[Stoves] Fuel and Forestry etc.

[Ronal W. Larson]

Crispin and List:

     Still in the spirit of having dialog before the ETHOS meeting (starts tomorrow).  I see three items missing from your test procedures and wonder if you can report on whether they are all included in the test procedures you have been developing:

   1.  Time spent tending the fire.  Maybe report test results for emissions and efficiency with different allowed times for tending?  Of course trying to bracket what happens in the real world.  My observations on the present test procedures is that they are unrealistic by encouraging no departure from adjusting the fuel.  How do your test procedures (now or projected) handle this issue?

   2.   Some measure of expected stove lifetime.  (maybe both years and cycles)

   3.   Annual cost of cooking with a particular stove.  This to include lifetime, efficiency, and the sale of char.  Maybe a way to include also health impacts?

Ron


On Jan 22, 2014, at 11:07 PM, Crispin Pemberton-Pigott <crispinpigott at gmail.com> wrote:

> Dear Samer Again
>  
> >In particular I will be keen to explore more deeply the ramifications for testing, actual fuel use, and the memes that relate these to problems of deforestation and health.
>  
> In order to complete the description and not leave the circle incomplete, I will cover also the major facets of the development of the new direction in testing.
>  
> I refer of course to the technical aspects of the method. There was a large number of people who had input to this because it is an accumulation of small ‘lines of code’ that resolved lots of questions and where possible a clear definition obtained.
>  
> The main ingredient to the successful performance test is to measure what the customer asked for and to report it in a manner they expected. It is communication of knowledge through the medium of numbers. This is the distilled version:
>  
> The question most commonly asked is, “What is the fuel saving ability of this stove?” The answer expected, as so often discussed here, is the amount of fuel taken from the available supply (a forest in this case) each time the stove completes a set of daily cooking tasks. The second question is the level of smoke to which the user is exposed, which is defined as the PM2.5 and CO emitted. (Sometimes the heating efficiency is wanted, but another time.)  These three simple requirements are, however, not sufficient to satisfy the questions posed by the social scientists who constantly reminded us that a stove assessment is a lot more than some narrowly defined technical metrics. I will leave the details out, but basically a technical evaluation will be followed by an assessment by focus groups, i.e. a two stage process. This protects the project in two ways: first it answers the technical requirements that are popular in the donor community. Quite why technical requirements dominate the popular notion of stove performance is worthy your investigating powers, but that is how it is at the moment. Second, it tests the social acceptability of one or more stoves before money is spent promoting them.
>  
> The issues that arise for social acceptance are centered on the ability of a stove to cook the local meals properly, and that is a very wide ranging demand if you look across the world’s cultures. So the first thing to do is to limit the test-cooking requirements to those in the area where the stove will be sold (obviously). We cannot be worried in the slightest how that compares with any arbitrary cooking cycle from somewhere else.
>  
> Cooking is the application to food of heat that is already in the pot. The cooking power, the rate at which heat is gained the pot can be expressed in Watts. It is not the heat delivered to the pot, only the heat retained and gained (a pot has losses).  It is possible to determine the cooking power (I like the term pot-Watts!) by reproducing the firepower and heating pots of water and monitoring the temperature change. Any cooking cycle can be reproduced in two forms, actually cooking using the firepower people use, and the same fuels of course, or using that same firepower cycle to heat water and determine the rate that heat gets into the pot at every stage of the burn. Knowing this, the emissions per MJ in the pot can be calculated directly.
>  
> Cooking tasks are selected and observed and the technical performance measured while reproducing the meal in the lab. Sometimes that takes practice, sometimes not.  The cooking power is separately determined and the total heat gained during cooking calculated from that assessment.
>  
> The result is the same metrics one gets from any popular water boiling test but instead of the complex manner of calculation so often applied, this is a direct measure of the heat gained by a pot that is put through an actual cooking cycle people use in the area. Combining two or more cooking cycles measured in this manner creates a lab test that can be reproduced quite accurately, and which is representative of the average cooking in the community.
>  
> The cooking tasks selected (by the social science team) are chosen to be as different as possible while still remaining ‘typical’. They can be ‘frequency weighted’.  If a new stove can cook properly, meaning reproduce the cooking power cycle in the pot, and on condition that the baseline cooking experience was acceptable in the community, so too the new stove will be acceptable to the cooks.
>  
> One of the surprising findings has been that the rate at which heat enters a pot per square centimeter of heated surface is surprisingly constant over a range of pot sizes for a stove running at a constant power. People can try it to see. What this means is that it is possible to use watts per sq cm as a common metric to compare stoves cooking with different pots. It is surprisingly useful and I expect it will become a popular metric. If a stove can heat the maximum practical size of pot for that stove at the same rate as the traditional stove, it will have the same cooking power.
>  
> By reproducing the lowest cooking power level experienced when cooking, the heat gain rate at low power is determined, and therefore a minimum turn down ratio required by the community is established. The ratio is typically 4 or so.
>  
> The heat flow rate per sq cm, or ‘Heat Flux’ provides a technical metric (a hard number) that is a reasonable proxy for the acceptability of cooking power levels, both high and low.  If the local community is satisfied with their present cooking power, they should be satisfied with a stove that meets the same performance measured in this manner, even if the pot size is different (very important). If traditional performance is not good enough according to the people, that fact is determined during interviews and the required performance level adjusted accordingly. People become happier with the new stove.
>  
> There are other practical observations made which depend on the type of stove – perhaps how easy it was to light, if it smoked a lot in the beginning and so on.
>  
> Because there are dozens of definitions and metrics I won’t mention them here, but each has been examined to be sure it is produced by the fewest number of steps possible and is derived from first principles. The validity of the metric is also checked.  The other measurements required from the test are the total mass of CO emitted and the same for the mass of particulate matter.
>  
> Because people (usually) save wood from one fire to use the next, the fuel consumption is determined by monitoring the raw fuel drawn each time the burn cycle is replicated. This ‘recycling’ of fuel means that it is far easier to determine the consumption and avoids many of the issues related to the energy content in fuel remaining. Because fires are run with old fuel, and ‘new old fuel’ is created each time, the heat content is not material. All that matters is what new fuel is needed. Sets of three tests are analysed as if it was one long test and a valid averaging process gives averaged performance numbers.
>  
> The list of people involved in developing this technical aspect of the overall system is quite long if I think of all the inputs received. Inspirational and technical conversations were held with the members of this discussion list, the ETHOS v4 test development team back in ‘08, Jim Jetter at the EPA, Tami Bond of course, the National Biomass Stove Standards Committees of both Indonesia and China, in particular the staff (Prof Dong) and grad students at the China Agricultural University, Profs Philip Lloyd, Harold Annegarn, Lodoysamba, Peter Verhaart, the SeTAR Centre plus Rowena Sace, David Beritault, and as before, others too numerous to mention.
>  
> There was one step left however. There was a process by which the institutional needs of all the major players were integrated, meshed, melded so as to produce a final product acceptable to donors, governments, testers, regulators, businesses, manufacturers and the public. There were two significant integrators and they are Laurent Durix from the World Bank whose strategic and conceptual skills are amazing (and quick learner) and Cecil Cook, one of the founders of the USA’s National Center for Appropriate Technology and too many other institutions to name. He is one of those rare people who are highly qualified in a social science but have as well decades of technology experience. These guys helped create the detailed plot for accessing the needed inputs and the producing final integration. Bringing the financial side, the business development programme, the social assessment and the technical evaluation ‘plots’ together into a single test protocol requires meeting everyone’s basic needs simultaneously. The number of reviews and changes was huge.  You can understand intuitively it took about a year just for that.
>  
> The team leader (who was mentioned before) is Dr Yabei Zhang from the World Bank who assembled the central team, produced the overall project concept and allowed us to find our way from some pretty dark places into the light. There were some really long dinners. Yabei is the brains behind the finance model which you will hear about in a few days, I hope. Connecting that model’s programme need for commercial success shaped entirely the testing requirements. It is a ‘results based finance’ model meaning that the stoves have to work as advertised, have to be purchased in the community and have to be accepted by the purchasers (meaning used a lot) to receive support. In order to have a simple enough lab test that makes meaningfully accurate predictions of future use, the social and technical investigations have to be pretty well matched to the local community.
>  
> So what is the result? It is a trial effort. Don’t get too excited. It is an experiment and expectations are we will change a number of things to refine how well and in what ways a lab test in controlled conditions can predict field performance in a particular community. So far indications from the budding YDD lab are good.
>  
> The degree to which this methodology as a whole addresses the many questions and objections raised inside and outside the stove community should be studied in detail. We did not have time to make those comparisons. If a list of serious objections was made, each solution could be compared with the CSI-WBT and CSI-WHT (water heating test) to see if that issue is either eliminated, avoided or address reasonably.
>  
> I hope, Samer, you and others will find the time to tackle this subject as comprehensively as you have the memes from Darfur. I feel it would be a great service to the stove and donor community. It would help create a discussion space in which alternative methodologies can be flighted and tried around the world.
>  
> Regards
> Crispin
>  
> _______________________________________________
> Stoves mailing list
> 
> to Send a Message to the list, use the email address
> stoves at lists.bioenergylists.org
> 
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org
> 
> for more Biomass Cooking Stoves,  News and Information see our web site:
> http://stoves.bioenergylists.org/

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/attachments/20140123/0571d66c/attachment.html>