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The best place to store your heat

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Bob Rohr, Jan 9, 2008.

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  1. Bob Rohr

    Bob Rohr Minister of Fire

    Joined:
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    SW Missouri
    will always be the chunk of fire wood. Once burned the energy starts slipping away. First the process of combustion, I suspect at least 20% goes up the flue, even with the best of gassers.

    Then the heated fluid needs to be circulated somewhere, somehow. you lose some there through to piping, and the best of the wetrotor circs run maybe 25% efficiency, on the sweet spot of their curve. many are not running at the best efficiency point. Then you need to store the 180F or so fluid and try to minimize the loss. you will never insulate 100%.

    Then it needs to be circulated from the buffer to the emitters, with some losses again.

    Ideally the wood fire would be built exactly to the load. not easily accomplished, as most have discovered. Although the pellet/ biomass boilers are fairly capable of adjusting, stopping and starting to the load.

    So buffers become a common addition to wood fired boilers. But don't over do the capacity. Of the dozens of brands I looked at in Germany at the ISH show, most had 1000L storage tanks. Most had at least dual, often triple coils in the tanks.

    Always keep boiler return temperatures in mind. Many boilers have 240F aquastats to pulse the boiler circ to accomplish this. I prefer variable speed circs. better yet the new delta t & P ECM circs. Must less power consumption.

    Expansion tank size will surprise you when you start adding hundred's of gallons of fluid.

    Primary secondary piping really makes the most sense to keep all the sources and emitters happy in their ideal temperature and comfort zone.

    Some of the new hydro separators work nicely also. smaller package with factory insulation. most of the hydronic components from Germany and other Euro countries have nice foam jackets. it's a code in many areas and a standard exisits for the insulation spec.

    That's what I know so far. Anxious to learn more.

    3 rd season on a EKO 40 with 500 gallon LP buffer tank.

    BR

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  2. mikeyny

    mikeyny Feeling the Heat

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    That makes a lot of sense. There is just no perfect system. We can't even come close to the efficiency's we think we are achieving, much less come close to manufacturers claims of efficiency's. One huge loss is in heat exchangers. And thats what all of these systems are, just big elaborate heat exchangers. The most effective way I have been able to become more efficient is by the way and frequency I fire the boiler. I grade my wood pile. I use the junk, (poppular, alder, pine, etc) on warmer days. I save the good stuff for the cold weather. In 4 yrs of burning in this boiler I have cut my consumption in half. Having good dry wood makes a HUGE difference in boiler operation.
    Mike
  3. Eric Johnson

    Eric Johnson Mod Emeritus

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    Welcome to the Boiler Room, BR. It's nice to have another EKO 40 owner with so much experience & knowledge.

    To me, the gasifier is twice as efficient as my old, conventional wood boiler, which is a huge gain. In the final analysis, I burn about half as much wood and do it without any smoke. It's all good.

    Of course, I'm as interested as the next guy (well, maybe not as interested as TCaldwell and nofossil) in squeezing more efficiency out of my system, so I appreciate your observations. You've identified some good places to start. I think you came to the right place. The show in Germany looked really interesting. I saw some pics posted on The Wall. Wish we had a selection like that on this side of the Atlantic.
  4. Bob Rohr

    Bob Rohr Minister of Fire

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    A moisture meter is a good idea for gasification operators. That moisture content is a big factor when burning high efficiency. one fellow told me he burns old diapers in his. How'd you like to be downwind of that fella :)

    It's interesting to hear all the piping and control configurations being used. Some frighten me! A gallon of super heated water has the power of a stick of dynamite! It needs to be respected and properly sized relief valves IN WORKING ORDER are a must. I've helped some neighbors with homebuilt boilers. 20PSI relief with a 790K or larger capacity are required, if I'm involved.

    I have a chance to visit the Resol factory in Germany soon. They have some interesting controls for solar and other hydronic heat source intergration. And some cool BTU meters, measuring flow and delta t for getting accurate data. Perhaps the best way to get some true output data on these things.

    BR
  5. Eric Johnson

    Eric Johnson Mod Emeritus

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    I always try to encourage people to have more than one pressure relief valve on their systems, and to test and/or replace them on a regular basis. It's a natural state of affairs when combining a wood-fired boiler with a fossil fuel system in most cases, if you pipe direct. And be sure to have expansion tanks on either side of three-way zones or other means of isolating either boiler. More is always better when it comes to safety devices, I think we can all agree.

    I think you're right about the moisture meter. Like so many things in life, I kind of sniffed at the whole idea at first, but there's a big difference between 25% mc and 30% mc wood, and I can't always divine that by using the "heft factor." Sometimes it's nice to have a number to work with, even if it's only a relative one.
  6. ISeeDeadBTUs

    ISeeDeadBTUs Guest

    Actually . . . the absolute BEST place to store your heat is in a Woman. The increased WAF will cause radiation that will keep you warm and other things ;-)

    And no, Eric, I didn't just have lunch at Slickers. That's tomorrow :coolsmirk:
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