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System Update Advice Needed

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by GreenMonastery, Apr 16, 2010.

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  1. Hunderliggur

    Hunderliggur Minister of Fire

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    GM - If you have radiant in slab you already have a large storage unit (at least for the slab areas). You do not have storage for any non-slab zones (if any). You should look at how you can manage the temps in your slab zones to use the heat the boiler is producing. A smarter, programmable, zone controler could do the trick. I am looking at the Audrino (sp) controller for temp monitoring and control with OneWire sensors and relays. Nofossil also has a system that may suit your needs. Basically, if you are running the boiler full out but are not using all of the available heat (boiler output temp is continuing to rise above some level), you probably want to divert some of the output into slab zones. This will ue a lot of BTUs and give you time before the room temps cool down and you need another fire. If your controllr is smart enough, you could vary temps by room based on occupant preferences, usage, etc. You would not want to get the cheese storage room too warm ;-)

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  2. ken999

    ken999 New Member

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    Thanks!...
  3. Hunderliggur

    Hunderliggur Minister of Fire

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    And of course for our European friends and Canadian cousins:

    Calorie - the quantity of heat required to raise the temperature of 1 gram of water by 1°C from a standard initial temperature, especially from 3.98°C, 14.5°C, or 19.5°C, at 1 atmosphere pressure.

    I never really tried to figure out what a ton of air conditioning is, but somone answered that in another thread of mine.
  4. Piker

    Piker Minister of Fire

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    Some more math for you all:

    OK... lets talk about the 10,000 square foot dwelling and the concrete slab.
    I will assume that the basement slab is roughly 1/3 of the total square footage. (picture appears to be a 3 story house?)

    3300 square feet of concrete @ 6" thick is equal to 1650 cu-ft of concrete.

    1650 cu-ft of concrete at 148lbs per cu-ft is equal to 244,200 lbs

    average specific heat of concrete is .2 Btu's/lb/°F (1/5th of water) which means that the entire slab can store 48,840 Btu's per degree F

    It would take 5884 gallons of water to be able to store this many btu's per degree F

    Neat huh?

    Ok, here's the kicker... you will only be able to stand a few degrees variation in slab temperature before the comfort level inside the living space drops off. Lets say you can run a 5° delta T on the slab and be comfortable. That means you will be able to store about 245,000 Btu's in the slab. A water based heat storage system with a 90° delta t would only have to hold around 330 gallons of water to store that same number of Btu's.

    even neater eh?

    The concrete slab is definitely a good way to store up some heat in lieu of running a boiler without storage... but nothing beat's a thermal storage system with good old best-in-the-world-specific-heat..........WATER. ;)

    cheers
  5. Hunderliggur

    Hunderliggur Minister of Fire

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    Of course, radiant will warm the slab and everything around the slab - furniture, walls, soil under the slab, etc. The actual storage capacity for "extra" heat is greater than just the specific heat of the concrete. Of course, some volume of water as storage is much easier to control than managing the heat aded to the structure, bt adding heat to the structur, even if it is just 5F, would have a large storage effect.
  6. Piker

    Piker Minister of Fire

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    I wonder what the specific heat is of a lazy boy? ;)

    I think we are in agreement for the most part... i guess the difference is what we consider to be a "large storage effect," which is ultimately in the eye of the beholder. I just wanted to point out the general difference between using concrete as storage and a volume of water. Both can be used effectively to increase how smooth the boiler runs...

    cheers.
  7. GreenMonastery

    GreenMonastery New Member

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    Very true about 3am mid-winter boiler feedings - not a big selling point for monastic life :)

    Our current OWB really never goes out until the heating season is over. It smolders like crazy but we've found that cleaning it once a month is much less work than starting it (it is a real brute to get going).

    I tested the splits at my cabin last night with our new MM, the average was between 8-12% -- I have recently heard that burning wood that is too try is a problem...?? Thoughts on that one? Most of our wood here is 4 years dead and seems to be really well seasoned but I will need to look more deeply into what is in our main woodshed to know for sure.
  8. GreenMonastery

    GreenMonastery New Member

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    We have 2 resident monks here at the monastery who have computer science degrees and I am sure they would be beyond excited to hook up and arduino contoller! :)
  9. GreenMonastery

    GreenMonastery New Member

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    Thanks for all the info Piker!! One bonus of being a Buddhist monk is that we spend most of our time sitting on the floor meditating, so having the heat stored in the floor is, well, ideal! :) -- Water storage is certainly still on our minds though, just a matter of finding a suitable option that will not be too expensive and will adequately meet our needs...the search continues. As well, thank you for the info on the thermostats - more research!

    General question for those Econoburn (past and present) owners...

    What is the starting procedure like? Time? How do you do it? Any advice?

    Thank you, thank you all...may you all be well, happy and peaceful (and warm).
  10. Floydian

    Floydian Feeling the Heat

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    Hello-

    re: Storage

    You may look into anhydrous ammonia nurse tanks. These are essentially the same as propane tanks with a different configuration of fittings-mine has three on top(one with a dip tube) and one on the bottom, all 1 1/4". It's a 1000 gal tank about 16' long and 41" in diameter.
    A local Ag supply might be able to point you towards a used tank.

    Good luck,
    Noah
  11. ewdudley

    ewdudley Minister of Fire

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    Water vapor is needed for some of the reactions during the reduction phase of wood gasification.

    For what it's worth the operator's manual for my gasification boiler specifies moisture content in the range 12% to 20%.

    --ewd
  12. Hunderliggur

    Hunderliggur Minister of Fire

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    [quote author="GreenMonastery" date="1271990410
    We have 2 resident monks here at the monastery who have computer science degrees and I am sure they would be beyond excited to hook up and arduino contoller! :)[/quote]

    This is the thread about data logging http://www.hearth.com/econtent/index.php/forums/viewthread/48079/ There are many options. If you look at the audrino controller and then you can search the web for various Dallas One-Wire devices. Could be an interesing and useful project.

    I love your place. My wife and I would like to visit someday if we get up that way. My brother in law lives in Seattle, WA.
  13. GreenMonastery

    GreenMonastery New Member

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    Thank you for this information I will see what I can find.

    Be well.
  14. GreenMonastery

    GreenMonastery New Member

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    I will have to pass on this info to our resident 'geeks', as they refer to themselves, it is way way too high over my head!

    Seattle is not too far away, although not a trivial drive either. We have many people who come for shorter and longer periods of retreat at the monastery from all over North America, though. You could come, enjoy the peaceful surroundings, meditate and program a data logger as well :)

    Thanks again for all your help - love to see that you are 100% wind. We had a wind monitor up for over a year logging wind speeds but it turns out in our area it would be much better to bulk up the solar.

    Take good care,
    Dhammavaro
  15. heaterman

    heaterman Minister of Fire

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    Another factor that raises the load on the storage has to be considered also. That is the fact that the building heat loss also has to be replaced at the same time the slab is being "recharged". Think of it as having to charge the battery in your car while it's being used to run the headlights.

    Picking up the building in addition to charging the slab and maybe the storage tank also can add up to a pretty fair load. It's not uncommon to see over twice the rated heat loss under those circumstances. Extra capacity in the storage tank comes in very handy during that situation and makes a good argument for at least double the water storage that one would think needed to satisfy the actual heating load. It's just something to consider when dealing with what amounts to basically two high mass loads. A control system can be designed to take the storage tank out of the equation during floor heating but you still have to address both the slab and the actual building heat loss. Call me cautious but I design for the worst case because if I don't, it'll come back to haunt me at some point..........and it won't be in July. ;)
  16. GreenMonastery

    GreenMonastery New Member

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    Thanks heaterman! Will add this to my list of considerations. Great point about when the problems occur...it is certainly our experience that if anything will ever go wrong it will be when the temp drops to -40 for a few days. That's the time when an outside pump needs replacing, or a hose, etc. Good reminder!

    Be well,
  17. GreenMonastery

    GreenMonastery New Member

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    Hello everyone,

    BIG thanks for all the help so far!

    We have just placed our order for the Econoburn today, very exciting for us. We met with a guy (living very close to our location) who manufactures and installs solar hot water panels, unpressurized storage tanks, hx's, control systems, etc yesterday and are now contemplating moving forward with this phase this summer as well. I have just started steeping myself in the world of hot water solar and have found builditsolar.com to be a wonderful resource. Anyway, the system we are contemplating would look as follows...

    500 sq ft of panels on a manually operated rotate-able structure to maximize sun exposure, 3000 gals of unpressurized storage (which the stove will obviously be hooked into as well). Any thoughts on this? Would love some advice and a point in the 'right' direction, whichever way that is. Just thought some of the people who have weighed in so far might be able to offer some suggestions in this new area.

    Be well,
  18. Hunderliggur

    Hunderliggur Minister of Fire

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    builditsolar is a good site. Lots of useful information. I would nix the rotatable stucture idea on the KISS principle (Keep it Simple Sam). The added cost to make a 500SF array rotatable would be better spent increasing your array by however many square feet. Your need to evaluate your monthly solar radiation and determine the best tiilt angle for what you want to achieve. Do you want the solar to heat the storage in the summer so you don't have to burn? Tilt would be latitude - 15degrees. Want to maximize winter as a backup to the wood tilt is latitude +15 degrees. I think if you run the numbers for your choices you will see where you can produce the most BTUs. You can always make the area under the panels a wood storage area.
  19. WoodNotOil

    WoodNotOil Minister of Fire

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    If you ordered the Econoburn 200, then I think that 2000 gals of storage may be better sized. I would worry that with a high heat load and trying to charge storage, the 200 may not be enough for 3k of storage. I also wonder about trying to heat so much storage with solar. Those with more solar experience can speak to that though.
  20. GreenMonastery

    GreenMonastery New Member

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    Great point on the tilt angle - it is certainly on our mind as we have had lots of experience with our PV's for the last several years. On our current PV array when we rotate them we add nearly 50% more energy into our battery bank. The guy I was talking to the other day (manufacturer and installer of solar HW panels) said it could double the efficiency! He had at his shop 700 sq ft of panels on an auto-tracking rotating and tilting structure - very impressive (and expensive)!

    Thank you again for the help.
  21. GreenMonastery

    GreenMonastery New Member

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    Very good point about the Econo being under powered for the 3k of storage, I guess we were now banking on the solar to be a big help in our calculations. From the looks of the system we have been contemplating it seems that the solar could bring in 150k btu an hour(!) in perfect conditions on a fall or spring day. We are still a bit awed by these figures...
  22. Nofossil

    Nofossil Moderator Emeritus

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    150K per hour from solar sounds really high. I get 100K per DAY during the summer.
  23. Hunderliggur

    Hunderliggur Minister of Fire

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    The tracking mount for PV panels is worth the investment. The panels are expensive/watt, light, and have a flexible connection (flexcable). The Hot Water panels are heavy, relatively cheap (compared to PV) and don't flex the connections well. I have two stacked 500 gallon tanks. The solar coil goes in the lower (cooler tank) so you get maximum solar benefit.
  24. GreenMonastery

    GreenMonastery New Member

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    This was my thought too...

    How many sq ft of panels do you have? What kind (flat plate, tube, etc?) - this company I have been talking to specializes in using solar hot water for space heating as opposed to just DHW - if this all true (he has many, many customers in our area) then the Econoburn would not need to work very hard, just the coldest 100 days.
  25. GreenMonastery

    GreenMonastery New Member

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    Good points. What size (sq ft) and type of panels do you have?
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