[Stoves] stoves and credits again

Frank Shields franke at cruzio.com
Fri Sep 22 17:11:06 CDT 2017


Dear Stovers,

The problems we have had for the past 10+  years and still seem to not realize is that we have used engineers and field research to come up with the solution. This is not an engineering or field workers problem. This is a simple grade school science project. Eliminate, reduce and get control over the variables. 

We have energy from a biomass and using that we complete a task. Along the way we have the cost of biomass ($ + time + work) and the task(s) (heat + hot soup + biochar + light). As to the value(s) to place on it that comes from the end user. NOT from a calculation. 

Efficiencies, heat transport, PM2.5, heat retained, moisture, fuel energy, etc. etc have no place in the lab testing. Its only that a biomass  > using the equipment supplied > can complete a task. 

To improve on that (less smoke, less fuel) the engineer can work with the stove developer to make improvements and then have it re-tested by the lab to determine the results of that improvement. Also; Field workers can then introduce the stove to the receiving site to test acceptance. Work with the stove developer to make changes , have re-tested and sent back to the field. 

Biggest challenge for us is getting control of the energy from the biomass. AND establishing standard tasks that represent the tasks likely to be of interest to the field researcher (based on what people are using it for). 

I have ideas about the testing of biomass. Mostly derived from Tom Reed (Thank-you Tom!) and his use of TGA and then adding to that size , packing densities etc etc. As for the tasks I am thinking of something like a Task Cube used to plot heat. But that is more an engineering problem. Heat transport and such. 

Regards

Frank 


 





> On Sep 22, 2017, at 10:28 AM, plloyd at mweb.co.za wrote:
> 
> His continued fighting etc etc. What nonsense - the equation is wrong, spurious, faulty, unscientific. Efficency is the useful energy produced divided by the fuel input. Char is not an input but a PRODUCT. Therefore it goes above the line in any efficiency calculation. You cannot subtract it from the feed, because it is a product ( positive) and not a negative feed. Please stop trying to use bad science to justify an untenable position. It gives the whole of stove science a bad name when the scientific illiterati try to justify their abuses.
> Philip Lloyd
> 
> Sent from my Huawei Mobile
> 
> 
> -------- Original Message --------
> Subject: Re: [Stoves] stoves and credits again
> From: "Ronal W. Larson" 
> To: Discussion of biomass ,Andrew Heggie 
> CC: 
> 
> 
> Andrew and list:
> 
> I think we are in agreement on all but your last response, where I and you say:
> 
> >> `Andrew - thanks for your above rebuttal to Crispin.
> > 
> > Ronal I don't see it in those terms. Crispin has a different viewpoint
> > but his goal is the same in promoting clean cookstoves.
> 
> 
> RWL: Afraid I can’t agree.  
> 
> I can remember no Crispin statement ever in support of char-making TLUDs, which all data shows are the cleanest. Plenty of Crispin support for cleaner stoves using coal - which I claim can never be justified - for both health and climate reasons.
> 
> His continued fighting against the equation e3 = e1/ (1-e2) is my major concern.
> Y t.v.
> Ron
> 
> 
> 
> > On Sep 22, 2017, at 3:26 AM, Andrew Heggie wrote:
> > 
> > On 22 September 2017 at 03:54, Ronal W. Larson
> > wrote:
> > 
> >> Andrew wrote
> >> There might be a slight case for saying a
> >> gasifier stove can achieve a lower massflow (particularly lower N2)
> >> because the primary combustion doesn't go to completion so less
> >> primary air is used, the corollary may be that the secondary flame
> >> also can be burned with less excess air because the offgas has a
> >> higher calorific value but not enough to make up for using 50% less
> >> energy..
> >> 
> >> 
> >> [RWL2: Given my response in “1” - I need to address the term “50”
> > 
> > Ronal I clarified this in my reply to Paul, obviously it is subject to
> > experimental measurements but from a desk study given that the char is
> > reacted at 600C AND 20% of the original biomass dry weight remains as
> > char then it looks like the energy remaining in the char is closer to
> > 1/3 than 1/2 of the original energy in the dry wood.
> > 
> >> Andrew: I am not understanding your last 15 words.
> > 
> > 
> > Partially dealt with above but also what I was meaning was that the
> > offgas from a TLUD, with just sufficient primary are to maintain the
> > descending pyrolysis front, will be largely the pyrolysis offgas plus
> > the small amount of gases from the combustion that provides the heat
> > to drive the process. So it will be little diluted by CO2 and nitrogen
> > than from a traditional fire which supplies enough under grate
> > (primary) air to completely burn out the char. Hence the offgas from
> > TLUD is of a higher calorific value and as such needs less excess air
> > to maintain a clean flame. On a larger scale with lower heat losses in
> > the primary region this may not be the case.
> > 
> > 
> >> 
> >> Disagree with Crispin’s statement that a case with 25% char retention
> >> involves “50% of the original energy” (as did Paul Anderson).
> > 
> > Also dealt with but we need corroboration from analysis of TLUD char.
> > 
> > 
> >> Agree with most by Andrew - but think the last sentence needs amplification.
> >> That is - lower temperature char can be a better economic choice, even if
> >> “fixed carbon retention” is less. This is better discussed on the biochar
> >> list. pH value is one criterion that could point toward lower T’s.
> > 
> > ...and of course lower fuel input cost would make it more economic
> > even if the carbon credit paid to the producer were based solely on
> > the fixed carbon.
> > 
> >> 
> >> [RWL7: I have seen NO data to show that LPG stoves do not
> >> have lower emissions than any solid fuel stove.
> > 
> > It seems unlikely to me that simple stoves could have lower emissions
> > than a LPG flame but Crispin did say as near as makes no difference
> > and good enough works for me.
> > 
> > 
> >> Andrew
> >> The trouble is I have a
> >> parochial view and not a good worldview of what types of persons
> >> depend on biomass fuelled stoves. Are they also predominantly growers?
> >> 
> >> 
> >> [RWL9: Yes to Andrew’s last question. I disagree with Andrew calling
> >> himself “parochial” - when he supports (as do I) the ethics of “a subsidy
> >> funded by the developed world”.
> > 
> > I was referring more to my lack of experience of stoves in the real
> > developing world compared with yourself, Crispin, Nikhil and many
> > others.
> >> 
> >> 
> >> So my contention is that apart from the carbon credit there is a value
> >> to the land in not having to export a cash crop.
> >> 
> >> 
> >> [RWL10: Agree totally.
> > 
> > It still means the grower needs to recognise that exporting a
> > conventional cash crop is removing mineral wealth from the holding, in
> > many soils with high initial fertility this may not be significant. So
> > whilst the cash that the grower/stove user might receive will be
> > linked to the carbon credit paid for using the resultant char as a
> > soil amendment he might also value not having to use the land for a
> > cash crop and possibly growing stove fuel.
> >> 
> >> `Andrew - thanks for your above rebuttal to Crispin.
> > 
> > Ronal I don't see it in those terms. Crispin has a different viewpoint
> > but his goal is the same in promoting clean cookstoves.
> > 
> > Andrew
> > 
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Thanks

Frank

Frank Shields
Gabilan Laboratory
Keith Day Company, Inc.
1091 Madison Lane
Salinas, CA  93907
(831) 246-0417 cell
(831) 771-0126 office

franke at cruzio.com




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