In loving memory of Kenis D. Keathley 6/4/81 - 3/27/22 Loving father, husband, brother, friend and firewood hoarder Rest in peace, Dexterday

Heat off of wood boiler?

Discussion in 'OWB's and Gasification Boilers' started by Lennyzx11, Dec 1, 2020.

  1. Lennyzx11

    Lennyzx11

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    I haven’t seen one in person yet so am asking.

    Will some wood boilers radiate heat like a wood stove ?

    I am thinking of replacing my old wood stove and installing a used wood boiler in my shop with water lines running to a baseboard heater in the second floor wood shop.

    I would like to have the radiant heat like the wood stove though in the lower level.

    The reason I ask is the steam boiler in my house and the hot water boiler in our cottage are both fairly cool to the touch on the outside.

    I’m a transplant from Oklahoma to Vermont so I don’t have a lot of exposure to boilers.

    This is all in the way of learning about wood boilers and systems in prep of an outdoor boiler installation in the next year or two to heat the house, cottage, and shop.

    Thanks,
    Lenny


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  2. Horkn

    Horkn

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    Yes, they'll radiate heat. The guy that owns the pile shed where I store my boat has an OWB in his garage and it keeps his truck nice and warm
     
  3. lukem

    lukem

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    They don't radiate but they will convect some heat into the space they are enclosed in.

    Gasifier might have better insight on how much passive heat to expect from an indoor boiler.
     
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  4. Horkn

    Horkn

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    I suppose it will be a combination of radiation and convection. ;)
    In any case, yes, they'll heat the enclosed area to an extent.
     
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  5. JWinIndiana

    JWinIndiana

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    I say it depends. My Central Boiler is designed to be outside so it is insulated as such. A fellow teacher's son has an Aqua Therm wood boiler. It is designed to be inside of a building and does radiate more heat than my CB. So he put it in his garage and has a somewhat heated garage (generally keeps the uninsulated garage at or above freezing here in Northern Indiana. Do your homework and purchase accordingly.
     
  6. Horkn

    Horkn

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    The unit I'm speaking about is also an aqua therm.
     
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  7. Gasifier

    Gasifier

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    All I can tell you is my Wood Gun gives off a lot of heat into the area it is in. The boiler has metal side panels that have insulation underneath them. But the front and back ends have no insulation or panels so the heat is radiated off like crazy. This is a great thing if you have an indoor wood boiler and want that heat in that area. I recently installed a door on the boiler room to contain said heat and let it out where I wanted it. We didn’t want it to all go out into the basement anymore because we are using that for something else now and didn’t want it to be so warm. I then installed a 14”x20” vent that opens up and allows a 1” filter to be inserted in. Now all the warm air that leaves the boiler room at the top of the wall near the ceiling is filtered and escapes to the staircase and upstairs. The door and filtered vent keep all the dust and anything airborne from the whole Wood process in the boiler room. Much better now.
     
  8. jrider

    jrider

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    Mine will have snow on the roof after a snowstorm. It won't be there forever but it's well insulated. By the sounds of it, it varies upon unit.
     
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  9. lukem

    lukem

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    Same with mine. I get frost on the roof of mine every once in a while too.
     
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  10. amateur cutter

    amateur cutter

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    Mine will radiate some heat from the door where the damper is, otherwise it's cool on the exterior. It would likely keep a well insulated space warmish.
     
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  11. fuelrod

    fuelrod

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    My inside boiler is in its own "room" super insulated with foam. It's attached to the outside of the houses "envelope" but it's where we dry our laundry on an old fashioned wooden clothes drying rack, it's regularly near 100* in there.
    A nice place to spend a little time after being outdoors and provides us with nice warm towels as it's just a few steps away from the shower :D.
    Drys my carhartts and boots nicely.
    So yes to the heat question.
     
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  12. brenndatomu

    brenndatomu

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    Indoor boilers will radiate heat to the building quite a lot...ask 3fordasho .
    Outdoor boiler (why would you put one indoors?) not as much
     
  13. fuelrod

    fuelrod

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    I understand the story about the "mess" and the smoke, but at minimum if someone had the room in a shop or garage, or the ability to build a small attached building to whatever space works best for them, capturing those btu's in my opinion is equivalent to adding a bunch of insulation to your space. It's otherwise "free" heat.:thumbs:
     
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  14. brenndatomu

    brenndatomu

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    This is what 3fordasho is doing...heats the garage just from "waste heat" off the (indoor) boiler.
     
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  15. 3fordasho

    3fordasho

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    Correct, the waste heat from my Attack 45kw downdraft gassifier, insulated piping and well insulated storage (2x500g propane tanks spray foamed and framed in w/R13 fiberglass) keeps my 24'x48' "boiler shed" above freezing all winter. Typically in the mid 50's F out there, it did get down to 38-40F when I had a week straight of -20F lows. That's just heat loss from the boiler and storage - there is no fan coils / radiant circuits or other heat source in that building.

    I should also add the boiler shed is standard 2x4 construction, R11 walls, maybe R19 ceiling, uninsulated concrete floor. Boiler fired once per day to bring storage from 55-60C up to 80C.
     
    Last edited: Mar 3, 2021
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  16. fuelrod

    fuelrod

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    I want storage!
    I'm just not really happy about sacrificing the space. I've had thoughts about building a well insulated under ground vault, or possibly altering a 1000g tank to be vertical. I have 16'6 ceiling height in the shop that a 4x4 footprint wouldn't kill me.
    I know that there's system considerations, but how big is your expansion tank for 1000g of storage?
     
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  17. 3fordasho

    3fordasho

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    I used the largest bladder type well tank from Menards, over 100 gallons I believe. Lowered the precharge pressure from 30psi + to under 10psi and it's working fine. The well tanks have a slightly lower temperature rating but mine never gets much more than lukewarm anyway. My system sits at about .6 bar when it's time to fire again and tops out about 1 bar when everything is up to temp (80-85C). Sorry for the mix in units, my euro boiler uses C for temp read out and bar on the pressure gauge.
     
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  18. brenndatomu

    brenndatomu

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    .6 bar = 8.7 PSI.
    1 bar = 14.5 PSI
    80-85c = 176-185*f
     
  19. Canadian border VT

    Canadian border VT

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  20. fuelrod

    fuelrod

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    Thanks, my units from Pennsyltucky USA:D
     
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