Storing Hot Water For Heating System In IBCs

I am in the middle of building my latest design wood gasifier "boiler" for heating our house and I came upon a number of articles stating that an IBC will handle heat to 150F with no problem. I just happen to have a spare 330g (1000L) IBC left over from our 2500gal aquaponics system build so I plan on mounting that on a sturdy platform about 4' above the garage floor for heat storage. I will be placing it that high to assist gravity thermal flow from stove heat exchanger to the "heat sump" in case of a power shortage and from this storage "sump" I will have a circ pump assist to the upstairs radiators spread thru the house which should also thermaflow in case of power outage. The 2 circulators will be digitally controlled to the sump for one and of course the room temps above.

My question here is has anyone else had experience using an IBC in this manner? Storage tanks are of course available but costs are high indeed. Wood fired "boilers" (they are actually never hot enough to boil by design) run most efficiently at full tilt so thus the storage. Otherwise they should just idle awaiting the next call when the sump temp drops to say 120F just like any oil fired "boiler". Let me know if anyone else has done such. Love to share notes. BTW in the AP GH we have 2500gal in the system which stores the heat in that instance but only to 60F where the bacteria are happy as well as the trout.

Here is a DIY tank. http://www.builditsolar.com/Experimental/PEXColDHW/TankConstruction.htm

Reading it and the tote materials, I think you can do the same thing with a tote safely if you stay @ 140 design temp. The trick is insulating it. I suppose you could set it up and just blowing cellulose around it if you have enough space.

Hey thanks for the fast reply. Yes I have plenty of room to use insulation panels and I plan on at least 2". Some loss is acceptable as I heat the garage and basement workshop from the heater as well.

I checked out the article you posted and I feel he needed a center surround support as well as that is where the tank or liner will push out the hardest by far and not at the top and bottom where he did all the bracing. There is no substitute for years and years of experience with bootstrap engineering:-)

Something to think about is that 140degF is 60degC and is right on the borderline for preventing the development of Legionnaires Disease bacteria from breeding in your tank. If your planned operating max temp is going to be 140, this means that a lot of the time the T is likely to be below this, or conversely, there will be days when you do not reach this temp.

You need to look carefully at the longest recommended time a system can be without reaching 140 or above. In some jurisdictions it is a requirement that hot water systems stay above 140, in others 140 needs to be exceeded for a given time in any period of X days (X depends on the jurisdiction).

Really? Oh my... I am planning a low heat reservoir to provide bottom heat to growing beds. By my calculations, it will never exceed 140 degrees F. What to do? Was hoping for an "open" system, no pressure, except the circulating pump. I never dreamed I could incubate some awful disease!

Yeah, me again... Jim, there's lots to read on thermosiphoning on the internet. I grew up in a 2 family flat in the city. We had a hot water system, was the most even heat ever. No pump, all thermosiphoning.

Well I have the stove all built and online since my last post. It has been about 3 wks since the first burn and I just keep improving on it and getting to know it's unique personality. Every new design has it's own for sure. A slideshow can be seen on G+. It is set in reverse order so you might want to start at the bottom first. She is a real honey for the money and my favorite build yet. We are toasty at last in this big unfinished house. The 330 IBC is doing great and the stove doesn't seem to have any bad habits. Like any true gasifier it likes DRY wood so I included a drying polishing rack to season the next days load and that has been great since I am way behind on firewood harvesting due to a blown appendix a few months back. Here is a link to the photos that are not yet complete (too many cameras involved:-) but there are about 225 with some captions as well. Still not sure my way around on here so not sure how to make it active but you can cut and paste.
https://plus.google.com/u/0/photos/100723918717226979447/albums/6111320016293960913

Gordon Claridge wrote:Something to think about is that 140degF is 60degC and is right on the borderline for preventing the development of Legionnaires Disease bacteria from breeding in your tank. If your planned operating max temp is going to be 140, this means that a lot of the time the T is likely to be below this, or conversely, there will be days when you do not reach this temp.

You need to look carefully at the longest recommended time a system can be without reaching 140 or above. In some jurisdictions it is a requirement that hot water systems stay above 140, in others 140 needs to be exceeded for a given time in any period of X days (X depends on the jurisdiction).

I wonder if there is an anti-bacterial chem that can be added to avoid such. My system is only vented thru a commercial bleach barrel vent cap that allows for expansion changes thru a fine filter so I am not sure where the bacteria would get in and other than working on the system like adding a HW coil to the IBC there is no contact with the water. I have been playing with the idea of adding metal protection such as exists in automotive antifreeze but once the O2 is used up the water runs clear. I could just as well add an anti-bacterial if anyone has any suggestions. I was under the impression that legionaires was only bred in air conditioning systems. There is also the fact that the heat exchanger does boil the water during gasification phase and the flue at the exchanger runs at about 700F at the 8" T during gasification.

Tim Malacarne wrote:Yeah, me again... Jim, there's lots to read on thermosiphoning on the internet. I grew up in a 2 family flat in the city. We had a hot water system, was the most even heat ever. No pump, all thermosiphoning.

Hi Tim, I always go thermo if possible but this radiator is 60 feet from the "boiler" and only one floor up so although it does a little it is way too slow. I am left using a circ to get the heat there in a timely manor.

Hi Jim,
I am a newcomer here but have been researching rocket mass heaters, mainly on line, for a little while.
Just getting geared up to build a water heater with ibc as thermal store. Your thread highlighted a couple of concerns I had, legionella being most important.
Does your system circulate from the heater directly through the ibc or does it work indirectly through a coil? If the latter, and assuming all other inputs and takeoffs are indirect, could the water in the ibc be treated with a chlorine bleach? I know that chlorine dioxide is used to kill legionella but I don't think there is a simple, cheap way of introduing it to the system.
Martin.