Swimming pool as a storage tank?

[leaddog]

Eric, If it was me I think I would fill the other side up with water for this winter and fine tune your system. the water would brace the wall and you shouldn't have any problem. Then this spring you could drain it with a sump pump and make any changes. It doesn't take long to drain with a sump pump, (redo) as I drained mine twice. The only problem I can see might be water migrating through the wall and wetting your insulation and lossing heat that way. If you rip out the wall and expand it you will have to splice the epdm but that might be easyier now than when you have had water in it. I wouldn't be afraid to splice it as it is in a hole and if you had a very small hole that didn't seal it wouldn't cause a problem. The bracing should be easy, just place a sheet of 3/4 plywood against The wall and then about 4 braces against the other wall will hold it.
leaddog

 

[Eric Johnson]

Thanks to both of you, and my apologies, Joe, for completely hijacking your thread.

I wondered about splicing the liner, leaddog--that was one thing I wondered about. I've seen the materials for sale, but I wasn't sure it could be counted on. I'll do a little more research.

Tarmsolo60, it's great to have another heating pro on the board.

 

[leaddog]

My 1200 gal tank cost very little as it was made with materials that I scrounged at autions and yard sales.
Tank frame and insulation (old walk in freezer panels,4in foam)------$20
old carpet padding to protect epdm-----free
spray foam to fill cracks etc,---------free with rebates from menards
epdm-------$180
1-1/2 pipe and fittings for bottem hx.------$25
Stainless top hx 1/2in finned with fittings$40
steel reinforcing $20
6in temp guage----$1
6 blocks of parifin ( ideaThanks to nofossil)----$12
Water treatment----$100
LOTS of time and thought and redoes------FREE as I'm retired
leaddog

Could you post a picture of your tank?

Thanks,
Joe

here is a couple of pic of my tank. it doesn't show too much. If you look at the ends you can see the thickness of the panels.
leaddog

 

[EForest]

lots of great info here. I've been planning to turn a 16x20 deck built on piers into a sun room but after reading these threads would consider adding a full basement below (i have a walkout basement). this would allow the construction of an indoor storage tank partially below grade to footing depth with @ 3' above grade. I would use poured concrete and the tank could measure @4' x 16' x 6' deep. The ceiling would be 5' above top of tank for easy HX removal/replacement.
I would use the remainder of the space for wood storage and a gasifier (still can't decide which to purchase).
the home brew HX that Eric designed seems to be the way to go in such a long tank as I could build them to any length.
Any thoughts or advice would be appreciated.

 

[Eric Johnson]

My advice would be to wait and see how mine holds up. I think it's going to work great, but that's not a universal opinion, and some of the naysayers know a lot more about it than I do.

But I spent part of my youth living and working on a farm. We made things work.

 

[Eric Johnson]

So knowing you can buy a 957 STSS for $2000, how much cheaper can you construct a insulated tank around 1000 gallons?

My 1200 gal tank cost very little as it was made with materials that I scrounged at autions and yard sales.
Tank frame and insulation (old walk in freezer panels,4in foam)------$20
old carpet padding to protect epdm-----free
spray foam to fill cracks etc,---------free with rebates from menards
epdm-------$180
1-1/2 pipe and fittings for bottem hx.------$25
Stainless top hx 1/2in finned with fittings$40
steel reinforcing $20
6in temp guage----$1
6 blocks of parifin ( ideaThanks to nofossil)----$12
Water treatment----$100
LOTS of time and thought and redoes------FREE as I'm retired
leaddog

well that is much cheaper....the discussion earlier in the thread people were talking about purchasing different kinds of new tanks that ran about 1$ a gallon than making them insulated. I still think there is no new "factory" type tank you could buy, insulate, and make much cheaper than a STSS. I think you could duplicate the STSS tank and save some money, It doesn't look like the material for one would be outrageous, as for labor I usually take some of mine into account because I could be out working doing the same type of thing(plumbing/electrical contractor) and making money. I do admire the ingenuity of people that have the time and skill to build useful things and save money at the same time. I like you like making things work.

There's a great thread around here describing how to make a STSS-style tank with stuff from Home Depot for around $700.

 

[EForest]

do you recommend I insulate inside or outside of the concrete walls of the tank.
I've read that concrete acts as a thermal mass great for heat retention.
I'll assume there are plenty of high temp epoxy sealers on the market to finish the inside of the tank.
If not then an EPDM liner would last forever.

 

[Nofossil]

do you recommend I insulate inside or outside of the concrete walls of the tank.
I've read that concrete acts as a thermal mass great for heat retention.
I'll assume there are plenty of high temp epoxy sealers on the market to finish the inside of the tank.
If not then an EPDM liner would last forever.

EPDM seems to be the weapon of choice - the temps in a storage tank represent a pretty hostile environment for any sealant.

I'd insulate wherever it's easiest. Concrete adds thermal mass, but not very much compared to water. I'd make my choice based on whichever configuration was easiest and best at reducing insulation gaps and heat loss. You'll want as much insulation as you can get, especially above the top.

 

[Burn-1]

do you recommend I insulate inside or outside of the concrete walls of the tank.
I've read that concrete acts as a thermal mass great for heat retention.
I'll assume there are plenty of high temp epoxy sealers on the market to finish the inside of the tank.
If not then an EPDM liner would last forever.

Since it's pretty germane to the topic, I'll recycle a link from one of my pre-Boiler Room era posts to a Tarm installation and tank construction where the user built a concrete tank and lined it with swimming pool epoxy paint.

 

[EForest]

those are well engineered tanks, thanks for the link.
Now I realize the need for insulation inside my tank design. The walls will be poured along with the room foundation.
The form ties will remain in concrete after forms are removed leaving many possible seal failures.
insul with epdm inside should resolve that problem.
You're right Nofossil the easiest insul job is the smart choice.
Thanks for all the insight.

 

[Eric Johnson]

If you look around, there's a thread showing some pics of my concrete tank with insulation.

 

[jebatty]

Good news first -- I picked up three used 275 gal fuel oil tanks, cleaned them out as best I could, and then plumbed them in series, with expansion space, resulting in about 800 gal storage. I pd $125 for the tanks; tank plumbing and other issues related to plumbing were perplexing, but solved - and the price was right. I use a plate heat exchanger so no need to try to make one to fit inside the tank(s).

Better news -- what about a septic tank? Capacity is around 1200 or more gallons; price around here is about $700; and now also available preinsulated (don't know cost). Bury the tank, designed to hold water without leaking, good access manholes. Easy to fit an exchanger in the tank or use a plate exchanger. Very likely this is where I am headed next summer to prepare for winter 2008-09.

 

[Reggie Dunlap]

I considered a pre-cast septic tank. My plan was to buy the lower half of a 1500 gallon tank and install it so the top was flush with my basement slab. I think it's a good idea that's probably only practical in new construction. Instead I built a 750 gallon tank out of concrete block, but I kind of wish I'd used a septic tank because it would take up no space in my basement. The only reason I didn't do it was because I was in a hurry to get the first floor framed and I hadn't quite worked out all the details in my head.

 

[MrEd]

Any other opinions on used oil tanks as a heat storage?

I have 4 new'ish 330 gallon oil tanks, already in my cellar. (less than 10 years old)

Obviously if I go forth with my Tarm Solo purchase, I won't need a 1400 gallons of oil in my cellar anymore.

Seems like if there was an easy way to convert 3 of them to heat storage, it would be a win-win-win. (they are free, it would get rid of 3 unused tanks taking up space, and they are already in the cellar)

Opinions? How hard will it be to clean them? How will they be fitted with a heat exchanger?

 

[Nofossil]

I've heard that they're really hard to get clean, and they're not designed to be pressurized. Means you'd need a flat plate HX or some such.

 

[TCaldwell]

I have 2 275 gal horizontal oil tanks plumbed in series, inline between the garn and the flat plate hx, located in a basement crawlspace. My system pressure is atmospheric and generated by headloss and pump curve, with 1 taco 13 on the supply side, i would run 13gpm at 9.5 psi, adding a second matching circ on the return to the garn i run 17gpm at 6 psi. I believe most oil tanks are ul rated for 5 psi, I called crown tank mfg co, they stated that they randomly pressure test their tanks to the point of bursting, what i was told is that a standard 12gauge oil tank that they sell to home depot will start to deflect at 12 psi and will burst between 15 and 35 psi. So i installed a 9 psi relief valve in one of the oil tank bungs for protection, as to rusting , in the garn's unpressureized tank i use a nitrite based oxygen scavenger,so i added the corresponding ammt for the oil tanks and monitor. My justification for the second circulator was for the flexibility in firing times with the added storage, i installed these last november, so far so good.