SB: Specific Heat of Straw (was Re: SB: Venting cathedral ceiling/roof insulated with cellulose?

["Robert W. Tom" <ArchiLogic@yahoo.ca>]

5/15/02 3:31:28 AM, nrk <alucinante@web.de> wrote:

>Can anyone translate "Btu/#F" into continental european units?


the Skillful Meany uttered:

>> 0.3200 Btu/#F


Believe it or not, I think that the number MagicSpongeHead John apparently 
pulled out of his hat is pretty good.

To convert, one mulitplies the Murrican value by 4.184 to get
units in terms of kJ/(kg*degK).

So the Meany's 0.32 Btu/(lb*degF) becomes about 1340 J/(kg*degK) in SIU.

The 1993 ASHRAE Handbook of Fundamentals (SI) does not provide a value for the 
specific heat of straw but it does provide a value of 1352 J/(kg*degK) for hemp 
fibre @ 1500 kg/m^3 density and a value of 1300 J/(kg*degK) for cellulose @ 54 
kg/m^3 density.

Based upon the above and assuming a density of 7.5 lbs/ft^3 density for SB and 
doing some interpolation, I had made a guesstimate that the Cp for straw bales 
would be around 1320-1330 J/(kg*degK).

Now if the Skillful Meany could either identify the "official" source of his 
number or provide some sort of background as to how the value was arrived at, 
then the NumberNoids amongst us can re-holster their calculators and put their 
pens back into their pocket-protector-protected pockets. Eh ?


 


--- * ---
Rob Tom
Kanata, Ontario, Canada
(remove the "chaff" from my edress if you hit "reply")

Please visit http://www.theHungerSite.com daily



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