[Stoves] Analysis of a two-stove cooking system
Philip Lloyd
plloyd at mweb.co.za
Mon Nov 30 03:34:57 CST 2015
Dear Crispin and other friends
The simple explanation given in your 4-pager example of feeding charcoal
produced in one stove into a second charcoal burner is really useful. My
only quibble is with the nomenclature of efficiency.
The nomenclature that we seem to have been driven towards in the ISO process
is:
Fuel Efficiency: The ratio of the Energy Used to the Energy Released
Where
Energy Used: The product of the Heating Value of the Fuel Consumed and its
mass, less the product of the Heating Value of the Unusable Fuel and its
mass.
And
Energy Released: The energy that would be released by the
complete combustion of the Fuel Fed.
Fuel Fed: The unburned fuel supplied to a Cookstove during the course of the
Burn Sequence, which may include fuel recycled from an earlier Burn Sequence
The italicized part of the last definition is not yet formally part of the
story, and the definition of Energy Used may need a bit more tweaking.
Thermal Efficiency: The ratio of Useful Energy Delivered to Energy Used
Where
Useful Energy Delivered: The energy transferred to the contents of a Cooking
Vessel, including sensible heat that raises the temperature of the vessel
and the latent heat of evaporation of water from the vessel.
Your definitions are exactly reversed! Yet the literature treating the
thermal efficiency as the ratio of the energy delivered to the pot to the
energy used is quite widespread and we have had numerous comments to that
effect, so I am inclined to think it is the preferred term. In the
interests of clarity, can we agree which is which?
Best regards
Prof Philip Lloyd
Energy Institute
Cape Peninsula University of Technology
PO Box 1906
Bellville 7535
Tel: 021 959 4323
Fax: 086 778 0257
Cell: 083 441 5247
PA: Nadia 021 959 4330
From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of
Crispin Pemberton-Pigott
Sent: 28 November 2015 12:38
To: Stoves
Subject: [Stoves] Analysis of a two-stove cooking system
Dear Friends
As a contribution to the discussion on the ways one might rate the
performance of a two-stove cooking system in which one stove makes charcoal
and another burns it, I have drafted the attached paper for discussion.
I would be pleased to edit or extend it to account for ideas you may have
about this topic. Because charcoal making stoves could be used to generate
fuel use in the same home or for sale, the question as to how such a system
can be rated will inevitably arise.
Please feel free to distribute it as you deem appropriate.
Regards
Crispin
Crispin Pemberton-Pigott
<mailto:crispin at newdawn.sz> crispin at newdawn.sz
Managing Director
New Dawn Engineering
<http://www.newdawnengineering.com/> www.newdawnengineering.com
Matsapha, Swaziland / Waterloo, Canada
This email has been protected by YAC (Yet Another Cleaner) http://www.yac.mx
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