Concrete HW Storage Tanks

[Como]

I have been pricing storage, one option is to bury concrete tanks, I have found a couple of local supplies and the cost of tank+delivery+insulating with 2" blueboard is about $1.20 a gallon. 2" is most likely not enough.

Just wondered if anybody else had gone that route and what their conclusions had been?

 

[stee6043]

Sounds like this would cost more than propane tanks. Any reason you'd rather do concrete than a used propane tank? I can't think of many upsides unless you absolutely cannot find a source for tanks in your area....

 

[Reggie Dunlap]

I have a 750 gallon concrete tank in my basement. It works fine with 4" of foam around it. A friend has a 1000 gallon pre-cast tank under his slab. It also works fine. Both of us wish we'd installed 1000 gallon propane tanks and eliminated the hassles of un-pressurized storage.

 

[Como]

Cost and shape I guess, I have a 1,000 and 500. 7 of the 1,000 lined up would be a big hole.

Unpressurised is a good point, I guess it is just because it is something I have been used to.

 

[jebatty]

Is there any issue with concrete leaching lime (calcium carbonate) or other chemicals to the extent that pH may get too high?

 

[Gooserider]

Is there any issue with concrete leaching lime (calcium carbonate) or other chemicals to the extent that pH may get too high?

Don't know about concrete tanks, but I know that new gunnite / plaster swimming pools can be a headache to maintain the correct pH and TA for the first season or three, less so as time goes on and everything cures. It is still neccessary to watch the "Calcium Saturation Index" and ensure that it doesn't get too high or low, as going to far out of range can cause corrosion issues and leaching calcium out of the concrete (bad thing!) on one side, or calcium scale deposition problems on the other...

Of course, if you have a tank w/ an EPDM or similar liner, then the tank material is not an issue...

Personally I would be hesitant about a buried tank, especially one under the slab. Sooner or later, all tanks are going to need some kind of service, and it seems to me like a buried tank would be harder / more expensive to deal with, let alone one under a slab. Also unless you are in well drained soil that is WAY above the water table, I'd be worried about high water possibly compromising the insulation and hurting your heat retention abilities...

Other than getting it out of the way, I don't see any real advantage to a buried tank, and I'm not at all convinced that getting it out of sight is worth it...

Gooserider

 

[Como]

It would be a very big tank, and for that size I have no where elese to put it. We have 5,000 gallons of tanks (3) for our septic system and I know how big they are. I got a quote for a SS tank, admittedly not a direct comparison much smaller and that would fit insider my Boiler space, $10 a gallon.

They have hatches so you can get in, they would need to be buried probably at least 4ft down.

 

[Fred61]

I have tried to read everything on heat storage since the seventies when I got interested in solar and my conclusion is that all efforts must be made to keep buried tanks dry. The smallest amount of moisture will wick away heat and any heat lost to the earth is gone forever. Around here it is nearly impossible to bury anything and have it stay dry.

 

[DaveBP]

I got a quote for a SS tank, admittedly not a direct comparison much smaller and that would fit insider my Boiler space, $10 a gallon.

Durango, cast an occasional eye to Ebay in the 'Business & Industrial' catagory and search on keywords "stainless steel tank". All kinds of stuff out there. Not likely there will be exactly what you want right across town, but you might get lucky enough to find one that will do for a lot less than $10/ gallon. Insulating a nonrectangular tank below grade will always be a challenge, though.

 

[leaddog]

I got a quote for a SS tank, admittedly not a direct comparison much smaller and that would fit insider my Boiler space, $10 a gallon.

Durango, cast an occasional eye to Ebay in the 'Business & Industrial' catagory and search on keywords "stainless steel tank". All kinds of stuff out there. Not likely there will be exactly what you want right across town, but you might get lucky enough to find one that will do for a lot less than $10/ gallon. Insulating a nonrectangular tank below grade will always be a challenge, though.

If you find a ss tank you can put in a concrete tank with drains etc and be able to insulate it quite easily. There are alot of ss tanks out there with so much industry going to china.
leaddog

 

[pybyr]

I got a quote for a SS tank, admittedly not a direct comparison much smaller and that would fit insider my Boiler space, $10 a gallon.

Durango, cast an occasional eye to Ebay in the 'Business & Industrial' catagory and search on keywords "stainless steel tank". All kinds of stuff out there. Not likely there will be exactly what you want right across town, but you might get lucky enough to find one that will do for a lot less than $10/ gallon. Insulating a nonrectangular tank below grade will always be a challenge, though.

I hope I am wrong and that the situation has changed since last year when I tried to look for used stainless steel tanks-- at that time (and, given, the prices of metals, including scrap, were then going through the ceiling) I found that most sellers were looking for prices on used tanks that floored me - one seller plainly told me that at the rate that people were buying scrap metal to sell overseas, he had no reason to sell at a low price. Again, that may well have changed given the very different economic turn, here and overseas, and I am not looking to discourage anyone-- just suggesting that you should probably also be exploring some "Plan B" tank options, too.

 

[stee6043]

Steel prices (as well as most other metals) have retracted by, on average, 80% since Fall 2008. We saw most metals rise by 80-120% late last summer and most of these metals have returned to their early 2008 levels, if not just a touch higher. Scrap went down even more. We saw scrap go from $0.05 per pound to $0.25 per pound for a period. I think it's back below $0.10....

 

[pgarch]

I am considering a precast concrete septic tank 4" of XPS insulation and a Polyethyene tank inner. The Polyetehelene with start to deform about 80 degrees but the concrete will restrict movement. I am also wondering about placing a membrane first, then insulation and then the concrete tank with the polyetehenene next to the concrete. The concrete is providing a backup to keep the tank dry and not allow disfiguration. Does anyone have any comments?

I considered just concrete but was not sure how prolonged heat might affect it, I looked into a fibreglass liner but that was going to be problematic too.

Thanks in advance

Regards Philip

 

[flyingcow]

Just thinking out loud(or typing). I have a 4200 gal insulated truck mount S/S milk tank that the undercarriage is not road worthy. Would work fine as a stationary tank. Has a manhole on top for access. I'd sell cheap, but it's a ways away for you Durango. But I think this would work good if someone would need that size of storage(unpressurized use only!). My thought is if I have one, seems like you might be able to find one a little closer. Just a thought. Locate some tank dealerships and also farm tank installers have various sizes they are replacing because of freon leaks, will hold unpressurized liquids fine. [u]TAKE NOTE, these tanks cannot be used for pressurized systems. Don't even think about it. [/u]