[Stoves] Test methods for cook stoves

[Dean Still]

Hi Jiddu,

It seems to me that it is not possible to know from a lab test if the stove
will do well in a market. And it is necessary to be in the market anyway to
sell the stove. Evolving the stove product with input from the potential
buyer and user in a market gets the information you need. How much food
should the stove cook?, what fuel will be used?, one pot, two pot, three
pot?, the price? These questions are answered in the market not in a lab
where the information is not available. Since the stove project is located
in the market anyway and needs to know the requirements we use the market
tests to inform the project.

For this reason the WBT, CCT, KPT combination was invented. Each test for a
different purpose but together to create a stove product that works on the
many levels required.

Best,

Dean

On Fri, Mar 20, 2015 at 2:36 AM, Jiddu Broersma <jiddu at praktidesign.com>
wrote:

> Dear Frank, Crispin, Philip and everybody,
>
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> Thank you for the interesting discussion.
>
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> I totally understand your desire to reduce the number of variables for
> testing. I would prefer it too if the stoves I design could be tested one
> single time in order to have it’s performance assessed, external testing
> costs money and each variable you add increases the cost (and time).
> The number of variables Frank mentioned (2*3*4*5*6) is not an
> overestimation in my view. There is many combinations of fuel and cooking,
> but we also have to consider that we are creating a product for the whole
> world (well at least 1-3 billion people).
>
>
> If you design stoves you would probably want to pick one (or a few)
> markets for your stove.
> Imagine you pick a market, optimize a stove for that market and then have
> average external test results for your stove because the ‘global’ test
> doesn’t represent the cooking in that market. You are now listed average
> out of thousands of products, how will that market ever pick your stove as
> most appropriate one? Even though yours is the only one optimized for that
> market.
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> Personally, I love Crispin’s analogy with race tracks so I use it now.
> (anyone who missed it, please read to understand the following, I copied it
> again underneath my message)
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> First, I agree with Crispin we need a universal set of equations (or at
> least scientific set up) on how certain metrics are calculated.
>
> But besides that imagine if each country/market has it’s own race tracks
> (cooking cycles) that explain the power levels, duration and more about how
> people cook. I could design and optimize a stove to a specific market and
> the external test results would reflect this! Now everybody can comfortably
> go and recommend my stove.
>
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> Imaging if this set of race tracks was available online as a resource, I
> could
> - optimize stoves from across the world simply by replicating the race
> track in my lab (assuming that I could get the fuel, etc.)
> - I can identify all markets that my stove is relevant for, simply by
> testing it against various tracks.
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> This looks to me like an optimal situation, but of course it is not that
> easy. How do you pick your race tracks such that they are representative of
> the population you describe and not too specific such that the population
> you describe is still large enough to represent an interesting market for
> manufacturers/distributors to enter.
> At this point a lab guy like me has to be quiet and let social scientist,
> and field workers decide whether this is actually viable. Although, it
> seems from the Indonesia example that it is.
>
>
> Best regards,
> Jiddu
>
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> RACE TRACKS
> *Like cars, there is a start and warm-up cycle which has to be included in*
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> *the test because that is part of real life. Power stations and
> fixedboilers, however, are usually run continuously and testing them
> under?constant conditions? is the norm (and is reasonable).Stoves are
> almost never run continuously and certainly not at a constantpower. Thus
> performance needs to consider not only the starting cycle, butthe running
> cycle with its ups and downs. When testing vehicles, this isdone: the car
> is put through a driving cycle on a test bed. It does not haveto go on the
> road because the road slope and the power requirement can bemodelled and
> reproduced in the lab. All Formula 1 cars are set up this way,per race. The
> fuel loaded and suspension and wing settings are tuned in thelab to the
> track conditions. The engines are tested by computer operatedservos while
> bolted to a frame, not even in the car! The engine and gearboxare ?run
> around the circuit? for a whole race to see if the gearing iscorrect and
> how much fuel is needed.Sticking with that analogy, we can test the stoves
> in the lab using knownconditions and requirements of the ?real track?. Each
> race track has a namelike Indianapolis which represents it cycle of
> distance, speed, elevationchanges, acceleration and braking requirements.
> In vehicle testing eachdriving cycle is given a name and number and
> represents a different type ofuse.There is no point in comparing the
> performance of an F1 car set up for Monzawith a car set up for Monte Carlo.
> You can do it, but it is pointless.  Itdoes not predict performance on any
> other track and the teams are well awareof this so they don?t do it.You
> cannot pick one race track and say every car must be compared using
> thattrack. Which track? Where is the ?average track??  The reason is
> obvious: acar can be tuned to the test track, say, a dirt oval in
> Charlotte, NorthCarolina, and get an optimal result, yet in real life it
> will be used as ataxi on tar roads in Jakarta. If you want to test cars
> that will be used asa taxi in Jakarta, you should use a Jakarta driving
> cycle, and proper tires.The core lessons are:-          A test protocol can
> be created that captures the performance nomatter what the track or
> conditions.-          Sets of conditions ? cooking cycles or ?burn cycles?
> ? can bedescribed and named or numbered.These ?conditions? are not part of
> the protocol. The protocol is themeasurement and assessment tool. The
> conditions are from the list ofavailable, properly characterised cooking
> cycles.Comparing performance means comparing stoves doing the same thing ?
> this isagreed. However it should also be agreed that having everything race
> on adirt oval in North Carolina is not an appropriate way to characterise
> theperformance of a Jakarta taxi.Innovation:  A motorcycle may far
> outperform any Jakarta car-taxi, and thatis why there are taxi-motorcycles
> in Jakarta. If the goal is to use lessfuel, take a motorcycle. If the goal
> is to stay dry, taker a car.  Customers(and cooks) have different goals. We
> have to measure appropriately and userelevant conditions when stating
> comparative performance.*
>
>
> *Jiddu Broersma*
> *Technology and Organization Officer*
>
>
> T    +91 413 262 34 37
>
> M   +91 894 055 94 30
>
> W   www.praktidesign.com
>
> A    Spirit Sense, Old Auroville Rd,
>
>        605 104, Bommiyarpalayam,
>
>        Tamil Nadu, India
>
>
> Previous messages:
>
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> Dear Crispin, and Philip,
> I like what you and Philip are saying and agree. Because the fuel differs
> at different locations there will need to be separate testing anyways so
> why not at the same time add Tasks that are common to that local. So we
> follow my  outlined procedure and replace the fuel with local available
> biomass that works for  the stove being tested and replace the water
> boiling task with a real task that is frequently used. There will likely be
> several tasks and may even involve several cooking utensils so it could
> involve many tests especially if they need to be in trilicate. So to make
> it manageable we need to keep the number of real tasks to one to two that
> represent typical usage expected and utensil(s) used. The results are still
> in biomass/task and time/task. Do we need to add taste quality of the end
> results? I don?t think so as that would be difficult.  And we need to
> establish a well defined end time when the task is completed. That should
> be easy with any task because all we need is the time from match to when
> the utensil is up to temperture and add on the time found to be average (as
> observed in real World) needed to complete the task. We still need to
> complete the task so to calculate the biomass used.
>  Is that how you both look at it?
> I don?t think we can add emissions to the test package when using real
> food - but not sure.
> Regards
> Frank
>
>
> Frank Shields
> franke at cruzio.com
>
> On Mar 19, 2015, at 4:31 PM, Crispin Pemberton-Pigott <
> crispinpigott at outlook.com> wrote:
> > Dear Frank
> >
> > You are getting onto the right path but are defeated by an excess of
> opportunities.
> > ?FRANK> We are in complete agreement in understanding the variables. But
> we can?t test all variables and any test we come up with will not be as
> good as the actual person using it (like everything in the World that?s
> sold). ?
> >
> > First, you do not have to test with all the variables covered ? it is
> simply not necessary. Stoves are made for markets. Markets have
> limitations, constraints. You test for places where you want to sell the
> product, just like perfume or shoes.
> >
> > ?Field tests may be the way to go but who gets to have their stove
> tested??
> >
> > You can do a field test in a lab. You can drag the lab to the field.
> What will you do there which you cannot do in another house, or town, or
> lab? We have to move away from the idea that a lab test cannot and should
> not necessarily represent use. Light bulbs are tested in labs, and
> represent use. I already mentioned cars and engines.
> >
> > ?It should be chosen from a ?most likely to succeed? based on
> preliminary tests ? like what I have been describing. IMO:
> >
> > No problem. Just test it doing what it is going to be doing. Anything
> else is a waste of money.
> >
> > Regards
> > Crispin
> >
>
>
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