[Stoves] Pressed biofuel - and Fire balls. Testing

[Crispin Pemberton-Pigott]

Dear Frank

If you come with a big eraser, you are going to make progress. You should
see my junk pile! Wish I could erase that....

>I believe there is a lot yet to learn regarding optimum air flow for a 
>type of fuel and void space. 

Yes, and there is a lot of difficulty getting meaningful direct
measurements. I am watching your method with interest. It seemed whacky to
start with but might work well for obtaining certain information.

I have managed to obtain two 8mm diameter velocity measuring probes that are
0.1 m/s accurate. At least it is a start. I suspect that chip/nugget cooling
is a major consideration when it comes to slow burners like gasifiers and
top loaded, downdraft stoves - basically continuous burners. The specific
challenge is how to predict the maximum time a stove can burn for based on
its dimensions. 6-8 hrs is needed for a space heating stove.

>We stovers work at such small scale that 
>test methods for coal and other procedures designed for large combustion 
>chambers do not apply and we need to develop our own methods.

This is an enormous part of the problem. I was looking at the stove
standards of a country in Asia for ideas and the standard covers domestic
stoves up to 80 KW (!) which is hardly realistic for a 4 kw cooker. It
called for on-site inspection every 5 years.

Regards
Crispin