So much to read. I read a lot of this stuff years ago, and have forgotten where/what it is. One could spend a lot of time here. I did not. I found this: Modifying a Retail Chinese TLUD Camp Stove for Improved Efficiency At first look, it looks like there are "Champions" of the Stove Camps held every year. 2 that I saw are the 2005 and 2008 'Champions. For purchase .. Champion Biochar TLUD Biomass Stove Construction Plans for the “Champion-2008” TLUD Gasifier Cookstove Quote from above: " In 2005 my TLUD-ND stove won an award for clean combustion and was named the “Champion” stove. Despite numerous efforts, it did not become a successful cookstove in markets or projects." I found this. Origins, History, and Future of TLUD Micro-gasification and Cookstove Advancement (Version 2.0) http://www.drtlud.com/history/ Exerpt: "Commercially viable gasifiers have long been understood and used in large industry and even in transportation (over one million vehicles during WWII), but not for small applications such as a household stove. In 1985 on a trip to South Africa, gasification expert Dr. Thomas B. Reed awoke one night thinking of a very small gasifier for the domestic stove needs of impoverished people. For ten years he worked to develop what is now called the TLUD (Top-Lit UpDraft) natural draft gasifier stove. Indeed, he is the recognized originator of what is now called Top-Lit UpDraft gasification." http://www.drtlud.com/introduction/ http://www.drtlud.com/history/ A list of resources. http://www.drtlud.com/quick-picks/ http://www.drtlud.com/resources/ TLUD Stoves in 2011 – Within a Classification of Stoves Groundwork Institute, 2014, PRT14910 3 Stove Tests What did you mean here? Ken in NC
@snwcmpr Brilliant, big round of applause there Ken. It was the Zen stoves website, they are predominately meths based but there is a link for wood burners which seems to be an old web capture. It must have been an article on Reed I saw many years ago that has stuck in the memory, and developments have continued. Why the wiki article refers to them as 'Chinese' was the interesting bit. Hence the why would they be clones if they had started them in the first place. Which led to the history question. If I scratch my head any more I'll have even less hair than I currently have. I'll save your reading list for a quieter moment.
Welcome to today's episode of the Chinese Top Light UpDraft Gassifier saga. Based on the smokiness of the full load of fuel + chimney, I elected to increase air capacity this time. Here we have ignition, with large air tube in place: Gassification soon achieved with no smoke. The exhaust off this setup smelled only of hot air, I didn't even run the exhaust fan. No smoke. Bluish blob in this photo is actually a puddle of natural light, cast from a window behind me, across the shop. Messed with camera settings, staring down into the maw of the beast: Spacers added, and kettle on top. Spacers were selected using my usual careful calculation methods. Unlike previous burns, addition of the kettle to this setup did not add any smoke or smell. Output was noticeably reduced, kettle took ~12 minutes to boil. Significantly longer than previous attempts, but for me it would be completely acceptable. This isn't a race. The camera doesn't do it justice here, but the flame was far more blue than orange in this photo. The large piece of orange flame at 8-9 o'clock is where I didn't get the central air passage exactly aligned, leaving a large spot that held extra fuel and created a slightly richer air/fuel mixture in that section. Proper alignment appears to be VERY important. Larger flame licking above the chimney: I forgot to grab photos, but putting a flat piece of steel on top of the spacers above completely eliminated the excess flame, while still burning cleanly. Other than startup and the obvious danger, from an air quality perspective this burned cleanly enough that I'd have no concerns operating this inside my house. The exhaust just smelled like hot air. On the right track, I think.
From a very very brief read of some of the info a couple of things have struck me. The improvement driver seems to be when the stoves are used with wood pellets and the excessive combustion by products. Therefore the need to optimise the fuel air mixture as much as possible. The improvements you are making look to mirror what the rest of the world of TLUD fans are also looking into. Obviously going in the right direction within a matter of weeks compared with years of effort from the TLUD community.
snwcmpr, Oct 5, 2015 https://classiccampstoves.com/threa...1-ounce-backpacking-stoves.30739/#post-311867
That must have been in my unread list. Solo stove is £75 on Amazon here. @Marc One of the modifications in the links @snwcmpr kindly posted was to 'reduce' airflow through the grate. Tin can lid with a few small holes punched in. Also added were extra holes drilled in the pot support ring.
Thank you Ken for compiling all that info, AMD thank you Simes for pointing out that mod. Looks like it reduces airflow through the fuel bed, while leaving the secondary air passages at full bore. This is a mod that bears looking into.
Had an opportunity to browse further and a couple of observations that might be useful here. Primary air through the fuel bed will control rate of pyrolisis, rate of combustion, can be controlled in these stoves by either reducing grate hole size or possibly cover the lower section vent holes. All the stoves referenced seem to have a chimney arrangement above the restrictor/concentrator. The drawings suggest 3 - 5". Also it seems they are used on a single charge basis not to add fuel during the burn, empty out and start again. Not sure about that bit but the arguments presented seem compelling as it disturbes the fuel bed too much. The upper layer is the charcoal producing the gases with the next layer below actualy combusting. There were no references to a central air tube to assist, but that pellets are probably the smallest fuel size that would work.
Has anyone else had problems with pellets expanding / crumbling and blocking off the air flow? All attempts o’ve Had at making a wood gasifier stove start well enough but they go out before half the guild used. There’s some interesting ideas here but I’m beginning to think I bought the wrong stuff. Regards John
Hi John @Jeopardy , it might depend on the type of wood your pellets are made from. Over here they come as pure pine wood, pure non-resinous and as a mix of different woods. Maybe you'll need to experiment a bit! Best regards, Wim
The only thing I can think of is they are damp. You've not been scooping them straight out of the cat litter tray? If memory serves they will expand and eventually crumble, but if hot enough they get consumed before they turn to dust which from you description is what yours seem to be doing too early.
Thanks @Wim , @Simes This started happening straight out of the new bag. I'll try a different brand but perhaps I also need to experiment with the amount of air that gets in at the bottom. Maybe it was not burning hot enough. regards John
@Jeopardy https://www.verdorenewables.co.uk/ These are the ones we use, seem to be ok but used largely in the pizza oven. Seem to mass produce for heating systems cor farms etc.
I only use pellets as an initial test. It is not real world use, so I use sticks I gather. My pellets are Oak.
@snwcmpr Not that I need an excuse to get the stove out again, but would really appreciate your views on using the stoves in real world scenario., ie with sticks/twigs. If I read the techy bits right they assume a one shot charge then start again, not continual feed. Charcoal on the top, burning fuel just below then fresh fuel right at the bottom. Adding fuel would suggest disrupting the process somewhat. Still have the chimney to fabricate as well.
I do not have a lot of experience with these. I use them at home once in a while. My point was simply that testing with pellets is different than testing with sticks. My experience with the Biolite resulted in the 'charging' not working after adding more fuel. I used pellets and sticks. I did it many times. That was 5 or 6 years ago. So, that fact of 'not' adding makes sense in my limited experience. I have kept the stoves burning by adding fuel though. I have not previously been too concerned about maintaining blue flame, just keeping it hot. I do remember adding a can as a chimney and watching the flame get better. That was many years ago. I was making DIY versions. The ratio of inner to outer holes makes a difference, as research has proven. Ken in NC
@snwcmpr Thanks for that Ken. Another reason for the interest is the stove fits perfectly in an old SS pot set I have, 2 pots and a fry pan. Was thinking it would make a practical set up for short trips as the only stove. Could possibly be combined with using Hexamine or a meths burner for flexibility. Have yet to test with those. And if you can get a burn time of 20 mins with a few oz of pellets then packing fuel shouldn't be an issue for short hops. I probably have a good excuse to use it again this weekend and take some pics of the bits and pieces I'm talking about. Sarah has a couple of friends round for dinner tomorrow and I can get out of their way and help with some of the cooking.
