[Stoves] Radical ideas from Paul and Philip {re: stoves and credits again}

[Jock Gill]

Nikhil,

I would agree that stoves are part of a much larger system.  Key parts of the system are emotional qualities:  Does the stove make the cook happier with his or  her kitchen?  Does it reflect well on him or her?  Does the stove give the cook a sense that they are able to cook better because of the new stove, a better tool?  Consider, if you will, how much time and money is spent on kitchen designers to give the the cook the best possible kitchen experience - to also add the greatest amount of value to the home.  If this is good enough for the goose, it better be good enough for the gander, no matter where they are or their economic status.

Another  metric for certainly any charcoal producing stove is its ability to support drawdown efficiently.  This leads to the suggestions below.  I rarely see mention of this essential function of a polytechnic device.

A metric I rarely see is how efficient is the system at capturing the carbon present in the biomass.  I suggest that this target should be 50%  of the carbon, or 25% of the weight of the initial feedstock.  This has to be very high quality Biochar that is clean and not full of residues.  If we do not measure this, it more or less puts the lie to any claims that the biochar is worth making because it has so many direct and indirect benefits - not limited to drawdown and regenerative agriculture. I note that this 25% is only for natural draft TLUDS. Fan assisted TLUDS, such as several in Asia, should have a higher goal, perhaps 30% of the weight of the feedstock, or 60% of the carbon in the feed stock.  I have seen reports from Viet Nam of 30% as a reality. Again,  if  carbon is too valuable to waste, it is too valuable to burn up in a poorly design TLUD.

Note:  For many years of making tin can TLUDs with more or less central apertures, I thought the upper limit of clean carbon capture was about 20%.  I now find that by covering 85% of the pyrolysis surface with a steel disk, insulating the reactor chamber, and tightly controlling the primary air, I can get 25% of the weight of the feedstock (50% of the carbon).  Starting with 450 grams of wood pellets, this is an increase of 28% - from 90 grams of charcoal to 115 grams.  This is a significant gain of 25 grams.  Why waste 25 grams of carbon by burning it up in a poorly designed unit?  See attached photos.

All of which is to say that a proper and inclusive  set of metrics will result in a well balanced device.

Regards,

Jock

Jock Gill
P. O. Box 3
Peacham, VT 05862

Cell: (617) 449-8111

Extract CO2 from the atmosphere!


36 holes made with a 3/32 inch bit (2.2 - 2.4 mm bit).



The gap for the gases is about 5mm.

> On Sep 28, 2017, at 1:24 PM, Nikhil Desai <pienergy2008 at gmail.com> wrote:
> 
> Paul: 
> 
> @ Philip's calculations: I am not used to kJ calculations, so this is how I understand: (100-15) refers to raising the water temperature from 15C to 100C and 4.186 is the conversion factor kJ/kCal. Wood LHVs are contextual and I imagine so too charcoal LHV, depending on the input and operating conditions. am not sure about his Case 2; a little confusing. 
> 
> Anyway, Philip is introducing the concept of "system efficiency". This is radically different from "stove efficiency" whose computations there seem to be allocating different inputs to different outputs. 
> 
> And you wrote of "FUEL efficiency measured by communities, not by single stoves."
> 
> Together, you two seem to suggest that whatever the lab tests and ISO TC 285 ratings, project design must be informed by appropriate contexts of fuel availability and relative costs, and a collective measure of "before" and "after" service requirements and community-level performance. 
> 
> I may add that "communities" also include users of wood and charcoal other than household stoves. 
> 
> It is ridiculous under CDM rules to have to destroy "old" cookstoves, or under Kirk Smith's rule to not permit "stacking". Projects with large enough % of users in a particular context, finding new cookstoves acceptable, cleaner, and usable enough to do many or most of the tasks from "old" cookstoves, are likely to yield measurable benefits promised. (Except climate benefits and aDALYs which are fictional.) 
> 
> Boiling water for coffee this morning as the weather is turning cooler around here, I realized that even boiling water is a multi-purpose activity, the steam warming up the kitchen. A cookstove will often be used for multiple products and "single stove" efficiency ratings for just boiling water have no practical counterpart. Or meaningful application. 
> 
> But we are on to the search for savior stoves. Let's pray. 
> 
> Nikhil
> 
> ------------------------------------------------------------------------
> Nikhil Desai
> (US +1) 202 568 5831
> Skype: nikhildesai888
> 
> 
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