An Underground, Walipini-Style, Greenhouse--for the Suburbs!
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- čas přidán 10. 08. 2022
- There is no way I am getting a walipini approved by our building department, but this was the next best thing--a partially buried, lean-to greenhouse design. I walk through the step-by-step process of how I used sun angles to place my thermal mass and shading for maximum benefit. The site I use for sun angles is: www.suncalc.org/ Enter your zip code, your target date, and time of day in the top left box and then look for 'Altitude' listed, below (the angle above the horizon).
I have never heard of walipini until today and you just explained the basics in such a clear and concise way! Thank you for sharing. I look forward to seeing your project as it progresses!
I will warn you that once you know about them, you will want one. :) I’ll do an update “tour” once it’s all complete-probably not until next spring
That's a good reason why I could not live near any city. All garden related projects should be approved by default. They are where I live :)
I whole-heartedly second this motion
Great video!
Thank you!
Being a relatively new subscriber, I am totally excited to finally be seeing a new project from start to finish. 😀
I’m glad! I’m even more excited to get these done :)
Really interesting, really helpful: thanks for sharing.
Glad it’s useful!
Walipinis have one huge flaw most people overlook that makes them much less efficient than they could be. Heat lost straight into the ground. You only want the geothermal ground mass effecting your Walipini temperature during cold nights below 50 deg and hot summer days above 85 deg. A much better design is to have all vertical walls and the floor that are in contact with the geothermal ground mass insulated with an air flow gap between the ground mass and insulation. This way, everything inside the walipini and including inside thermal mass, can be isolated from the constant 50-55 deg ground temp and all your solar gain heat during the day isn't lost into the ground. Then at night when the temp inside the Walipini drops to around 50 deg and lower, the air everywhere in the geothermal air gap behind your insulation will rise and go through vents to automatically heat your greenhouse during the cold nights. No fans needed,the air will naturally circulate, and when the day time temps again rise above 55 deg, the air will stop circulating and not flow out of the air gap. This design is way more efficient. People don't realize they are losing a massive amount of daytime solar gain heat straight into the ground in normal walipini designs.
Interesting! I don’t think I could’ve pulled that design off with this context (attached to a conventional suburban build) but it sounds fascinating.
Very interesting on your plans. Well thought out, don’t know where you live, we live in Louisiana in the sun belt, north La.
We have 2 greenhouses and raise orchids, a lot of orchids for over 30 years. If you are in the sun belt, you will need fans to get the heat out in summer months or everything in that oven will cook. 1 of our houses is 2’ deep in the ground and is best in winter for heating the other is built on top and is harder to heat in winter. Of course both are covered with 60% shade and have wet walls and lots of fans to keep cool and pathogens at bay.
Nice! We are in Michigan so very much NOT the heat belt 😂. I’m jealous of your growing season. Mine will mostly be used to start transplants earlier in the spring, and for growing winter greens.
Just today I was showing my boyfriend that the foundation blocks under the solarium are tilted. We were discussing different things to do about the problem and I remembered daydreaming about a walipini a couple years ago.
With the possibility of it possibly going to happen I’ve been watching walipini videos and here you are.
I see this was a year ago. I’m wondering how things are going for you now. I’m gonna look for an updated video but I’d there isn’t one then please do let me know how it’s going for you. What works well what not so well… what would you do different.
I was thinking… you have a lil bit of room under the water tanks according to your design there…. Would be a good spot for mushrooms!😉☺️😁
Hey! I did do one update, here: czcams.com/video/8DxIa-F2S8U/video.htmlsi=CwBQ03gpwdXRBbCD. Summary-it’s working well, without any extra thermal mass; and I was able to not add the water barrels. I’ve got a revised design in process for the interior to make use of the space and will post a video on that once I’ve got it all worked out in Sketchup. 👍
This is super cool and a very clever way to get around permitting restrictions! Do you have any ideas for what you'd like to grow in there? Are you thinking about making it easier to overwinter plants or are you trying to climb up a couple of zones to grow some things you wouldn't otherwise be able to? It's so neat to see your plans going from paper to reality - congratulations!
Thanks! I am mostly going to use the space to start seedlings earlier in the spring, but I’ll measure the temps the first winter and if they stay in an ok range, I will try and put some perennial trees in there: avocado and mandarin orange, specifically :)
another sneaky way to get past permitting is put it on wheels.... whatever it is that you plan to build... if you can find a way to make the structure be on wheels... it bypasses the need for a permit because wheels means "not permanent" at least from what I understand... but I am not an expert so look into it especially since laws can change from state to state.
We live directly next door to the municipal offices, so in general I can’t get sneaky with anything 😂🤷♀️
@@WellGroundedGardens it's legal though, is what I am saying. If you make it "temporary" by putting it on wheels then you don't need the permit (in the couple of instances this has come up for us and we were looking for solutions to things). Even if the structure sits where you want it to all the time... the fact that it is on wheels makes it not permanent. What I am saying for sure is to look into the laws for your area because it's possible this doesn't carry over to every place.
Attached to your house, you definitely don't need water barrels. Your concrete house wall will lose heat via conduction, to your walipini. The conduction from your warm house, combined with that same back wall storing heat from the lower sun in the winter/early spring, early fall. Should heat the structure really well.
In theory, yes, but we built this as new construction with a double wall with foam insulation inside the concrete. We get very little heat bleed as a result. Good for our energy bills, not great for the walipini concept 🤷♀️
@@WellGroundedGardensOk 👍. That makes sense. How has it performed so far? I built a simple half hoop house against my house that I use for dormant fig tree storage. It's right against the concrete block house wall but its not attached. It's typically 10-15F warmer in there due to conductive heat loss through the block wall getting trapped in there during cooler outside temperatures.
I love your thought process and explanations if everything! Such a efficient use of your space! Using the suncalc website what data points can be interpreted to be the winter and summer angles that I need to have in mind. I'd share the screenshots of my results if I could but is it the altitude or azimuth? Or some calculation? My January 15th at noon is Altitude: 29.86°
Azimuth: 177.79°
While my July 15th at 1300 is Altitude: 72.28°
Azimuth: 176.20°
Could you help me? I'd so greatly appreciate it!
You want to use altitude 👍. My specific dates in the video were tied to my coldest days; if you want to find your absolute lowest sun angle you would look at December 21st and for your highest angle you would look at June 21st.
Thank you for the information. Very helpful. Would you ever consider using your greenhouse for passive solar gain to heat and humid your house in winter?
Our winters are too overcast here in Michigan to yield much solar gain-otherwise, yes!
Doesn't the house, itself, provide the necessary thermal mass? I assume the house is heated, so you'd be putting insulation (the barrels) between the hot house and the greenhouse. Absolutely fascinating video.
The house is heated but also super insulated (we did spray foam throughout for energy efficiency). The back wall of the greenhouse is concrete (with a layer of studs and foam inside); I don’t think there’s a ton of heat bleed from the house, but I’m sure there’s some, and then the concrete itself is painted black and hopefully acts as a bit of thermal mass. I think we have a secondary benefit of less heat loss from the house, as it now has a sheltered pocket of air against it rather than wind or cold soil…
I couldn't see how you get in and out. Is there access from the house? The other thought I had was drainage if water gets in. Excellent analysis of the sun angles and modifications of the design.
There is a door from the house (currently covered in plywood) and there will be some stairs inside the greenhouse down at the west end, walking up to a door built into the polycarbonate wall. That door gives access from the backyard. I will show that once it’s installed, but for now I didn’t want to make a 20 minute video… 🤷♀️
This is exactly what I had in mind for my back yard, so great to see this! Was your stem wall & slab already poured? Have you considered using a GAHT system to help balance thermals?
Hi! The house was a new build and I designed the greenhouse in from the beginning, so the slab and stem wall were poured at the same time as the foundation. I wanted GAHT or earth tubes but couldn’t get it done with the timeframe, budget, code, and available trades. I’ve seen a version pulling hot air from the ceiling ridge down tubes and through a floor of crushed stone to create sort of a thermal battery. I may try that (though the current system is performing shockingly well, as is).
is there a followup to this project yet?
I wish. :( The roof and side walls are done but we are still waiting on windows to fully enclose it (three cheers for global supply chain issues). I’ll build out the interior as soon as it’s weather tight and give an update
If a barrel is half exposed to sun, wouldn't the lower half heat up and have the warm water rise, effectively circulating the cooler upper water down to heat up, thus allowing you to expand your thermal mass barrels taller than direct sunlight level by taking advantage of the natural circulation? Obviously not as effective as 100% direct sunlight on the barrels, but better than no thermal mass above the barrels at all.
I do think a thermal siphon is likely to happen (and to help) anywhere I can get sun. My total thermal mass may ultimately be as much about the weight and engineering for tipping as it is about anything else…
have u thought about using templok tiles for thermal mass instead of water barrels? that would save space.
The prices I’ve seen on those are above my budget-but I love the concept. 👍
I had a house burned down to the ground I was wondering can I use the basement with the break-in walls for my underground garden
Well I’m super sorry about the fire, but that alternative use sounds AMAZING. I believe a few people have done that with old pools. The one thing I’d double check is drainage; we added a floor drain to ours that links into our foundation drains and sump pump. If your old house has something similar in the basement you should be good-I think you’d just want to avoid standing water or flooding issues?
Thank you for the quick response I'm looking for a construction company here in Flint Michigan now to get it done I'll send you pictures once I get it done
Update!!!! Please. :)
I am about to post one! So far it’s working better than I’d hoped. No thermal mass, yet, but we’re staying well above freezing overnight (mid-40s, Fahrenheit) even with overnight temps below 30.