[Stoves] Radiation Analysis for Gasifier

[Crispin Pemberton-Pigott]

Dear Paul

 

We are developing the science of a future industry. It is important that
basic issues be discussed, pounded out if necessary, so that we lay the
foundations of a better future for all. 

 

As you are fully aware, stoves are complicated and involve many sciences. On
this list we tend to concentrate on the technical aspects of stoves because
of mutual interest. The inclusion in recent years of more and more young,
talented 'engineering' oriented people has been such a welcome sight. EWB
had been doing things with stoves in the field creating enthusiasm for what
has been a pretty obscure side of development.

 

Through careful effort and sometimes conscious plotting, the World Bank, the
FAO, USAID, many national governments and NGO's have dipped their toes into
the 'hot water' of improved stoves. It has gained respectability and full
time professional careers are now possible in this field.

 

The discussion about radiation and thermal efficiency is not new to this
list, but missing has been the worked examples how the physics of stoves
plays out. We misunderstood your message about boiling rates. So what? We
had a great discussion, we learned about radiation physics and now we have a
tool that can be used to teach the important of my favour topic: excess air!

 

If you reduce excess air, you raise the temperature of the flame and all
radiation parts! Play with that spreadsheet for a while and see where the
radiant energy peaks and then it is nearly zero. I found combinations of
parameters that are believable and showed 50% of heat in the pot was from
radiation.

 

Further on this point, Prof Annegarn stated categorically this morning that
the amount of energy you can get to a pot from convection cannot be
increased by transforming it to radiant heat. Something about the second law
of thermodynamics.  Your experiment of with-and-without the dome showed this
to be the case, even with a large dome. Very valuable work. 

 

Keep it up!

 

Regards

Crispin

 

+++++++

 

Dear Paul.
Who amongst us has has not fallen short by times.
 If ye gnarly doers leave then kiss the list goodbye.

As list member, or not, your contributions are appreciated by many.
Best wishes, have fun,
Alex



 

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