construction details of wood storage water storage?

[4acrefarm]

I am planning a wood water storage system and would like input. I saw somebody had a 1000 gal wood box, and I would like to know how it was built. here is what i'm thinking.
8'x8' foot print
2x6 framing
plywood
5' in height
I figure with 8'x8' footprint it works out to 250 gal per foot in height, for a total of 1250 gal. Any ideas would be appreciated. thanks.

 

[Jackpine Savage]

Here is the tank that I am working on: https://www.hearth.com/econtent/index.php/forums/viewthread/32453/P0/

I'm probably a week away from filling it.

 

[WoodNotOil]

You can see my tank project from the link in my signature. I would caution going over 4' mostly because you have to get in and out of the thing so much when working on it and you need the clearance to get all the stuff into it while you are insulating, lining, piping, etc. Good luck!

 

[Medman]

I would recheck your math - a 7' by 7' interior on your tank, at 7.481 gallons per cubic foot, gives you 366 gallons per foot of height.

 

[WoodNotOil]

I would recheck your math - a 7' by 7' interior on your tank, at 7.481 gallons per cubic foot, gives you 366 gallons per foot of height.

You also have to deduct any Polyiso that you line it with from the interior dimension. That includes the underneath insulation too. Medman is correct with the gallons per cubic foot.

 

[Medman]

Even at 6.5' x 6'5' interior its still 316 gallons per foot of height. At 4' of water height, thats 1260 gallons. I think you could reduce the dimensions somewhat, or if you have the space, just build it and use the extra storage. Check out WoodNotOil's pages for info about the heat exchanger - I found this great info.

 

[Duetech]

One gallon of water is 231 cubic inches. Convert your footage into inches and multiply H x W x D then divide by the 231 and you will have the total gallons your tank will hold. You can even get "geeky" and deduct the thickness of your liner and the displacement of your heat exchanger if you really want. I've entertained myself with various calculations for hours over the last few months and I'm not quite done yet but it's been an education and things are firming up. Have fun.

 

[pybyr]

While we're all getting collectively geeky, which is not a bad thing, also consider the expansion of the water with the temperature change-- with my 1350 gallon tank, I expect to have it overflow (out a designed-in overflow port) with the expansion of the water between about 50* and about 200* to the point that, if my calculations are correct, the net remaining volume will be about 1200 gallons.

 

[ohbie1]

I felt that it would be easier to expand the floor and stick with the 4' height. I used 1/2 ply. on the floor but criscrossed the pieces(= 1" floor) to come out to 8' 8 1/2" X 6' 1/2" footprint. After allowing for lining with 2" of polyiso, a 2x4 frame, and 3/4" plywood, this leaves 7'8" X 5' X 3'10"= 1098 gal..........not filled to the brim, about 1k. gal.

 

[4acrefarm]

thanks for all the sugestions. I agree woodnotoils's piping plan rocks, I plan on ueing it. I was planning 5' in hieght to increase stratification, is this overkill? I plan the 8'x8' foot pint because I have the space. I plan to put lopps of pex in bottom for solar input. I agree with a post I saw some where that we need a sticky note for home-made open storage. thanks again to all.

 

[WoodNotOil]

thanks for all the sugestions. I agree woodnotoils's piping plan rocks, I plan on ueing it. I was planning 5' in hieght to increase stratification, is this overkill? I plan the 8'x8' foot pint because I have the space. I plan to put lopps of pex in bottom for solar input. I agree with a post I saw some where that we need a sticky note for home-made open storage. thanks again to all.

Just note that my system is currently in series and the return water mixes. I am repiping in parallel this summer. I will post a new piping diagram at some point. What are you using for an hx, copper loops, flat plate, pex?

As for a pex solar loop, you would most likely want that located in the vertical center of the tank because solar water is less hot than wood boiler water. Putting it in the bottom would mess up stratification. Nofo has some good stuff on integrating solar hotwater with the tank.

 

[4acrefarm]

my system i still in the very early design stage. I would use a flat plate hx. I know about the stratification issues with the loop in the bottom but I was planning to run the solar through a hx for dmh first. the pex in the storage tank would just get the last of the btu's out of solar system. Is 4' high enough for good stratification? Thanks again.

 

[WoodNotOil]

my system i still in the very early design stage. I would use a flat plate hx. I know about the stratification issues with the loop in the bottom but I was planning to run the solar through a hx for dmh first. the pex in the storage tank would just get the last of the btu's out of solar system. Is 4' high enough for good stratification? Thanks again.

4' should be fine for stratification. As I said before you have to be able to get in and out of it, so you don't want it much taller than that unless you have really high ceilings. Sounds like you are on the right track here...