[Stoves] Global Alliance for Clean Cooking Stove catalog

[Cookswell Jikos]

Well, the devil is certainly in the details - thank you for laying this out
so well Crispin.

On another note - does anyone know of any plans for the Alliance (or anyone
else besides Google) to address the lack of reliable information linking
small/medium enterprises across the developing world to quality
raw-material suppliers? A specific stove makers tools and materials catalog
of sorts - even it just comprised certified addresses and product lists of
reliable sheet metal and allied products suppliers (ideally from
'green/ethical' manufacturers/supply chains...it would such a shame for a
stove to be made from products of illegal mining operations or highly
polluting factories etc.)  would, at least to me and many other
manufactures in Kenya - be a huge help in reducing production costs.

Teddy

*Cookswell Jikos*
www.cookswell.co.ke
www.facebook.com/CookswellJikos
www.kenyacharcoal.blogspot.com
Mobile: +254 700 380 009
Mobile: +254 700 905 913
P.O. Box 1433, Nairobi 00606, Kenya

Save trees - think twice before printing.







On Fri, Jun 6, 2014 at 12:07 AM, Crispin Pemberton-Pigott <
crispinpigott at outlook.com> wrote:

> Dear Erin
>
>
>
> Thanks for that link
>
>
>
> http://catalog.cleancookstoves.org/#/stoves
>
>
>
> Regarding the emissions and metrics: It will be in interest to the stove
> community know that some consideration has been going on behind the scenes
> and on this list for years about what metrics are the most useful to
> report. There is not yet full agreement so I am bringing it forward again
> as something that needs work:
>
>
>
> This is the list at the bottom for an Oorja Stove from India
>
> [image: cid:image002.jpg at 01CF80E0.8C342150]
>
>
>
> Note that the emissions of PM are given as BC (black carbon) per kg
> burned, PM2.5 per kg of fuel burned and PM2.5 per minute.
>
>
>
> I find this PM mass per kg burned almost uniquely American in that the EPA
> started off giving emissions per unit of mass and everyone copied that, at
> least among the early adopters. Not sure really where it started, but it is
> misleading as we have discussed several tiems before.
>
>
>
> The problem is that the numbers are not useful directly unless you know
> what the kg of fuel was, and a comparison cannot be made with other fuels
> unless a conversion is made first to get the heat content normalized, and
> then to incorporate the system efficiency (not the heat transfer
> efficiency).  Because the system efficiency is not reported, it means from
> the above numbers, one cannot get the most practical metric from the list
> (because some info is missing).
>
>
>
> A stove is used to cook, and people burn the fuel until the cooking is
> done. If the heat transfer efficiency is poor or the stove wastes a lot of
> fuel (making leftovers that are not useful in the next fire, for example)
> then the amount of PM emitted will be high ‘per useful MJ’ but not
> necessarily ‘per kg’. In short, one cannot tell if the total emitted to
> cook something is higher or lower than for another stove.
>
>
>
> If a stove a) burns all the fuel put in it, b) has a high heat transfer
> efficiency and c) has a lower mass of PM emitted *per useful MJ of heat*
> then we have something that can be compared across the board: any stove,
> any fuel, anyplace. All you need to do is plug in your burn cycle.
>
>
>
> So if you can report the mass of BC and PM2.5 emitted per useful MJ
> delivered to the pot, you have the analogy for emissions smoke per unit or
> per task of ‘cooking’.
>
>
>
> The most useful metric is PM2.5 mass per MJ(net) accumulated in the pot.
>
>
>
> I say ‘net’ because heat transferred that is lost from the sides is not
> accumulated. If you were perfectly simmering, all heat gained by the pot
> would be lost from the sides in which case there would no net gain (no
> change of enthalpy). When ‘boiling’ this same process is going on it is
> just swamped by the gain of heat in the water and food, but it is still
> there.
>
>
>
> It is the *net* heat gained by the pot that is useful cooking energy. As
> people will, say, boil 5 litres of water, it takes about 1.8 MJ each time *in
> the pot*. How much PM is emitted per kg is not nearly as important as the
> emissions per MJ. You get my drift?
>
>
>
> Thus when comparing the emissions we are interested in two numbers for PM:
> The mass emitted per MJ delivered, and the rate of emissions into the room
> (which is the last number on that list). Depending on the kitchen
> architecture, that rate sets the smoke concentration in the room if it is
> an open fire type device (no chimney).
>
>
>
> Apart from checking the validity of the metrics, we should investigate the
> underlying assumptions about how the number will be used to make
> comparisons.
>
>
>
> Regards
>
> Crispin
>
>
>
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