Backyard Aquaponics
A place to discuss aquaponics

I've been collecting bits and pieces for this system for a while but still haven't commited to the layout. I purchased a 10x12 HF greenhouse but one will not comfortably fit all I want to put into it. So what I've decided to do (so far) is to connect two of them as has been posted here and there. The general idea is to pour a 10x24 slab and brick the four outside walls 3 bricks high with 8x8x16 cinder blocks. Then connect to these 4' out to make sump tanks along the walls 2' deep and mount IBC growbeds over top of them. It should give me some huge sumps for crawfish or prawn. Along one of the 10' walls I was going to put two IBC fish tanks or just make cinderblock fish tanks.
I believe I can use ventilation to get thru the hot summers but still unsure of a winterization plan. Cold winters are infrequent but still happen often enough to make things difficult.
Idea's and comments are welcome.

Try to get as much thermal mass into the greenhouse as you can. Keeps the system cooler during the day and warmer during the night, and also a bit warmer during winter.

If that's not enough, you can always actively heat the greenhouse during winter.
If you get longer periods of cold weather then you could even look into underground thermal storage; using a heat pump during summer to put some of the energy (that you'd otherwise have to ventilate out) into the ground. You could use that during winter to keep the greenhouse warm. It's much more efficient than electric heating, but it's expensive to set up.

Another option is a composting box - if you have access to some fresh manure then you can use that. The composting process creates a lot of heat for about a month (iirc). If you don't have room for it inside, then you can maybe duct some hot air from the composting box into the greenhouse?

Since you're in the south, I don't think you should worry too much about thermal mass for heat storage. You'll have some from the water and GB medium. I would rather use the space that it would consume and use it for plants & fish. In your zone, my guess is you get very few freezing nights, so your plants should do just fine.

In my HFGH, I have the north wall and ceiling insulated which helps a bit. During the winter I have two 1500 watt heaters that run at night which keeps the temp around 36. They can keep up until the temp goes below 10. The other night it was 2 and it got down to 33 in there. I calculated it once...for the 10x12 GH, you need about 5000 btu's/hr to keep the inside 20 degrees warmer than the outside.

For you, I think vents are the most important. The HFGH has 4 vents. The plans show to put 2 on each side, but I put all 4 together so I could insulate the north roof. They manually open, which is a pain to do every day, unless you just keep them open at night too to keep things cool, and, they only open about 3 inches - almost useless!. (No surprise), I automated mine http://www.youtube.com/watch?v=VVpZxXUi4HQ. During the summer when it's typically in the 80's on average, I will keep the vents and doors open, and it still is quite hot in there. In your zone, you may need a fan to help circulate the air. The fan should also help draw in fresh air....my AP GH gets very humid which invites all kinds of other problems - especially mildew & mold. My water temps can easily go into the 80's also...which is a bit warm for my goldies.

Good luck with your GH. I love mine!

My plan is to add radient heat in the concrete floor of GB, FT, and ST. Sounds like you could do something similar. Just something to think about. Mornings posted on how he used corrigated drain pipe for his subterranean heat:

viewtopic.php?f=1&t=6700&p=217957&hilit=mornings#p217957

I was trying to figure out how I could make that work, but with all the concrete I'm going to poor, it would not be easy for me to dig it up for repairs....still thinking about that. The benifit of his system is that it appearently does cooling in summer also.


Mark

I'm assuming this system is for Tilapia yes? You will definitely need to actively heat for the really cold spells, all my tilapia that were out in the greenhouse and outdoor systems died during the cold spells this past winter because I did not actively run hot water into the system on the freeze nights this year. If you are only aiming to keep them alive, you won't need to heat too much. If you are aiming to keep them growing year round, that is another story. The water in my "coldframe/greenhouse got down to 40 F which is about 15 degrees too cold for good tilapia survival. I was running some solar heating for the water but with all the cloudy days it wasn't effective enough when I needed it most and the days are really short so even when it was sunny, it didn't do enough.

Even now we are not really cold but it has been cool and cloudy so the water in the system has not warmed up much. I don't really expect the water out there to be comfortable for Tilapia till the end of April and they would start breeding in May.

If you can make it easy to run the system constant flood during the cool season, at least at night, that might help save some warmth.

I would definitely advise making the sides of the greenhouse so they can roll up or be removed for the summer to allow plenty of ventilation far more effective than just using some vents. If you need to keep it enclosed/secure, use screen sides or panels for the summer and perhaps add some shade cloth over the tops. I'll be removing the sides of mine by March I'm sure. I like to leave mine open enough to allow bees and other pollinators easy access.

I do plan on putting lots of thermal mass into it (mostly gravel and water) but yes a lot. I don't really want to do a lot of digging and to keep the Tilapia I have to be above the flood plane or above my house slab level. I definitely will have both heaters in the water as well as the air for the plants. I think I lost two citrus trees this winter. That hadn't happened in quite a few years but I would like the fish and plants to be able to survive it and just basicly extend the warm season to about 9 months to grow out the tilapia. From what I'm picking up in my climate it should realisticly take about 1.5 years to grow out the tilapia. I will be putting 4 Aquarium systems in there also. My 75 gallon for breeding, my 150 for fingerlings and a couple 10 gallon ones for fry. I will have a seperate pump for these but will drain to the big common sump. The grow out tanks will be the two IBC's described in the first post. I am interested in mornings ground heat system. Doesn't look like too much work to do. I will also try to maximise the solar stuff with a pool heater. I'm also considering a hoop house over this in winter and shade cloth in summer 6" gap in between.

If you have a lot of sun during the cold season, you could look into solar hot water - here's a very cheap DIY setup: http://www.iwilltry.org/b/projects/buil ... er-heater/

You probably don't want to use AP water directly, so you'll need a reservoir and some form of heat exchange. Don't use polycarbonate by the way - it leaches and breaks down quickly in hot water.


Anyway, good luck, and do make pictures!

Hi Bill,
You can put the Ground loop in vertically if you have or if it is easier to use a bore hole. Either bring ground water up through a heat exchanger or run a loop down and back.
The loop down and back I think is a little cheaper to run because the weight of water in the down loop cancels that in the up side of the loop so the pumping head is less - bringing ground water up you also have to have another hole to put it down or put it in at a different level if the turnover in the borehole is quick enough to stop it mixing.
The bloke I have been speaking too about it doesn't use the net so I can't put you in touch but a search might find something in your area

Regards
John

Another suggestion I'd throw in is that since you keep small livestock, integrate them into the greenhouse during the winter. Their metabolic activity will provide heat and CO2 for the plants.

Also, not sure how well this would work with your prefab GH, but if you can situate the structure so that it gets winter sun and shades summer sun, it may make your life a little easier.

Deciduous trees are great at that - providing shade during summer that automatically goes away in the winter!

I have an ash tree over most of it and will have evening shade. Also have a shed north of it so that may help in the winter also. I'm kinda scared of putting the animals in it as I put rabbits in my old greenhouse one winter and they all died of a resperitory infection. Not enough winter ventilation is bad for the animals. Better for them to be cold, even though emotional tendences is to try to make them more comfortable. In theory the heat and CO2 is good for the greenhouse, but the greenhouse isn't good for the animals.

To be fair, most plans I've seen have the animal portion attached to the greenhouse where they share thermal mass but not much air.

I agree and I've seen plans where they are in it/part of it. But no real photo's, This site is kinda like myth busters...BS doesn't get a free ride

Here is what I do: I cover the glazing at night, using pond liner on the outside of the south windows. The vents above the windows and the east west glass remains uncovered. I have thermal mass in drums under the grow beds in addition to the FT and gravel. Still I couldnt keep FT water over 50 deg. to keep my bluegill growing. I added a biodiesel oil stove and run it at night and on cold days. Remember my greenhouse is a converted garage insulated on the roof and north walls. Air temps in the morning run in the 60's with outside air in the 30's.
I am now eating vine ripened tomatoes from the GB.
The pond liner slides over 1/2 in. schedule 40 pipe by carbiners that are grometed to the liner. It slides easily over the glazing at evening feeding time and is easily opened in the mornig for light. The is no room to run it inside with the GB right against the glass for max light. The pond liner is expensive but UV stablised and tough stuff. It seals infiltration thru the sliding glass door cracks and radation of heat thru the glass and alluminum frames. It is heavy stuff and your green house may not support it with out additional support. If I run the stove with out the cover on at night It takes to much fuel. With the cover at night I can run 24 hours on about a gal. of BD for a cost of about $1.00

Here's one such plan:

http://www.youtube.com/watch?v=nQVPRoRZTjQ

Rough plans are at 1:10