It's all Plain to Sea

[mrhobbithhnet]

This just across my desk:

[esk]

Thanks for the advice. I'm in the process of figuring out all these thermal mass calculations. I will be building an aquaponics set up in the greenhouse. I have a small one in the house which is providing me with lots of tasty greens and soon peas. I plan on building a small commercial set up that i hope to have going by next fall.
The design is not finished because i still am undecided on exactly which style of frame i will be using. I will be bending my own pipe for the frame. I am going to attempt to hook up a bubble insulation layer so the larger frame needs to be pretty darn sturdy with having minimal support from the inside. I am wondering if the r-1 per inch is correct but even if its half that it should make a pretty big change in how warm the space will stay at night.
The aquaponics system will be another thing that should change the dynamics of how the space is effected by temperature fluctuation. As it stands now which will probably change by the time i have the final plans laid on this spring. I will have two large tanks roughly 1800 gallons of water in the greenhouse. These will be filled with fish. And then another tank that will be used as a sump that is dug into the ground that will hold around 800-1000 gallons . Depending on the ability to heat the water in an efficient way we will be growing tilapia for there minimal diets and easy breeding compared to other fish. If we cannot keep a high enough water tempature we will be growing trout. I like your suggestion in another post about the crustaceans, yabbies which i guess are similar or are the same things as the ones you talked about seem to do really well in these systems.
The growbed system will be atleast 4 beds that are 23ftx4ftx1.5ft and another 4 beds that will be 23x4x1. These will be all filled with gravel and water will flood and then drain on a cycle.
On one end of the GH we will be putting a winter chicken coup/equipment shed/vermicompost/airlock. We will push air through the coup and use a soil filter to hopefully lockout the harmful compounds and provide at least a bit of C02 and warmth.
I was originally going to dig out and backfill completely with gravel but i think because of costs i am only going to partly fill the space with gravel. Do you think it would be better to dig the whole space out and mix gravel and the soil together or have them as separate levels. What is the air speed that you recommend for the tubes now? I noticed in other posts you said that it can be faster then originally thought.

[mrhobbithhnet]

Sounds like you're on tap for another interesting adventure in a multipurposed gh.

As always, the thing in most design is to keep in real simple. Complexity may solve some problems quite effectively, but it introduces a deadly amount of brittleness into the picture.

For one thing, I can't imagine anyone but and expert plumber and metal fab man getting up a bubble roof that works consistently and perfectly to the design concept. They are very, very complex to sort out, but even harder to execute. And, please, keep in mind that they increase the opaqueness of the film and structure. And that the mission is grow plants and be as transparent to the sun and ALL the skylight as is possible. The world is going through a serious drop in light levels these last few decades, and it will not get any better from what I've been seeing... so be careful betting on any design that doesn't increase the transparency. It could be a good thermal choice, but it could also cut off too much light in winter to have real plant growth or solar gain during the day. Eliot Coleman's Winter Harvest houses all have single layers in Maine, and he personally has told me that even that is far more than he'd like to see. Twin inflated covers limits it even more, woven films for northern house even more, great gaps and soap films and residues even more, more framing members even more.

Keep in mind that your situation is not nearly as light dependent as a pure growing environment, it's more a heating problem. So what you do with the structure could easily move away from optimal light levels. But do keep that in mind for any winter varieties and plant production plans in the dead of winter. And keep in mind that it's ALWAYS smarter to walk away from the Dec, Jan growing challenge if you can, and do something else, let the building coast and go into a hold mode. Those two months, if designed for and built for virtual tropical environments, can easily double the dollar and stress costs of the entire structure. Timing is everything - if you do a superior job for the other 10 months, you could easily put those months to better use in the building.

As to optimal air tube air speeds: the verdict is still out. That's why I now say be prepared. The spacing (three layers about 18" OC) and arrangement of the matrix of tubing using culverts as we cover here, with a fan at both ends of the system seems to be that simplest arrangement there is a reasonable amount of agreement on. It's worth committing too. So, once that is in place, the only other variables are air speed, direction, control, and GH house AIR VOLUME. Randy here has some good thoughts on limiting the air volume at night so that the soil sink gains go further at night. Also a first stab at a reversable flow culvert system.

My choice after putting in as much tubing and well drained soil sink as you can, is to build your own fans with 3 phase variable speed 1/4 - 1/2 hp motors controlled with single phase powered controllers. With computer interfaces to that system you can easily design it to do anything you feel compelled to try and are virtually guaranteed to get it dialed in dynamically and perfectly. The key would be to includes some sort of digital sensor net to give you the feedback you need. If anyone did that, then they would be the ones you'd be asking for the answers from. I don't have any land to play on, and can see that this tech is dead in the water until some dynamically run and sensed systems are put in place. Then.... well then the potential can be realized. Without that kind of sophistication, it can give 100 times return on your electric dollar, with it I can see that creeping into twice that. We do not need to worry about the cost of this anymore. AutomationDirect.ca drop ships to the USA and have all the costs for motors and motor control down to a very, very good price point. And using two wire sensor nets, it's now possible to do 25 temp and RH computer linked sensor nets for way less than $1000.

Betting on knowing what to do by putting your money into variable air control and good sensor nets is, in my opinion, the way to go. There really is no one out there who can tell you what to do... but we can make some guess at the consequences of any design. So keep throwing them at us. I for one can't wait to hear more feed back on your design.
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[esk]

Complexity is a troublesome friend this is true. To me both of these systems are still in the anything can happen phase where there can be lots of oh sh*t moments and lots of great discoveries. Ive had the winter harvest handbook for some time now. I like many of his Ideas and I think that the information his has been providing is great for the greater public to start being able to transition into a more localized food system. The location where i will be building this greenhouse is much better suited for intense rotational grazing and perennial food production which we will be doing. The greenhouse space will be the location for much of the annual food we eat and potentially sell as well as a an protein source from the fish.

Light is a big concern for any greenhouse especially for one in the winter. Coleman mostly uses single layer covers except for a few of his houses where he uses the double layer inflated system. He also uses a cover that lets in 85% of the light. So that would be 15% light reduction which if you had that plus a double layer would be killing your light. But if you do not have to use the cover because you can keep the warmth generated by your thermal mass then you could be getting the same or a little more light. Even though the SARE study left me with more questions then answers it did show that the filling of the north side of the GH with bubbles during the day increased the light by a 1/3 or so if i remember. Would that make up for the lost light I dont know but that is why were are doing this stuff right? To experiment.

I am pretty much a rookie when it comes to doing electric workings. I use to go to radio shack and by all sorts of different electronic circuit kits to build but that was a long time ago. So building a fan I can figure out but I will need to learn a bit. I'm taking two hands on classes this winter for wiring a house so that should help me. If you know of any good sources to start with that would be great.

[mrhobbithhnet]

Start here for one wire sensor nets... it's THE cat's meow

http://www.ourcoolhouse.com/WEL/

If you find anything juicier, you must post them here. Or we'll come steal your first born or right arm, whichever is easiest.... what can I say, we're lazy pirates giving away our precious treasures:

http://www.uigi.com/WebPsycH.html
http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html#ahph
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/phase.html
http://www.degreedays.net/#generate
http://www.green3dhome.com/calculators.aspx
http://books.google.com/books?id=rJsVoRw1geoC&pg=PA207&lpg=PA207&dq=ambient+soil+temperature+at+one+meter&source=bl&ots=IylPreSWQi&sig=zqKNzvBcPBGc20jil43uNZmS1LE&hl=en&ei=RfCwSauHAqWoM-25yfkE&sa=X&oi=book_result&resnum=1&ct=result#PPA205,M1
http://hoopbenders.net/doityourselfebooks.html

http://aes.missouri.edu/bradford/education/solar-greenhouse/solar-greenhouse.php
http://www.motherearthnews.com/Organic-Gardening/2004-02-01/Earth-Sheltered-Greenhouse.aspx?page=3

http://www.greenvalleybuildersinc.com/index.php?pr=current

http://www.appalachiannativeplants.com/id16.html
http://web.missouri.edu/~neelyr/May%202008%20Greenhouse/
http://dynamicgrowingsystems.com/

http://www.amhydro.com/

http://www.fourseasonfarm.com/main/photos/greenhouse.html

http://cat.inist.fr/?aModele=afficheN&cpsidt=2936622

http://mb-soft.com/solar/intake.html
http://www.arduino.cc/
http://www.cs.arizona.edu/people/jcropper/desguide.pdf

http://durisolbuild.com/
http://www.undergroundhousing.com/primer.html

ENOUGH ALREADY....

And now for some meaty shrooms... and a wee bit of a rant I'm afraid. Courage though, hobbit rants are boring and hardly a threat.... LOL

[esk]

Wow thats a lot of meat in that there post. It will take me awhile to get through it all. I finalized my the size of the greenhouse based on the cost of the pipe I have found. The usable footprint will be 25 by 48. I made a sketch of a layout for the piping. This first idea of a layout places the intake in the center of the house and has 4 outlets 1 in each corner. Each outlet will have 21 pipes running to it. Im not sure how well this set up will work since the new findings are that a higher airspeed is better. After looking at it now i think I will be eliminating 4 pipes on each level. The pipes that run down the middle of the greenhouse will be reduced to 1 on each side. Which would take me down to 78 pipes. Can you fit 78 pipes in a 55 gallon barrel? I haven't tried to figure that out yet.

I still am going to try out the bubble design. I'll building my own generator and delivery system. And it will not change the cost of the upfront cost to drastically because if it doesn't work then I'll be taking down the internal frame and turning it into a second greenhouse.

This next year will be its test run. I wont be putting in my aquaponics system until I have proven that I can keep a decent temperature. I will be planting some cold hardy veggies so in the event of a crash of the system the loses will not be to significant.

We are also planning a few 9 foot wide terraces. On those we will be trying different season extender methods. We will have some mini movable greenhouse and small hoops. I can't see a large movable greenhouse on the type of property we have unless we built a large terrace and that is not on the current agenda.
Thanks for all your input so far it is great.

[mrhobbithhnet]

[esk]

I was looking at those pictures last night while looking at the links you provided. I am curious about the fan set up with that method. Does the placement along the length of the culvert change the length of the pipe? Since the air has to travel further to get to the pipe that starts farthest away?

[mrhobbithhnet]

[esk]

ah that makes sense. The pictures are a little small and I couldnt make out the details. I've located my source for the pipe for the greenhouse and I started pricing out tubing today at the local contractors supply store. I'll be redesigning a layout tonight. It is a lot of fun doing this part of the project, since im learning so much and haven't had to break out the wallet yet. Once I can figure out when I can borrow the excavator. I'll be set to order up all my pieces. Thanks for the quick response and info.

[esk]

I just finished reading Yonatan Strauch paper which was an interesting read and I hope there will be continued study on these techniques. One of the things I had a question about was the puddling they found in the corrugated piping because of the lack of perforation in the deep sections. I was wondering if you have also seen this and if you have discovered a way to deal with it. And to go along with that do you think that if the puddling was solved there would be a drop in the increase in humidity during the night?
Josh

[mrhobbithhnet]

Great to see you've got what you need to move ahead.

I posted a big blowup of the 3D ISO view of that plan as a Sticky topic under Subterranean Systems - Projects

I wouldn't get too fussy with the tubing puddles. There can't be much more than a few teaspoons per foot and shouldn't happen in all tubes all the way down their length. It's just a matter of having the perforations end up on the bottom if the plan were to have a dry UACT. From what I've seen of the number, size and distribution of the perforations, there's only a 25% chance of puddling happening with random rotations of the tubing anyway.

As far as the heat transfer changes that a few gallons of water in the whole UACT system would make... Suppose at night relatively dry air colder than the soil is moving thru the system. At the inlet, the air enters the hottest part of the UACT, gaining temperature and consequently, becoming "dryer" or thirstier. As it moves thru to the end of the UACT, it will begin to approach the temperature of the soil average along the length. How close it gets to that point is dependent on the air speed. Whatever the case is, it exits warmer and with a higher vapor load because the warmed air becomes thirstier. Most of the heating capacity of that air exiting is then in the vapor, not the air. The air will probably only be in the 50-60 deg F range. As the exiting air moves back towards the input, it is chilled by cold leaves and walls and begins to condense, giving up that energy to what ever it encounters that is colder. So you are essentially heating the plants without having to heat the air too high. If what I describe here as what I believe to be happening is true, then you are better off having a water source available to cause the night air to get vapor loaded so that it's heat delivery potential is higher. In which case, you are better off with some puddling going on. It would be absorbed at night and re-introduced during the day.

As far as the fears that some outlandish fungus gets a hold of the UACT and kills everyone, well we've yet to even smell anything bad. As I've said before, with the soil microbes in such intimate contact with any and all liquid water in a typical UACT, undoubtedly that water will be saturated with the entire spectrum of soil microbes. We know that only isolated strains are in a position to grow to dangerous concentrations, so with that not likely to happen, it makes sense that you'd never see any instances occurring where there is evidence of high concentrations of any one toxic microbe. I suppose if someone ran their UACT thru some soil that was already compromised and somehow had only one toxic strain in it, that you could very well get in trouble. But generally speaking, having control over the soil surrounding the UACT install as you do normally, single fungal strain issues are minimal, and isolated highly toxic single strain concentrations are even less likely to happen. One things for sure is we've yet to hear of any issues from builder operators.

I hope your design layout comes together for you. If you want feedback on your design, be sure let us take a peek at it.
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[esk]

That makes a lot of sense. I was not all that concerned about it but I just wanted to see if there was an update that I hadn't read concerning it. It seems like as long as you have enough breathing room for the plants the build up of moisture would not have to much effect. I've seen over planted greenhouse that stay really moist at night and they usually end up with something rotting.
I have a design almost finished in sketchup and not surprisingly it looks somewhat like the design you posted. I'm away for the next couple of days but once i get home ill post them.

[mrhobbithhnet]

Great to hear you'll be showing us what you've got. You say you've been able to do it in Sketchup eh? I was wondering how it did with mechanical models... my first stab at it here wasn't too promising. I use TurboCad Pro Platinum... much, much better for mechanical 2D/3D.

An over crowded greenhouse can be a problem if it isn't kept dry during the day, either with venting and fans, and/or the SHCS. It's the 24 hour wet cycle that does the plants in. If they get one good hot dry period to break it up, they do much better.
_________________
Just because it looks that way doesn't mean the Universe is about us, you or me. It's about Life.

learn | read |
locate | talk |
listen in tech | listen in humor | videoz

[esk]

So here are a few shots of the layout of the system. For the amount and type of design work I need to do the price point of sketchup works a lot better then the different cad packages. Im going to start bending pipe by next weekend hopefully.




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