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</o:shapelayout></xml><![endif]--></head><body bgcolor=white 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 Paal<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'>It is this point (your last one) that I have been trying for two years now to bring to your attention: the inclusion of the entire energy chain, as well as the costing of the whole process.<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'>Your point about turning down the charcoal stove is well taken – a stove that has not ability to be turned down is not as practical as one that can be, but if the cook chooses to move the pot aside instead of turning it down, the usefulness of the invention is lost.<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'>There are charcoal stoves that can be turned down, and simple ones, but people do not promote them. People tend to promote whatever they invent or represent, no matter how practical it is in the circumstances.<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'>As you have reported several times, the Peko Pe can cook with a high heat for some time (I understand it is about 30 minutes) followed by a lower heat when burning the charcoal produced by the initial fire. Is this true?<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'>This is perfect for a cooking task that requires this burn cycle. A ‘burn cycle’ is the power and duration profile of a cooking event. Notice please that I did not say the ‘temperature and duration’. The temperature of a fire is not the same as the power because if the fire is very small or large, the power is quite different even if the temperature is the same. This is an important point that Roger was picking up when he first joined the stoves group.<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'>Now consider the cooking of beans as you described. The burn cycle should be a larger fire to get the water boiling followed by a low power simmer for several hours. If you used a Peko Pe this would be appropriate and one could imagine that the cook would learn just how much fuel to put into the stove to begin with in order to have the perfect burn.<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'>What happens when the fire is not large enough to keep the simmering going? Can you add some fuel and keep it going at a low power for another 2 hours? Is there any control of the firepower or is it what we call ‘fuel metered’? By that I mean the power is controlled by enough adding fuel at a time to give the correct heat output to match the cooking need.<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'>Generally speaking (and I think this applies to the Peko Pe) there are no controls on a batch-loaded TLUD stove. The gasifiers that Paul Anderson was promoting 5 years ago did, but I am not sure about ‘most’ of the simple stoves. Controlling the primary air supply certain <i>can</i> control the firepower during the initial part of the burn when creating the charcoal, correct? The problem I see in practice (and it seems it will surprise you that I test stoves with actual cooking) is that TLUD’s in general cannot be fuelled in any practical sense. This makes it a problem to cook the beans. To keep a fire going for a long time at a controlled heat is quite difficult. It is common in Kenya for example for people to cook beans for 5 or 6 hours. The beans can be softened by soaking them overnight but people cook them anyway.<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'>With regard to your question about factoring in the loss of energy during charcoal production (which could be used for cooking or some process heat like drying mangoes or fish or generating electricity) and the transport: I can recommend you study the calculations I have provided from time to time to see how costs and energy are account for to see if you see a way to improve the whole situation. Improving some part of it is not difficult and I encourage you to continue to do so. <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'>What will be a ‘difficult sell’ for you and Otto is the idea that we should be opposed to all production, transport and use of charcoal. It is easy to be ‘against something’ but far more difficult to understand all the implications of an entire fuel industry and food preparation industry to implement radical changes based on an ideological opposition to a major 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='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>In closing I want to reiterate that there are charcoal stoves that can be refuelled, turned down, that have low emissions, that can burn a wide range of charcoals and they have some advantages people really like: high thermal efficiency, high power, clean pots, low smoke, portability, low cost, and local fabrication. These are very strong selling points.<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 fuel supply were improved instead of removed, the overall energy chain is pretty attractive <i>in some places</i>. In other not. There is no ‘one size fits all’. <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'>Suppose the water lily that is clogging Lake Victoria could be turned into charcoal powder! That would be wonderful: a non-wood fuel supply right next to a huge market in Kampala and it would turn a dreadful environmental mess into a clean, valuable 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='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><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0mm 0mm 0mm'><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>+++++</span><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span lang=EN-GB style='font-family:"Calibri","sans-serif"'>Dear Stovers and especial Crispin and Richard <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-family:"Calibri","sans-serif"'> There is a big difference between practical cooking and scientific tests.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-family:"Calibri","sans-serif"'>A cook used to cook on charcoal will automatically remove the pot from the hot zone for simmering and will do the same while cooking on an el hotplate <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-family:"Calibri","sans-serif"'>We had that situation in a huge institutional kitchen in Uganda in the middle of the 90ties. 11 of 12 five kWh hot plates were out of order due to the fact the cooks removed the pots for simmering and let the hotplate glowing instead of switching down. I saw the same in Zambia in 2008. The reason could not be anything else than the fact it is not possible to switch down a charcoal stove.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-family:"Calibri","sans-serif"'>Crispin is always talking about you are transporting more “mj” by transporting charcoal than biomass. When 50-60% or even more of heat is lost by the use, how do’s this occur on the transport costs at the calculation of the efficient of the stove?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-family:"Calibri","sans-serif"'> Another thing, while cooking small quantities of beans 900 </span><span lang=EN-GB style='font-family:"Arial","sans-serif"'>°</span><span lang=EN-GB style='font-family:"Calibri","sans-serif"'>C is to hot and you have to constantly to ad more cold water due to evaporation. How do’s that enter the calculation? To boil un- soaked beans on a TLUD-ND like Peko Pe you will bring 1 kg un-soaked beans to a boil on the loss of energy producing charcoal, and then continue simmering for two hours directly on the charcoal produced emptied on a tray. How will that occur on the calculation. It’s the practical use, which are the reality and let us have a real calculation based on all facts, losses and costs included, on all levels of the process of clean cooking.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-family:"Calibri","sans-serif"'>With regards Paal W<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></div></body></html>