we added HOT rocks to our coop

Discussion in 'Coop & Run - Design, Construction, & Maintenance' started by BBK, Dec 30, 2009.

  1. BBK

    BBK Chillin' With My Peeps

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    Apr 14, 2009
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    yesterday it was SO cold, we were afraid that our smaller coop(silkies/cochins) would freeze. It sits out in the yard. Dh found 3 pretty big rocks. We put in our oven 200 degrees for about an hour, last night. Heated our house a little (plus). they were really hot...We carried them out around 5PM(dark) placed them in the coop. hope they liked them. and hope it worked...will know soon, going out around 8AM to feed....it's supposed to be warmer today.. [​IMG]

    I didn't hear any noise when i took the dogs out at 5AM...don't know if that's good or not. Usually I hear crowing.

    Melinda
     
  2. jacyjones

    jacyjones Chillin' With My Peeps

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    Hope they weren't cooked!!
     
  3. BBK

    BBK Chillin' With My Peeps

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    me too...i'm hoping they were SMART enough to get away if they smelled chicken cookin...LOL

    melinda
     
  4. briteday

    briteday Chillin' With My Peeps

    Dec 16, 2008
    Northern NV
    I do the same for our silkies in the A-frame, either warm river rocks in the oven or on the hearth. But I usually wrap the rocks in an old towel so the birds don't get scorched.
     
  5. RocketDad

    RocketDad Chillin' With My Peeps

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    Jul 25, 2008
    Near US 287
    Water would be better, even at water-heater temps.

    1 BTU = 1 pound of water, 1 degree (technically, from 60 to 61, but we'll extrapolate). So "specific heat" of water is 1. Specific heat of rock is 0.19, for granite.

    1 pound of water @ 200 degrees (boiling temp at my altitude, roughly) will dump 168 BTU dropping to 32 degrees.

    1 gallon of water =8.35 pounds, call it 8 pounds. That's 1344 BTU of heat, roughly equal to 390 Watt-hours of electrical heat (0.29Wh/BTU), which would be equal to running a 60W lamp in a cookie-tin for 6.5 hours. (Of course, the output of the cookie tin is constant, but the water cools over time.)

    At 120 degrees (water heater output - yours may be set as high as 140, mine is lower for child safety) that's 88 degrees of drop to 32. A gallon of water will dump 704 BTU, or about 144 Watt/hours.

    A 5-gallon bucket of 120 degree tap water will dump 3520 BTU dropping to freezing, equal to over 1000 Watt/hours, equal to about 16 hours of 60W lamp.

    Granite rocks will hold 0.19 BTU/pound. At 200 degrees, that's only 32 BTU to drop to 32 degrees, per pound. Eight pounds of rock will only dump 256 BTU from 200 to 32 degrees. If you heat 8 pounds of rocks to 500 degrees, you get over 700 BTU of storage. Don't set your coop on fire.

    Advantages of rock: won't crack the container if it freezes; won't spill; can be heated above boiling temp of water.

    Disadvantages of rock: Lower specific-heat capacity; many rocks will explode when hot if water spills on them (not all "river rocks" are granite or basalt); very hot rocks more dangerous to handle.

    I'd suggest a 5 gallon bucket and a lid.

    http://en.wikipedia.org/wiki/British_thermal_unit
    http://www.engineeringtoolbox.com/specific-heat-solids-d_154.html
    http://www.convert-me.com/en/convert/energy
     
  6. KatyTheChickenLady

    KatyTheChickenLady Bird of A Different Feather

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    I keep them in my booder, letting the heat lamp warm them. The chicks always are leaning against them.
     
  7. RocketDad

    RocketDad Chillin' With My Peeps

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    Near US 287
    Quote:I like that idea!
     
  8. CityChook

    CityChook Chillin' With My Peeps

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    Apr 9, 2008
    Minneapolis, MN
    My Coop
    Wow RocketDad - impressive information. Thanks for sharing!
     
  9. Grapefruit Moon

    Grapefruit Moon Out Of The Brooder

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    I put them on the wood stove, then at the foot of my bed to keep my toes toasty at night! (rocks, not buckets of water)
     
  10. grandmaof5

    grandmaof5 Chillin' With My Peeps

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    Aug 8, 2009
    Central N.S.
    Quote:[​IMG]
     

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