[Stoves] Cooking with retained heat

Dr.-Ing. Dieter Seifert doseifert at googlemail.com
Tue Mar 3 09:18:48 CST 2015


Dear <http://solarcooking.wikia.com/wiki/Heat-retention_cooking> Christina,

Referring to your note: “Here people typically cook beans for long 
periods of times on wood. Typically households in Guatemala that use 
both wood and LPG tend to use wood for cooking beans and tortillas. Most 
families that have a pressure cooker here use it every 2-3 days to cook 
beans. If you cook beans with wood it can take typically 3 hours, but 
some families leave them cooking all night long so they don't have to 
tend the fire. If you cook beans with gas typically 2 and a half hours. 
In the pressure cooker 1 hour 15 minutes total."

May be that "families who leave the beans cooking all night long so they 
don´t have to tend the fire" are using a heat retention cooker (fireless 
cooker)? With this thermos-technology the active time on a stovecan be 
reduced to about half an hour, if the beans are soaked overnight before 
and, after bringing them to the boil with enough water (e.g. 5 liter), 
the simmering is done in the “fireless cooker” (e.g. hay basket) up to 
about 4 hours (without need of attention, without harm to health, 
without cost for fuel, without emissions). On the website of SCI there 
is more information: 
http://solarcooking.wikia.com/wiki/Heat-retention_cooking. 
<http://solarcooking.wikia.com/wiki/Heat-retention_cooking>I have heard 
that households immediately adopt this simple and sturdy technology when 
they are informed.

Kind regards,
Dieter



Am 02.03.2015 um 20:45 schrieb Christina Espinosa:
> On Mon, Mar 2, 2015 at 11:32 AM, Crispin Pemberton-Pigott <
> crispinpigott at outlook.com> wrote:
>
>> Dear Christina
>>
>>
>>
>>> Its a good first step to testing something for larger scale, but funders
>> will want to see that their investment is having an impact and fuel
>> stacking will continue to provide problems for us in the cookstoves sector.
>>
>> The critical things seems to be that program funders what to know that
>> they are getting what they are paying for. It has been a concern to me that
>> most lab tests don’t predict what the stove will do, yet they are almost
>> always used to ‘select stoves’.  After that, they are promoted there is
>> only some field checking.  We call that ‘picking winners’. A ‘winner’ is
>> the lucky product that gets promoted. Often behind that promotion is a
>> claim that ‘this is the best stove’ based on numbers that are not typical
>> of what is going to happen in the field.  We have to be practical about
>> this. The idea that there is a ‘best stove’ is alive and well, yet the best
>> is different in different circumstances. That is why we are doing
>> ‘contextual testing’.
>>
>> The first thing to do is not to ‘pick winners’. The screening should be
>> something like, ‘remove from the candidate list everything that is not
>> worth promoting as far as we are concerned’ which in the case of the CSI is
>> anything that does not get one star in each category of PM, CO and fuel
>> consumption. Depending on how picky you are, you might end up with one or
>> five products. You have to test and see.  High altitude stoves burning dry,
>> woody biomass (bushes) will be quite different from stoves burning damp
>> wood in the Congo.
>>
>> But performing that elimination round means having some clue what people
>> are burning and what they are going to do with the stoves. You can’t pick a
>> stove ‘in absentia’. If you want low PM, you have to test them using the
>> fuels and burn cycle people are going to use because the PM production is
>> strongly affected by the fuel. Some stoves are designed to burn particular
>> fuels (well, hopefully that are) and they should perform much better than
>> stoves that aren’t.
>>
>> What this means is that there must be foreknowledge of the community
>> before one picks or ranks stoves to perform there.
>>
> I agree. Another thing that I find very difficult with non-market based
> approaches is that the consumer at times doesn't get to choose the stove,
> the program does. They don't get to choose the style, color, and options
> that regular consumers do.
>
>
>>> We are getting ready to do SUMs and an adoption study here in Guatemala
>> with LPG, but most of the households are adopting pressure cookers, so it
>> will be interesting to see if we have lots of fuel stacking with the
>> pressure cooker.
>>
>> Do you mean people are going to be using LPG for a pressure cooker and
>> then wood for something else? I want to be clear if you consider stove
>> stacking and fuel stacking as separate things, then how do you count that
>> in your surveying?
>>
> The study includes CO, PM and SUMs monitoring. The baseline before the
> introduction of the LPG stove will include SUMs monitoring of any stove in
> the household. At the time of the introduction of the LPG stove both stoves
> (or all stoves) will be monitored with the SUMs.
>
>> What do people cook in a pressure cooker, and what effect does it have on
>> fuel consumption?
>>
> Here people typically cook beans for long periods of times on wood.
> Typically households in Guatemala that use both wood and LPG tend to use
> wood for cooking beans and tortillas. Most families that have a pressure
> cooker here use it every 2-3 days to cook beans. If you cook beans with
> wood it can take typically 3 hours, but some families leave them cooking
> all night long so they don't have to tend the fire. If you cook beans with
> gas typically 2 and a half hours. In the pressure cooker 1 hour 15 minutes
> total.
>
>> Cecil Cook is very clear there should be a period of re-selection (viewing
>> the lab tests as ‘pre-selection’ or ‘winnowing’) that involves focus
>> groups. Focus group composition is very important. Being a random person
>> does not necessarily make one a good focus group member.
>>
> This is interesting what do you mean by re-selection? We are not trying the
> funding model I was thinking about. Our air pollution and adoption study is
> market based, so consumers are picking the stove model that works for their
> needs (home, baking, business, etc.). We ran lots of different types of
> focus groups before we designed the components of the business model and
> educational material.
>
>> A difficulty we faced with the CSI Pilot is that people have several
>> stoves and replacing one of them does not mean they use the new one only.
>> We have to accept (and hope) that eventually all will be replaced with
>> improved products. How are you going to deal with that? Do people have
>> multiple stoves, burners, rice cookers etc that they use every week?
>>
> Some people are ready to abandon wood completely and other families will
> continue to use both fuels for different things, it depends on the type of
> current stove. We are working now in urban and peri-urban areas. We
> obviously hope for full adoption, but thats unrealistic in many cases.
> Currently we are trying to study when families do switch, do they continue
> to use wood (yes, for certain things), what do they use that wood to cook
> (usually beans and tortillas), and if they purchased a stove package that
> included a pressure cooker and a plancha for torillas did they fuel stack
> less or stop using the wood stove completely. The idea is that we are
> trying to learn about behavior of consumers that switch from wood to LPG.
> There is an educational component as well, but again we are trying to
> assess everything.
>
>> Thanks
>> Crispin
>>
> Best,
> Christina
>
>
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>
>
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