How To Build a Climate Battery - Day 3 - Construction In Passive Solar Greenhouse
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- Опубліковано 9 жов 2020
- In this video we continue the process of building the climate battery for our new passive solar greenhouse. Climate batteries also called GAHTS and subterranean heating and cooling systems store energy in the earth when there is a surplus of heat in the greenhouse for later use.
We spent most of the summer performing thermodynamic analysis on our greenhouse to determine if they even worked and to our amazement they do. In fact our analysis showed that they have the ability to store energy seasonally which was better than I was expecting.
Our model anticipates that we should be able to keep our greenhouse above zero until January 15th of most years without any fossil fuels to keep it heated. This should provide us with 3 seasons of robust food production with minimal costs.
See the videos for all 3 days of climate battery construction:
Day 1 - • How To Build a Climate...
Day 2 - • How To Build a Climate...
Day 3 - You are here!
If you're ready to build a life changing greenhouse, Register for the course at: vergepermaculture.ca/passive-...
Introduction to Passive solar greenhouse design manual vergepermaculture.ca/product/...
Greenhouse design course vergepermaculture.ca/product/...
Links to topics in this video:
3:03 Backfilling considerations
3:21 First backfill
3:31 Remove tape covering holes
3:40 Pull out the second set of pipes
3:51 Connect the pipes to both manifolds
4:00 Second backfill
4:25 Adding Topsoil
4:58 Rob’s conclusion
6:05 Subsoil
6:20 indicators of soil health - Rastafarian roots7:35 lesson learned about backfilling
8:13 Why no insulation under the pipes?
8:57 Were the pipes too dense?
10:07 Air collection in the greenhouse plan
About Rob Avis and Verge Permaculture:
In less than 10 years, Rob & Michelle Avis left Calgary’s oil fields and retooled his engineering career to help clients and students design integrated systems for shelter, energy, water, waste and food, all while supporting local economy and regenerating the land. He’s now leading the next wave of permaculture education, teaching career-changing professionals to become eco-entrepreneurs with successful regenerative businesses. Learn more and connect with Rob & Michelle at vergepermaculture.ca/
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Thanks for the vid, I have 56f 5 feet down in a basket with collector on hose in center. I am just about to add 20-25 feet of hose next week. I am using emergency foil blankets on top of tubes like you said. Our frost line is only 18" so think I am safe. Greenhouse is 42 sq/ft full of citrus in Canada. :)
Amazing, I think I'm as excited about this as you are Rob!
I think this is super cool!
This couldn't come at a better time! We are planning our own greenhouse for 2022 once we get our other projects completed. I will be watching and learning.
These are wonderful vids!!! Just eager to see what’s going on currently
Great job Rob!! It appears that you're using numerous build concepts from the passive solar market green house that you designed a couple of years ago.
I'm guessing that the Avis clan has moved out of suburbia and into a more rural setting. Good choice, not only for the channel but mainly for family security.
We have used self tapping screws to hold PVC pipe together for years,. It works out very well for systems that you want to take apart and be able to reuse in other places.
The heat intake manifold is a great idea!. Would totally heat the air up more. i havnt seem that in any other green houses with a climate battery!(on my limited online searches over the last year or so). I am in the trades and its building code to have insulation underneath your floor. Hot air rises! But heat is conducted through solids in all directions. But the earth has a fairly constant tempature and in this type of greenhouse maybe it is not a concern! My main concern is water filling the pipes...and water will also conduct heat extremely well...i really want to build one of these on my farm but i may have to raise it above the water table. Once again thanks for the videos.
when you talk about why you did not use insulation underneath I think the statement that heat rises is incorrect , as it is only true for convection not conduction
Rob that’s a great way of doing the battery, a manifold at both ends and straight run pipes. Simple, lower cost and efficient. Way to go. As far as the connectors, as long as the material of both sizes of pipe is the same (poly) you should be able to weld them with a heat gun or a torch. A little tricky but super strong, much better than a couple of screws.
Good day Rob and team!
I couldn't find your video(s) about the making of the wooden frame of the greenhouse. Could you or anyone else help me out, please?!
can likely use tecbolts to fix pipes to the manifolds they are self-tapping so cut their own hole - saves pre-drilling. they can cut through metal - that is their most common application - to fix metal roofing sheets. you can get them from 1/2" upto 8" and more.
Great video! Thanks guys. But I'm always wondering why the manifold diameters are so small? I would really appreciate it, if someone could explain that to me. In my mind... for perfect flow the manifold circular area would best be the exact sum of the ground pipes circular areas. Am I wrong?
What I mean is, that how I understand it a 500mm/20" diameter manifold could actually only accomodate 25x 100mm/4" ground pipes.
But did it create a 4 season greenhouse that worked well. Question is for the Channel Producers
Thank you for posting such an interesting video! Noting that this was from a couple of years ago, I'm interested in how it worked out, particularly without bottom insulation.
I know comon knowledge says heat rises, but that's not strictly true. Hot air does, but only because the medium is fluid and hot air is less dense. In soil, I would expect heat to be conducted in all directions, seeking cooler matter, until stopped (or slowed) by insulation.
The fact that nothing has been posted as regards the performance tells you all you need to know. Long tubes and low airflow rates makes for very poor cooling performance. The bulk of the heat stored in the mass comes from cooling.
one thing you could potentially have done is put thermal probes in the ground to keep track of the temperature. That would have allowed you to make real time models estimating when you'll get your first day of freeze and what not.
Amazing!!! One question. My greenhouse floor plan is 12' x 16'... How can I design the number of pipes, etc... Thanks for your help! Love your videos.. Soo much fun.
Did you optimize the manifold diameter? I wonder if larger diameter manifolds would reduce air drag, lowering fan power needs. Also, has anyone measured heat and humidity going both in and out of a greenhouse climate battery/GAHTS?
Very interesting videos! Love your scientific approach! We're thinking of building a climate battery greenhouse using water rather than air as the heat transfer fluid. In this case we'd place a grid of water pipes about 9' in the ground like a geothermal heat pump system but not necessarily connected to a heat pump. The heat capacity is much greater for a water/glycol mix vs air. Could use a heat pump or just coils and a fan as the heat exchanger in the greenhouse. Comment? Is there any data on such a system? Also a passive water/glycol-filled trumb wall along the back wall will of any greenhouse will supply significant heating. What does your model say - trumb wall vs in-ground airflow battery, how much of an advantage is the in-ground piping particularly in less extreme climates?
How do you know that the air is moving through each pipe equally?. Seems that if its only going through some of the runs then you wasted money. Maybe you should have tested the flow in each run before backfilling and possibly install dampers to get it dialed so you are using the most area possible underground.
Hex head self tapping screws.
Does this concept work in the southern US where it’s hot and humid? Curious how much it would cool down in 100+ degree weather in the south to be able to grow vegetables. Thanks for all your content!
Take a shot every time he says pipes
I’m curious how much topsoil and compost I should be trying to fill over the top of these pipes? I wasn’t exactly sure from your video
Viva Christo Rey
So why did you not separate the two levels of tubes more? Wouldn't it have allowed more heat/cool storage and better efficiency of the system? Also why everything inside the greenhouse?
Would you consider running shorter 4inch tubes? The intake in the middle and one on each end? Or not necessary.
Hi Rob, have you considered rammed earth walls for the perimeter rather than concrete?
What's the construction of your retaining walls ? Are the walls and floor slab insulated to stop cold bridging ?
Would a base layer of insulation followed by a 1' of so layer of earth, then the pipe, then more earth keep heat from escaping downward or does the constant earth temp from below help the system?
Do you get significant moisture / condensation coming out of the ground?
2 questions about improving performance:
1) Would reversing the direction of airflow between heat storage and extraction improve performance? (I imagine it would, if the heat bank builds up a differential in soil temperatures between the inlet and outlet corners over the course of a day).
2) Would it be feasible to operate heat storage at a slight positive pressure (~1-3psi) and heat retreval at a slight negative pressure. This would augment the system with a regrigeration/heat pump cycle.A 5-10 deg C raising or lowering of temperature would substantialy increase heat energy cycled/day, and might enable reduced sizing of excavation & piping. I would expect a very high coefficient of performance on a heat pump cycle with such small temperatire differential.
Is there a follow up video? Looking for more information or contact info? Thank you!
I have built a geothermal system as well . Now I want to control the fans. Do you have a recommendation for a controller that will turn the fans on at a high set point ( 21C) then off at 20 C and on at 5c and off at 6C? I’m struggling to find anything but electronic controls are not my strong suit.
Hi there we are leaving In TaTa Creek BC. We are in early planning of 3/4 season green house 30/8 miters. Wondering if you can recommend contractors for building it?
Does the air flow dry the soil out fast?
did you consider using sand as your backfill material since sand holds heat longer (or so i am told) than soils and clay? Some good research on that in Norway i think.
I wonder if this can be done in a house.
Is it necessary to connect each of the smaller pipes at each end? What would the impact be if you, for example, ran one pipe from the inlet side, down to the other side, back to the inlet side, back to the outlet side and then connected it to the outlet manifold? I understand that that would increase resistance to airflow, but since you are trying to exchange heat, that may not be a bad thing. This would significantly reduce the number of fittings (cost and time). What is the practical limit on the length of one of the small pipes?
What are the white pipes made of? They look like the earth would crush them.
Have you looked To other materials that hold heat better around the cross pipes instead of soil?
That's a good question! I've watched the LDS guy & he used gravel & said that wasn't as good ... not sure what he concluded to use. He said something about using the sock over the pipe if you used gravel wasn't necessary???
I was wondering the same thing... debating whether a material that held heat was better than one that transferred heat. Seems to me you'd want to disperse the heat as fast as possible for an efficient system. All soils aren't equal too- does a higher clay or organic content help?
Thank you for this amazingly detailed video! Question: We are in Ontario and in the design phase (taking the PSG Design Course) for a similar ICF foundation, 825 sq ft GH with earth-battery. How much depth of soil between each layer of weeping pipes? For e.g. we'll dig our foundation 6ft below grade and I'm figuring with 2 layers of pipes (similar to yours) they would sit about 2ft-3ft apart (vertically). The thinking is to allow the pipes to heat the maximum amount of soil without the problem of each layer 'double heating' the same soil, as might occur if the layers were too close to each other vertically. I hope this makes sense. Thank you!
Hope u put some Solar Hot Water
@@guiltfreehotwater4354 I don't think I understand, can you elaborate? The question is regarding the earth tubes and how much separation is between the layers. Thx
no rocks/boulders in alberta soil ??
Some Solar Hot Water would help?
As far as I know heat only rises when convection is involved in a liquid or gas, it conducts in every direction in a solid like earth.
A picture of the header would have been nice 🙁
What is the size of the greenhouse?
been following you and your work for a long time now. incredibly valuable (and timely) information. Thanks so much for everything you do and making so much available to the masses. would you give a rough estimate of the cost of a project like this (including your time as a consultant) so we could formulate what would be feasible for someone else to replicate.Thanks again so very much. Rusty R.
whats the lifespan of those pipes?
If you use gravel instead of earth you would not need any pipes & you would store more energy.
Why wood , it s going to rot.
heat doesn't rise hot air rises. :)
Warm air is less dense so it rises to the top of the building. In the atmosphere it condenses and becomes clouds then rain or snow.
It might be that in the underground pipes, the warmest air is generally in the top of the pipe, so the bulk of the stored heat is stored above the pipes versus below.
I must correct one point: heat does NOT move upward. That is a popular misconception. Heat doesn't know up from down, it simply moves from hot to cold. That is, heat will move in any direction that is cooler than the source. It IS true that hot FLUIDS can move up, but that's completely different. When dealing with solids, heat will happily head straight down if that's cooler.
Would your greenhouse perform better if you had laid foamboard down under those pipes? Absolutely. I think it will perform moderately well anyways, though. Great job overall!
What about the destruction of the trees? Why wood? Aluminium is lighter,strong and less obstructive. The technology has been vast on this/Even triangles for curves. Plastic is an insulator and conducts heat very poorly. Are those pipes plastic? If so you will just be moving most of the heat in one end and out the other with very little being transferred to the earth. A fan can to that above ground.
Secondly there is an ambient temperature of the ground at a certain not so seep level. That is how trees survive winters.
This latent heat would be almost the same as the heat coming from the plastic pipes making them redundant.
So much talking....and repeting. It is boring to wait for Real Info.