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Hot water storage

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by ericjeeper, Dec 29, 2007.

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  1. ericjeeper

    ericjeeper New Member

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    Loc:
    central Indiana
    This is a question everyone ask.
    I am new to the forum but not new to hot water heat. My house is 3200 square feet pole barn house. With radiant slab heat. I wanted to cut back on feeding the oil people so I wanted solar panels.. Got six of them 3x13. Next came the decision on storage and heat exchangers. I was thinking concrete cisterns and septic. But.. they run about 700 and will still need tobe insulated and wrapped to prevent ground water from touching the concrete and wicking the heat away. So I have a buddy with a bobcat with a hoe.. He dug me a pretty square hole. we lined the hole with alternating layers of 2 inch pink board. Then through in a epdm liner and I poured a 4 inch thick 4x8 lid with a 2x2 access hole... Then built me an outhouse for a mechanical room. Its kinda cute.. Moon in the door and the whole nine yards..
    For heat exchangers with the price of copper skyrocketing I chose to manifold 1/2 inch pex. with a crossover return.
    Basically have 1 inch pex glycol filled from the solar panels feeding into six 84 feet loops of 1/2. was a 500 foot roll.. And the same from the house. So in this tank is water.. and two heat exchangers consisting of 1,000 feet of non barrier pex. The tank holds roughly 600 gallons.
    after all the solar was installed we had the farm timbered. So here is all this firewood laying everywhere.. I was cutting it up and giving it away to get the tops out of the fields. I decided it was time to build a boiler.. So last December I built myself a outdoor woodboiler.. But the firebox was to small.. (dad said it would be) at one time the firebox was his old forced air woodburning furnace. so he knew every four hours you would need to feed it.
    So Over the summer I designed a new larger model.. The boiler is basically fed from the tank water with a grundfoss pump into the bottom and feeds back out of the top. I do have a pressure valve on the boiler in case of failure.. But I figure if something goes bad it will just melt off a hose and vent.
    firebox is 30 inch diameter by 48 inches deep.. That ought to do it.. LOL every 12 hours is more than enough feedings for this "Magic Box"
    I will try to answer any questions..
    http://www.pbase.com/ericjeeper/solar

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  2. wdc1160

    wdc1160 New Member

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    I don't know what your asking, but as a fellow hoosier who burns wood welcome. It looks like you put some real work into the system you have there.
    I looked at the pictures you posted and just wanted to comment
    that jake's deer was a real tasty looking doe. Also, I liked the cupalo on the pole barn-- nice touch

    Where was I when you were giving away wood???

    Bill
  3. Eric Johnson

    Eric Johnson Mod Emeritus

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    Central NYS
    Welcome to the Boiler Room, ericjeeper. I've run across your website before--I think when I was researching storage options.

    Threre's a lot to digest in your pics, but it looks like a pretty neat heating system. We have more than a few other members with solar components to their systems, so I'm sure that will generate some interest. As to the boiler, we've got a few other homemade around here as well, in addition to a sticky link at the top of the Boiler Room with links to some boiler DIY project pics.

    So please feel free to hang out and contribute.
  4. brad068

    brad068 Feeling the Heat

    Joined:
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    Central Wisconsin
    How much heat are you getting from the solar panels? Can you go without firing the boiler a day or two? What are you all heating?
    I'm curious, because my setup is going to be alot like yours by next heating season.
  5. Eric Johnson

    Eric Johnson Mod Emeritus

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    I'm having a heck of a time getting my rectangular EPDM liner to fit neatly into my rectangular tank. I don't think there's a neat way to do it, but the one in your pic looks better than what I've been able to achieve so far. Any tricks or tips, or is it just a matter of making sure that the inside of the tank is covered by the liner and then worry about fitting the lid around the foldovers?
  6. Reggie Dunlap

    Reggie Dunlap Feeling the Heat

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    Eric,
    I fought that same battle a couple of weeks ago. My liner weighed 200 pounds and it was all we could to get it in the tank. The end result is not pretty but it works fine. I couldn't get most of the folds out of it but the weight of the water holds it tight against the tank.

    I don't think it's possible to get a rectangular liner to fit a cube shaped tank without a lot of wrinkles and extra folds. One option would be cut the liner and glue it together in the exact shape of the tank, then drop it in. Roofers are able to somehow weld the EPDM together and make it watertight. I don't know if it would still hold up to high temps. Either way, I just dumped mine into the tank and straightened it out best I could.

    The EPDM is pretty rugged but watch out when you are soldering. I put a couple of inches of water in the tank before we assembled the heat exchangers in case solder dripped on the bottom.

    Reggie
  7. kuribo

    kuribo Feeling the Heat

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    SW WI
    why would someone need a liner in a concrete tank?
  8. Reggie Dunlap

    Reggie Dunlap Feeling the Heat

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    Northern Vermont
    With a pre-cast one piece tank you would probably not need a liner. My tank is a rectangle with 3 sides concrete block butting into the poured foundation wall. It may be watertight but a 750 gallon spill would not be pretty. The EPDM liners are pretty inexpensive so I look at it as cheap insurance.

    Reggie
  9. kuribo

    kuribo Feeling the Heat

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    if the wall fails how will the epdm liner help?
  10. Reggie Dunlap

    Reggie Dunlap Feeling the Heat

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    Why would the wall fail? The tank alone may or may not be fully waterproof. The joint where the block walls meets the poured foundation wall would be the likely place for it to leak.
  11. kuribo

    kuribo Feeling the Heat

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    SW WI
    I was thinking that with all the concrete waterproofing products available now that it would be much easier and maybe cheaper, to coat the inside of the concrete rather than use a mechanical liner.....
  12. ericjeeper

    ericjeeper New Member

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    Loc:
    central Indiana
    How much heat are you getting from the solar panels? Can you go without firing the boiler a day or two? What are you all heating?
    I'm curious, because my setup is going to be alot like yours by next heating season.[/quote]
    Last winter I used the panels.. I have a bad 10k sensor somewhere in the mix. Last winter my panels really boosted my boiler. They work great in the fall. They will take six hundred gallons up from 100to 150 on a nice clear sunny day/.If it is not buttnumbing cold that will get me through a night.
    Once the boiler is fired it pretty much stays fired. This new "Magic Box" puts out plenty of heat.
    I am heating 3200 square feet.
  13. ericjeeper

    ericjeeper New Member

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    Loc:
    central Indiana
    Honestly.. My 72 year old dad put on his knee boots and got down in it as we filled it with a hose. Me and a buddy worked the liner from above.. It was alot like wrapping a Christmas present from the inside out. Dad said "It was a lot like putting socks on a rooster"
    We folded the liner back over the top and tucked it down along the outside. I used some 1 inch foam Backer rod to aid in the seal between the top six inches of foam along with the concrete lid.,
  14. Eric Johnson

    Eric Johnson Mod Emeritus

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    Central NYS
    Thanks Reggie. After I posted I actually took a cardboard box and a handkerchief and played around with it. Unfortunately, as you suggest, there ain't no pretty way to lay it in there, but as long as the liner is above the lid of the tank, it will work.

    I did think about painting epoxy or some sort of mortar product on the inside of the tank and forgetting the liner, but then you have a big problem with insulation. I would only be able to insulate three walls of my tank from the outside. The parts against the foundation and the floor would be huge heat sinks, I think. Maybe not. With the insulation sandwiched between the liner and the concrete walls, you know you're getting good coverage.

    As to the solder, you can drip it on your jeans and it won't burn the cloth, so molten solder isn't going to damage the liner. But you wouldn't want to space out and burn a hole in the rubber with the torch. I'm probably more likely to do that.

    Anyway, I gave up for the day. Start fresh in the morning.

    Reggie, did you cut holes in the lid liner for your piping, or just squeeze them in at the edge between the liner and the lid? That's what I'm thinking about doing. Then goop it up good with whatever. What did you use to seal the lid with?
  15. Reggie Dunlap

    Reggie Dunlap Feeling the Heat

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    I cut holes for the pipes and I keep the water level a few inches below that. Right now my lid is just two layers of 2" Celotex. I don't think that will last long because of the high heat and condensation so I plan on ordering more EPDM to wrap it with. My tank is roughly 4' by 9' so I'll probably do two different lids with plywood on top of the foam to stiffen it and to staple the EPDM to. One lid would be too big and heavy.
  16. ericjeeper

    ericjeeper New Member

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    Loc:
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    If I ever remove my lid I will do something to encase the pink board.. It soaked up some moisture.. That is not a good thing.. But then again It was not designed to see boiling water.I hate to admit this out loud. But My tank has seen temps close to 210 degrees.
    Once maybe even a lot higher as my tank to boiler pump took a dump on me..and I did not catch it for a day or do.. The boiler was making steam.. and I mean a lot of steam.Thank goodness I caught it before I boiled it dry. I replaced the pump and filled it very , and I do mean very slowly..
  17. Eric Johnson

    Eric Johnson Mod Emeritus

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    Reggie, my tank opening is roughly 4x7. My plan is to wrap a second piece of EPDM around the last piece of foam and use that for a lid, putting silicone or some EPDM roofing cement at the seam where the two pieces of rubber meet. I don't want to cut the rubber for the pipes, but I think squeezing them between the lid and the wall will work alright.

    eric--Sorry for totally hijacking your thread. I've heard of overheated water taking out underground pex lines. I've melted cheap foam insulation to copper pipe on more than one occasion. Kinda lived on the edge with my previous boiler--it was a bit undersized and it tended to smoke, so I liked to run it hot. Sometimes you overshoot.... I thought I read somewhere that the upper limit on EPDM is 180. Guess that's a conservative estimate. That's good to know.
  18. ericjeeper

    ericjeeper New Member

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    No biggie on the hijack.. I chose to notch out the lid material where my lines come from the house and enter the tank.. all of that is above the epdm level.. I sprayed a whole can of expanding foam into the end of my 5 inch tile to seal it up.. God knows that crap will stick to everything like glue.,
  19. Eric Johnson

    Eric Johnson Mod Emeritus

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    That's the worst damn stuff to get on your hands or clothes that I've ever seen. It looks pretty innocuous going on, but you CANNOT get it off your hands for a couple of days at least. It must be made of super glue. I hate wearing gloves, but I won't touch that stuff without them anymore.
  20. brad068

    brad068 Feeling the Heat

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    Another great feature of the Garn. The storage tank is the boiler. No pump between boiler and buffer tank. Although I boiled over my Garn WHS-500 model. Its quite a sight when 500 gallons of water are boiling. The whole tank was moving. I have yet to boil my homemade unit and I really don't want too.

    This subject reminded me of a boiler that I seen. The supply hookup was at the top and return down low. At first I thought this was a mistake but then thought, if you were to spring a leak in the heat system the pump would cavitate and water would stay in the boiler and not damage the firebox. A check valve would also have to be installed in the return.
    Is this hookup more common than I think? I draw off the lower half and return on the upper half to equalize the boiler better. Maybe I should try this.
  21. Eric Johnson

    Eric Johnson Mod Emeritus

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    Every boiler I've ever owned had the supply tapping on the top and the return on the bottom. But with that much onboard storage, the dynamics might be a lot different. Presumably if that's the way Garn pipes them, that's the way they should be piped. I have a circulator that pulls water off the top in a primary loop and pumps it into the return to avoid low temps and balance things out.

    What happened to your first Garn, if I may ask? I assume, from what you've said in the past, that they last forever.
  22. leaddog

    leaddog Minister of Fire

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    Loc:
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    I used the same 4in foam freezer panels for my top. I glued epdm on the bottems and folded it up to the sides and nailed it down. I used two panels so where they come together I folded some foil/bubble/foil into a U and wedged it between. All the pipes come out in one corner so I cut out just enough to clear and then can foamed it.
    I beveled the top edge of the tank and used carpet foam under the epdm so when I put the top on it made a seal between the pieces of rubber. That way any condensation would run back into the tank. It seems to work well. but my panels with epdm probably weigh #100 each. You must cover any foam with epdm or they WILL waterlog. If you have ever had a hot tub you will know what I mean. They wrap the cover in plastic and after a couple years it gets really heavy. Then the insulation is gone.
    I don't know how well spray closed cell foam will stay next to hot water but the can stuff will water log after time if it isn't protected.
    leaddog

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  23. brad068

    brad068 Feeling the Heat

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    A few owbs that I've seen pull off the bottom half and return on the top half. The Garn manual shows supply between 4 and 5 O'clock close to the front and return on the back top half. Once again, way ahead of the curve! To me this seems like a better way to balance out the boiler. I wonder how the downdrafters would work by changing around the water flow?
    If you were to look at my pics, way over to the right are pics of the unit I acquired from a guy that needed the bottom of the water jacket patched. It rusted through after 19years of service. I don't think that it had enough, if any chemical treatment in it and he said the boiler was not grounded good. I repaired it and I got to see first hand the quality and simplicity of this boiler. None of the flues or the firebox were rusted threw, though. And this boiler works just fine now, but I wanted more water storage and I wanted to do a few tweaks to the original design. You know, this boiler could run for another 15 years yet. It is for sale.
  24. Eric Johnson

    Eric Johnson Mod Emeritus

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    I thought about reversing the piping recently when nofossil posed the question of what would happen. I think I came to the conclusion that the thing is designed to be piped one way, and it probably wouldn't be a good idea to reverse it. But with pex, it would be pretty easy to do just by swapping the connections. Of course, you'd have to open or remove any flow controls. I'm still trying to figure out what you'd gain. I think pumping supply water into the return is a pretty good way to balance things out, but it does require an extra circulator.
  25. EForest

    EForest Member

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    this looks interestingModuTankInc.
    They claim to make tanks of all sizes and for all uses.
    The add says modular tanks, any size, any shape, any place.
    sure could take the guess work out of the equation!
    I will call them tommorow and report back.
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