PASSIVE SOLAR GREENHOUSE grow for $130 a year?! Pt 2: Greenhouse Build Details
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- เผยแพร่เมื่อ 20 ก.พ. 2021
- Part 2 of our February passive solar greenhouse tour. How does a four seasons greenhouse work? He grows in the snow for about $130 in electricity cost per year. Details on the climate battery and much more.
#passivesolargreenhouse #howtobuildapassivesolargreenhouse #fourseasonsgreenhouse #growinthesnow #passivesolargreenhousetour
Part 1: The Plants - • PASSIVE SOLAR GREENHOU...
Shannon's webinars:
Intro to Passive Solar Greenhouses: Session 1: • Intro to Passive Solar...
Session 2: More specifics on building a passive solar greenhouse: • Intro to Passive Solar...
Shannon's facebook page: / waywardsprings
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ABOUT OUR SUFFICIENT LIFE
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We live on 8 acres in rural Iowa and have what feels like the perfect place to become less dependent on buying things in stores and the electric company. Dan and I are in our mid-50s and we are gearing up to retire early and make a self-sufficient living right here. Our goal is not just to survive, but thrive and we want to take you along with us on our homesteading journey. On our channel you will find videos on building things, recipes, canning, deep winter greenhouses, chickens and much more - anything we are doing to build our homestead! Subscribing to our channel, liking this video, and commenting below will help us to grow our channel and keep producing content.
Karyn has been a farm girl, teacher, software instructor, hospital office worker and a general nerd. She shares the recipes, kitchen and home tips, and works the garden.
Dan grew up in the Appalachian mountains of Tennessee. He has been a soldier, assembly line worker, farmer, and a sign maker. He works on improving the property, building things, and fixing things.
We post a new video every Sunday - sometimes more during the week. Looking forward to seeing you around!
Wonderfully informative. TH-cam needs more info like this.
Glad you think so, Jenny - thanks for watching!
Thank you for sharing this very informative 2-part Passive Solar Greenhouse video series. Our goals are similar, to become more self-sufficient, confident that the food is truly organic and sustainably raised/grown (non-toxic), less concerned with fragile supply chains and resistant to socio-economic fluctuations. My idea for an affordable and efficient greenhouse for Western Colorado includes a rammed earth foundation (fire-proof and 1,000+ year lifespan), clay berm North wall, green roof, rainwater capture & storage tanks, 2 to 3 stories of glass or triple-walled polycarbonate panels on East & South sides, Solar Photo-Voltaic Panels, Solar Hot Water Panels, Geothermal, Hydronic Floor, auxiliary wood heat with copper geothermal loop integration, 8" minimum Climate Battery air duct(s), tropical fruit trees & vines, Aquaculture (fish in tanks), Hydroponics (plants in water fertilized by fish), Aeroponics (plants not in soil), Mycoculture (mushrooms grown on logs or in soil around trees), Vermiculture (worm farm to speed composting, aerate soil and feed fish) indoor wetlands water filtration (in miniature) and indoor pollinators (honey bees and possibly a few chickens). Our soil is heavy clay, so there is plenty of building material for a rammed earth structure, however our growing medium for the trees will need to be a custom mix to meet their species' specific nutrient & pH needs. I know it will be worth the effort. Keep up the good work! Love, joy and blessings to all. Namaste
Thanks, Celia! Your design sounds ambitious - will you be sharing it anywhere when you build it? Well thought-out - we've been thinking and planning for a couple years now about our own. So much research goes into it. Would really like to see yours as you are building or when it is finished!
Very informative. Thank you!
Outstanding
Thanks for sharing your field trip! Good info
Way to go!
Great video thank you
Glad you enjoyed it
Good information thank you. I would have thought the perforations in the heat battery pipes would have helped with the humidity issue more.
James, condensation occurs because the surface of the glazing is cold. The only way to stop it is to have glazing with more insulation or have the humidity below a healthy level for the plants. The humidity isn't high, the glazing is cold. Tht is why the structure needs to be built with a plan for managing where the condensate goes.
@@waywardspringsacres
A lot of the water that condenses inside the tubing when storing heat is returned to the greenhouse when the system is used to heat the greenhouse. Excessive RH% is almost always bad news, especially when combined with a low temperature. It can spread disease, encourages algae, mildew etc and reduces light If the RH% is 95% anything approx 1.5 deg F cooler than the greenhouse air will be a potential surface for condensate, including the plants themselves. An Infrared thermometer is very handy for checking surface temperatures and invaluable for checking leaf temperatures to calculate the VPD.
Humidity is relative . In a sealed structure the Humidity goes up as the temperature goes down.
I recommend insulated side walls but they need to be run at an angle for longer hours of sun. But 100% correct. I really like the build. lots of great ideas. I am building a green house this summer. I have been planning for a few years now. I'm from norther Canada. -40'c is common here. the odd rare time we see -50'c. That's also a temp that is not including the wind chill factor. We also experience much shorter daylight times each day in the winter here.
That’s exciting and I’m happy you can do that! What a blessing you are 🙂
Ours will have insulated east and west walls. Growing year round is our goal - we will see if our plan works. Hoping to at least get the climate battery and main part of structure done this spring/summer/fall. Wish we had time to work on it all day every day.
@@OurSufficientLife I 100% agree. I have a very busy life and so much going on it's impossible to find time. Soon things will slow down for me. I want to build a green house but have not even started yet! I have a lot of respect for you and all the amazing people on youtube for putting the information on here so people like me can learn and one day maybe I will get to make a similar video to share with others.
After your climate battery has been running for hours, and you turn it back on to regain the heat, how hot is the air temperature? How long does the temperature stay above your average?
This is genius. Your design so shockingly simple but equally shockingly efficient. if you add a solar concentrator next to the structure or on top I think this would be a freebee ! What do you fill up those tubs with and at what temperature ? Can you please also explain this design in a separate video ?
Yes. I did several webinars for SDSU Extension. They are available on their channel.
I am interested in trying this technique in West Africa. What would I change in this system to adjust to the heat of West Africa?
Looks good, I'm building something similar to this design nestled into a south facing hill, got some of the excavation done already and will continue in spring here in a zone 4. You say you don't need to go all the way up with your intake tubes but you also say you'd wish you'd have made improvements so you could store heat faster. So wouldn't it be better to take those tubes up higher to access that warmer air to recharge faster in your case?
The air is not warmer up higher. That is a fallacy that only occurs in a structure where the air velocity is very low. If you have fans to circulate air it will break up the temperature stratification that occurs in a fully stagnant system so there is minimal benefit to routing the intake up to the top (I actually started with it at the top and removed it because it was coolest up top because thats where the most heat loss is.
@Roy: I think you are correct about harvesting the hottest air at the top of the structure.
@@EtudianteAviendah I am the researcher/engineer/owner of this greenhouse. I monitored temperatures at multiple heights for several month. Maximum air temperatures occur at the height of the plant canopy when the fans are sized correctly.
@@waywardspringsacres Will the GAHT system work with water instead of air?. I was thinking a car raditator at the top of the canopy and pex tubes in the ground?
Construction could be a bit cheaper with auger drills + pex and you wouldnt have to worry about radon gas or other bacteria buildups.
I have an old house on my property like this one, i could do the conversion quite easy, if i didnt have to dig the GAHT under the house.
if water based system is used it could get additional heating from solar collectors.
Im in climate zone 8, with around 4 hours sun in the winter, do you think it could work?
@@abekattenkatten3036 Sure, It wouldn't be "GAHT" which stands for Ground-to-Air Heat Transfer because it would be Air-to-Water-to-Ground heat exchange. Zone 8 is much warmer than my zone 4 so you have a lot of much simpler and cheaper options available for your situation.
I wonder if substituting the plastic tubes by aluminium tubes gives a better heat exchange. Maybe the improved heat exchange allows the battery to be charged faster.
Alternatively, I was also thinking that a wider plastic pipe with 30% filled with gravel (inside the tube!) may improve the performance of the battery.
What is your opinion?
The thermal conductivity of the tube isn't the bottleneck for heat transfer. It is the soil conductivity and specific heat.
Is anyone using can/tubing solar heaters or solar vacuum tubes for added effect?
If you make a few collector panels you could potentially increase the ground temp during winter.
Very interesting - we had to look that up. Don't know of anyone that is using it in this way, but the idea certainly has potential!
Living in Alaska and seriously considering homesteading up here, I’ve been researching ways to lengthen my growing season and to my surprise I’ve become hopeful for year-round growing. Woven into researching this I’ve stumbled into an unexpected problem. I try to mention it when possible because in researching a solution I haven’t found much. So either I’m not asking the right question or it just hasn’t been considered much.
At any rate… permafrost. As the climate changes, this is melting. It melting is in a process that feeds into the climate change issues which perpetuates everything quicker.
I’m not here to debate if climate change is real or not. I’m not here to debate what all is involved and who is to blame. I don’t care. What I care about is the planet and if there is a chance I can prevent a possible problem from being worse then I’d like to have that in mind when building my homestead. It’s about mitigation.
So now with all the “disclaimers” about intention and trying to steer responses to my comment toward a hopefully productive answer … is it possible to have a walipini or even a style like this without melting the permafrost (sometimes deep and even sometimes not so deep) below? Or maybe it’s more that this type of greenhouse is just not responsible to do in the Arctic. Still hoping to find a way to make it happen by bringing it up. We are smarter collectively than individually 😉
This is an interesting topic that I have not come across - the permafrost issue you speak of in regards to passive solar greenhouses. As far as I am aware, there isn't a real solution - although if you were going to do a climate battery and it was heavily insulated that might provide somewhat of a barrier to the effects of melting surrounding permafrost. But due to the fact that you would essentially be storing heat from the sun in the ground, I don't think there would be a way around it. Interesting topic - let us know if you do find a solution!
Really interesting question I definitely do not have a clear answer to, but in doing some research there could be options. I've seen "Earthdwellers homestead"'s video using compost heat transfer instead of underground - something I'll leave to people with greenhouses to comment on. New-ish research seems to suggest "combining passive screening of solar radiation with active solar-powered cooling of the near-surface soil layer" - insulation of stored heat seems very wise: would be excited to see someone's experiments with adding in a heat pump/siphon, or more distributed community-based approaches. Definitely a very interesting question.
I live in SK, Canada; I don't have to deal with permafrost though! I think the key environmentally would be to insulate around and under very well, and structurally to provide a wide footing or piers to distribute the structure's load. Otherwise, a couple things:
1) Consider opening it completely up at the peak of summer, or at least not using the "battery" at that time. That is when any additional heat being conducted into the soil would have the greatest effect on the surrounding ground. (In winter, the energy draw of the surrounding ground's mass will completely overwhelm the comparatively small amount of heat stored in your "battery" from the energy gained in your short hours of sunlight.) With your hours of sunlight in summer, the interior areas of AK probably won't need more heat than the greenhouse itself will give you, and the areas that may need more heat in summer (coastal and mountain) don't tend to have much permafrost unless you're up on the North Slope.
2) The thermal mass of any type of ground is incomprehensible, including permafrost. Yes, you can heat a small area directly under and immediately adjacent to your structure sufficiently to thaw it to a certain depth (which is why you often build on piers up there), but you're not going to damage/thaw anything outside the confines of your structure and a few inches immediately around it except perhaps at the peak of summer, and then still only very close to your structure and near the ground surface, which thaws into muskeg anyway. The heat your structure will trap simply cannot affect the enormous thermal mass of the soil to a great degree, as directly outside of your structure the temp gradient will quickly shift back toward ambient air or surrounding ground temp. In winter, the frost zone (not in permafrost) is far deeper in your climate than this structure's "earth battery" is (unless maybe if you're really near the southern coast).
3) The heat that is stored will always primarily rise back toward your structure rather than conduct very far down or laterally. Any doubts, insulate the foundation perimeter more, and consider insulating under the "battery".
4) Directly around the area that does thaw, where the warming and cooling fluctuate back and forth, you'll get a layer of crystallization (ice) built up in the moist soil that becomes increasingly hard to thaw due to the massive latent heat requirement for phase change, which will act as an insulation in a different sort of way.
If you still have concerns, consider building on a higher point (less potential conduction of heat outward, although more exposure and therefore a less efficient "battery" in winter), bring in additional soil from elsewhere and build up a higher area, or fill the "battery" with dense material like layers of brick or compacted road base (clay and aggregate) and then insulate the hell out of the entire perimeter and underneath.
By the way, I love AK! Kenai is still one of my favorite places even though I haven't visited in over 25 years. Enjoy!
@@bradleybaggins6 check out edible acres. He is experimenting with using compost to heat his greenhouse.
@@jcalloway7527 thank you for your thoughtful response. These are also things I was considering and having other people mentioning similar things helps me know I’m thinking along the right track 😉👍
Is there an insulation layer under your first layer of tubing? Or is the insulation only along the foundation?
No, just along the perimeter. I want to make sure water can drain downward. In the coldest part of the winter, some heat comes upward also.
Are those pipe trusses DIY? What size pipe was used?
They are not pipe trusses. It is extruded aluminum. I salvaged them from a used greenhouse. The OEM is no longer in business.
Do you know or think that there is a benefit to going deeper than 4 feet? I am considering doing a aquaponics system by digging a 10 to 12 foot basement with the fish in the basement and the plants at 2 to 4 feet below grade. I would put the geothermal system at 14 to 16 feet?
This sounds like an interesting concept. Are you modeling after something similar? There would be a benefit for a climate battery thicker than 4 feet deep. It would increase the "capacity" of the battery, however if it is quite far down already I'm not sure there would be a big benefit. Maybe Shannon will chime in here. We do have one concern about your idea and that is the plants being below grade. If the sun is low in the sky during winter and you want to grow, shadows may prevent enough light for some of your plants. Would like to see a diagram of your ideas!
It depends on your location. You want to go below the frost line. Check the building codes for your county and city as most require foundations and footings to be below the frost line.
@@OurSufficientLife it would be cool to see designs! Do you think using reflective material or even mirrors could help that problem?
$30k structure and $130 a year to grow less than $130 worth of food. Great designs
Without the extra cost of research instrumentation it was about $15,000. I grow and sell starter fruit trees, which give a good return per sqft. You are correct that this is far too expensive for competitive general produce production.
Great tour and great questions! 🙏. Question: can soil compaction become an issue?
Of course! The soil can be tilled and worked up as needed.
@@waywardspringsacres tilling would be one way to go. That does destroy the microbiome community nurturing the plants.
I’ve heard soil compaction is less of an issue when the soil is healthy. It’s my understanding that with a healthy microbiome compaction won’t happen. You can help the aeration of soil by making sure worms feel welcome (or adding them to your soil). Also growing some things that have longer roots can help with aeration too I’ve learned.
@@jalenejohnson8484 Yes! This year I am planning to experiment with clovers as a ground cover. I know it works in my climate outdoors, but I'm not sure how much the white clover will like a year-round tropical climate.
@@waywardspringsacres isn’t it fun learning in this “playground” of growing things! I was so hoping to have a garden this year but it looks like it isn’t going to happen. I should be speeding now and we aren’t even showing the house we’re selling yet let alone moved! I should be able to get future me set up well for next season though. ☺️
NEEDS MORE BIOMASS . GREENHOUSE PLANTS HOLD HEAT ALSO
I was wondering whether the design would benefit from a poured concrete northern interior wall & more/several full black water barrels as well.
Yes, but I would need to supplement light to maintain biomass with our day length. Also some of these are deciduous fruit trees that need to lose leaves in order to trigger blooming and fruiting in the spring.
You’re headed in the right direction with your greenhouse ideas but there is a better plan and a better built greenhouse search for the TH-cam videos of “secret greenhouse of survival “ it totally blows that greenhouse of yours out of the water
@sillydog70 the greenhouse in this vid is one we visited while trying to decide how we want to build our own. Ours will be attached to our house and be focused on growing food like the video you suggested! We'll be doing the earth tubes. Got a couple good tips from your vid suggestion - cement block planters and adding clover to the beds for nitrogen. Thank you!
Why you do not like condensation? The plants were/could use them just like rooting; terrariums. We're the underground tubes continuous; where from and to it ends?
I think the idea with condensation is the increased possibility of growing mold, etc inside the structure. Unlike a terrarium, these greenhouses don't stay completely sealed up all the time. The tubes in Shannon's greenhouse in this video are a continuous grid underground. Both the entry point and the exit point for the moving air is in the greenhouse structure itself.
Condensation occurs on the glazing because it's surface temperature is below the dewpoint of the air inside the greenhouse. Prevention of condensation isn't really realistic due to the temperature difference inside-to-outside. With that in mind it isn't bad, but you do want to control where it pools so it doesn't rot or mold your structure or cause root rot of the plants.
I just don’t get why this greenhouse is so darn high? Seems like there is an awful lot of space that doesnt grow anything. Maybe pt 3 will show how you actually use all the empty space to grow plants.
Because i reused truss, added a passive intake and exhaust vent, which made it tall. However, toward the end of the growing season it is pretty packed. This video is the dead of winter. Plants have been pruned back.
How do you get CO2 inside in the winter? Plants live on CO2.
Hey Robert - it's true the CO2 levels would likely decrease inside a sealed greenhouse. I'm not sure if that is a big factor for just the winter months when Shannon has it sealed up, but I haven't seen any of this type of greenhouse that supplements the CO2. They all just seem to work. Perhaps supplementing the CO2 during the winter months would increase production?
@@OurSufficientLife Commercial greenhouses have huge tanks outside filled with liquid CO2. The CO2 is injected into the greenhouses computer controlled. No CO2, PLANTS DEAD.
Is this the Chinese greenhouse system?
The structure is somewhat similar to a Chinese style greenhouse, but in a Chinese greenhouse, the north, west, and east walls are insulated in some way. Only the south has glazing. In Shannon's system in this video, he has a climate battery underneath, which it's our understanding that Chinese greenhouses do not. Rather they rely on a thermal blanket that traps heat at night. Good question!
No, the standard CSG stores heat in thermal mass of the north wall and uses a retractable blanket over the glazing. A CSG is capable of frost free growing year round only in climates below 40 degrees latitude.
Nice use old grow bricks for that 6 inch rock wool.......get them free where ever hydro grows are popular.
Like the idea but the plants dont look that health?
Hi Repurposed Art! Our tour was in February and the peppers and tomatoes and his tropical plants were dormant. They were just starting to come back. 🫑🌶🍅
get a windsock for your microphone dude.
Agreed - it was bad! This was early on in our TH-cam videos. Back then all we had was a phone camera.
I see the same mistake being made over and over. This system is a series-parallel hybrid. The cross section of the 6” “manifold” is 28 sq-in. That is a little more than 2x the cross section of the 4” heating tubes. That means the air really moves mostly through the first 2 heating tubes. He thinks there is not fast enough heat exchange because he doesn’t have enough heating tubes. But in reality he’s saturating one part of the system and starving the rest by undersizing the manifold. All the hard right angles are also constricting the airflow, creating even greater unequal distribution. Adding more heating tubes in such a system will not help at all. He should get rid of the manifold altogether and run all the heating tubes (equal length) into a plenum. That ensures even and completely parallel distribution. Just size the plenum and supply duct/blower cross section to equal or greater than the total cross section of all the heating tubes.
nauy - this is really interesting information! Dan and I are going to look into this before starting our climate battery, which should be this summer. 😀
@nauy This video doesn't delve into the engineering calcs or CFD models, but you are correct. The manifold diameter is small relative to the desired flow rate causing significant pressure drop. The issue myself and many other builders have run into is the availability and cost of materials greater than 8" diameter (sometimes only 6" is available). If you have any ideas for plenum materials capable of direct burial that are cheap and readily available, I would love to hear your ideas! In this study I did track sufficient data to verify that the tube spacing is a significant part of the issue, but more airflow with less pressure drop would also be a big improvement!
@@waywardspringsacres Thanks for replying. I totally understand the cost angle. That’s why I suggested what I did above. There are two issues. One is the equal distribution of airflow through all the heating tubes. The other is the sizing of the supply tubing such that it does not create a bottleneck for the rest of the system. Using a manifold creates a series-parallel system that creates unequal distribution because each subsequent section of the manifold between heating tubes and 90 deg bends create incremental resistance. The sizing of your manifold is too small for the number of heating tubes you already have as mentioned above. The usual method that solves the first of these issues and simplifies the second is to eliminate the series part of the system by using a plenum, which in practice is just a plastic barrel (eg 55 gallon drum) where you run all the heating tubes from (0 length manifold). As long as you keep all the heating tubes roughly the same length and have roughly the same amount of curves in each of them, air flow will be equally distributed. Bury most of the barrel underground. Then run a normal HVAC flexible duct from the highest point into an inline blower, and the inline blower into the barrel. Size the cross section of inline blower and flexible ducts to be at least the sum of the total cross sections of heating tubes. For example, if you have 9 4” diameter heating tubes, the total cross section is 9 x 2” x 2” x pi = 9 x 12.5 sq-in = 113 sq-in. A 12” diameter duct has a cross section of 6” x 6” x pi = 113 sq-in. So the 12” diameter duct and 12” diameter inline blower would be the minimum size for 9 4” diameter heating tubes, or conversely, 9 4” heating tubes is the max for a 12” supply line. What was expensive for you is the large diameter drainage pipes used for the manifold. We have eliminated that. The barrel you can get used for around $10-20, new, $100. A 12” 1000 cfm inline blower (Diversitech) goes for less than $100 at Homedepot. 25’ of 12” aluminum duct (AC Infinity) goes for $54 on Amazon. I think these are reasonable prices. Upsize the diameters of ducts and blower if you want more heating tubes and/or more powerful blower for more CFM. If you need a larger system, you might want to compare just n times everything and run n different zones vs increasing supply side diameter and number of heating tubes. I haven’t done this, but I think the 12” supply size is the sweet spot from just browsing online for prices of some of the items.
Good sources for cheap, used, and supposedly food safe plastic barrels are food companies or dairy farms. A place near me sells 55 gallon blue plastic drums that were used to transport glycol for $10 each.
all those dead plants in the greenhouse
take care of the plants please
aggravating wind noise.
plants look sick
the looks of the plants in there to me looks worthless
no food inside.Is it a experiment or ....joke