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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Rok<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Good to hear from you and thanks for providing measurements. Numbers inform.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>></span>I've experimented with top-feed briquettes quite a bit and figured out a few points:<br>- the gap around the briquette as you've also found out, needs to be there, around 3-5mm all<span style='color:#1F497D'> </span>around, if not, there<span style='color:#1F497D'>’</span>s some kind of a choking smoke coming out at sides and the fire doesn't seem to progress well<span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I agree but hold that there are several ways to burn the same fuel, including having no gap. The short version is that it has to do with what is happening on the outside. The photos are shown looking straight down and there is a small provision for primary air in the outside of the briquette. The need for it is later in the fire when the charcoal is burning as the primary/secondary air split changes when the fuel is pyrolysed. You are correct, however, under certain conditions.<o:p></o:p></span></p><p class=MsoNormal><br><span style='color:#1F497D'>></span>- i think its better to have more shorter briquettes than one or two long ones, as the gap between the briquettes provides an extra air-pocket that seems to help the fire going <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If the centre hole is large enough (basically, exactly the right size) you can burn a very long briquette. I think the reason for your observation is that the hottest briquette is able to pyrolyse more completely before developing a fire in the next in line. If the fuel is really dense they have to be even smaller (vertically).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>>…</span>from 3-5cm to 10-12cm, but stayed with around 5-7 cm<span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>George is on that upper range at 7.5 cm.<o:p></o:p></span></p><p class=MsoNormal><br><span style='color:#1F497D'>></span>- now comparing the top or side-feed, i found quite a few reasons to proceed with the latter, side feed: <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>You are using a bottom-fed updraft tipped on its side (side fed crossdraft) and that has some advantages. The stove in question is portable even when the fire is running and I think there are safety advantages with a fully contained fire. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>>…</span>when you insert a briquette from the top on an existing fire, there is a much bigger fluctuation in fire volume,<span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Agreed.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>></span> higher CO emissions and you have to lift the pot while doing it.<span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I always work about pot lifting. I found that the people who complain about it the most are stove designers, not users. </span><span style='font-size:11.0pt;font-family:Wingdings;color:#1F497D'>J</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> They don’t like it theoretically but skilled users are able to do amazing things. I have heard about a 2 hours burn in a Vesto without touching it. 30-45 minutes is common. The problem is overestimated in my experience.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>></span> The major difference is that with the top feed, the cold briquette mass is instantly all exposed to the fire, while in side-feed the briquette burns inside-out, starting through the hole, which gives a much steadier flame volume and way less smoke and CO emissions, also the briquette is always inserted where the fire is the coldest - from the side. <br><br><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>That is a major difference and it depends on what the user wants. There are many cooks who want a string flame-low flame-strong flame. It is easy to mediate that with the number of stacked briquettes. For example you can have the remainder of one plus a new one, or three new ones. The power is thus controllable to a certain extent. I foresee people dropping in briquettes made of completely different materials to get the burn they want. <o:p></o:p></span></p><p class=MsoNormal><br><span style='color:#1F497D'>></span>Top feed was my first briquette stove in Malawi, with 16cm briquettes outer diameter and cca 5cm hole. What did work much better than, was keeping the fire going and manipulating the steady volume with few wood-sticks from underneath, <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I remember that. It was a combination of fuel wood and briquettes. That is a perfectly reasonable approach if both fuels are available. I believe that one can make a stove to suit the fuel, even when it is difficult to burn the fuel.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>>…</span>Also it was easier to persuade local people for using briquettes as it was an easy-learning curve. <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I completely agree. George is working with people who have to buy their fuel wood so there is a huge motivation to save. He will report shortly on the savings. The money side of the cooking is a significant factor in adoption of odd fuels or stoves.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>></span>I haven't gone in this direction yet, but i'm sure that with some air-supply regulations, it would be possible to improve the top-fed stove as well! <br><br><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The key is to be able to burn multiple fuels. The Vesto Junior is a really good charcoal stove which is perfect for some meals. It is being used with wood and with briquettes, in both cases providing an economic benefit.<o:p></o:p></span></p><p class=MsoNormal><br><span style='color:#1F497D'>></span>I would be happy to hear about how the locals are satisfied with the stove you're posting about and if the fire volume fluctuations is not a big problem for them! <span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>George will report that.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>></span>Would be also great if you could post some photos of the whole stove body<br><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>Here: (nothing unusual)</span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Combustion chamber:<o:p></o:p></span></p><p class=MsoNormal><img width=378 height=346 id="Picture_x0020_1" src="cid:image005.jpg@01CD7188.56235720"><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Stove body (not all internals shown)<o:p></o:p></span></p><p class=MsoNormal><img width=378 height=371 id="Picture_x0020_2" src="cid:image006.jpg@01CD7188.56235720"><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>A user of a Vesto Junior<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><img width=302 height=647 id="Picture_x0020_3" src="cid:image008.jpg@01CD7188.56235720"><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>There is too much wood in the combustion chamber – that extra fuel makes it smoke but increases power (a lot) so people do it anyway. The fuel should not be above the rows of secondary air entrance holes. There used to be a standard plastic grip on the wire handle. You can just see a double top lip. The inner part is all the innards you can see. It is sitting on that groove and is removable.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></body></html>