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Gasification Design Help Request

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Mtn Fire, Jan 21, 2013.

  1. Mtn Fire

    Mtn Fire New Member

    Joined:
    Dec 12, 2011
    Messages:
    20
    Loc:
    New Mexico
    Hello to the forum experts,

    I am designing a small/medium 175,000btu boiler for use inside the living room area of a house. Many attributes of the Garn gasser but much smaller at about 500 gallons storage.

    If some experts would be able to provide feedback on the below questions:

    1. Is the secondary gasification chamber best located on top or to the side of the initial firebox?

    2. For 175,000btu size output what would the recommended size and type of construction of the secondary chamber? Size of opening from firebox to secondary chamber?

    3. Do you think 3" exhaust/exchanger pipe out of A53 schedule 40 steam pipe at about 30' length a good choice? Is 4" a better selection? Can a thinner walled stainless pipe be used after the first 10' or schedule 40 A53 as a means to get faster heat transfer and thus a possible shorter exhaust/exchanger length?

    4. Inducer fan design/sizing/mounting? 2 or more speeds seem to provide fine tuning options? 1/4 horsepower? How to mount on side of unit prior to the last heat exchanger run? Does cavitation of air sometimes occur? Brand and model numbers if you have preferences.

    Thank you for your knowledge,

    Alex

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  2. Nofossil

    Nofossil Moderator Emeritus

    Joined:
    Oct 4, 2007
    Messages:
    3,398
    Loc:
    Addison County, Vermont
    You're putting a 500 gallon 175kbtu boiler in your living room? Man, your wife must be a lot more understanding than mine!

    From talking to people who've 'rolled their own' with varying degrees of success, the best advice I can provide is to spend a lot of time studying existing designs. There are a lot of things that seem trivial but are not. I've only worked with downdraft gasifiers where the secondary chamber is beneath the primary. For HX tubes, more tubes with smaller diameters gives you more working surface area and keeps more of the flue gas in close proximity to the water jacket.

    A few years back, one of the members here built a gigantic Garn type boiler - worth searching for.
  3. PassionForFire&Water

    PassionForFire&Water Minister of Fire

    Joined:
    Jan 14, 2011
    Messages:
    568
    Loc:
    Billerica, MA
    Here you go .... check out this website: www.hydro-to-heat-convertor.com
    Scroll down till you see the indoor wood gasification boiler in the living room.
    It's only 1/3 of what your are planning to build.
    175.000 BTU/hr will be a lot of wood loading.
    Don't forget to post pictures here on the forum
    Good luck!
  4. bmblank

    bmblank Minister of Fire

    Joined:
    Jan 17, 2013
    Messages:
    644
    Loc:
    Michigan
    I like the idea of turbulators in the flue tubes also. My Tarm has 7 tubes of 2 it so inches. Inside the tubes are removable "swizzle" turbulators. They look like a helix. My dad's and brother's are just zig zaggy though, but same concept.
  5. maple1

    maple1 Minister of Fire

    Joined:
    Sep 15, 2011
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    3,779
    Loc:
    Nova Scotia
    You must have a HUGE living room. Do you realize how big that would be? Not to mention all the wood that would be travelling through or get piled up in the living room to feed it - 175,000 BTU would be a pretty big & hungry boiler.

    I'd say downdraft is best - gravity dictates that's where the hot coals will go, and you want the fire to get drawn through the coal bed for good gassification. And on turbulators - too many can be a bad thing if they restrict your draft too much. I don't have much more to offer - if you do this make sure to take pics of it installed in your living room.
  6. stee6043

    stee6043 Minister of Fire

    Joined:
    Aug 22, 2008
    Messages:
    2,298
    Loc:
    West Michigan
    Even mentioning an idea such as this would leave me instantly wifeless. She'd probably even take the dogs.

    I wonder if the folks who have built their own would do it again, given the chance? And if they paid themselve minimum wage for the time spent on the project I wonder if it was actually a cost savings?
  7. Mtn Fire

    Mtn Fire New Member

    Joined:
    Dec 12, 2011
    Messages:
    20
    Loc:
    New Mexico
    Hello to all,

    Thanks for all the postings from everyone. There is a lot to absorb. I am sorry I am not near the computer during the day.

    So, Is a 3" intake and 3" heat exchanger tubing about right?

    Would the gasification chamber of 6" ID by 12" in length sound approximate?

    thanks,

    Alex

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