Dear Christa
>There are other initiatives to make stoves based on the approach Alexis has taken. Paul has other models that show some promise as well. CR: Which Paul do you mean? I was talking of Paul Olivier below, who has taken Belonios concept to a new era. Yes I meant Paul Olivier. I have been assisting him on the QT. The new secondary air heating system looks promising. The main advantages are that the flames are initiating much close to the pot centre, the excess air could/should be reduced a lot (which is a big problem with Alexis' version of the stove) and there is less total material. >The Mayon Turbo Stove is not perfected yet and I don't think much is being invested in trying. It holds promise from the point that it does not require a fan. I worked on one here (in Waterloo) earlier this year together with two interns from REAP. We doubled the overall efficiency but created new problems that it got too hot. It needs additional work to keep the fuel cool. There are of course other ways to burn the fuel with natural draft. Maybe with the advent of cheap power from TEGs we will all make fan stoves and not worry about natural draft any more. >The MTS has the important advantage that is can be refuelled continuously at your convenience. It does not need to be loaded in batches. CR: But the disadvantage I noted is that it needs a lot of attention: we had to tap the stove every two minutes last year in Belchertown with the colleagues from REAP to assist gravity and make the rice husks fall down, otherwise there was no continuous feed adn the fire would go out. Maybe that 'spoonfeeding' can be reduced with skills and acquired habits, but as an unskilled user I found it rather inconvenient. I completely agree with the assessment. The user convenience is an issue and it needs to be worked on. In the same way that several of the more promising devices seen in the past few years, it will work much better when some effort has been put into refining the principles. Several stoves work in principle and that has been demonstrated. The no-fan option for rice hull stoves is a very attractive alternative for rural manufacture. In principle I like the idea of having the fuel enter from a single point instead of all around so that a smaller quantity is heated by the stove body at a time, and that it feeds in at a higher rate at that single point. This will help to keep the fuel temperature down. The heating issue came to the fore when the interns went to the Gambia and set the fuel hoppers on fire! I had reduced the (very high) excess air to the point that the heat transfer efficiency doubled (!) but the result is that the single layer combustion chamber overheats the fuel. Oh well! It needs a longer re-think than the two days we had available. I made 4 changes to it but it looks pretty much the same. Actually it works really well as a natural draft pellet stove, if anyone wants to try it. I found the best size is 6 or 7mm. It might do well with 5mm which is hard to burn in a regular stove, even a TLUD without a fan because it packs so densely. The frequency of tapping is greatly reduced with the denser fuel which addresses your main complaint. Regards Crispin
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