[Stoves] Development of culturally appropriate stove testing methods

Fri Jun 8 23:37:08 CDT 2018

Crispin:

Your reference to water pumps reminded me of some charts I saw decades ago,
probably in connection with PV.

1. What did those charts for water pumps measure? Efficiency and emission
rates as functions of power for diesel pumps? (I think this is a dumb
question, but let me confirm).

2. The practice of generating performance curves, reflecting
'heterogeneity', is a remarkable breakthrough. Indeed, quite radical,
compared to the US fantasy of NSPS max/min and period averaging. A small
household cookstove is not a continuous boiler, which is why I have hated
the WBT as a tyranny of theoreticians.

What is more, I think debates about power levels, pot type and size,
turndown ability, all become secondary when performance curves are
generated instead of single numbers or for min/max regulatory approvals
(for which I don't see much promise anyway, until WHO starts funding
 Kitchen Kops).

And, as you add, as needed, other performance measures - including
subjective ones - and other variables - fuel chemistry, foods - you may get
designers to produce stoves thatsel to the users and not to the grantmakers
and their expert advisors with cuckoo ideas about what must be given to the
cooks whether or not it is good for them.

For example, a cook decided what to cook at a particular time depending on
the timing of meal delivery, identity or status of the eater, availability
of enough water, and of course, availability of ingredients.  Such things
vary home to home, day to day, leaving aside partially or fully cooked
purchased foods.

A heterogeneous testing method opens up the possibility of designing real
stoves for real users, not academic stoves for academic papercookers. Once
a convenient, usable product is designed, let marketers and subsidies do
their work. No need to continue with infantile efficiency equations for a
single number.

Do I understand you correctly? What next steps for common sense for
cooking?

Nikhil Desai

“Good food, good eating, is all about blood and organs, cruelty and
decay.” Anthony
Bourdain

On Jun 8, 2018, at 2:09 PM, Crispin Pemberton-Pigott <
crispinpigott at outlook.com> wrote:

Dear Paul and All

I have a few comments on the content, mostly for clarification.

*Re:*
https://www.researchgate.net/project/Development-of-
Culturally-Appropriate-Stove-Testing-Methods
<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.researchgate.net%2Fproject%2FDevelopment-of-Culturally-Appropriate-Stove-Testing-Methods&data=02%7C01%7C%7C5969836a85d44460ce7608d5cafe95bc%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636638117133194506&sdata=szGgIihrZ1%2FrxJvbf%2By0Vue3IWmBOIx2CY3bLcdldfE%3D&reserved=0>

>2.  It is about stove testing METHODS.   Key is the water heating test
(WHT) as an alternative to the water boiling test (WBT).

The WHT was written up by Christina from YDD and me a few years ago with
specifics on how it was applied in the WB Pilot in Central Java. I am sure
that document was provided to this list.

>Bring the pot of water to 80 deg C and then put on another pot to continue
heating, repeat as long as the test time.

This method is applied in the Indian IS13152 1992, as I recall. That test
also requires the use of a specified pot size selected from 27 standard
pots, selected on the basis of the firepower of the stove. The intention is
to introduce some contextuality related to anticipated use.

>3.  The changing of the pot of water means no intentional changing of the
power of the stove during the test.   That is, there is no "simmering"
stage (which is a major contention in the WBT).

That is not a complete description. The firepower can be varies to reflect
various patterns of use. Usually we operate the stove at three different
power levels (minimum) and using two different common pot sizes.

>And no "fiddling" with the turn-down abilities.

Well, if you wish. The method can be applied to any burn sequence you like.

>A stove can be run at high power, and again SEPARATELY at middle or low
power.  But not mixing the power levels.

You can do either. It depends on what you are investigation. If you are
rating the performance for regulatory purposes, it is very likely there
will be a test sequence that is relevant to the cooking culture.

>I am not so sure that the word "heterogeneous" is the right term, but that
could just be my personal opinion.

The word is used to reflect that use of multiple conditions in order to
produce performance curves, rather than a single performance number. The
HTP is based on a concept of providing the sort of information you get when
selecting a water pump. There are pump curves, not a single number. There
are several SeTAR Centre publications containing performance curves for
different pot sizes. The efficiency, combustion efficiency and PM vary on a
curve and do not have a single value.

>…the publication does not make an issue about culturally appropriate
testing of cooking methods.

It is implicit in the method: swapping pots is a very inexpensive way to
get real time efficiency testing during any proxy cooking sequence you
like.

>5.  "Solid-Fuel" is a key term, and in this publication does NOT refer to
wood or dry biomass.   The fuels discussed are charcoal and coal.   That is
fine, but they are a limited subset of the varieties of solid fuels.

The method is not restricted to certain fuels. We have even used it for
electric stoves.

6.  …the common South African [Imbaula] (bucket burning of coal) that was
IGNITED IN TWO DIFFERENT WAYS.    The traditional way is to ignite at the
bottom (call it bottom lit or BL) and the other is at the top (top lit or
TL).  See the report for the differences.   My one comment is that the use
of the "TLUD" name (normally associated with wood micro-gasification) is a
bit of a stretch when presenting a single-walled, metal, "largish" bucket
with many side holes and filled with coal.

The TLUD combustion approach has been promoted by the South African
government since at least 1975. In those days it was called ‘the Scotch
method’ which dates back to at least 1895. The Mbaula can be (and is)
constructed to optimise the combustion using primary and secondary air
holes in various patterns. The hole patterns strongly affect the combustion
quality.

>Maybe Crispin or Taffy can tell us about any further plans (or options)
for stove testing with the WHT.

The CSI test method as currently employed in, for example, Indonesia, China
and Mongolia, is the WHT in terms of the cooking performance assessment.
However we no longer use pot-swapping. We have installed a heat exchanger
in the pot so we can cool it continuously. Water is circulated in a copper
pipe.

Considering the input and output temperatures, the mass of water inside the
pipe, the water mass in the pot, and the pot mass and material, the total
heat gained by the pot can be calculated on a continuous basis. This is
automated in the HPT Spreadsheet.

Similarly, the water heating ability of a low pressure boiler (hydronic
heater) is assessed using the same approach. Water is circulated through
the heat exchanger, the volume is known, the metal mass of the heater
portion of the stove is known, and the expansion of water within the heat
exchanger is compensated for temperature changes. This, together with the
flow rate and two temperatures (in and out)  yields the heat gained by the
heat exchanger.

The cooking and water heating function can be conducted simultaneously.
Using the Chinese Hebei test sequence, there is an ignition period, a high
power heating period, a long low power heating period, a high power cooking
period, and then a high power heating period. The total test is 6H45. This
has been shown to replicate the comparative performance of 24 hr tests
duplicating actual behaviour of farmers in Hebei province. Thus it is a
WHT, it is contextual to Hebei, it is culturally appropriate, and it
provides a comparative performance rating. This method was used to select
stoves to be supported in the Hebei Clean Air Programme (800,000 homes).
Many stoves already on the market were tested. Some of them were found to
be very clean burning relative to a ten-year-old stove which served as the
baseline.

Regards

Crispin

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