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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Dear Friends<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Although the stove has been around for 10 years, there is never anything heard of the emissions performance of a Vesto so I have decided to send a little to the group.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I found a really old Vesto (2004) at YDD in Yogyakarta a couple of years ago and ran it as a TLUD with locally produced wood pellets to see how it worked.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>This is Prianti Utami holding the sample tube.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'><img width=271 height=465 id="Picture_x0020_2" src="cid:image001.png@01D02685.40C91450"></span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>This is the steady state combustion: <o:p></o:p></p><p class=MsoNormal>CO2 5.6% (by calculation)<o:p></o:p></p><p class=MsoNormal>Excess air —290%<o:p></o:p></p><p class=MsoNormal>CO concentration 183 ppm<o:p></o:p></p><p class=MsoNormal>CO/CO2 ratio 0.03%<o:p></o:p></p><p class=MsoNormal>High power heat transfer efficiency —35%<o:p></o:p></p><p class=MsoNormal>Low power heat transfer efficiency (burning remnant charcoal) >60%<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'><img width=227 height=148 id="Picture_x0020_1" src="cid:image003.jpg@01D0268A.EAC5FA90"></span><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The combustion chamber has a lever-controlled primary air supply with free flowing secondary air plus a portion of the primary air is preheated and supplied as secondary (sorry, but it is complicated). <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In later years the secondary air supply holes were reduced in number by 25% which limits the excess air even further.š It reduces the high power limit but improves combustion generally.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Note to Saloop and others: This stove architecture with descending preheated primary (and/or secondary) air has proportions that are dictated by the % of oxygen in the atmosphere, the density and the thermal mass of air. In other words, the entrance heights and primary/secondary air split follows a set of ratios dictated by The Earth which taken together with the oxygen content of the fuel itself, show where the optimum performance lies.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Here is a picture of the flame from a Vesto burning switchgrass pellets in TLUD mode (it can also burn in a regular updraft mode):<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='mso-fareast-language:EN-CA'><img width=302 height=294 id="Picture_x0020_3" src="cid:image006.jpg@01D0268A.EAC5FA90"></span><o:p></o:p></p><p class=MsoNormal>Note the complete absence of any central spire of flame. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Solid fuel combustion regulations often seek a CO/CO<sub>2</sub> limit of 2% in part because it is (apparently) not considered dangerous given ‘standard’ air turnover rates and also because it is achievable. Lately the performance of wood-fired heating stoves and cooking stoves have greatly exceeded these standards when using pellets (processed fuel).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Given that may ‘high end fuels’ like LPG and kerosene and ethanol are highly processed, it seems reasonable that the wood burning community demand ‘equal treatment’ meaning that there is no sound reason for solid fuels, as a group, to be rejected as ‘modern fuels’ as has apparently been done in the Nov 2014 WHO document which basically claims they are inherently unable to burn cleanly. šThere is mention repeatedly in documents that ‘only stoves with a fan’ can burn biomass cleanly which is disproven by this one measurement (if it was necessary to demonstrate it at all – there are lots of other examples).š The biomass stove community as a group needs to understand this and its implications, and demonstrate how these widely available, inexpensive and low cost fuels can be applied safely and consistently to cooking and heating tasks.<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><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:8.0pt;font-family:"Garamond",serif;color:black;mso-fareast-language:EN-CA'>Crispin Pemberton-Pigott<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='mso-fareast-language:EN-CA'><a href="mailto:crispin@newdawn.sz"><span style='font-size:8.0pt;font-family:"Garamond",serif;color:blue'>crispin@newdawn.sz</span></a></span><span style='font-size:8.0pt;font-family:"Garamond",serif;color:black;mso-fareast-language:EN-CA'> <o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:8.0pt;font-family:"Garamond",serif;color:black;mso-fareast-language:EN-CA'>Managing Director<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-size:8.0pt;font-family:"Garamond",serif;color:black;mso-fareast-language:EN-CA'>New Dawn Engineering<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='mso-fareast-language:EN-CA'><a href="http://www.newdawnengineering.com/"><span style='font-size:8.0pt;font-family:"Garamond",serif;color:blue'>www.newdawnengineering.com</span></a><o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='mso-fareast-language:EN-CA'><o:p> </o:p></span></p></div></body></html>