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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>These comments are interesting.š However, I seem to have missed the beginning of this conversation (I’m looking at Stove Digest issues 7 and 8).<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I’d love to see some diagrams of the stoves you are discussing.š Or links to sites that discuss them.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>In thinking about rocket stoves it had occurred to me that having a separate air inlet, rather than a raised grate that lets air in at the fuel magazine, could be useful.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>It also occurred to me that it might be useful to have a door on the fuel magazine (as well as the air inlet) to give greater control over inlet air.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Some people I think used sloped magazines to “automatically” feed in fuel.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>It seems like one might be able to incorporate some of the features of old fashioned U.S. wood stoves (which were expensive and cast iron) that were very convenient, flexible in use (ovens, multiple burners), had chimneys to take smoke outside and didn’t get any smoke in the room when starting the fire, and started easily, and didn’t require a huge amount of tending.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Or some of the features of airtight wood heaters.<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'>Huck<o:p></o:p></span></p><p class=MsoNormal><a name="_MailEndCompose"><span style='color:#1F497D'><o:p> </o:p></span></a></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Crispin Pemberton-Pigott [mailto:crispinpigott@outlook.com] <br><b>Sent:</b> Monday, October 6, 2014 12:43 PM<br><b>To:</b> 'Discussion of biomass cooking stoves'<br><b>Subject:</b> Re: [Stoves] Help with rocket stove for Cameroon<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>Oh…I wasn’t talking about sending a stove anywhere. Just mentioning a major upgrade for anything that has side fed sticks and a firs on the floor.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>I think the advance is fundamental and can be applied to almost all Asian stoves. I had a couple of grates made, one from cast iron and another couple from re-bar. The round rebar were the best – something to do with the curve and bar spacing but not clear what the full details are.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>The bar spacing is important – about 4 or 5 mm gap and 12mm bars. Generally speaking all grates have bars that are too far apart. As a result of the gaps being large, the char falls through and fails to burn usefully. Jikos with big holes have the same problem.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA><o:p> </o:p></span></p><div><div><div><p class=MsoNormal><span lang=EN-CA style='font-size:12.0pt;color:black;mso-fareast-language:EN-CA'>Thanks Crispin,<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-size:12.0pt;color:black;mso-fareast-language:EN-CA'>but then issue then is getting what ever here. A stove can cost 25.00 and then it costs 200.00 dollars to ship it here. <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-size:12.0pt;color:black;mso-fareast-language:EN-CA'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-size:12.0pt;color:black;mso-fareast-language:EN-CA'>Michael<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-size:12.0pt;color:black;mso-fareast-language:EN-CA'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-CA style='font-size:12.0pt;color:black;mso-fareast-language:EN-CA'> <o:p></o:p></span></p></div><div><div><p class=MsoNormal><span lang=EN-CA style='font-size:12.0pt;color:black;mso-fareast-language:EN-CA'> <o:p></o:p></span></p></div></div><div><p class=MsoPlainText><span lang=EN-CA style='color:black'>Dear Michael<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'> <o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'>There are a couple of other alternatives in use. One is the grate developed by the Rocketworx people in Durban. This seems to be very effective at getting the char burned to ash with very little remnant (means high energy from available fuel). The other is the Improved Keren Stove which was developed at YDD in Indonesia in 2012 that has a tilted grate, very low to the floor. It is about 20mm high on the near (fuel feed) side and 40mm at the back. This also has an air entrance at the back about 20 x 40mm (rectangle). The grate bar spacing is important, as is the shape.<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'> <o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'>This also burns virtually 100% of the fuel put in. The additional modification to the Keren stove is to lower the pot significantly on the stove body to serve as an excess air controller. The traditional pot rest height was FAR too high - about 25mm. At 7mm it controls the excess air to a reasonable level.<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'> <o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'>The combination plus one other modification increases the thermal efficiency from —16% to —33%.<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'> <o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'>Regards<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-CA style='color:black'>Crispin<o:p></o:p></span></p></div></div></div></div></body></html>