[Stoves] A review of chronological development in cookstove assessment methods: Challenges and way forward
Ronal W. Larson
rongretlarson at comcast.net
Fri Nov 27 12:10:11 CST 2015
Art et al:
Thanks for the complete responses below.
Only a few more clarifying questions/comments:
1. My misread. Re Jed Guinto’s stove. It does look like a Rocket, but the air flow is very different - and it uses holey briquettes. So I withdraw my earlier comments - not realizing you were talking about his stove. After the briquettes are carbonized, they can be withdrawn and some char saved (if thought of as batch). As you say, the TLUD has more controllability.
2. Glad to hear of your great TLUD results. TDR will always be much higher with Rockets; I think we will eventually get to TDR = 5, but glad you are happy enough with TDR=3.
3. Can you expand on “ loop-sided pyrolysis temperature curve.” .
4. Here is an idea that I wonder if you (anyone) has tried. (I haven’t)
a. Start a TLUD in the normal way - maximum primary air may be best (since mostly we want high power only at the beginning).
b. As soon as the pyrolysis front is clearly well established - then add a “thin” layer of the same (?) combustibles on the top.
c. There should be no ignition at the bottom of the new layer, as there is no oxygen there. But new pyrolysis should occur - so increased power. The top of the new added layer could ignite, if there is plenty of secondary air there.
The down side of this is that you probably need to control the secondary air so that you don’t have too much latterm Most os us never do this. But there could be some inherent control of the secondary (that secondary follows primary naturally)..
5,6. Nothing new.
Ron
> On Nov 26, 2015, at 2:40 PM, Art Donnelly <art.donnelly at seachar.org> wrote:
>
>
>
> Art Donnelly
> President SeaChar.Org
> US Director, The Farm Stove Project
> http://shop.seachar.org/collections/all <http://shop.seachar.org/collections/all>
> <http://email2.globalgiving.org/wf/click?c=1Oy%2FmZbgIyjS5WI580KXwShvfKBcF2eaJvtN7Pi6p7Jl%2FiR4938EMMCBwY%2FuYALeA%2BQYUWN4RpvnxBsBC7e2%2BGIHcONTozBmvsUU5LTL%2FTNk4Q3vxE%2BKdXTV2cxIsFplSPh%2F9nMG3bQMQf4bz9ZK9SHMy46Z8OPLAtMAnPG9SKkPuLCWvofBTLC%2BImqax%2BZTkkF2RvDri5UdgH19NHjHOBj5WMUrS4L62Z2xxUJbBsJdDUOfeifheNFXH546Xm0yul4P2stm%2FTUOJxYnI0nFjXEaYfzxDSc%2FwgqVkR1t0USDHk30%2Fgt9UpDpyzLj37HWtnNQ0q8Jh1gZCkB4Y1Fgbg394gYFkyNqFN4MchxO2Js%3D&rp=wrhiOr2wAxUyDMDlMSqbOkKa0FpPoiCSHffb%2ByfHGClRxIFjEIrUDwAF%2BFD%2BpAPuvam9BDwvSMcadhFv7aFwKoyAXYrFk00%2B92xPIeMHXaTDJ3x0VIj6ZYwjm1win65o&up=YDTqBOjidbCUo%2Far1oAtZjp5ji73zPEvmoO14mevuXzIDUdb6Ac9W13SPOXmzL5NflZkH0HxLp0v4dT9UwEHDV0wSZ1qusv09bIKkUliWs4%3D&u=LHuflw_1TAib_lgCu2JvQw%2Fh0>
> "SeaChar.Org...positive tools for carbon negative living"
>
>
>
> On Wed, Nov 25, 2015 at 4:09 PM, Ronal W. Larson <rongretlarson at comcast.net <mailto:rongretlarson at comcast.net>> wrote:
> Art and ccs
>
> Another message from you a little later said you would be creating (I think) a place to archive this series on how to report on TLUDs in a consistent and helpful way. Thanks for that.
>
> See inserts below.
>
>
>> On Nov 25, 2015, at 12:18 PM, Art Donnelly <art.donnelly at seachar.org <mailto:art.donnelly at seachar.org>> wrote:
>>
>> Hi Ron and all,
>> I am sure that there are others of you that share experience with biochar producing cook-stoves that parallel mine: I have ran TLUD cook-stoves thousands of times over the past 6 years. I also built and experimented on "Anila" style retort stoves and Rocket Stove-Gasifier hybrids.I want both an easy hands free way to cook and I want to harvest high quality charcoal at the end of my cooking process. I quickly settled on TLUDs as the most viable and consumer of the various approaches.
> RWL1: I have never built an Anila-type (which can produce char) - because of an inability to control power levels. Was that what bothered you? I was unhappy with my emissions profile, however there is much to recommend this approach, especially in the ability to use very marginal input materials. The poor emissions were directly related to the inability to control power. My brief experiments with Rocket Gasifiers was an attempt to solve the control problem by side loading the fuel, while introducing secondary air below a constrictor lid. Can you expand on what you mean by a Rocket-Gasifier. You are familiar with this approach and I could point to several variations, but in it's simplest form this is what Jed Guinto is doing. However my experiments also included a retort pyrolized with the heat from a rocket elbow. Doesn’t seem likely to produce char very effectively. Not batch I presume. Bottom line is that neither of these approaches is an easier way of making high qualilty char. And in my experiments neither of these hybrid approaches burned as clean as a TLUD.
>
>> Although I own a Paul Olivier, stainless steel rice-husk gasifier stove, it is using bamboo and wood as input materials that constitutes the vast majority of my experience.
> [RWL2: You have shown me this one from Viet Nam - which is very handsome - and uses a small fan, so there is power level control. How much control have you found with your use of bamboo and wood? TDR of five possible? I believe this has 150 mm ID (approx 6”). Can you report the stove height and max and min operating times you have been able to achieve? Sorry, I gave you the wrong impression. All I meant to say was that the experiences I am sharing relate specifically with my experience of using wood and bamboo in Paul Anderson style TLUDs. The Estufa Finca or the Prototype stove I am working on are Natural Draft TLUDS. Utilizing the principle of "Early Secondary Air" as promoted by Kirk Harris, I am getting a great TDR, speaking as a cook, but I would imagine that it is more in the range of 3>1. This is also thanks to having a very effective primary air damper. The Olivier stove is everything Paul says it is, when utilizing rice husk. The blue flame is amazingly like that of a gas stove. His is a fantastic example of the kind of success you can with having a mirco-gasifier stove with consistent performance, by designing the optimal stove for the preferred input material.
>>
>> TLUD stoves if run correctly give the user very consistent experience and performance across the following metrics, I will use the stove I am currently prototyping (it has an 7" (17.78cm)dia fuel chamber as an example:
>> With a batch load of bamboo or wood of approximately 3lbs (1.360kg) the stove will burn for approximately one hour and 15 minutes
>> If quenched at the point complete carbonization has occurred and the pyrolysis front has collapsed, (which indicates all the volatiles that can be released at the stoves peak temperature have been combusted ) your dry weight yield in charcoal will consistently be near 20% of the dry weight of input material.
>> The stove will average a temperature, in it's pyrolysis front, of between 550C-750C
> [RWL3: This must be for min and max fan settings - or does this stove have manual power level control?. Answered above. Good data. Can you report the duration that goes with each of these temperatures? TLUDs have a loop-sided pyrolysis temperature curve. You could measure that curve using thermo-couples and a k-type digital thermometer. I have done that with the 55-gallon J-ROs, but not my smaller cook-stoves so I can not give you an accurate answer.
>> It will currently boil 5-liters of water (no lid) in approximately 25-30 minutes
>> It will then hold the water at a high simmer for 45-50 minutes
>> As the maximum temperature of carbonization is the same as that of the Estufa Finca cook-stove that we have been using for the past 5+ years, we expect that we will see a similar result when we have samples of this biochar laboratory characterized for estimated available surface area. IE; 450-500m2 per gram
>> In the lab using the WBT our "Low Power Specific Consumption" score looks terrible. But I do not believe that means that these are an inefficient or wasteful stove.
>>
> [RWL4: Can you expand on why “terrible”? We got a Tier 1 rating on an earlier version of the prototype in July. That has improved since then but not by enough to be bragging about. Problem is with a batch loaded gasifier I can not take fuel out of the chamber for the simmer phase, like you can with a Rocket stove or a three-stone fire and I can only turn down so far with out extinguishing the flame.
>
>
>> Not only do I hope that new methdologies can be developed that do not penalize "batch loaded " stoves, I also hope we can build up a robust data base of Controlled Cooking Tests, which will provide a more relevant assessment of the TLUDs fuel efficiency.
>>
>>
>
> RWL5: I am perfectly satisfied with what Jim Jetter and EPA are already reporting. I cannot understand anyone ever saying that char produced should neither be measured nor reported.
> Controlled cooking tests need to report time spent in front of the stove - and someone should report on tests that limit the amount of time that can be spent there.
>
>> RE: the value of the charcoal : sure you can burn it. I've barbecued on my stove's charcoal many times. But , as you have produced a product which can be sold at a higher price for use in soil amendments, water filters, personal care products and medicine, we found we could charge more for it and that there is a real market for this product.
>>
> RWL6: Most important of all (hard for some to believe) is to place the ground for climate reasons (the topic of Prof. Jain’s paper).
>> These are cook-stoves. But I have now sold over 500 of the classic Estufa Finca design to US gardeners, who are mostly interested in making biochar with as little pollution and waste as possible.
>>
>
> [RWL7: Glad you used the term “biochar” here (= soil amendment). I don’t think we should call char used for many purposes as biochar.
>
> Art: Thanks for all you are doing with biochar and stoves. Especially moderating this new web site.
>
> Ron
> I hope my answers clarify what I was trying to say.
>
> I also hope that like me you have the chance to celebrate and give thanks today for the gift that is our bountiful earth. . Everyday is a good day for thanks giving.
>
>>
>> Art Donnelly
>> President SeaChar.Org <http://seachar.org/>
>> US Director, The Farm Stove Project
>> http://shop.seachar.org/collections/all <http://shop.seachar.org/collections/all>
>> <http://email2.globalgiving.org/wf/click?c=1Oy%2FmZbgIyjS5WI580KXwShvfKBcF2eaJvtN7Pi6p7Jl%2FiR4938EMMCBwY%2FuYALeA%2BQYUWN4RpvnxBsBC7e2%2BGIHcONTozBmvsUU5LTL%2FTNk4Q3vxE%2BKdXTV2cxIsFplSPh%2F9nMG3bQMQf4bz9ZK9SHMy46Z8OPLAtMAnPG9SKkPuLCWvofBTLC%2BImqax%2BZTkkF2RvDri5UdgH19NHjHOBj5WMUrS4L62Z2xxUJbBsJdDUOfeifheNFXH546Xm0yul4P2stm%2FTUOJxYnI0nFjXEaYfzxDSc%2FwgqVkR1t0USDHk30%2Fgt9UpDpyzLj37HWtnNQ0q8Jh1gZCkB4Y1Fgbg394gYFkyNqFN4MchxO2Js%3D&rp=wrhiOr2wAxUyDMDlMSqbOkKa0FpPoiCSHffb%2ByfHGClRxIFjEIrUDwAF%2BFD%2BpAPuvam9BDwvSMcadhFv7aFwKoyAXYrFk00%2B92xPIeMHXaTDJ3x0VIj6ZYwjm1win65o&up=YDTqBOjidbCUo%2Far1oAtZjp5ji73zPEvmoO14mevuXzIDUdb6Ac9W13SPOXmzL5NflZkH0HxLp0v4dT9UwEHDV0wSZ1qusv09bIKkUliWs4%3D&u=LHuflw_1TAib_lgCu2JvQw%2Fh0>
>> "SeaChar.Org <http://seachar.org/>...positive tools for carbon negative living"
>>
>>
>>
>> On Sun, Nov 22, 2015 at 12:58 AM, Ronal W. Larson <rongretlarson at comcast.net <mailto:rongretlarson at comcast.net>> wrote:
>> Professor Jain
>>
>> 1. Thank you for a tremendously useful document. Especially that you (Elsevier?, TERI?) have made it available on a non-fee basis (for a SHORT time).
>>
>> 2. I am a little surprised (and delighted) that I received this on the climate change list. I am alerting four other lists who will also find this most useful.
>>
>> 3. To me, interested in both climate change (through biochar - not mentioned) and stoves, the most important sentence in your exceedingly thorough (161 cites) is this partial paragraph in Section 2.3.1 (emphases added):
>>
>> “The energy expenditure in the form of fuel for boiling and evaporating water is calculated by standardizing the amount of raw fuel with fuel moisture content, ambient temperature, charcoal formed fuel and calorific value of fuel and charcoal. This is called the ‘equivalent dry wood consumed’. Charcoal utilization after the cooking process in real households has not been validated in any of the studies. If the charcoal disposed by targeted population then the fuel consumption can be corrected. If a certain community has a habit of utilizing the charcoal then …..
>>
>> the energy stored in the charcoal should be considered as a useful energy.”
>>
>> 4. As I know you know, there is more than one way to report the impact of charcoal production in stove comparisons. Examples coming.
>>
>> 5. I could not find an email address for Ms. (Dr?) Pooja Arora. I intend to look up other papers she and you have published. Please congratulate her as well.
>>
>>
>> Again, thanks for a very useful stove assessment document. I am aware of nothing like it.
>>
>> Ron (first/past “stove” and “biochar” lists coordinator)
>>
>>
>> On Nov 21, 2015, at 10:09 PM, S. Jain (Env. Engg.) <sureshjiitd at gmail.com <mailto:sureshjiitd at gmail.com>> wrote:
>>
>>> Dear Colleagues,
>>>
>>> We are sharing with you an article on Chronological development in cookstove assessment methods: Challenges and way forward. We hope to receive your inputs and comments on the same.
>>>
>>> Abstract
>>> This review intended to collect and collate the information related to cookstove testing methodologies applied in lab and field conditions and their output in the form of energy and emission parameters. The important information related to progression of cookstove testing techniques was segregated in order to understand the relationships in different indicators of cookstove performance and to understand the sources of uncertainty in emission data. The major research issue that has been dwelt upon in the recent literature is the establishment of relationship between lab and field results of cookstove performance. It is observed that controlled cooking test and kitchen performance test are the two field based tests which provide a better picture of a particular cookstove performance as it involves the user perspective. Misrepresentation of actual cookstove performance based on laboratory based testing puts the present standard protocols in question. Solutions have been put forward by some research studies; however a validation is needed through multiple scientific investigations conducted at various temporal and spatial scales. It has been observed that cookstove testing methodologies are still in their nascent stage compared to the research that has already been conducted for other sources where biomass combustion emissions have studied thoroughly. Still the shift in focus of upcoming research studies towards field based integrated cookstove testing methodologies has the potential to drive future cookstove research in the new direction.
>>>
>>> We are providing you with the following personal article link, which will provide free access to your article, and is valid for 50 days, until January 10, 2016
>>>
>>> http://authors.elsevier.com/a/1S4Na4s9HvhN9u <http://authors.elsevier.com/a/1S4Na4s9HvhN9u>
>>>
>>> Best regards,
>>>
>>> Suresh Jain, Ph.D.,
>>>
>>> Professor & Head,
>>> Department of Natural Resources
>>> TERI University, New Delhi - 110 070 / India
>>> https://scholar.google.com/citations?user=_jfHgNcAAAAJ&hl=en <https://scholar.google.com/citations?user=_jfHgNcAAAAJ&hl=en>
>>>
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