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#1 |
Journeyman EcoRenovator
Join Date: Jul 2014
Location: Austin, TX
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![]() I'm hatching a plan for my solar hot water collection. I need a storage tank and it seems the 255 or 330 gallon ibc totes would be ideal candidates. I believe the max temperature rating for the plastic is 230F. The tank would be located underneath my house and heavily insulated by me. This will be an open loop drain back system pressurized by pumps. I haven't found any posts of these in use besides rain harvesting. Has any one else tried this ?
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#2 |
Journeyman EcoRenovator
Join Date: Feb 2010
Location: Arab, AL
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![]() I'd go to Build it Solar for this type setup and look at what is posted there to get started. There is a design there I plan to mimic when I get my {nearly} never-ending garage/workshop project finished.
BuildItSolar: Solar energy projects for Do It Yourselfers to save money and reduce pollution Last edited by gasstingy; 03-10-15 at 12:57 PM.. Reason: Add web address |
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The Following User Says Thank You to gasstingy For This Useful Post: | gtojohn (03-11-15) |
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#3 |
Administrator
Join Date: Aug 2008
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![]() I seem recall this not being a good idea. I can't for the life of me remember why though...
![]() I emailed gary from builditsolar. Hopefully he will chime in.
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The Following User Says Thank You to Daox For This Useful Post: | gtojohn (03-11-15) |
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#4 |
Apprentice EcoRenovator
Join Date: Nov 2008
Location: SW Montana
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![]() Hi,
I asked one of the makers of rotomolded polyethylene tanks what temperatures the tanks could withstand -- the answer was: "Our tanks are rated to spike at 140 and run a constant temp of 120. If you store the water at 150 degrees it could soften the tank. You might try finding a cross linked tank that can withstand the higher temps." I believe that the IBC totes are made from polyethylene and made about the same way as the rotomolded tanks, so I'd guess the same temperature limit applies? I think the rating that they gave of 120F is probably on the conservative side, and the fact that the IBC totes have the metal pipe frame would make them good for more than 120F, but I think its pushing it for solar hot water storage. I believe that they do make polypropylene versions of these tanks, and they would be fine for solar tank temperatures -- but, I don't think these polypropylene ones are common. Gary |
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#5 |
Master EcoRenovator
Join Date: Aug 2012
Location: Toronto
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![]() I don't see why you cannot use the IBC with a wire cage for hot water up to even 180F. The plastic may soften SLIGHTLY but not enough to make a difference. I would just set your controller to limit the tank temp to a comfortable level. If you have enough collector area, use two tanks.
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The Following User Says Thank You to Mikesolar For This Useful Post: | gtojohn (03-11-15) |
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#6 |
Journeyman EcoRenovator
Join Date: Jul 2014
Location: Austin, TX
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![]() What I've read through so far is most are made of HDPE which can withstand up to 230F continuous. I've found a few blanket heaters for ibc totes, their thermostat ratings range from 130, 160 and 212F all claiming not to scorch. From one source it sounded like the tanks without cages were made thicker, around 1/2" thick. I haven't been able to find any temp ratings for totes yet. I'm looking at a few later this week.
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#7 |
Apprentice EcoRenovator
Join Date: Nov 2008
Location: SW Montana
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![]() Hi,
I did a little more searching around on the IBC totes. Talked to Hoover in Nebraska. Asked about using IBC totes for solar heated water storage. He said that the lighter wall thickness blow molded IBC totes should be good for 120 to 140F. And, that the thicker wall roto molded (3/8th to 1/2 inch walls) should be good for 140 to 160F. Talked to Encore Reconditioned Totes | 275 Gallon Totes Their website has an interesting video showing how they manufacture their blow molded IBC totes. On asking them about using IBC totes to store hot water in solar heating systems, and what temperature should be limited to, they put me on hold, talked it over for a while, and came back with no more than 180F. Not sure how much actual science or experience went into either of these answers. It would be nice to find a published spec for IBCs -- I suspect its out there somewhere. Or, better yet, someone who has actually used the totes for solar heat storage -- I'm sure its been tried before. The other issue is life of the container when filled with hot water over a long period. I asked the Encore guy about this, and his response was that he had no idea -- when I said months or years, he thought maybe years. I think that if I gave it a try, I'd set the high limit on the differential controller to 140F and see how that works out. I did use a 300 ft coil of 1 inch polyethylene pipe as a heat exchanger immersed in an EPDM lined tank. I limited the temperature to 140F and had this in service for more than a year with no problems before changing it to a pex coil. Gary |
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#8 |
Apprentice EcoRenovator
Join Date: Nov 2008
Location: SW Montana
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![]() A little more.
This email response from Mike at IBC North America "150 F is the max people put up to 180, but we don't recommend it." The question to him was: What is the maximum recommended temperature for liquids stored in IBC totes? Gary |
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#9 |
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![]() Here is a project someone storing heat in a IBC
Storing Excess Daytime Solar Energy to Heat Greenhouse at Night |
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#10 |
Apprentice EcoRenovator
Join Date: Jul 2014
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![]() I don't know the answer to your question, but I suggest you consider the risk. If the tote fails and dumps 250+ gallons of hot water, will this be a disaster or merely an inconvenience? If it would be no big deal then give it a shot but if you keep your spare Picassos in the same room then why take a chance?
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