Crispin (and [forgotten, now re-added] list):
Thanks for agreeing with my suppositions:
a. You have no test in mind for reporting on differences between
char-making stoves. They all achieve zero efficiency in your mind.
b. You believe the current 4.2.2 test to be erroneous, because it reports
efficiencies using the A/(B-C) formula (since C is energy in char and you
won't measure that parameter).
Ron
On Oct 22, 2013, at 3:08 PM, "Crispin Pemberton-Pigott"
<[email protected]> wrote:
> Dear Ron
>
> 1. Can you clarify your view on two points, which I take to be your
> viewpoints:
>
> a. There is no way to accurately test a char-making stove (I say
> because you have not answered my requests for a test you would favor) .
>
> It is very easy to test a char making stove. It has always been easy. There
> is nothing special or difficult about testing char making stoves. Nearly
> every wood-burning stove that has ever existed makes some char.
>
> If we speak of fuel consumption, it is the raw fuel needed to complete a burn
> cycle. If there is fuel remaining that can be used in the next burn cycle, it
> is discounted from the raw fuel consumed on an energy content basis. What
> remains, whether fuel or not, that cannot be used in the same stove for the
> next burn cycle is considered to have been consumed.
>
> If we speak of energy consumption, it is the raw fuel needed to complete a
> burn cycle expressed in terms of the energy content potential in that fuel,
> as received. If there is energy in the form of fuel remaining that can be
> used in the next burn cycle, it is discounted from the energy consumed. What
> remains whether fuel or not that cannot be used in the same stove for the
> next burn cycle is considered to have been energy consumed. The rating given
> is for the particular stove and the fuel needed for it to complete that burn
> cycle.
>
> The emissions of PM and CO are determined and expressed on the basis of mass
> per MJ delivered into the cooking pots. This was agreed at the IWA meeting 18
> months ago. The WBT4.1.2 has since been modified to suit this agreement.
>
> b. The present 4.2.2 WBT (Water Boiling Test), used by Jim Jetter and
> approved by the GACC, which reports both amount and energy of produced char,
> is fundamentally in error.
>
> The WBT 4.2.2 used by Jim Jetter and approved by the GACC takes exactly the
> same approach to reporting the testing. Fuel consumed is that necessary to
> replicate a burn cycle. We have been in agreement on this for more than a
> year.
>
> If one wants to know the energy content of the usable or unusable fuel or
> other materials remaining one is free to ask for such an analysis. The energy
> content of unusable fuel remaining does not affect the calculation of the raw
> fuel consumption. The fuel consumption is based upon the mass of fuel
> consumed but it is expressed in the form of Energy (MJ) in order to make
> possible comparisons between stoves that consume different types of fuel.
>
> However the WBT 4.2.2 still contains fundamental errors of concept and
> execution in terms of calculating the energy content of fuels, the mass of
> water boiled, the specific fuel consumption, the average performance during
> the cold and hot start phases plus several other things. The metrics for low
> power do not have a solid physical basis and are thus misleading. The method
> of averaging the results of multiple test results is probably in error.
>
> Is there anything else?
>
> Regards
> Crispin
_______________________________________________
Stoves mailing list
to Send a Message to the list, use the email address
[email protected]
to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
for more Biomass Cooking Stoves, News and Information see our web site:
http://stoves.bioenergylists.org/
