[Stoves] [biochar] [biochar-stoves] A review of chronological development in cookstove assessment methods: Challenges and way forward
Frank Shields
franke at cruzio.com
Tue Nov 24 13:08:09 CST 2015
Dear Ron,
This is my thinking for today: : )
For your ‘char making stove’ the 'percentage of importance’ for making char is 100%. The gases going off goes into the air, flamed or used for some little task.
For a lab test to list stoves in order of best at making char to worst needs to have Box 1 (fuel) controlled. The fuel the lab picks needs to resemble the same fuel that will be used in the field. So like cooking stoves we pick the fuel to use in two parts:
1) closely resemble the fuel based on type, size, shape, description etc. etc.
2) for char making we separate the fuel into two (of the three) components: volatile weight (dry basis), total fixed weight (DAF). Using a TGA.
So depending on the results of a TGA from the sample on site we adjust the fuel needed to make, say, one Kg of char. it may end up being one lab needs to use more of their fuel selected or less fuel to normalize its values to the ‘on-site’ fuel.
If it takes 4 kg of fuel to make one kg char from the material on site based on a TGA and it takes 5 kg of fuel at the lab to make the one kg char (TGA) then the results from the lab is for every 5 kg of my fuel = one kg fuel on site. Of course I hope they select fuel more like the fuel on site so to have very little adjustment.
Note: The char produced is determined by total weight (including ash). But the ‘working’ part of the char for benefiting soil or cooking, is the carbon part. That is why I added the DAF to be measured. BUT my thinking may be in error for the purpose of comparing char making stoves.
Note: A big problem is the char produced varies in quality and the above tests assumes all the char produced is of the same excellent quality as produced in the TGA. From my testing of biochar samples this is hardly the case. So there will likely require additional testing of the char. Im thinking a run through the TGA to see how many volatiles are left. If there is above a percentage we can say this stove does ‘not produce char’ and leave it as that - even though it looks black and like char. And char to be added to soil will be different than that wanted to do additional cooking (some volatiles). So there may be a ‘end use’ rating for the char produced.
For char making stoves we do not need energy values because we are not requiring energy to cook something. The char left over (good quality) and reporting DAF values will be mostly carbon and, as later I mention, we should be able to report accurate energy value of the char.
BUT if the process of making char has another ‘percentage of importance’ that requires energy for cooking then we need to normalize based on energy for that task.
The task are: produce 5 kg char OR cook a 7 liter pot of rice. One or the other. When one is completed do you keep the stove going to finish the other OR turn it off and leave the other unfinished. Pick one.
Regards
Frank
> On Nov 24, 2015, at 5:38 AM, Ronal W. Larson <rongretlarson at comcast.net> wrote:
>
> Frank et al
>
> Those of us working on char-making stoves (a category bigger than TLUDs ) don’t have the “don’t know what to do with” problem. Even better is that they seem cleaner and are apt to save time and money (maybe make money). The issue is reporting - if you feel such a stove (stove not char-maker) has merit. What is your answer to my two questions?
>
> Ron
>
>> On Nov 23, 2015, at 12:36 AM, Frank Shields <franke at cruzio.com <mailto:franke at cruzio.com>> wrote:
>>
>> Dear Ron,
>>
>> If your task is to make char your calculations is dry weight of fuel IN and weight of char (DAF) OUT. Boiling water is just something to do so you can have a cup of tea while you wait.
>>
>> If your task is boiling water and you are left with char you have a byproduct to add to your garden.
>>
>> If you want both I suggest you place an importance on each (percentage of importance) for the span of a year or season. Then with each run you keep track of the char produced and water boiled and try to achieve your percentage ratio. At the end of the year you may need to just boil off some water to get more char or have left over char you don’t know what to do with.
>>
>> Regards
>>
>> Frank
>>
>> Frank Shields
>>
>>
>>
>>> On Nov 22, 2015, at 9:36 PM, Ronal W. Larson <rongretlarson at comcast.net <mailto:rongretlarson at comcast.net>> wrote:
>>>
>>> Lloyd et al: Adding “stoves - as that is where we have had a similar dialog in the past
>>>
>>> I promised an example. Use energy of wood and charcoal as measured to be 18 and 30 MJ/kg - both possible.)
>>>
>>> Assume 1 kg of wood into the stove - or 18 MJ.
>>>
>>> Assume water boiling away calculates to 6 MJ; Effic1 = 6/18 = 33% (Some say stop here; this is a typical number for many stoves including TLUDs)
>>>
>>> Assume (to get easy numbers) 26.7% (a little high but a possible number) by weight char production - gives .267* 30 = 8 MJ in the char. Effic2 = 8/18 = .444 = 44%,
>>>
>>> Using the pyrolysis gases in the denominator - Effic 3 = 6/(18-8) = 6/10 = 60% (This use of the char energy in the denominator is the most common way of handling char- added (60-33 =) 27% to the reported value of the stove - )
>>>
>>> But I think it more proper to add the first two efficiencies: Effic4 = Effic1+ Effic 2 = .333+.444 = .777 (17.7% bigger than the 60% value - and I think also an honest way to look at what is going on. Last I saw, EPA did not add these together, but they did report Effic 1 and Effic 2. Sales people for biochar and TLUDs are apt to add them of course. We obviously want both numbers to be as high as possible.
>>>
>>> The losses are 18-6-8 = 4 MJ or 4/18= 22.2% (mostly hot gases). This is what we should be concentrating on - not 100-60 = 40%. In inefficiency terms, I claim the losses we want to reduce are nowhere near 40% - if you want both char and water boiled away. 40% is the portion of energy in the pyrolysis gases that we failed to capture.
>>>
>>> If we burnt the wood (no resultant char) rather than pyrolyze it, we might expect to have a 60% efficient stove - but no-one measures any wood stove that high. Why not? I don’t have a good answer, but suspect it might relate to how hydrogen fits in. That is - with little hydrogen in the char, the hot gases are more hydrogen rich with a pyrolysis stove. Better heat transfer with more hydrogen? A hotter flame? Or is the effect due to oxygen - which also is a lower percentage in char than in wood? Or both?
>>>
>>>
>>> Comments appreciated when we are striving to make char in a stove:
>>> Q1: are the losses 22%, 40%, or 67%?
>>> Q2: Is the efficiency 78%, 60%, or 33%?
>>>
>>> Ron
>>>
>>>
>>> On Nov 22, 2015, at 5:40 PM, Lloyd Helferty <lhelferty at sympatico.ca <mailto:lhelferty at sympatico.ca>> wrote:
>>>
>>>> Thanks, Ron.
>>>>
>>>> I know nothing about the Jetter/EPA total efficiency calculation(s) that "use the char’s energy value".
>>>> Could you elaborate?
>>>> Is the Jetter/EPA total efficiency calculation your preferred methodology as a next step to the "WBT"?
>>>>
>>>> (Yes, I am quite out of touch with the latest in "Stove testing" methodologies. What "efficiency" methodology does the GACC currently endorse when testing stoves that produce biochar? Is it still an open question?)
>>>>
>>>> Regards,
>>>> Lloyd Helferty, Engineering Technologist
>>>> Principal, Biochar Consulting (Canada)
>>>> www.biochar-consulting.ca <http://www.biochar-consulting.ca/>
>>>> Earth Stewardship consultant, Passive Remediation Systems Ltd. (PRSI)
>>>> http://www.prsi.ca/ <http://www.prsi.ca/>
>>>> Promotions Manager, Climate Smart Agriculture Youth Network (CSAYN)
>>>> http://csayouthnetwork.wordpress.com/ <http://csayouthnetwork.wordpress.com/>
>>>> http://www.fao.org/climate-smart-agriculture/ <http://www.fao.org/climate-smart-agriculture/>
>>>> https://www.linkedin.com/grp/home?gid=6756248 <https://www.linkedin.com/grp/home?gid=6756248>
>>>> 48 Suncrest Blvd, Thornhill, ON, Canada
>>>> 905-707-8754
>>>> CELL: 647-886-8754
>>>> Skype: lloyd.helferty
>>>> Co-manager, Sustainable Agriculture Group
>>>> http://www.linkedin.com/groups/Sustainable-Agriculture-3866458 <http://www.linkedin.com/groups/Sustainable-Agriculture-3866458>
>>>> Steering Committee coordinator
>>>> Canadian Biochar Initiative (CBI)
>>>> Community Sustainability (CoSWoG), A working group of Science for Peace
>>>> was: http://www.scienceforpeace.ca/currents/ <http://www.scienceforpeace.ca/currents/>
>>>> President, Co-founder & CBI Liaison, Biochar-Ontario
>>>> Member of the Don Watershed Regeneration Council (DWRC)
>>>> Manager, Biochar Offsets Group:
>>>> http://www.linkedin.com/groups?home=&gid=2446475 <http://www.linkedin.com/groups?home=&gid=2446475>
>>>> Advisory Committee Member, IBI
>>>> http://www.linkedin.com/groups?gid=1404717 <http://www.linkedin.com/groups?gid=1404717>
>>>> http://www.facebook.com/group.php?gid=42237506675 <http://www.facebook.com/group.php?gid=42237506675>
>>>> http://groups.google.com/group/biochar-ontario <http://groups.google.com/group/biochar-ontario>
>>>> http://www.meetup.com/biocharontario/ <http://www.meetup.com/biocharontario/>
>>>> http://www.biocharontario.ca <http://www.biocharontario.ca/>
>>>> www.biochar.ca <http://www.biochar.ca/>
>>>>
>>>> "Unless someone like you cares a whole awful lot, Nothing is going to get better. It's not."
>>>> — Dr. Seuss (The Lorax)
>>>> On 2015-11-22 3:13 PM, Ronal W. Larson wrote:
>>>>> Lloyd etal
>>>>>
>>>>> I am imagining a charcoal-making stove owner who has 2 clients to whom she sells charcoal. One client (A) burns the char; the other (B) uses it as biochar. How can one say the stove has two different efficiencies?
>>>>>
>>>>> But another argument is that if all the produced char is used by C as biochar - it must be that the char’s soil value exceeded the energy value. So perhaps the efficiency value for client C should be even better than for case A. This soil use for the char is where I think we are heading.
>>>>>
>>>>> In sum, I see no reason to do other than use the char’s energy value when calculating a total efficiency - as is being done by Jetter/EPA/
>>>>>
>>>>> Ron
>>>>>
>>>>>
>>>>> On Nov 22, 2015, at 7:48 AM, Lloyd Helferty <mailto:lhelferty at sympatico.ca> [biochar] < <mailto:biochar at yahoogroups.com>biochar at yahoogroups.com <mailto:biochar at yahoogroups.com>> wrote:
>>>>>
>>>>>> Ron,
>>>>>>
>>>>>> In reading that quoted/highlighted paragraph, my expectation is that the term, "utilizing the charcoal" (..."should be considered as a useful energy") is probably meant to assume that the leftover/residual charcoal would subsequently be utilized as a fuel, and probably not asbiochar. If the resulting charcoal is used in a non-energy application (i.e. as biochar) then one does not normally talk about or refer to, "theenergy stored in the charcoal" as being "useful" anymore, if one considers the classical [non-regenerative / linear] energy models. (Of course if one understands the use of biochar from a holistic** perspective, it can make sense to use biochar in a non-fuel application if that application results in a boost to the actual [biomass] fuel -- and food -- production capabilities of the soil from which the original stove 'fuel' was derived... but of course those are more complex calculations that must also consider time and a number of other variables which are not normally taken into consideration.)
>>>>>>
>>>>>> **Note: If considered in this holistic perspective / context, the use of soil-health enhancing materials like biochar will very likely eventually be aprerequisite of the very definition of "sustainable" biofuels / biomaterials.
>>>>>>
>>>>>> CC: Biochar group
>>>>>>
>>>>>> Regards,
>>>>>> Lloyd Helferty
>>>>>> On 2015-11-22 3:58 AM, Ron Larson 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.) 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>
>>>>
>>>
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