Underground water storage?

[PNWguy]

Has anybody put their hot water tank underground?

I can buy a 2,000 concrete water tank and wondered about insulating it and placing it in the ground. Crazy?

 

[leon]

Has anybody put their hot water tank underground?

I can buy a 2,000 concrete water tank and wondered about insulating it and placing it in the ground. Crazy?

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Its not crazy, I believe that people have buried spray insulation coated surplus propane tanks on concrete slab foundations.

You would be better off buying a couple of 8,000 gallon surplus insulated tank cars, selling the trucks and wheel sets back to the auction company and mounting them on two sets of concrete saddles as it is done for large propane tanks and doing it that way.

It would take a huge amount of sprayed insulation and I am sure the weight of the tank and water would crush the sprayed foam insulation under the base of the tank. If you did not insulate the base of the tank the heat would radiate into the dirt which has a temperature of 52 degrees or less.

You would need to purchase the 15 dollar per foot pex or contracting for foaming the trench or trenches too.

 

[PNWguy]

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Its not crazy, I believe that people have buried spray insulation coated surplus propane tanks on concrete slab foundations.

You would be better off buying a couple of 8,000 gallon surplus insulated tank cars, selling the trucks and wheel sets back to the auction company and mounting them on two sets of concrete saddles as it is done for large propane tanks and doing it that way.

It would take a huge amount of sprayed insulation and I am sure the weight of the tank and water would crush the sprayed foam insulation under the base of the tank. If you did not insulate the base of the tank the heat would radiate into the dirt which has a temperature of 52 degrees or less.

You would need to purchase the 15 dollar per foot pex or contracting for foaming the trench or trenches too.

A couple of 8,000 gallon tanks? That seems a bit overkill for my needs, as well a long list of logistical problems.

 

[peakbagger]

Its been done. But lots of "ifs" water ground water has a lot more conductivity than air so ideally the tank would need to be well above the water table. Cellular glass would be the best insulation to use as it will not absorb water and has very good compressive strength.

The biggest issue is access, inevitably you may need to drain it and get inside it. A buried tank is PITA to do either task. Due to the temperature, you cant use the fairly affordable rotomolded HDPE tanks so you need to buy a coated steel or stainless tank as ground contact can slowly eat away at tanks unless you put in an active anode cathodes system.

 

[Fred61]

Yes crazy! Your odds of failing are too great VS a successful installation. Could be costly.

 

[maple1]

I would definitely not try that one. Way too much chance for too much disappointment.

 

[PNWguy]

Its been done. But lots of "ifs" water ground water has a lot more conductivity than air so ideally the tank would need to be well above the water table. Cellular glass would be the best insulation to use as it will not absorb water and has very good compressive strength.

The biggest issue is access, inevitably you may need to drain it and get inside it. A buried tank is PITA to do either task. Due to the temperature, you cant use the fairly affordable rotomolded HDPE tanks so you need to buy a coated steel or stainless tank as ground contact can slowly eat away at tanks unless you put in an active anode cathodes system.

Thanks for the details; sounds like an expensive and finicky solution.

Any recommendation on where to buy the tank?

 

[tom in maine]

Concrete does not like to be over 140F. Access for any kind of service or inspection is a concern. As Peakbagger said, water infiltration into the usual foam insulation is much more likely.

 

[NateB]

if you are looking for unpressurized storage. I would say American Solar Technics is a good place to get one. I agree with the others on the logistical nightmare of putting a tank outside. I would guess it would be cheaper to build a building for the tank and boiler.

 

[PNWguy]

Thanks Nate.

I'll talk to the AST folks, but since they are 3,000 miles away, shipping could be absurd. I'll keep an eye out for something on the west coast as well.

 

[PassionForFire&Water]

What is/are the reason(s) you want to install this thermal storage tank underground?

 

[maple1]

Thanks Nate.

I'll talk to the AST folks, but since they are 3,000 miles away, shipping could be absurd. I'll keep an eye out for something on the west coast as well.

You can build your own tank. Out of wood. (As long as it's built right). And put their liner in it.

 

[PNWguy]

What is/are the reason(s) you want to install this thermal storage tank underground?

Mostly for looks.
But if I can fit the storage into the wood shed/boiler shed/garden shed, it'll be fine above ground.

 

[leon]

Mostly for looks.
But if I can fit the storage into the wood shed/boiler shed/garden shed, it'll be fine above ground.

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Is a surplus 8,000 gallon insulated tank car out of the question? They have them on the west coast.

 

[PNWguy]

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Is a surplus 8,000 gallon insulated tank car out of the question? They have them on the west coast.

• I cannot imagine a scenario where I'd need 8,000 gallons of hot water.
  
• I have no idea what would happen to my well if I drained 8,000 gallons from it over a short period of time.
  
• I do not want to look at an 8,000 gallon tank sitting above ground, or to have a woodshed larger than my house (seriously, my house will be 40x20).
• I do not live near a train yard, so a tank would need to be delivered several hundred miles on the back of a truck.
  
• Tank delivery would be quite expensive, plus the crane rental at my house.
• I'm not sure a tank would fit down my driveway.
• The post you replied to and quoted said that I didn't want to look at an above ground tank, which is why I was asking about a below ground tank.
  
• I do not want to have a train car (or even just the tank) in my yard.

Clearly you're passionate about train car tanks. It simply will not fit my situation.