Cold weather water storage

[JDR]

This question is for the folks that love in colder climates.
Trying to think of ideas for cold weather water storage. I found some grain bins on Craigslist for sale. I had the idea of buying a grain bin, erecting half of it and putting a 1500-2000 (or larger) gallon above ground water tank in it then assembling the bin the rest of the way. My question is, what's people thoughts about spray foam insulating the inside of the bin and then also insulating the tank itself. Would a galvanized grain bin radiate enough heat along with the insulation to keep the water liquified during the coldest winter temperatures?
Thoughts.. Thanks!

[MountainDon]

Insulation slows down the transfer of heat from hot side to cold side. Unless the water is continuously being replaced with water above freezing I would think it would cool to the point where water freezes.  The insulation works both ways, so I would not expect a lot of warming of the water (inside the insulation) from the sun shining on the metal.

I think burying a tank makes more sense. Maybe a burial combined with insulation on top to slow the escape of the earths own heat.


We have some experience with this problem. We have a 325 gallon buried spherical shape cistern. It has a manhole neck that rises above ground. The first winter we discovered that let the frosty temperatures penetrate the tank and freeze the upper area of water. I had a make do interim solution that permitted us to draw water all winter, but it was a bother in everyday use.  Last summer I excavated around the upper half of the tank. I installed rigid sheet XPS insulation around the tank to a depth of three feet... our maximum frost depth. I also laid horizontal over that, the idea being to trap the earths heat. The exposed neck was boxed in and insulated as well.  This last winter we never had any freezing. The electric submersed pump worked fine.   

You could do something like that on a larger scale. One issue with buried tanks is that most tanks need to have at least 25% of their capacity left in the tank at all times to head off collapse and/or popping out of the earth. The uplift can be a big problem if the ground water table is high. The spherical tanks do not require leaving a minimum level.

This summer will see the addition of an DIY electronic water level gauge so I don't have to dipstick it any more.

Hope that helps.

We don't have the coldest of climates. We are in NM but the cistern is at 8800 feet so at times it is fairly cold.

[JDR]

Makes perfect sense, I had not thought about that.
Idk why, but I just assume not bury a tank. My biggest reason I suppose is the ease of checking on things and repairs if need be (although I hope not). My home will be off grid and I was moreso hoping to fill the cistern once a month or so and rely on gravity flow to feed the homes needs, short of a small pump for the shower pressure.
If I dug down below the frost line and built a concrete vault (that way i can still check on the lines, etc) to set it in and insulate it, do that sounds viable or I wonder if I would still have the same issues as you brought up about heat transfer like from the grain bin?
Thanks for the link to your other thread..
Also, would a shur-flo pump give out adequate pressure to push water through a on demand water heater?

[MountainDon]

Gravity flow... 0.43 PSI per foot of elevation difference from water in cistern/tank to point of use.  If you use large pipes you can get a reasonable rate of flow with low head but the pressure is still low. May not be enough to operate some on demand heaters.

Shurflo....  A shurflo or Flojet RV type pump can run most heaters okay. Check on the minimum flow rate (GPM) and the minimum water pressure. But they may not be able to run several points of use at the same time. Also check on the degrees of temperature rise at different rates of flow. Some on demand water heaters can't give sufficient rise for a shower if the water is at 45 F for example. FWIW we use a Shurflo but not an on demand water heater.

Burying... We run all the penetrations, pipes and electric, through the manhole cover or through the sides of the manhole extension. So no penetrations through the tank itself. That removed a lot of doubts about burying in my mind. A cast in place, underground concrete tank could be built. It would not have the potential flotation problem but might cost more. Depends I guess.  A buried tank would only need insulation in the upper areas, to prevent heat loss from the tank and ground upwards. Heat always flows from warm to cold. If you dig down, depending on climate zone, the earth is at a fairly constant temperature year round. In our case it is about 55 F  at a depth of 7 feet.


US ground temp map

[Gary O]

This question is for the folks that love in colder climates.
Thoughts.. Thanks!

The mature person would leave this alone,

but

a Freudian typo, well, I can't

ans; we require less covers

and now, back to our regular programming.........

[DaveOrr]

Here in the arctic a lot of places (mine included) have a water tank inside the home.
Mine is a 500 gal tank that is in an addition to my place.
This is how we keep ours from freezing.
Now I don't know where you live but up here temps can get down to -60 or colder during the winter.
Larger places have larger tanks indoors.
Filling is done by water tanker through outside fittings.
I will be doing something similar @ my cabin but will be draining the system in the winter.