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Homemade Pellet Water Heater

Post in 'DIY and General non-hearth advice' started by homemade, Jul 29, 2012.

  1. homemade

    homemade New Member

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    central wisconsin
    Looking for someone/s to help test out a pellet water heater prototype that as of last night is running at 95 % efficiency using book values of 8000 btu's for pellets and was doing a 45 degree rise continous now for the last 20 hours @ 3 pound per hour. That is the good one the bad time is not working at all and don't know what the difference was besides the moon changed or etc.....

    forgot to say 1 gal of water a minute

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  2. smoke show

    smoke show Guest

  3. ScotO

    ScotO Guest

    You come up with a ultra-high efficiency wood fired water heater, I'll drive out there and help you test it! That's something I'm yearning for......something you can chuck three or four splits in per day and keep a good supply of hot water, that's what I want......
    PapaDave likes this.
  4. homemade

    homemade New Member

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    no chucking any wood runs on pellets and they feed automatically out of 10 ton tank, this is the tank but pipe is now 2 in pvc
    see if you can watch this
  5. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    I am changing the thread title from "central Wisconsin" to reflect what the topic actually is.
  6. DexterDay

    DexterDay Guest

    Do you have pics of the entire set-up? Or a Video (a walk through) describing it?

    There are a lot of smart and talented individuals here. Help is something that is not in short order. But we love pics and they only help tell the story.

    Welcome to the Forum.
    ScotO likes this.
  7. homemade

    homemade New Member

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    will do soon, what i need is some one to sit and drink a case of beer and just watch and see, very small adjustments now
  8. ScotO

    ScotO Guest

    That's a great idea, but I'm not a pellet stove guy. My biggest thing with pellet stoves like the one you are building is it relies on an electrically driven feed system, what happens when the electricity is out? I like burning cordwood, but guys like smoke show and Dexterday can lead you in the right direction. Still interesting to see how you make out. My offer still stands whenever you come up with a plan for an ultra-efficient wood fired water heater!
  9. homemade

    homemade New Member

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    Loc:
    central wisconsin
    central wis is lots of farmers, big farmers that can't be without electricity so power is usually no off more than a little while, but i do have a generator that a guy gave me said it might work needs a motor too, oh well
  10. ScotO

    ScotO Guest

    By the way, welcome to the forum. You keep building stuff like that, you'll fit in just fine on this forum.....;)
    DexterDay likes this.
  11. homemade

    homemade New Member

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    the first video is the steam or water vapor coming out since it was cold then it rose real easy now that summer is here i had to put a small blower to get it up and out, the second one is the char coming out so i don't have to remove ashes, and worst or best thing is that makes good charcoal.
    so here is some picts

    first attempt on getting it running had to put umbrella on so it would not soak up into the paper ceiling


    auto fill from big tank cost 180 bucks but well worth it i don't have to fill no more
    autofill.JPG

    that char that comes out, i was dumping it behind garage then an idea struck, very slow process but needs to get automated or ????


    then final product that makes people look twice, we drank a lot of beer that night
    brats.JPG

    will post more when more progress is made
    Defiant, ScotO and DexterDay like this.
  12. ScotO

    ScotO Guest

    Now that last picture will get you some brownie points, Homemade! Yer making charcoal briquettes out of your char? Sweet! I take it you are using hardwood pellets, no?
  13. smoke show

    smoke show Guest

    Good luck. I hope it works out for ya.

    Brats look good!
    ScotO likes this.
  14. homemade

    homemade New Member

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    ya thought that would catch some eyes, pellets i don't know my boss gets bulk truck loads so i don't really know but i think so
  15. homemade

    homemade New Member

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    does any one here understand btu's and efficiencies the way i understand it so far is that 8000 btu per pound of pellets and 3 pounds a hour equals 24000 btu's and the heat realized is one gallon water per minute or 8.5 pounds water raise it 45 degrees continuously equalls 22950 btus per hour divide that by 24000 input btus equal 95.63 efficiency ratting now to get that heat off in a radiator and in floor heat which i do have and have been using for the last 5 years but just with different burners and fuel, i used to use corn, but the price and RODENTS are just insane especially the mice, chew up lots of stuff in garage.
  16. DexterDay

    DexterDay Guest

    There are some good # gurus here. But being the Off season, this place slows down. In the middle of the season, this thread will quickly make it to the 2nd or 3rd page within a few hours! Lots of people. Lots of traffic. Lots of info!

    So be patient and even if you get this figured out, repost in the Winter and you may get some new and better ideas..

    Im intrigued by stuff like this. And knowing that a by-product comes from it! Thats spectacular. I hope you get the answers your looking for. As for the BTU #'s. The average wood pellet does create 8,000 BTU's per lb. There are some Super Premium Softwoods that reach North of 9,000 BTU's (some Hardwoods too :)).

    As far as your efficiency rating. Thats best left to the "Pros". . . .
  17. smoke show

    smoke show Guest

    with efficiency numbers like that the exhaust must be pretty cool?
  18. homemade

    homemade New Member

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    just a web site i found bout this bio char stuff, nuts ain't it

    nuts.JPG
    ScotO likes this.
  19. ScotO

    ScotO Guest

    That's what I was thinking too.
  20. mepellet

    mepellet Minister of Fire

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    Not claiming to be an expert but by my calculations you are close.

    To raise 1 gallon per minute of water 45 deg F it requires 22,500 btus. ( GPM = ((BTU)/(500*deltaT)) If you are using 3 pounds of pellets at 8000 btus per pound then your net efficiency would be 93.75%.
    DexterDay likes this.
  21. homemade

    homemade New Member

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    sorry its 3.15 lbs per hour
  22. homemade

    homemade New Member

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    Loc:
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    ok non expert is a btu a btu in your most humble opinion
  23. DexterDay

    DexterDay Guest

    Mepellet is pretty good with #'s.....

    Im not gonna say what he did for me, but it was free and it took him some time..

    There are some people here that are good at this stuff... Mepellet is one good with #'s. IMHO

    Im no expert either. But a BTU is a BTU. Whether is Pellet, Gas, Oil, Etc... Dont know why it would be different? ?
  24. Corey

    Corey Minister of Fire

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    Numbers seem to be pretty close:

    1gpm x 8.5lbs x 60 min/hr = 510 lbs water / hr

    510lbs water x 45F delta T = 22,950 btu

    You say 3.15lbs x 8000btu = 25,200 btu input

    Finally 22,950 btu out / 25,200 btu in =~ 91.1% efficient "apparently"

    I throw the "apparently" in there because several things can affect this calculation. What types of actual temps are we talking? What is the initial temp of the water? What is the final temp? What is the ambient temp while the run is happening? We are talking 1gpm of 'new' water for the whole period...'cause circulating 10 gallons of water at 1gpm changes things substantially! Is there electrical input for pumps, augers, conveyers, blowers, etc.

    For instance, I could draw a 55 gallon drum of well water at 60F, leave it to sit in the afternoon sun with a small candle beside it and come back to find it's 105F in the afternoon. I find the amount of candle burned is a few hundred btu and the water has increased by thousands of btu. So did I get 1000% efficiency from that candle? Well, no, not really - heat snuck into the system from sources which weren't considered in the original equation... the sun! A super efficient water heater in the summer is not hard...on a -10F winter day...considerably more challenging.

    Likewise if this is a circulating system...you can only consider the weight of water in circulation, not the actual gallons of flow. Say I have a 100 gallon tank and a 100GPM pump and the heat goes up by some amount in an hour...I can only consider the 100 gallons or 850 pounds, not 100gpm x 8.5lbs per gallon x 60 minutes = 51,000 lbs. Further, relatively large pumps on relatively small volumes can add a notable amount of heat. I have a hot tub heated only by the 7hp jet pump...1hp is about 2550 btu - so if this heat is fully captured, it can add to the total considerably.

    On the 'plus' side, technically you should consider the heating of any storage tank, piping, water pumps, hoses, etc. Those all have thermal mass and are being warmed by the heater as well.

    Modern 95% efficient boilers can be had...so efficiency of this level is not out of the question, but they need a clean burn and actually condense the water out of the flue gas to recover that extra bit of steam energy. Of course, heat pump water heaters can approach a 'coefficient of performance' (COP) of 2.5 or better...which is 2.5 btu out for 1 in, or an apparent efficiency of 250%.

    One concern - you mention a lot of charcoal being produced in this system? Charcoal is carbon and carbon is energy, so if the charcoal is piling up in huge amounts a lot of energy is going with it. You also show a pipe with steam coming out? Heated water or wood exhaust? If this is wood exhaust, that steam itself has recoverable energy when it condenses, so again piping away more energy.
    smoke show likes this.
  25. mepellet

    mepellet Minister of Fire

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    so 89.3% net efficiency. Still good in my book!

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