AJH,
Are we mixing calories per gram and kJ per kilogram
I was under the impression that the specific heat of water was 1 calorie per
gram and all other materials was in relationship to water so 316 ss at .5 is
half that of water?
Lanny
----- Original Message -----
From: <[email protected]>
To: "Discussion of biomass cooking stoves" <[email protected]>
Sent: Saturday, October 05, 2013 9:11 AM
Subject: Re: [Stoves] Water heating fuel efficiency formula
[Default] On Fri, 4 Oct 2013 18:14:31 -0400,"Lanny Henson"
<[email protected]> wrote:
2- A few points I am still trying to understand is how to calculate the
pot
mass since metal has a different specific heat than water. I am using a
316
stainless pot so I am using .5 as a factor. Is that about right?
Specific heat of water is 4.187kJ/kg, a quick google suggests 316 ss
is 0.5kJ/kg so it's less than water by a factor of ~10 but of course
it weighs 8 times as much so they are similar on a volume basis.
3- Also I still need the formula for calculating the loss from woods
moisture content. I an drying a batch of wood as I type. Before the
moisture
here in NW Georgia USA has been but we have had a wet season and the last
batch was 14.5%. Wood sure does burn well at 14.5% in my stove.
4- Another confusing point is the difference between net and gross
calorific
I addressed these two points in my earlier post. Weigh the wood first,
then dry it at 110-125C until it loses no further weight. Reweigh it
and subtract the last figure from the first to get the water content.
As a rule of thumb the useable heat (Lower Heating Value), net of
losses due to latent heat of vaporisation, is the dry weight times the
calorific value for dry wood (18.6MJ/kg its LHV) minus about 2.7MJ/kg
for the water content calculated from the above.
AJH
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