[Stoves] Test methods for cook stoves

[Crispin Pemberton-Pigott]

Dear Frank

 

1) 

We only need biomass/task and time/task as final measurements. The energy
going into the water in a WBT (for example) is no more important than
determining the energy going into bacon frying or energy going into a turkey
roasting. Fuel efficiency calculations are just more unnecessary variables
that increase the 'noise' of the test and result in poor precision amongst
labs. 

 

I disagree about the purpose of testing. Programmes that promote fuel saving
stoves what the amount of fuel consumed to be reduced. If the stove does not
save fuel, it is not going to be promoted. If the test (like the WBT)
doesn't report the fuel consumption, then it is not serving the purpose as
required by the stove promoter.

 

The main purpose of CDM stove funding is to reduce fuel consumption. Knowing
how much energy was used doesn't tell us that because people are making
charcoal these days and that is fuel consumed but not energy released. This
issue is fundamental. There is little point in providing a test metric that
is not required.

 

2)

Suppose we want to list stove testing labs around the World (thats what we
want to do -right?). We have 25 that send in their money to be tested to get
Qualified. We send each a like stove and like fuel for testing. We form a
bell curve of the results (biomass/task and time/task). Five are outliers so
leaving 20 Qualified labs. 

 

That is how to test labs not how to test stoves. The lab is supposed to 'get
a result'. But that result is making the stove 'do something'. If that
'something' is a task no one on planet Earth does, then the 'performance
rating' of the stove is meaningless. Performing another task with another
fuel would have produced a different result - sometimes very different. If a
stove is designed to be great for simmering there is no point testing it as
a fish dryer.

 

Example A:

 

Example B:

 

I understand about how to test labs. We are trying to test stoves. Let's
assume you have 13 qualified labs. Now what?

 

Testing stoves in a manner that does not reflect use is basically pointless
because you don't learn anything about how they will behave in use.

 

>Until we do the above - We Go Nowhere!

 

I agree with that!  :) 

 

>.All this testing means nothing (except research) until we have enough
control such that all labs get the same results and the results are
meaningful to the group being marketed (using their available fuel and
tested using their task(s)). 

 

Again, let's assume the labs can get reasonably similar results for a stove
and a burn cycle and a fuel. Now, how do we rate a stove that is going to be
used to make maize porridge in Lusaka.  Should we use a cooking cycle in the
lab that represents making maize porridge? Or not? How do we select a good
stove for Lusaka?

 

Rating a stove on a maize porridge cycle burning dry square Douglas Fir is
not going to tell us much about Lusaka because everyone there burns
charcoal. You get my point? Testing out of context gives answers out of
context.

 

You could provide really good analogies for this. What fertilizer should be
used to grow Beans? You cannot answer that question until you know something
about beans and the soil in the field. You don't just 'pick the best
fertilizer'.  The field, and the bean variety, and the rainfall, and the
insolation are all part of the context.  Every farm is different.  You
assess fertilizers in a context. So must it also be with stoves. 

 

No more 'universal test cycles'. You can have a universal testing framework
and universal protocol with approved calculations, but the burn cycle is
local, or selected from a set of standard burn cycles which have been
created to represent certain common cooking patterns. Once a fuel and
moisture spec is added, that testing context becomes unique.  No emissions
or performance numbers, even for heat transfer, are relevant to other
contexts. Stoves should be optimized for the tasks they should perform. 

 

Any qualified lab (as you describe) should be able to perform the same test
cycle with the same fuel and pot (etc) and get a similar result. That in no
way means that all stoves should be tested using the same cycle, pot and
fuel. You could do it but the result would not be useful.

 

Regards

Crispin

 

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