Avoiding freezing in water tanks
Avoiding freezing in water tanks
(OP)
What are the most common systems to avoid freezing in water storage tanks i.e fire water storage tank...?
thanks
thanks
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Avoiding freezing in water tanks
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Avoiding freezing in water tanksAvoiding freezing in water tanks(OP)
What are the most common systems to avoid freezing in water storage tanks i.e fire water storage tank...?
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RE: Avoiding freezing in water tanks
Don
Kansas City
RE: Avoiding freezing in water tanks
RE: Avoiding freezing in water tanks
RE: Avoiding freezing in water tanks
I've seen the immersion heater. The other thing I've seen done is to have a bypass system which pumps water out and back into the tank to keep the water flowing ... and maybe add a bit of heat from the pump. Of course, this only works if you don't have really deep freezes.
Patricia Lougheed
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RE: Avoiding freezing in water tanks
underground tank
immersion heater
water return
which of these options is the cheapest. Obviously not the underground tank, but of the other two?
Also, which of these systems is most common in fire water storage, or recommended by the NFPA?
RE: Avoiding freezing in water tanks
Don
Kansas City
RE: Avoiding freezing in water tanks
Per NFPA 22, tanks in many southern areas don't require anything.
Otherwise, it's a matter of balancing cost of insulation against energy costs.
Bayonet heaters can be used; separate water heaters with pumps can be used; steam coils can be used. You can inject steam directly into the water, for that matter.
RE: Avoiding freezing in water tanks
TTFN
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RE: Avoiding freezing in water tanks
If you post the tank size, the region you live in, then a cost effective solution could easily be suggested here. It may be just as simple as a layer of insulation and a cheap immersion heater which would be used only during sustained below freezing condition over days.
For example, where I am in southern CT, so far the average temperatures over any 24 hour period this winter season has been below freezing, so the layer of insulation would have been sufficient to maintain above 32 in the tank without turning on the heaters.
RE: Avoiding freezing in water tanks
Mike Halloran
Pembroke Pines, FL, USA
RE: Avoiding freezing in water tanks
RE: Avoiding freezing in water tanks
Mike Halloran
Pembroke Pines, FL, USA
Mike,
Southern CT is not Pembroke, but by any objective measure it aint that cold there.
And by the way, I meant to say that AVERAGE temperatures over any 24 hour period so far has been ABOVE freezing, not as I stated.
RE: Avoiding freezing in water tanks
There are some handleld fire extinguishers used on aircraft that use water. We used to use "anti-freeze" in these. Not sure why you couldn't do the same in your application.
RE: Avoiding freezing in water tanks
The tank is 433,000 GAl (1039 M3). We are talking about south of buenos aires in Argentina. the lowest 24h average temperature would be about -10 degrees C (14 F)
RE: Avoiding freezing in water tanks
Charlie
www.facsco.com
RE: Avoiding freezing in water tanks
RE: Avoiding freezing in water tanks
The calculation assumes a spherical container which, from your data yields a radius of 20 feet and a thermal time constant of 15 days (meaning it would take 15 days for a tank at 45 F to drop to 25 deg with an outside average temp of 14 F without insulation and 90 days with R=6.
So the benefit of insulation is that if the average temperature over about a few months is above freezing, you probably won't need to turn on the heater.
RE: Avoiding freezing in water tanks
The example of the thermal time constant should be:
If the OT is 14 F and the tank is 45 F, then without insulation it would take 12 days to reach 32 F. With a blanket, R=6 it would take 24 days to start freezing without the heaters.
RE: Avoiding freezing in water tanks
Your tank is not required to be insulated, but in any practical sense it will need to be, and is probably more cost effective in the capital equipment let alone the long term to do so.
NFPA 22 has tabulated heat loads for tanks of varying proportion and capacity that will specify the heat load including insulation, temperature and wind factors.
In summary, NFPA 22 is a one-stop-shop to solving this problem and should be your primary resource.
RE: Avoiding freezing in water tanks
RE: Avoiding freezing in water tanks
I want to thank all of you for your help. I really appreaciate all the ideas that arrived. When i really started searching, we found that in our case, NFPA only accepts one answer, insulation and a heater.
Once again, tanks (chessy joke) for all the expertise of our faithful eng-tips friends
RE: Avoiding freezing in water tanks
You can add common anti freeze also known as ethylene glycol in a concentration approximately 1:4 with water. This makes the system good to -40C. If you are talking about a tank with potable drinking water, then you need to bury the tank below the freezing line. Typically this is six (6) feet or so.
The other way of doing it is head to your local corner grocery and buy a bottle off the shelf. Works every time!
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada
RE: Avoiding freezing in water tanks
It's probably illegal to allow it to flow down city sewer systems.
TTFN
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RE: Avoiding freezing in water tanks
Don
Kansas City
RE: Avoiding freezing in water tanks
Interesting! What would you boys recommend as an automobile anti freeze for your radiators, rated -45C?
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada
RE: Avoiding freezing in water tanks
It had already been reported by the OP that a heater and insulation is the only acceptable answer for the NFPA anyway.
Don
Kansas City
RE: Avoiding freezing in water tanks
The question isn't to to protect a few gallons in a closed loop system from freezing, it's for a large storage tank (433,000 gal) that supplies water for fire fighting!
Not sure the "owner" would want to purchase 100,000 gallons of antifreeze to provide a 1:4 mixture, also not sure any wildlife (or people) in the area would appreciate having tens of thousands of gallons of antifreeze being sprayed in the open air.
Ethelyne glocol is hazardous, and that's why it should be properly handeled and disposed of, even in small quantities (in my state, it's illegal to dump ANY quantity of antifreeze, including from a treated radiator, in the environment or sewer).
RE: Avoiding freezing in water tanks
One response was to increase the salinity concentration of the water volume. Probably price will be an issue here also. Another has suggested water heater and mixers for stirring the volume. Probably you need worry about the electrical bill on a monthly basis.
Short of throwing ice cubes at the fire, I guess you have a real problem. Sorry nothing matched your particular specifications for a viable solution set. Good luck with it, none-the-less.
Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada