All, In the column, Dr. Smith does not reference his $10 price-limit. I have heard this value several times and no one seems to know why $10 was deemed appropriate. I've been digging and cannot find the source of this "decision". Does anyone have further information? In my opinion, its extremely naive to cast a blanket price for all hh stoves around the world.
Cheers, Boston Nyer On Mon, Nov 29, 2010 at 9:55 AM, <[email protected]> wrote: > Richard (cc two lists) > > See some questions/notes below on your message today. You said: > > "*I would buy the one that burned some form of densified non wood > biomass "cleanly" ......* > > *[RWL1: Those of us who are promoting char-producing stoves believe > that they are much cleaner than those that only combust. The usual low-cost > stoves in developing countries almost universally use only wood (with some > still-minor use of your briquettes of course). For those new to the > subject, the difference is whether there is a single air supply or two. > Does anyone reading this think that char-making stoves are not inherently > cleaner?* > But I especially want to support your use of the term "densified > non-wood" - which I think is also much needed in char-making stoves. Nat > Mulcahy of World Stoves always emphasizes the use of "densified non-wood" > as one of the main advantage of his Lucia stove (which could combust or > gasify - but he chooses to operate in only a pyrolysis mode). See his > website for his rationales - which are (in part) similar to yours. > Several questions to you (as the person who probably knows the most on > this densified non-wood cooking issue): > 1a. What are the relative advantages of making (not using) pellets > vs briquettes? > It would seem that it should be much easier to "press" (I like your > closing below) pellets than briquettes (especially the "holey" type). Do > you have any data on the relative power or energy and/ or cost requirements > for production of pellets vs briquettes? > > 1b. For those wanting char and not ash, the charred pellet is > already in a wonderful form for application to soils. Pellets mean some > extra costs for the fuel supply in the front end of cooking - but could be a > wonderful boon both in burning more cleanly and evenly and in later > application of Biochar to the soil. The same is possibly/probably true for > briquettes - which I presume break up easily after being pyrolyzed. Do you > have any reason to think briquettes would be better than pellets in either > pyrolysis or char-application terms? > > > You concluded:] > > "....and would avoid both the wood supply and the char producing problems > in one go." > > [RWL: 2a. Re the first issue of supply (with which I agree), I > have recently read an article (author's name forgotten - I will try to find > it) that showed a breakdown of the well known global net primary > productivity (NPP) number of about 60 Gt C/yr. They had about half going > into wood and half into leaves - a ratio I had not previously seen. Since > you are promoting the former (leaves) over the latter (wood) - and because > almost all rural stove users are now using only wood (and even many > briquettes and pellets seem to be made up of ground-up or chipped wood), > have you seen this relative photosynthesis production ratio - which would > seem to imply a huge wasted resource all over the world? > > 2b. But I don't understand your term "char producing problems". To > me there are only benefits and advantages (at least with kitchen stoves). > If you meant the horrible production of most charcoal out in the boondocks - > with global warming and carcinogenic gases much worse than CO2 being > produced - then I agree. To prove that it is better for society to promote > household production of Biochar (char placed in the ground) will be the > subject of my next message. Briefly it is that we need to make the economic > argument that Biochar's two main advantages (carbon sequestration and soil > improvements) outweigh the further combustion of the char for its energy > value. Two main reasons that I think we can make this argument (which I do > not contend has already been proven). First is the 2:1 advantage in the > three-flows of money (which seem in the same ballpark). But more important > is that the first two monetary flows (climate and soils) are both > investments - with good payback over long time periods. The energy > application of the char is only a single use - no out-year advantages at > all. More coming on the many out-year advantages of Biochar. > > This is not to suggest that you do not believe in all this already - but > others could interpret your sentence to favor burning of "densified > non-woody biomass" rather than pyrolysis of the same. > > Ron] > > pressing on, > > Richard Stanley > www.legacyfound.org > > > On Nov 29, 2010, at 4:12 PM, Crispin Pemberton-Pigott wrote: > > [RWL: I have snipped this to keep the responses separate - being different > issues.] > > Dear Friends > > I agree with Ron that $10 is a believable figure for an improved stove with > a dramatic (90%) reduction in emissions of PM. For the +$50 stove > > <snipped> > > > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > Stoves mailing list > > 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://www.bioenergylists.org/ > [email protected] > > http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org > > -- Boston Nyer Graduate Student Department of Civil, Environmental, and Architectural Engineering University of Colorado at Boulder (585) 503-3459
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