Home Brew Forums > BrewTarget - Specific Heat Question???

11-23-2011, 01:22 PM   #1
mpmccann
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 BrewTarget - Specific Heat Question???

I mash in a 15.5 gal SS keg that is rubberised or coated in rubber. I figured it would work out great for extra insulation. My question is, in BrewTarget what would your best guess be when entering in the "Specific Heat" of such a vessel. I would think somewhere between a cooler and just a plane SS keg like .250???? Any thought or input would be very much appreciated.
Thank you,
Matt...

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11-24-2011, 01:13 AM   #2
PintoBean
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The thermal conductivity of Stainless is 16 W/m*°C and Rubber is 0.13 W/m*°C. The conversion to US units is 1 W/m*°C = 0.5779 btu/ft*hr*°F. If you know the thickness of the steel and the rubber coating you can find the total thermal conductivity. I don't use BrewTarget, so I'm not sure what units on "specific heat" are, but I'm thinking they mean thermal conductivity.

11-24-2011, 12:44 PM   #3
mpmccann
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Thanks for the info PintoBean maybe I should have payed more attention in Math class... LOL...
In BrewTarget the mathematical equation in the example shows this “(cal/(g*K))” , and when you mouse over the area it gives examples like Aluminum–.215, Copper-0.092, Iron/Steel-0.108, Plastic-0.359. I am not sure how they are calculating these figures, I just guessed 0.250 because it falls between Steel and Plastic on their example, and at least in my feeble mind that made sense. I don't even know if it matters if you have anything in this field, but it does look to be important...
Thanks again,
Matt...
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11-24-2011, 12:51 PM   #4
PintoBean
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Yeah, Cal/g*K is specific heat, not sure how they're using it. I'm guessing to figure how long it takes for the vessel to absorb and emit heat. I would take the average of the steel and plastic/rubber value, 0.234, and call it good.

11-24-2011, 01:07 PM   #5
mpmccann
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Yeah, I agree... Thanks for the reassurance...
Matt...

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