[Stoves] New document from ESMAP

Crispin Pemberton-Pigott crispinpigott at outlook.com
Wed Aug 5 16:43:36 CDT 2015


Dear Philip

 

I bring for you attention 6 or 7 stoves by way of reports, and one by way of
reputation. The 5 paraffin stoves are known to me as RSA regional. One is
not better than you report. The others range to 'quite good'.

 

The set of three has two paraffin and one LPG.  Both of them exceed the
45-50% range but note that the pot size has a strong influence. 

 

We have seen two paraffin stoves peak at 70% efficiency. The last one is the
Janata stove which is widely used in India. Hirendra Chakrabarti reports it
is about 50% efficient.

 

One not available (as far as I know) are the FSP stove which was in the mid
50's across a range of powers, and sort of independent of pot size (because
the flame area is quite small). The side-tank with a pump and a Servals
evaporator I tested in Chennai and I am looking for the data. I believe it
is well over 40% but will wait for more info.

 

The radiation from a hot evaporator under a pot with no top deck can be a
huge loss, but the big loss seems to be when there is an open space under
the pot - as if the gases were supposed to rise and get near the pot by
buoyancy alone.  There is a lot of turbulence under there and heat goes
sideways, literally.

 

Regards

Crispin

 

 

 

Dear Crispin

You say "A good kerosene stove is going to be above 45-50% efficient." I
have yet to find one doing above 42%, and a good average value was 35%.  The
better ones were pressure stoves; wick stoves were invariably poorer.  

The interesting question is where all the losses come from. In the wick
stove it is outward radiation from the heater, which glows red-hot in
operation to provide the energy to evaporate the kerosene from the wick.
But the loss of efficiency in the pressure stoves really puzzles me.

 

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