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<DIV><FONT size=2 face=Arial>Crispin,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><FONT face=Calibri>Dear
Kirk<BR><BR>From your original post:<BR><BR>>The high power used in the tests
was around 3.25 kw. <BR><BR>What was the cooking power during the hot start
test? That means, from ambient to boiling, the heat gained divided by time to
gives Watts (J/sec), and further, what was the heated area of the pot? I want to
calculate the heat flux to see if the cooking power is acceptable to, for
example, people in Central Java.<BR><B style="mso-bidi-font-weight: normal"><I
style="mso-bidi-font-style: normal"><U>The stove was always at ambient
temperature when the tests were started.<SPAN style="mso-spacerun: yes">
</SPAN>I don’t recall the pot size.<SPAN style="mso-spacerun: yes">
</SPAN>The pot was sent back to Aprovecho with the stove.<SPAN
style="mso-spacerun: yes"> </SPAN>I’ll ask Dean to measure it.<SPAN
style="mso-spacerun: yes"> </SPAN></U></I></B><BR
style="mso-special-character: line-break"><BR
style="mso-special-character: line-break"></FONT></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><FONT face=Calibri>>At 24C
room temperature there was no problem keeping the water in the 93C to 97C test
simmering range. At 30C room temperature the simmering water temperature could
not be held below 97C. The pot skirt had to be raised to release some heat to
maintain the test temperature. <BR><BR>You do not 'fail' by not having the water
between those temperatures. Yes, as a result it will increase the evaporation of
water from the simmering pot.<BR><BR>>Raising the skirt....<BR><BR>This will
reduce the draft and reduce the burn rate and reduce the heat transfer
efficiency (aka thermal efficiency).<BR><BR>The effect of this on your
calculated result is important. If you evaporate more water, you get a smaller
number of litres at the end. This is divided into the mass of fuel you burned
(well, not the mass of fuel, but the dry fuel equivalent of the energy that was
released from the mass of fuel that went missing). <BR><BR>The result is that
for any given dry mass of fuel equivalent, you get a higher SFC number. Because
the number of litres has not effect on the fire (at all) we do not really know
what the fuel consumption is, only what the dry fuel equivalent divided by the
number of litres remaining is. <BR><BR>It would be helpful for us if you
reported the dry fuel equivalent, or better yet, the actual mass of fuel needed
to complete the whole test (hot start and simmer). The reasons is that we can
consider what effect the various conditions such as skirt elevated or not, have
on the performance.<BR><BR>For example I would be very interested in the power
(burn rate) with the skirt in the two positions, and the Heat Flux as well. That
is very useful information, particularly if the skirt increases the firepower
and set the minimum power level. It is quite legitimate to make a stove with a
skirt and the instructions for turning it down include - 'raise the skirt', or -
'remove the skirt'.</FONT></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><B
style="mso-bidi-font-weight: normal"><I
style="mso-bidi-font-style: normal"><U><FONT face=Calibri>Berkley Lab has a vast
amount of information that I don’t.<SPAN style="mso-spacerun: yes">
</SPAN>We measured the weight of the stove every 5 minutes during the
tests.<SPAN style="mso-spacerun: yes"> </SPAN>Would this give you what you
want?<SPAN style="mso-spacerun: yes"> </SPAN>If it won’t, I can do a
limited number of tests at stove camp working in the evenings when no one else
needs the equipment.<SPAN style="mso-spacerun: yes"> </SPAN>You design the
tests to get what you want and then let me know.<SPAN
style="mso-spacerun: yes"> </SPAN>Be clear and simple because I am not an
engineer and remember my time will be limited.<SPAN
style="mso-spacerun: yes"> </SPAN>This is something I wanted to test for
anyway, so let’s do it such that you can get what you want too.<?xml:namespace
prefix = o ns = "urn:schemas-microsoft-com:office:office"
/><o:p></o:p></FONT></U></I></B></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><B
style="mso-bidi-font-weight: normal"><I
style="mso-bidi-font-style: normal"><U><FONT face=Calibri>There is so much left
to learn about this stove.<SPAN style="mso-spacerun: yes">
</SPAN><o:p></o:p></FONT></U></I></B></P>
<P style="MARGIN: 0in 0in 10pt" class=MsoNormal><FONT face=Calibri><B
style="mso-bidi-font-weight: normal"><I
style="mso-bidi-font-style: normal"><U>Kirk H.</U></I></B><BR><BR>The Chinese
heating and cooking stoves almost all have a mechanical insert that is placed in
the top of the stove when turning the power down to a long 10 hr burn. Without
that device they can't possibly burn 8 or 10 kg of fuel for 10 hrs and have
enough left to raise the flame back to life (which is part of the national
test). <BR><BR>You get the idea? There is no problem with having 'mechanical
controls' on the stove to bring the power down to 0.5
kW.<BR><BR>Regards<BR>Crispin</FONT></P></DIV></BODY></HTML>