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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'>Dear Philip<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'>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’.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'>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. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'>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.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'>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.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'>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.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'>Regards<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US><o:p> </o:p></span></b></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Dear Crispin<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>You say “</span>A good kerosene stove is going to be above 45-50% efficient<span lang=EN-US style='color:#1F497D'>.” 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. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>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.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p></div></body></html>