Re: Stove efficiency

["Kevin Chisholm" <kchisholm@ca.inter.net>]

Dear Paul

There is no problem if one distinguishes between "combustion efficiency" and
"furnace (or stove) efficiency."

Kevin
----- Original Message -----
From: "Paul S. Anderson" <psanders@ilstu.edu>
To: "Stoves" <stoves@crest.org>
Cc: "Bob and Karla Weldon" <bobkarlaweldon@cs.com>; "Ed Francis"
<cfranc@ilstu.edu>; "Tsamba--Alberto Julio" <ajtsamba@zebra.uem.mz>; "Lily
Coyle" <astrozen2000@hotmail.com>; "David Kennell - ISU" <drkenne@ilstu.edu>
Sent: Monday, May 06, 2002 1:16 PM
Subject: Re: Stove efficiency


> Stovers,   Please allow the novice to argue about words, because the words
> are exactly where the confusion lies.  Please read on:
>
> >John wrote:
> >
> > >It is my conclusion that the above statement is irrelevant.
> > >We need minimum air pollution, so keep on finding better
> > >ways to capture the heat from good combustion.
>
> >At 12:36 AM 5/5/02 +0200, Crispin wrote:
>
> >I agree with this approach.  It is easier to collect heat if it is there
in
> >the first place.
>
> While APPEARING to disagree with my earlier questioning about "stove
> efficiency", BOTH John and Crispin have provided support for my position.
>
> We must not use the word "efficiency" to refer to two very different
> aspects of stove functions.   ONE is "how well the fuel is
> consumed",    The SECOND is "how well is the available heat captured".
>
> If you re-read the opening two statements (from John and Crispin, and
there
> was another one also),  BOTH are mixing the two uses of the concept of
> "efficiency"
>
> John wrote:  "finding better ways to capture the heat from good
combustion."
>
> Crispin wrote:  "easier to collect heat if it is there in the first
place."
>
> "from good combustion" and "there in the first place" refer to getting the
> fuel converted into heat energy.  A very worthy cause.  and let that be
> known as "combustion efficiency"
>
> "Collect and capture" deal with "getting the heat to do something
> useful".  That is another worthy cause.   and let it be known as
> "heat-capture efficiency".
>
> They are VERY different, and we should NOT use the expression "stove
> efficiency" because BOTH efficiencies (combustion AND heat-capture) are
> playing roles simultaneously and often in ways that cannot be separated.
>
> Therefore, FOR ISSUES ABOUT POLLUTION FROM STOVES (that is, the fuels and
> combustion chamber aspects of stoves), combustion efficiency is extremely
> important.
>
> And FOR ISSUES OF COOKING AND SPACE HEATING (that is, the physical stove
> structure and the cooking aspects of stoves), heat-capture efficiency is
> what is important.
>
> example:  98% combustion efficiency that is only 50% captured yields 49% ,
> while a 80% combustion efficiency that is 80% captured yields 64%
>
> Our work on stoves must be concerned with BOTH aspects of
> efficiency.   Both aspects are linked together (and overall we do evaluate
> them together in a "replicable" stove that many people can acquire and
use).
>
> But we need to find ways to measure EACH ASPECT SEPARATELY, that is, to
> hold one of the two constant during the tests of the other one.  Said
> differently, the shape and material of the cooking pot impact
"heat-capture
> efficiency" while primary air and moisture level impact "combustion
> efficiency."
>
> Please note that we are NOT in disagreement on the importance of
> efficiency, but that we need to be careful to distinguish between the two
> in both discussions and measurements.
>
> Paul
>
>
>
>
>
>
>
>
> Paul S. Anderson, Ph.D.,  Fulbright Prof. to Mozambique 8/99 - 7/00
> Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL  61790-4400   Voice:  309-438-7360;  FAX:  309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders
>
>
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-
Stoves List Archives and Website:
http://www.crest.org/discussion/stoves/200204/
http://crest.org/discussiongroups/resources/stoves/
>
Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
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>
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-
Other Biomass Stoves Events and Information:
http://www.bioenergy2002.org
http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
For information about CHAMBERS STOVES
>http://www.repp.org/discussiongroups/resources/stoves/Chambers/Chambers.htm