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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext;mso-fareast-language:EN-US">Dear Paul<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext;mso-fareast-language:EN-US">The second design is the ‘retrofit’ in the other folder. It involves breaking a new hole in the back to provide the dehydration
air and a shortened mixing chamber. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:windowtext">>…</span>And the .pdf number
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span style="font-size:10.0pt"><a href="http://www.newdawnengineering.com/website/library/Stoves/fish_dryer/Ghana_downdraft%20v0.5/61%20DD1%20v0.5%20Complete,%20no%20doors.pdf">61 DD1 v0.5 Complete, no doors.pdf</a>
</span><o:p></o:p></p>
</blockquote>
<p class="MsoNormal"><span style="font-size:10.0pt">gives a view. But it still leaves me with questions about how it is working. What air flows, etc?<br>
<br>
</span><span style="font-size:10.0pt;color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Very briefly, there is a fire chamber with a tall vertical combustion chamber with very low PM. Part of that hot gas stream is channeled into the chimney to
make sure it has enough energy to work properly using buoyancy. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">The chimney then pulls a much larger amount of air into the air entrance over the firebox. This is mixed with the remaining hot gases and spreads (pretty effectively)
over the underside of the top of the drying chamber. These gases are pulled down towards the floor by the chimney, exiting through a channel in the bottom.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">The plan is to keep the maximum temperature of the gas air mix below 105 C at the top, never above 120 even briefly. This is managed by controlling the amount
of hot air vented into the chimney and the fire size.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">There is an excellent report on PAH formation written by ‘our’ David Beritault that forms part of the whole report. I do not know it that is publicly accessible
yet. I think it should be – anyone know?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt"><br>
</span><span style="font-size:10.0pt;color:windowtext">></span><span style="font-size:10.0pt">And any price info to build either or both?
</span><span style="font-size:10.0pt;color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Well it was $150 but that was early assessment. It can be done for different prices by changing the materials. Bricks are grossly over-priced in Ghana for
some reason. That favours hollow blocks. It should be available after a few months of use, but perhaps in 3 months. High season just ended and I did not hear how many were constructed in a rush.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:windowtext">></span><span style="font-size:10.0pt">And economic impact and labor savings etc would also be useful. For these or any other good innovations to move forward, we need the "functional" info,
please. Maybe there are some reports (SNV documents?) that could be made available.<br>
<br>
</span><span style="font-size:10.0pt;color:windowtext"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">I didn’t look for the SNV documents. Anything paid for by the US public (EPA) should be available by asking for it. I suspect they are still in the proving
phase and will report perhaps at or just after year-end. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">James, what is the status?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">The development of a very low PAH(4) dried fish with ordinary wood fuel is a major advance in smoker technology. The FAO has been promoting ‘improved smokers’
since 1969 and this is the first really big change. Originally it was to reduce the horrific fuel consumption of mangrove wood. This new one saves something like 70% of the fuel as well as reducing the PAH content. All those promoted since 1969 have increased
it. David B’s research confirmed how to have it brought down, the downdraft approach shows it is possible using the same fuel and materials. “Drip down” is a major part of the solution.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">To give you an idea, an operation with two or three of these can produce about ¼ of a ton of ‘soft dried’ fish, with a shelf life of about 3 days, good enough
to distribute over a radius of 200km.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Hard-dried fish has a high PAH(4) content but it was still dramatically improved. I think this is the first system that meets the EU standard for smoked fish
without using charcoal followed by a separate flavouring stage. It saves a huge amount of money and equipment investment. SNV should be promoting this globally as it is easily explained and operated.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Crispin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></p>
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