See I couldn't find heat specs on the actual tank so I looked them up for HDPE plastic.
http://en.wikipedia.org/wiki/High-density_polyethylene
"That is where I got 120 °C/ 248 °F for short periods, 110 °C /230 °F continuously"
I know that tanks weren't designed for continually storing heated liquid but I was thinking the properties of the plastic could handle it. Wouldn't that be regardless of whether it is insulated or not? Even if I was running 180 degress that would be well below the HDPE specs.
Yes at 180f it should be alright but the concern expressed, as I understand it, is in the insulation "softening" the outside of the tank which would normally be more rigid because of its direct contact with cooler ambient temperatures. Along those lines if your boiler were to overheat and saturate the storage containers at 212f, even for a short time, there could be some softening of the hdpe. However by the spec's in the link you should certainly be able to start out at a lower 165f and eventually edge up to 180f. Shoulder seasons are great times for learning curves.
I like the idea of a diffuser and that I could use them unpressurized. The the circ pump is located at the bottom of the tank, pumping away from the tank? is that right? I still haven't entirely figured out the best and simplest way to plumb the storage / boiler / heating loop.
Yes, normally speaking the circ would belocated at the bottom of the tank or the line out from where the tanks manifold.
If you did have more flow going into one tank I guess they would all equalize if the were paralleled together. (I am guessing I would have to have them side by side and not stacked or one would drain out into the next, and then all over the floor)
Stacking would not be a good idea for the very reason you have expressed. Equalizing would easily be seen if you had temp guages on the lines leading to the manifold as temps would be normalized. However, even when all parts are identical manifolding can create eddy currents and you will have manifolds going in and going out of the tanks. Aside from the manifolding having separate boiler valves is advised incase of a partial system failure like leaks and such. (not ball valves as they are meant to be either full on or full off and not to be used for metering as that leads to leaking valves)
Yeah reselling seems viable It was looking like just and EPDM liner was going to be over $100 for $500 gallon plus still all the labor of building a tank frame. Only thing is shipping would be ridiculout on something as massive as one of those tanks While there is lots of people in this area that have big outdoor wood boilers, there is very few that have have gasification boilers, and so far I am the only one I know of that is planning thermal storage around here (but maybe that is just the ticket to a good local marker)
