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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Dear Testers<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Here is an update for your WBT v4.2.3 spreadsheet if you are using it and if you are one of those who makes corrections to it. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>WBT v.4.2.3 Cell WBT!W32 (Effective mass of water boiled) currently contains:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>=((AA12-$N15)*(AA8-W8)/($N$20-W8)+(AA13-$N16)*(AA9-W9)/($N$20-W9)+(AA14-$N17)*(AA10-W10)/($N$20-W10)+(AA15-$N18)*(AA11-W11)/($N$20-W11))<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>One part of each section of this formula [*(AA8-W8)/($N$20-W8) etc] creates a variation in the calculated results that is not present in the raw data if the boiling point on the day of the test is not the same as the ‘official’ value. It should be edited to <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>=(W12-$N15)+(W13-$N16)+(W14-$N17)+(W15-$N18)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Note the shift from Col AA to Col W. This removes an incorrect ‘correction’ of the water mass for the temperature reached when boiling. It is an error that dates back decades. Another correction (normalisation) is applied further down in Cell W38. The abbreviated formula will also correctly report the mass of water boiled.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Note for PEMS/LEMS Hood users, some labs are using spreadsheet v4.2.1 “for all Sensor Boxes”:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>If so, the correction from Col AA to Col W has already been implemented. You should check your spreadsheet cell contents, however. The current version date in Cell DATA IMPORT!A5 is 3/21/2013 (21 March 2013) but the change seems to have been made after that date.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The current content of WBT!W26 (Effective mass of water boiled) is<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>=((W12-$N17)*(AA8-W8)/($N$22-W8)+(W13-$N18)*(AA9-W9)/($N$22-W9)+(W14-$N19)*(AA10-W10)/($N$22-W10)+(W15-$N20)*(AA11-W11)/($N$22-W11))<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Note the use of Column W, not AA, which is correct.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>To remove the unnecessary correction for the difference between the local ‘official’ boiling point and the boiling temperature achieved, it should be changed to<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>=(W12-$N17)+(W13-$N18)+(W14-$N19)+(W15-$N20)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Charcoal:<o:p></o:p></p><p class=MsoNormal>If you are testing a stove that produces charcoal that the stove cannot burn, or if it is local custom to discard all remaining char and little bits of burned wood, enter the mass of the char container (only) in Cells WBT!N21, AA17 and AO17 or leave all three blank.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>For stoves that produce a lot of charcoal, it will give a large difference in the performance rating for ‘fuel consumption’, something much closer to its actual consumption.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In general be cautions what is put into that cell (AA17). Ash is considered by the calculation to be unburned char which is in turn considered to be unburned fuel. Penn Taylor proposed a correction for this but it is safer to have a manually calculated set of numbers. Enter a “Weight of container” of Zero in WBT!N21 and enter actual, reusable charcoal mass in cells AA17 and AO17. If you make the claim that it is reusable, reuse it on the next test as part of the fuel consumed, if that is what people actually do.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Specific Fuel Consumption:<o:p></o:p></p><p class=MsoNormal>There is an incorrect, persistent belief that the heat transfer efficiency in a biomass stove is analogous to the fuel consumption. That belief is why a converted ‘energy consumption of burned fuel’ is reported as “Specific fuel consumption” in Cell WBT!W30. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Making the above changes (and leaving the unburnable char remaining <i>out</i> of the two cells) and using the corrected water mass formula, the “Thermal Efficiency” becomes the “System Efficiency” which <i>is</i> analogous to the fuel consumption. As a result, the Specific Fuel consumption is automatically corrected for consumed ‘dry fuel’ mass.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>For TLUD pyrolysers that SFC number will increase more than 200%. Don’t be shocked. It is now reporting “Fuel Consumed”, not “Energy Theoretically Released turned into a dry fuel mass equivalent”.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>You lab test result will now be much closer to your field observation numbers. Please don’t use the CCT 2.0 spreadsheet without making a similar set of corrections or they still won’t agree.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards<o:p></o:p></p><p class=MsoNormal>Crispin<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>