Good article, Stan. This agrees with my premise that mass is a better
basis for buying wood (once moisture is accounted for) than is volume
(e.g., the cord). The exception to that is that volume is easier for
folks to measure. Who has a scale at home that is capable of checking
the mass of 2000 kg of wood? I think that when those folks I wrote to
add that column for heat output divided by mass, they will see that.
Might I suggest that you spell out "ft3" and "m3" in your article, since
you precede those with "per"?
In comparison to the efficiency of a stove mentioned in your article (50
%), I have a Dutch West large non-catalytic stove (model 2479) and the
manufacturer (Vermont Castings) claims a 63 % efficiency. I cannot
verify that, but it's noticeable that I get a large amount of heat out
of it for a given amount of fuel. It burns much less wood in an hour to
do so than a fireplace does. (Fireplaces with external combustion air
sources might achieve 10 % efficiency and those fed from room air might
have negative efficiencies due to cold drafting air more than negating
the heat output.)
Jim
Stanislav Jakuba wrote:
Article about energy in wood.
Stan Jakuba
On Mon, Jan 25, 2010 at 10:08 AM, James R. Frysinger
<j...@metricmethods.com <mailto:j...@metricmethods.com>> wrote:
I've experienced a small, potential success.
I searched for data yesterday on various kinds of wood to see which
would put out the most heat in the woodburning stove in the basement
of our new house. I came across a number of pages published by
government and by private concerns. In one case
http://www.engineeringtoolbox.com/wood-combustion-heat-d_372.html
I emailed the following comment, encouraging them to provide
information in metric units, and I've just received this reply in
the affirmative.
I suspect that once the data is provided indicating the specific
heat value of wood (in kJ/kg) it will be seen that there is not much
variation between, say, oak and pine. Most of the variation seen in
existing tables (usually given as Btu/cord) is due to the variation
in the density of the various types of wood. Moisture of course
plays a large part in this, too, so variations in the heat value for
one type of wood at various "moisture content" levels reflect the
mass of the contained water.
As you can see, I also commented on the inanity of using a cord as a
unit of measurement, especially for tables that boldly provide
four-digit precision in their published values.
The Forestry Service (USDA) is hopelessly non-metric, I fear. I saw
no way to comment on their table. My comment probably would have
fallen on deaf ears anyway. But this private concern was responsive.
Jim
-------- Original Message --------
Subject: Re:
http://www.engineeringtoolbox.com/wood-combustion-heat-d_372.html : Wood
and Combustion Heat Values
Date: Mon, 25 Jan 2010 05:31:17 -0800 (PST)
From: Tom .....
To: James R. Frysinger <j...@metricmethods.com
<mailto:j...@metricmethods.com>>
Thanks for your feedback,
we will do our best!
Regards,
Tom
--- On *Sun, 1/24/10, James R. Frysinger /<j...@metricmethods.com
<mailto:j...@metricmethods.com>>/* wrote:
From: James R. Frysinger <j...@metricmethods.com
<mailto:j...@metricmethods.com>>
Subject:
http://www.engineeringtoolbox.com/wood-combustion-heat-d_372.html :
Wood and Combustion Heat Values
To: .....
Date: Sunday, January 24, 2010, 5:32 PM
While I appreciate the inclusion of conversion factors at the bottom
of the table, I feel it would be much more convenient if you
provided a metric table. This would be in terms of kilograms, cubic
meters, and kilojoules. Otherwise your metric readers have to do all
those conversions on their own.
Further, since the volume of a stack of firewood varies considerably
based on whether or not it is split and how it is stacked, it might
make sense to include a column showing on the heat value of a
kilogram or a thousand kilograms (metric ton, or tonne). In either
case, moisture content also plays a role and you don't state a
value. Thus, your four-digit values overly express a precision that
is not to be had.
James R. Frysinger
Chair, IEEE SCC 14
-- James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
