all of it to radiate into the greenhouse. The denser and deeper the floor, the more heat it can hold for a longer time. Look at what Michael Reynolds did with earthships. Water might be a great heat TRANSFER mechanism, but not STORAGE.
Heat moves in all directions, but stratifies in the presence of cold air because it's less dense. If you're saying it doesn't travel down, is that something to do with the thermal delta of the ground vs the open air? I'm too tired to think about it, atm.
@@noneyabidness7226 Heat moves up and out...not down. That is physics. Heat will be similar to a light. Most of it is concentrated near the source, and the rest is hovering all around. When heat moves, it flows to the "lowest point of resistance." In this case it will be to the atmosphere.
If your underground system goes bad, would the absorbed moisture clay freeze and buckle concrete? Or with heat and time cause clay ground below the concrete to become crumbly and unstable?
Good stuff, been following for decades, not as intensely as you. Understand the moisture content of either sand or clay can be an affect, drier holding the most heat. Can you comment?
I have loads of clay where I live and I want to build a thermal greenhouse. Everyone on here is talking about the ability to store heat and transfer it from the ground to the pipes. My limited understanding is that you need good thermal coupling to transfer the heat? Surely if clay expands and contracts then sand must have a more efficient thermal coupling with the pipe?
Correction, clay soil does crack with 100% certainty. Sand does not. Even select fill cracks as it is a mix of sand and clay. It's the clay that makes it crack.
Years ago I watched a video of an African village where the used salt heated by magnifying glass which’s used for cooking. I have a couple of magnifying glasses but lazy enough to run any experiment to beam it in water to creat a heating/boiling point. Can you experiment with salt water in a smaller or separate line to see if it’s any better or not?
Just a guess but with the total cost of all of your innovations to reduce heating bills I could build an old conventional greenhouse and propane heat for many years.
For your barn i would consider using a sand battery for an air exchange unitas ventilation is crucial for animals. If you put it under the barn you will make a perfect area for bacteria to grow. As the warm bacteria rich air rises your animals will get sick and your barn will stink. Dont ask me how I know.😢
This content is amazingly useful for cold weather locations. Also, good to see someone say, "I've built something cool, here's how to make it", then admire others improvements :) Love this, good job!
Good info Dean, clay has far more surface area than sand so it makes sense that it would store energy. The nice thing about sand is that it has 100 percent compaction from a building point of veiw. Its good to note that we both used what we had available, you can't let perfection get in the way of excellence.
It was great that you guys were sharing info on here!
If there was a future leak with a clay mass, what would happen? Clay swells and expands with moisture. Just a thought. Thanks guys
@@dickdavidson3616 as long as it doesn't freeze it should be fine
Ya, expansion and contraction over a concrete pad might be an issue?
@@ArkopiaUA-cam
hey, have you ever heard of PCM, phase change materiel, to store a huge amount of energy at a constant temperature, store in the latent heat of fusion.
worth digging
New ways of thinking and applying new methods of heating large green houses! Clay vs sand!
So interesting for our future homes and green houses!
Really exciting, guys!
I am an artist !I live in Maine and love these types of sharing with You Tube 👏❤️✅❤️👏🥰👏👏👏
Please keep up your great work to promote natural green houses in cold climates!!
In your skittled rant, you actually made sence. I appreciate the insight of could have, would have thought. That is why we all seek whatever information we can to improve our plans.
Bottom line, your ultimate greenhouse build will inspire even better builds.
Awesomeness is contagious 🤠
I think your current concrete setup is already fairly good at capturing heat. What your friend in Alberta did was slow down heat loss by putting insulation under his sand and concrete. I think you could do the same, but rather than dig it up, think about where you are losing your heat. There is a community in Alberta, (might be Drake Landing, I don't remember) where they rely on the ground to be a thermal mass just like you (but with vertical pipes installed), but what they did was install insulation two feet underground outside, to keep the heat from escaping upwards. My theory is that you aren't losing heat straight down, as that is "charging the battery" and eventually the heat gradient will slow the heat loss downwards. Rather, you are losing heat sideways and up through the ground. Near the edge of your greenhouse the path for heat to travel involves let's say going down 2 feet, out 2 feet, and back up 2 feet, so travelling a distance of 6 feet total. Imagine putting insulation horizontally in the ground around your greenhouse - now the heat has to travel down 2 feet, out 10 feet, and back up 2 feet, so 14 feet total. I remember watching a youtube video of low-energy mobile homes being built this way where they didn't insulate the bottom of the mobile home, but insulated the ground around the mobile home and turned the ground beneath the home into the battery - with good results. Your greenhouse is likely already sitting on clay, just with perhaps a foot or two of non-clay near the surface. Just some food for thought.
Regardless of if I'm right or wrong, thanks for posting the video and giving us something to think about! Keep it up!
4 ft of verticle insulation around the perimeter, and 8-12 ft out of horizontal just under the surface around shop, greenhouse and house. That really helps.
@@ArkopiaUA-cam Ah, so you've already addressed that. Very cool! :)
Drake Landing is dead. In spite of millions of tax payer dollars, it never worked well. The homes always sold for less than comparable
@@bobboersema362The climate control worked well, though, which is what they're referring to. Shitty communities can always be a thing--people don't choose where to live based on the heating setup generally
@@bobboersema362 Aw man, that sucks. It would be nice to see one of these projects be wildly successful.
Like the jacuzzi!❤️👏❤️ in the greenhouse!
Really cool!😎🥰✅👏✅
The massive advantage that sand has is how much easier it is to work with.
I'm sure you've looked at the Drake Landing Project. It is practically a community heated with stored summer thermal energy.
Well I am interested in that 'passive solar' barn you mentioned. 🙂
Wow. Good information. Thank you.👍🏼
7:37 “at night time ‘heat rises’ “…. It doesn’t rise it radiates but you are correct with your rigid insulation underneath. It can only radiate to the floor surface at which point the air in contact with the floorsurface increases in temperature. The air itself, then expands and is displaced by the denser colder air, i.e. creating impression that heat rises through the movement of warm air up. The heat in the floor it will be radiant heat but the insulation prevents the energy moving down …sorry I’ve just been pedantic. 🤓I absolutely love your videos. Well done they are fantastic. They give me a lot of knowledge as I intend to follow your example and build a passive solar greenhouse. this is one of the best channel out there. Thank you😊
Great thinking out loud man 👍🌴🤠
Sand can be superheated to over 1000 degrees in a fully insulated container for long term storage of summer heat using parabolic mirrors. Then release it in the winter.
Great information; thanks for sharing!
Oh boy have you got my little brain thinking! I need to go back and see if I've missed any of your videos or if I've just forgotten some details (it happens a lot these days with everything else going on) because I'm suddenly full of questions and more to research. I've been so impressed with your greenhouse since the first video you put out about it and I dream of being able to replicate it as much as I can, but our leaders seem to want to drain our bank accounts more than any of their other goals.
Valuable information. Thank you. I'm bookmarking this video for the time if and when I get my own property in the Pacific North West. I want to achieve "Tropical" (not sub-Tropical) green house with aquaponics Tilapia and Fresh water Prawns, and exotic Tropical fruit trees.
What you say about the heat moving down is 100% correct. If you have temperature sensors installed in and below the thermal mass at different depths its easy to see heat moves down in the summer and up in the winter. It takes a huge amount of heat to charge the deep ground, most of which you wont get back. If you have temperature sensors outside the greenhouse in virgin ground at the same depth, you can confirm the average temperature of the deep ground under the greenhouse steadily increases and eventually becomes stable at a new norm based on the in/out energy balance. In my case this took 5 seasons. Insulating below the sand will fix the amount of mass which isnt an issue with evacuated tubes, as they are able to charge the mass to higher temperatures. The downside is heat loss increases with temperature and you cant plant directly in the mass. The upside is the heat stored is 100% sensible. A sand bed without bottom insulation will have a higher moisture content which will increase its thermal capacity, conductivity and diffusivity compared to dry sand. Fwiw, you would increase the overall system efficiency by installing air tubes in the planting areas. The sand battery essentially only heats the air. You can transfer some of that heat ( oxygen and condensed water) directly to the root zone, resulting in increased productivity. The primary function of a greenhouse is to grow plants :)
Only use sand for this. Clay expands and contracts an insane amount with temperatures. Sand is little to no expansion. Your cement would heave and crack. Or lift
Love your insights!!! Thanks so much for sharing. It helps us all improve. I'm building a tropical 4 season dome greenhouse with solar heated radiant PEX along with radiator fans to heat the air.
I'm on the plains and have almost exclusively clay so that will save the sand/gravel cost just using my local material.
I also wanted to put the PEX below the entire greenhouse including the plant beds, with the intention of only heating the soil to 90F where tropical and other beneficial soil microbes max out.
I plan to burry and insulate a 1000 gallon water tank, headed by thermal solar panels and use that for thermal storage, and supplement it on the cold cloudy days with a Liberator Pellet Stove in the greenhouse that I'll also use to heat water for the same radiant system.
Thanks again for sharing the info.
02:15 it´s not "in theory", as Daimler-Benz did some research decades ago, and they accnowledged, that the thermal loss down to the ground is an absolute thermic sinkhole and so is absolutely endless.
Admire your honesty though and the spirit, so absolutely: Thumbs up!
That then means the earth has endless heat rising up (a certain temperature well above freezing anyways).
I have done some calculations based on the water thermal capacity. The easiest way to store a huge amount of thermal energy, cheap, is to dig a big 1/4 swimming pool size whole, lay down poly and insulate it with straw bales from the bottom and all sides, add more poly and add water and cover it with straw bales. Run the energy from solar thermal panels through that water battery for the entire summer. 1 cubic yard, water can store 52KWh at around 55C temperature. A 30x15x1.5 yard pool will store about 35.5 MWh (and that is a lot of thermal energy - 127.6GJ) at 55C temperature. Clearly, increasing the size of the thermal pool increases the temperature proportionately. With a layer ( horizontally placed) straw bales the energy loss is around 3-6% per month! Clearly depending on the ground temperature as in the summer that loss is drastically lower.
Maybe just water is the best answer like you say. Makes sense to me
@@ArkopiaUA-cam looks like I'll have to build that swimming pool
Yes, water is the best choice, the storage of that water brings significant challenges. Sand and clay don't have these problems. You cannot use straw bales in or near the ground as they will degrade and eventually decompose. Foamboard is outrageously expensive but dependable and durable.
@@paulmaxwell8851 of course straw can not be used directly in the ground, this is why I mentioned poly, below them ( and clearly above them), as the PE or PP (or generally) any plastic based molecules are extremely sable in the ground ( no sunlight ). The cost effectiveness of this method is extremely favorable.
Furthermore if one could use flax bale straw with a baler that packs insanely tight, that bale, encapsulated on a 20mil poly will not rot in anyone’s lifetime and more. This thread/line of thought is worth serious R&D investment.
Honestly the difference seems to be that Patrick has a basic understanding of science. What you have done is nice but the knowledge of why things work is the reason his system seem so much more effective. Good to see you pushing the boundaries and seeing what can work.
We are in northern BC just south of the Yukon border. Our zone is 1A. This is very useful information!
Great video bro. Thanks.
I love this stuff so much.
Great info Dean, saving this video for some future projects!
Someday I would like to have a greenhouse like yours. Very nice. Just found your channel.
Patrick in Alberta has the added advantage of chinooks, periods throughout the winter of mild temps.
I've had many of the same ideas as you guys, it's great to hear someone putting this into practical application !!!
You also need to be very careful with using just water. Water freezes and expands if you allow it to freeze. That will destroy your piping or your storage tanks. That’s why glycol mixtures are used for heating buildings.
FYI -40C is the same as -40F
Thanks for sharing the info.
Buddy you going to have to build greenhouse 2.0 !!! Great video and great ideas.
There are many different types of clay, and some get real wild as to expanding and contracting when wet vs. dry at a single given temperature. More variation over different temperatures. So before spending the money it is safest to check out your own local clay for its physical characteristics. A good thing to read up on is "mudjacking" or talking to a local mudjacker about what you can get away with using your local clay types. One way to protect yourself is to have an underground curtain of French drainage around the building, so soil moisture variability is kept in check.
Great video mate I really liked the information you gave me and the idea of creating the heat sink for winter in a greenhouse.
Have a ripper mate!
Thank you for the great video !!!
Awesome video
If you want to regulate the temperature of the in-ground pipes, have it as a separate system by heating the ground loop through a heat exchanger from the heat source that is at a higher temperature. When you need to use lots of pipe in the ground, the cost of a heat exchanger could easily be offset by saving on the pipe.
*MY SYSTEM:*
4" gravel.
4" sand.
2" concrete floor.
*Greenhouse uses compost heating all winter long, using passive rebar radiator along the entirety of the rear wall, and a solar backup fan (rarely used) for circulation of temperature zones. Plantings customized to temp and solar zones. *It's very cheap, and it works down to -25c around here. Plus we get awesome compost for the next growing season.*
Smart ! 👍
Love it Dean,
Once I sell my house and build my own greenhouse - I’ll have you out too. Around Prince Albert National Park area… also, water is THE BEST heat sink of all per unit of volume vs. Other materials - with 1 caveat. That stops at 100 Degrees C. If one has a way of superheating the battery beyond boiling temp using solar mirrors or something crazy, then the best way to store heat beyond the 100C barrier is a sand battery.
Still going to recommend like I did in the last video that you pick up Anna Edey’s book Green Light at the end of the tunnel and look closely at her solar passive heat designs, it’s possible to direct heat air up to about 80C using a combination of metal roofing and polycarbonate air chambers, and to also run water lines along the back side of the metal. I just see so much wasted opportunity to use the summer heat to provide heat in the winter, and to also use the power of the sun to pull cool air through the ground for passive a/c and then to use that heated air for heat storage.
I plan to dig the biggest hole possible (way beyond 4’ down) and install channels of 3/4” washed rock just big enough for hot air infusion, with very large clay batteries between the layers of gravel protecting the gravel with landscape fabric. Water lines placed directly into the clay, and I’d even be curious to have a serviceable pv direct heating elements embedded into the middle of the clay batteries as a way to possible superheat certain areas… so many ideas flowing out of these videos!
I’ve never thought of the pv direct to heating elements before watching your videos - I would like to run a lot of experiments too - but of course have to utilize cash as efficiently as possible, and I think the PV direct might be too expensive to start.
Another technology I’m interested in trying out would be to order solar cooking (oven) vacuum tubes off of Alibaba wholesale, and run copper lines through them vs. The expense of the water heating specific vacuum tubes (would like to do a cost comparable on that idea).
Thanks for the great videos!
I looked for that book, and people want a ton for a copy. Must be good. 👍
@@ArkopiaUA-cam I’ll let you have mine when the occasion arises.
@@ArkopiaUA-cam Crikey! I just looked at the extortionist prices on Amazon! $350 USD??!! I bought mine direct from a different source in the US about 2 years ago and paid about 40-50… I need to see if the website still exists, if so, I’ll provide it here.
The book is up to 700$ by now 😅
an issue that may arise is time delay i.e takes a while to warm up but more importantly takes time to cool down. I have electric storage heaters and the issue I have had is the temps outside can vary wildly so making storage inefficient.
One of the primary advantages of sand over clay is that it is easier to compact. Clay needs to be spread and packed in thinner layers.
Even compaction is important to prevent settling and cracking in your concrete floor.
❤it’s not a theory,the earth has taken the heat almost endlessly ❤
I don't have sand or clay but I sure have a ton of rocks ... of course that's why they call it Rocky mountains where I live
Thank you for the very informative video!!!
Before they were called the Rocky Mountains they were called the Stony Mountains.
@@jackieow Interesting as Calgary has Stoney Trail now
a Batch rocket mass heater would be awesome in this setup. A mass heater just makes sense for this kind of setup.
Hey, really appreciate the content. I am going to copy a ton of your designs and save myself a ton of time and money. I got an offgrid greenhouse youtube video coming out next week that you would like. All passive, no electrical, Zone 6. earth tubes. Uses Finches and frogs to control bugs
I think one of those duvet style insulation blankets that they use on Chinese greenhouses would probably put you over the top. Anything that could reduce your heat loss out the big glazing side would make a huge difference.
You should look at parabolic heat put in front of your greenhouse and use oil and a small pump have a 4 foot sand battery box in front of your window. Cheap to do and just insulate it so it doesn’t give off to much heat. I believe you could heat it up to 300 F
You don’t need more water lines in layers to store more heat. That is the most expensive component of the system. You simply need to insulate your heat battery and make sure that it’s big enough to radiate for the length of time you needed to radiate. Adding heat to that system will last a long time because of the thermal mass.
I wouldn’t recommend running well water or anything through those pipes. Keep it a closed loop and use a heat exchanger if you want to cool the loop because you don’t want a bunch of dirt or any kind of debris accumulating in that system. Keep it a closed loop so that you don’t have to dig it up and have massive issues with it.
I like the idea of warming up the ground instead of trying to store large amounts of hot water somewhere, seems a bit more realistic. Seems like there are lots of upsides to my soil being 95% sand.
Like it. Why not also add a thermal blanket that rolls out across the ceiling windows at night. That combo would be awesome
One of the northern European country uses sand, as power plant. Saw it within the last 4 years.
yes that is when you can take advantage of the high temperature capabilities of material like sand even though they have far lower heat storage capabilities per degree x mass....(latent heat)...so with sand or rock or clay you can charge a smaller amount to very high temperatures (red hot, thousands of degrees. One issue with going for very high temps is the heat loss is grater because of the increased differential in temp that drives it.... In my case I place the 2000F mass inside the living space..that way any amount that "leaks" through the insulation is not wasted to the outside. Of course one needs to be careful with high temp rocks. In the UK they have been using similar "storage heaters" for a very long time as thermal batteries, they were very common, not as easy to find in the USA.
Polar Night Energy? XD In Finland.
I think Dong Jianyi's chinese passive solar greenhouse in Alberta could give you perspective on using clay - I'm pretty sure he uses 1 meter wide wall on the north side, with a bunch of insulating materials. Dan bostan's passive greenhouse experiences in montreal/quebec is pretty genius too. He converted big barns into low-to no energy input for growing fruit trees. I hope these two folks can help you perfect your greenhouse! cheers.
One thing you could do to additionally insulate your greenhouse is build a “Frost Proof Shallow Foundation” around the outside. What that means is you can excavate around your building, install rigid foam around the outside perimeter, 16” under the soil, out to an area of around 3 feet around the building. Exact numbers would need to be calculated, but that’s a ballpark figure.
What that does is move the frost line away from your foundation by slowing the heat loss from the soil during winter. This technique is generally used to prevent frost heave without digging a basement through the frost line, and it generally works even in completely unheated spaces like garages.
Just a bit of food for thought on your next greenhouse build…
Did that. 12 ft out around greenhouse and shop. 4ft out around barn. 👌💪
@@ArkopiaUA-cam Oh wow. Well, I guess you’re already not doing too bad!
If you skipp the concreat and idé clay and strax for the surface it Will be easier to re do if necessary. Also it will cost les. The surface of the clay and straw use to be treated with linseeds oil and then become water resistant.
A few thoughts: Firstly, clay shrinks and expands with humidity - so be careful about having it support a layer of concrete if it is going to be seasonally heated. Secondly, I think your larger earthern battery could still out perform a smaller sand battery in the long run. The longer it takes to heat up the longer it will take to cool down and I think that a cooler heat source that can buffer tempertures seasonally is more usesful in your contex than a hotter heat source that can only buffer temperature for tens of weeks.
I don't know much about greenhouses but as a physicist my guess is Patrick's idea will work fine, and for your greenhouses its a good experiment, but you'll probably need moisture in the soil to use the earth effectively.
If you add a layer of hydration pipes below the pex might be smart. You could also use it to pull the extra heat out when it gets too hot.
Heat rises, thermal loss down will be minimal. With the perimeter insulated your heat sink is very effective.
NO!!! This is a common misperception. Heat energy moves from an area of warm to cool, regardless of direction. It doesn't 'know' up from down. Heat loss through the bottom of an insulated cube will be exactly equal to the heat loss through the top, or any one side. Warm FLUIDS (air, water) do move upwards, but that's an entirely different matter.
To do this kind of thing without the complications of water, you can have underground tunnels full of 6-12" rock and blow hot air through it, including outdoor chambers pre-intake with glass underground roofs open to the sunlight to concentrate the solar heat before it is taken fully underground to heat the rocks. Minnesota DOT has used this to heat their highway rest stop buildings.
Maybe instead of burying water pipes in the sand or the clay, you could bury an electrical resistance as it can heat above 100°C and so transfer more energy. If it is well calculated it could work directly on a solar panels array.
In Eastern Europe where temperature reach -40C they made the house floors more than hundreds years ago from few layers of clay mixed with dried straws and cow manure. The thickness of the floor was 50cm build pn top of packed river stones The walls were built with bricks made with same combination of materials. Are still parts of England where they still houses where they used same technique. The house needs an exterior coating to keep the moisture away. The ticker the walls or floor, you get better insulation. Was a very common way
In Canada we have nothing older than barely 150 years, and no old tech like that. Most houses are wooden sticks.
@@ArkopiaUA-cam Siberia and Yakutsk use wood for construction as the best resistance to heating and thawing cycles. That includes not washing laundry indoors, to avoid moisture getting into the walls and lousing things up. Which is why they have separate outdoor buildings for laundry and bathing (the banya). Trees figured out what works best millions of years ago, and the ones that didn't went extinct.
Both your project and Patrick's are very, very impressive. Sure, you could have done more to improve the performance of your greenhouse, but you're standing among tropicals while you point this out! I do like the idea of foamboard down deep, under the slab and a sand or clay bed. And I'd love to see some clever person do computer modeling on these ideas before we spend a lot of money on one of them.
We have three evacuated-tube solar collectors on our home's roof to supply all our hot water needs. They work really well, but they do have some challenges, like the need to run glycol through a heat exchanger with an additional pump, which adds to the complexity. If I could do it over (and I might yet!) I'd have the collectors on a ground mount, because keeping them clear of snow is a bit of a chore. It means I need to use a very long-handled snow rake, followed by a brush. It's a daily ritual that could have been made simpler if the panels were closer to me.
Keep up the good work! It's people like you, willing to take chances and spend hard-earned money on new ideas, who advance our knowledge of better building practices. Cheers from Williams Lake, B.C.
My panels are steep enough angle that snow doesn't really stay on them for long. Frost does but simple solar says it let's enough light through that it doesn't really limit the heat production.
On pv panel it matters a lot more
The University of Minnesota has a deep winter greenhouse concept that applies this idea if you haven’t seen it, you should check it out.
Dude, what awesome content! All the best to you from B.C
Yea sand battery's are pretty cool , watched sum videos on it on UA-cam. Thermal battery an copper coils. .
5:06 ...Clay would be a very good material for a Thermal Battery (which is fully insulated from the outdoors), yet that Thermal conductivity makes it an heatsink when exposed to the rest of the ground.
Your current setup is better, clay only makes the bill get higher.
Have you thought about putting the electric heating elements directly into the sand or clay and deleting the water part of the system? From the chart it looks like sand and clay both transfer heat better then water. If you spaced the elements evenly through the medium you might be able to eliminate a chunk of the complication and cost. Just a thought.
Really like what you've done.
Probably take a lot of elements scattered through, which is why water is usually used to distribute heat
Styrofoam floats and you have a pond, may make a great heat sink
I would say a huge no to the insulation under the slab due to lack of drainage. I'm sure this is why Patrick has problems keeping the humidity down. He mentioned some issues getting the watering dialed in. I suspect lack of drainage is contributing. I would be concerned about the long term effects, like mold and fungi growth.
Insulation drains, a vapour barrier would not.
@@ArkopiaUA-cam Why not build an air space below? Not saying anybody needs a nuclear bunker, but would an air gap using some gird style support structure be interesting?
I think sand batteries are used in industrial situations because they can be heated to thousands of degrees and have no retained moisture. Clay would not compact well with zero moisture, and if you try to charge it with more than the boiling temperature of water, you would have issues.
Sounds like the back wall can have an integrated sand battery, that could be insulated to not allow the heat to dissipate in the summer. Then uncover the front wall to allow the heat to dissipate in the winter. Or buy a shipping container and create a sand battery, then have a heat exchanger integrated into the greenhouse/house.
So then the back wall of the greenhouse can be a shipping container filled with sand/clay...plus the shipping container is structurally sound to build a roof upon. Include a water tank to preheat water and then you can also have domestic hot water.
How about insulating the sand/clay bettery (also water proof) separate from the house or greenhouse and put a heat exchanger in between that and the house/greenhouse to keep the temp where you need it for in-cement PEX? Then you could store heat all summer and should be able to make it through the winter
Very interesting. Have you worked out the pay back period on the greenhouse?
I'm curious about valuable grow space being used as mass, I've thought about solar water into 2X 300L HWC then use a DIY heat exchanger as a heater. Or run copper pipe around the base plate or option A and B
The other thing is, i dont think we can get away with not heating our greenhouse without a Chinese style blanket . On those -40 days the amount of heat loss through the windows is to great to be overcome by the sand/clay battery alone.
Agreed. Maybe that’s money better spent.
Dean, I was just wondering how easily you could add a role up blanket on the inside of your greenhouse to stop heat loss in the evenings. It seems to me that it would be very practical and functional to have a system like they use on the Chinese greenhouses. Just a thought I wanted to share. Keep up the good work.
Yet another great info video from Arkopia!! Thank you! Would you build your own water/solar panels? Could you not heat under your plants using a separate pump and water line circuit with a thermostat?
You don't want to heat under your plants , their roots don't like it. Some of my lemon trees that are planted close to the concrete don't do well because some of the heat migrates over to their roots
My concern would be when the heat dehydrates the clay it may shrink and form cracks that cause the plastic water line issues. Just something to think about. I would do a test of the clay in an oven before doing what you suggest.
Ya, or heave the concrete pad above
@@ArkopiaUA-cam a proper concrete slab should handle the stress. Heaving is water expanding as it freezes in the soil, if anything the concrete should thank you for preventing freezing:) The worst outcome is probably a kinked hose or leak.
I like what you are saying but a couple questions come to mind. Clay doesn't pack well and it retains water. As the Clay gets hot it will drive off water causing it to shrink under your concrete. Should your floor be floating to prevent it from sinking and cracking?
You could have a 40' container insulated & as a heat battery buried below the battery you describe as a secondary system.
I am interested if this can be done in reverse in deserts and keep the greenhouses cool.
actually, you do not want layers of water line. i built my first geo-greenhouse (like an earth home) in the 80's. the whole greenhouse is below grade. when you stand inside, you can just see outside horizontally. my thermal mass was 3m below floor where the insulation layer is, above which is 20cm of clay, then the tubing, then more clay up to floor level. i did not have concrete floor. i grew heat loving crops in summer and charge the thermal mass but i did not have evacuated tube heaters, just the old school solar water heaters. i hope to build another of my greenhouses here at my current food forest project site in a year or so. here in zone 7a, i am still going with old school solar heaters as i was able to get 3 used ones very cheap. if they end up not being enough, i may later change them to evacuated units. i doubt i will have to as i am not planning on having tropical plants in mine. that will be a different greenhouse which will be on the south side of my cabin which i am going to setup with evacuated collectors and radiant heating with wood backup. in my projects, i try to reuse materials as much as possible and keep the cost and environmental impact as low as i can. great channel 🙂
Great video. We have been thinking of a sand battery/earth battery and were especially impressed with the figures coming out of Finland for sand batteries' potential. The idea of using clay is quite appealing, as we too have it in abundance in Sweden. However, or headache is bedrock... We have it at varying levels under our structures. Can we use that as a heat battery or is it futile without insulation from below?
I think it works either way. Insulation or not. Your ground is probably warmer than ours, so maybe no insulation is better too
"minus 40 or worse Celsius!" - you heard it here first folks
How would you pack the clay? How much moisture would be in the clay? Thanks for all your videos!!
Just a plate compactor I suppose. I guess have to make sure don’t squish or puncture water lines. Sand might be better in that respect.
i love the idea the only concern I would have is should a line ever be punctured. I suppose one could just run many different zones and cut off any trunks that are damaged.
@@ArkopiaUA-cam For clay a jumping jack (small) or sheeps head vibrartory roller (big) is ideal
@@ArkopiaUA-cam I've got some rocks in my clay, could use sand for the pipe layer for protection.
my brother always has his bedroom window open because his computer puts out probably near 1000w of heat. i've wondered if it would be worth building a pc that has all water cooling tubes that then feed out of the case and into a sand battery built under the bed in the room, so that it heats up during the day while he's using the computer, his room doesn't get hot, he doesn't have to waste all the heat out of the open window, and then the heat comes out steadily during the night.
though i have no idea how to balance such a design, how to know how thick to make the insulation, how large to make the mass. i picture spending ages building it and it just cooks him during the night :P i think its an interesting idea though.
I think my main computer is 1500 watts.
Question... have you ever done some core samples or testing to see what the ground temp is, permafrost or such...? to see what your absorption gradient would be... maybe auger out some 30 cm holes a meter deep, put in a temp probe and backfill with various media - sand, clay, concrete etc. to collect some data for your particular area and geological conditions... the drawback to the sand or clay batteries is probably the extra cost and time to excavate, backfill and then make it firm enough to support the concrete and structures on top... but that is a one time capital cost... perhaps you can try these ideas in the animal barn floor...
I’m not sure what I’m going to do with the barn yet. Super insulating for sure though.
Heat does NOT travel down. It bleeds off through the top and sides. You will have a zone of heat near the surface of the floor. Once that heat in the concrete equalizes with the air above it, the transfer stops...upward. As the air in the greenhouse loses heat to the atmosphere, your heat in the ground will equalize with the air in the greenhouse until all three are the same temperature. Heat will also radiate out the sides at the same time it is radiating into the greenhouse. It's best to have a "bathtub" of insulation below and around the foundation so that you can store more heat and focus all of it to radiate into the greenhouse. The denser and deeper the floor, the more heat it can hold for a longer time. Look at what Michael Reynolds did with earthships.
Water might be a great heat TRANSFER mechanism, but not STORAGE.
Heat moves in all directions, but stratifies in the presence of cold air because it's less dense. If you're saying it doesn't travel down, is that something to do with the thermal delta of the ground vs the open air? I'm too tired to think about it, atm.
@@noneyabidness7226 Heat moves up and out...not down. That is physics. Heat will be similar to a light. Most of it is concentrated near the source, and the rest is hovering all around. When heat moves, it flows to the "lowest point of resistance." In this case it will be to the atmosphere.
If your underground system goes bad, would the absorbed moisture clay freeze and buckle concrete? Or with heat and time cause clay ground below the concrete to become crumbly and unstable?
My greenhouse doesn’t have anything going, is protected from frost, and will never freeze.
What would be your advice for a zone 4 passive solar greenhouse construction in pure sand?
Good stuff, been following for decades, not as intensely as you. Understand the moisture content of either sand or clay can be an affect, drier holding the most heat. Can you comment?
Not a lot. I had concerns about expansion and contraction under a concrete pad though.
I have loads of clay where I live and I want to build a thermal greenhouse. Everyone on here is talking about the ability to store heat and transfer it from the ground to the pipes. My limited understanding is that you need good thermal coupling to transfer the heat? Surely if clay expands and contracts then sand must have a more efficient thermal coupling with the pipe?
Correction, clay soil does crack with 100% certainty. Sand does not. Even select fill cracks as it is a mix of sand and clay. It's the clay that makes it crack.
Years ago I watched a video of an African village where the used salt heated by magnifying glass which’s used for cooking. I have a couple of magnifying glasses but lazy enough to run any experiment to beam it in water to creat a heating/boiling point.
Can you experiment with salt water in a smaller or separate line to see if it’s any better or not?
Just a guess but with the total cost of all of your innovations to reduce heating bills I could build an old conventional greenhouse and propane heat for many years.
Biomeiler and biogas/bio digester are potentiel options.
This could be done under mobile homes that need to keep their pipes from freezing in winter and to keep the floor warm.
For your barn i would consider using a sand battery for an air exchange unitas ventilation is crucial for animals. If you put it under the barn you will make a perfect area for bacteria to grow. As the warm bacteria rich air rises your animals will get sick and your barn will stink. Dont ask me how I know.😢
Yes. Stale, humid air is not good.👍
What about oil instead of sand, couldn't it store even more heat than water to heat up the sand to a much higher temperature?