[Stoves] [biochar] [biochar-stoves] A review of chronological development in cookstove assessment methods: Challenges and way forward

[Crispin Pemberton-Pigott]

Dear Friends

 

Lloyd wrote

>I noted in the presentation (which is from more than 2 years ago -- Aug
2013) that:

>with a specific note in the text that, "there is a need for a testing
protocol for batch-fueled stoves" (as expressed in a Resolution in the IWA),
and I also noted at the end of the presentation that EPA may assist with the
development of "a procedure for testing batch-fueled stoves" via EPA
"participation in the ISO process to develop standards and test protocols
for stoves" with "experts from many countries", and that, "the timeline is
likely to be three years" (beginning Nov 2013).



> So at this point in time I guess that I should assume that there is still
no "standard protocol" (stove testing methodology) for stoves that produce
biochar, and that we might expect something to be published by the ISO by
around the end of 2016?



There is a possible misunderstanding worth noting: it is not necessary to
have an entire protocol to test a slightly different stove. A different or
adapted 'procedure' is adequate. There are many ways to burn fuel.

 

There is a standardised procedure for testing batch loaded stoves which has
been in use for 5 years in Mongolia and now in other countries. The
Heterogeneous Test Protocol from the SeTAR Centre has been used to guide
batch-loaded stove product selection with a value of over $45,000,000
(subsidy value, not total sales). 

 

The test method was externally, expertly reviewed by SGS Netherlands, a
requirement of the IWA that has not yet been applied to other test
protocols. It is currently being used in the CSI Indonesia Pilot which has
selected 16 stoves as being worthy of support, many of them being batch
loaded. Thus it has been shown in some 500 tests (at least) that a protocol
for batch loaded stoves exists, works well, and is applied. 


Ron L wrote:
Comments appreciated when we are striving to make char in a stove: 

            Q1: are the losses 22%, 40%, or 67%?

            Q2:  Is the efficiency 78%, 60%, or 33%?


All stoves should treated the same way when it comes to testing their
cooking performance. That should be established separately from other
functions such as space heating, lighting, smoking or the production of char
which are ancillary functions.

 

An energy loss, with reference to cooking, is any energy that is not
released from the fuel during a cooking event. This includes partially
oxidised gases and fuel components. If one puts fuel into a stove, cooks,
and there are remnant fuel constituents that did not fully burn, including
gases, they are losses. Is anyone going to collect all the CO and pass it to
another stove because it is 'available fuel'? Of course not! What about the
carbon in the ash? What about small pieces that, in the judgement of the
tester, as 'too small' to be recovered?

 

Any fuel recovered and used in the next replication of the test sequence can
be considered 'fuel' and anything that cannot (or is not if one is testing
in a social context). Creating a stove crafted to produce a large waste
component with certain properties is quite possible. It doesn't have an
effect on the calculation of the cooking efficiency which continues to be
calculated according to the energy in the fuel drawn per cycle, and the work
delivered.

 

For Q1, the answer is the losses are 67%.

 

Q2 is not well stated. The cooking efficiency is 33%.

The inexactly named "thermal efficiency" (in a common sense: referring to
the energy available in the missing fuel mass and composition) is higher.
The heat transfer efficiency is even higher because it refers to fuel
actually thermalised. The "thermal efficiency" number refers to energy that
has not been thermalised generating more confusion than necessary.

 

Lloyd wrote:

>Creating an "importance" factor is a very subjective thing to do, however.
;-)



Agreed. Users, vendors and funders may have very different rankings of
'features'.

 

Regards

Crispin

 

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