[Stoves] Stoves Digest, Vol 31, Issue 16

[Crispin Pemberton-Pigott]

Dear Nat

So we are headed in the right direction? Thinking about these things and having a spreadsheet are very different matters. I look forward seeing your 'interlinkings' on paper.

All you say makes perfect sense. I will try to build a coal stove that is not a borderline case because that makes it finicky so the idea is to build it wa-ay into the safe zone of stability. Thermal efficiency comes second to proper functioning.

In Mongolia and South Africa the situation is pretty much the same in terms of need. I expect the West Bengal state in India will be different (they also burn a lot of coal, badly). The products are likely to split into cooking and cooking + space heating. This will require different parameters on the particle size in that the space heating long burns are much more difficult to do properly for a number of hours without attention.

Regards
Crispin

-----Original Message-----

Dear David,  Frank, Crispin and Stovers,

I have been traveling and have fallen behind on my stove mails. Tom and all are correct in stating, “superficial velocity (average, as if there is no fuel) through a combustion bed is a number to watch”.  But superficial velocity is only one variable in a stable equation and is fickle for surface smoothness of the feedstock can alter it. For example high-end wood pellets have a lower surface drag than manure pellets of comparable size and density. If however we consider superficial velocity, volumetric flow rate, and pressure as interlinked variables, we can control not only combustion or gasification but also any number of other processes that take place in our stoves. I too will be at ETHOS and will bring colored pencils and my trusty (albeit old TI-85) .  Looking forward to meeting you all.

Cheers

Nat