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I'm in need of sizing help on a farm setup (long)

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by farmerblue, Dec 22, 2012.

  1. farmerblue

    farmerblue New Member

    Joined:
    Dec 22, 2012
    Messages:
    19
    Loc:
    VA
    My location is north west of Roanoke, VA. Were at the base of a mountain and do get snow and cold nights around 0*. I have seen it get down to -15* a few times during the night with -10* days.

    I have triple 350,000 BTU waist oil boiler with a quad 1000 gallon storage tank. This is a unpressurized system.

    I'm trying to heat a new building that is 150x30' with 9' ceilings. It has 2x6” walls (R21) with a 2” polystyrene (R10) facing the inside of the building. The ceiling is 2x8” (R25) with 1” (R5) facing down. I know the slab was insulated, but not sure on how it was done. The building needs to stay between 68 and 72*. The building has a few double pain picture windows and a few out side doors. There is a garage door and it's 25x15' with a second garage door to get into the main building. The lighting load is very low.

    We also have to raise the temp of all the water we use 20*. We use about 15,000 gallons of water a day. Most of the water flow is during the day. Based on the pump curve it should 35gpm max.


    Friday it was low 30's during the day and low 20's during the night. Our back up heat ran part of the day and all night. The building temperature dropped and we suffered some production losses. We knew that we were going to have sizing issues at some point, but hopped it would happen at a much lower outside temperature. There has been lots of different estimates for the heating and cooling loads.

    Yesterday and today we have been blowing in 13” (R38) of fiberglass insulation. With 110 bags it took 3 cities to get what we needed, but we got it finished. This gets us over R60 after settling witch is what all the HVAC numbers were based off of.

    My HVAC contractor is suggesting we add one more 350,000 unit. I contacted the boiler manufacturer yesterday with the issue. They called me back today and tell me that they re ran all the numbers and “think” we need two more units.

    At this point the wife and I are unsure what to do. She just wants to add a single unit, but I would like to add two. I think two would be better in-case one needs parts or that 4 units would give us the needed BTU's. The other thing I keep thinking about is each unit uses about 62 gallons a day at full blast.


    I'm wounder on your thoughts.
    Dose anyone want to take a guess on the BTU's needed for us?
    How much storage do you think we should have?
    Dose anyone have any better ideas on heating for us?

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  2. 711mhw

    711mhw Feeling the Heat

    Joined:
    Dec 7, 2010
    Messages:
    440
    Loc:
    Western ME
    Are you heating with radiant in slab? You must have a heck of a good used oil supply! I'm not a heating guy but if I'm not missing something, you are currently using 233 btu/sf. with your 3X350k = (1050000 btu's/ 4500s/f).
    Like I said, what am I missing? Welcome to Hearth.
  3. farmerblue

    farmerblue New Member

    Joined:
    Dec 22, 2012
    Messages:
    19
    Loc:
    VA
    No I do not have radiant slab heat.
    I do have a good waist oil supply and hopefully I’m able to continue with the supply over the next few years.
    I'm not a heating guy and I still do not understand all this heating stuff yet.

    Did you factor in heating 15,000 gallons of water a day 20* for the fodder and for the livestock? I'm thinking that's where most of the calculations are off, but not sure. I'm thinking that's 2,493,000 BTU a day just heating the water, but I’m not sure if that’s right.

    Thanks, 711mhw
  4. 711mhw

    711mhw Feeling the Heat

    Joined:
    Dec 7, 2010
    Messages:
    440
    Loc:
    Western ME
    Your 15k/day water threw me off, way off. I've never heard of gal/day for radiant heating, but that's what I thought it pertained to. I am unfamilair with adding water to your feed, why warm or hot? What does this do?
  5. farmerblue

    farmerblue New Member

    Joined:
    Dec 22, 2012
    Messages:
    19
    Loc:
    VA
    Sorry.
    Yes we use 15,000 gallons of water a day. We use spring water that’s about 47* year round.

    Part of the water is for our fodder production. Cold water creates a thermal shock to the plants. Cooling the plants to much messes with the growth.

    Most of the water is for the cattle to drink. Giving them warm water is better for there feed exchange.


    Fodder is more or less sprouted grain that has had some time to grow. There are other types of fodder...

    It's mostly done with barley and is a 6 to 8 day process. In 7 days I turn 10 pounds of seeds in a tray into a 90 pound mat of grass and roots about 8” thick. Yes there is a lot of water weight, but by sprouting the grain you change the feed value of the grain. The system uses low light levels. My current output is about close to 4 tons a day and I'm not at 100% production yet.

    Temperature fluctuations make controlling mold harder. Just think about 4000sqf room with hundreds of pounds of wet grain...
  6. 711mhw

    711mhw Feeling the Heat

    Joined:
    Dec 7, 2010
    Messages:
    440
    Loc:
    Western ME
  7. farmerblue

    farmerblue New Member

    Joined:
    Dec 22, 2012
    Messages:
    19
    Loc:
    VA
    I did not think about location or building orientation with the thought of solar. I do not think solar will help much, but I will look at that.
  8. heaterman

    heaterman Minister of Fire

    Joined:
    Oct 16, 2007
    Messages:
    3,291
    Loc:
    Falmouth, Michigan
    Let's take the hot water production part of the equation first.

    15,000gl x 8.33#/gl x 20* rise = 2,499,000 btu's per day for your hot water load alone. Which is really not so much if you break it down per hour......
    The question is at what rate do you need to make hot water? All at once or can you heat it and store it for later use?
    Put another way, is the warmed water pretty much a constant steady demand or a few big batches dumped all at once?

    I have to think from your description that the actual building load is pretty low on a btu/ sq ft basis unless you have a lot of air exchange going on from open doors etc.
  9. farmerblue

    farmerblue New Member

    Joined:
    Dec 22, 2012
    Messages:
    19
    Loc:
    VA
    The water is heated as needed. Most of the water is used during the day as the cattle drink. Lager amounts are ingested around 8:30 am and 5:00 pm after they eat.

    Currently we only have 1 meter showing us the total amount of water that we use. Monday the HVAC contractor is coming back out to add a few more; water for cattle, fodder system, building (rest rooms), and a boiler top off meter. We should be able to log the information off them so I should have better numbers mid week.

    We try to keep the doors shut, but 4 to 6 times a day trailer is brought in or out. We only open one of the garage doors at a time to keep down the exchange.
  10. fuelfarmer

    fuelfarmer Burning Hunk

    Joined:
    Oct 18, 2010
    Messages:
    112
    Loc:
    VA
    farmerblue, have you considered using wood chips or other biomass for heat. I am using a 500,000 btu wood chip burner from LEI Products. I am not that far from you, (2 hours North) if you want to see one operate.

    Often with biomass the up front cost of admission is higher, but on the back side the cost of fuel is lower. I would be happy to talk to you if want more info.

    [​IMG]

    [​IMG]
  11. farmerblue

    farmerblue New Member

    Joined:
    Dec 22, 2012
    Messages:
    19
    Loc:
    VA
    I would love a wood chip boiler, but have been over whelmed when my twins decided to do collage full time at the last minute.

    Are the chips like the size of a standard wood chipper?
    Bark or no bark?
    Whats the moisture % that you burn?

    I would like to check it out.
  12. fuelfarmer

    fuelfarmer Burning Hunk

    Joined:
    Oct 18, 2010
    Messages:
    112
    Loc:
    VA
    A wood chip boiler could help put the kids through collage. :)

    The chip size I think is 2 inch or less. I am burning some wet chips. I don't know the moisture content, but the chips are very wet. The unit will burn green wood chips just out of a chipper. Bark should not be a problem.

    Email fuelfarmer "at" yahoo.com
  13. farmerblue

    farmerblue New Member

    Joined:
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    19
    Loc:
    VA
    Thanks. 6 years ago I made sure all my kids would have money for collage. The bad part is losing 2 good employes and it's hard to good employes.

    I have been reading up on on wood chip boilers for the last 2 hours and defiantly something I want set up before next heating session.

    With a bit of work I’m able to fill my waist oil tank for about a $.76 a gallon. Who knows how that will hold up in years to come.


    I think I found the issue with my system about 3 hours ago. One of the boilers has mixing valve that's stuck a little less than half open. It causing the boiler to throttle down to not over heat. I shut her down night and hopefully can get it changed out tomorrow.
  14. Paso

    Paso Member

    Joined:
    Dec 10, 2008
    Messages:
    68
    Loc:
    Western Canada
    Hi Farmer blue
    Nice to see someone else burning waste Motor oil. I am in the process of converting my OWB to run on WMO exclusively.
    I have been burning WMO in a smaller oil burner ( 140,000 btu ) sending the water to the primary loop and am confident that I can keep the WMO burner running consistantly and not having to rely on burning wood at all. I have been running both side by side and by next winter I will be able to switch to full time WMO The OWB ( 350,000 Btu ) I will have three modified burners able to blast into the fire box if required. We commonly get -40 weather and I need to have redundancy. I have had problems with power outages and the problems associated with that ( runnaway boilers )
    What type of oil burner are you running?? How many burners ?? Do you collect your own WMO for .76 /gal ??
    Glad you may have nailed down the issue with your boiler.
  15. farmerblue

    farmerblue New Member

    Joined:
    Dec 22, 2012
    Messages:
    19
    Loc:
    VA
    Were using B300's from AgSolutions. There set up stock. There 100% automatic so I don't know off hand how many hours they run a day with out looking at the hour meter.

    We burn all of our old oil and and have told all of the farmers around us to let us know when they need a pick up and I would come get it. Were pumping it into a 5,000 gallon #2 tank that we had not used in a few years and bought a 500 gallon #2 fuel trailer to do pickups.

    The more I read into wood chip boiler the more I want to add one to the fodder building.
    We don't get many power outages where I’m at and the building is on a back up genset.


    In our house we have a wood boiler with a back up propane boiler. I do not think my wood boiler has ever ran away with a power outage yet.

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