That TLUD looks nice but I couldn’t put something like that in the house. Might be perfect for use in a workshop or greenhouse though. I couldn’t find any actual drawings or plans for that device but the comments made it sound like the hopper is just a stove pipe:
The fuel container is made out of stove pipe. The primary air is forced down one of the vertical square tubing supports that holds the heat exchanger. The heat exchanger can be removed and replaced with a cooktop. It only takes between 2 and 3 watts to run the primary air fan which is a 12 volt computer fan with a speed control added to the circuit.
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When the pyrolysis front burns out the charcoal starts burning and produces more heat that trips the thermostat that shuts the fans off.
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I know this is an older video but i’m just now seeing it. To answer your question oxygen (air) enters through the bottom of the fuel can and migrates up through the fuel until it reaches the fire. The fire depletes the o2 and leaves the char behind, migrating down the can as it burns. The spent gasses go up the fuel can. At the top where more O2 is introduced the hot gasses reignite and go up the stack. The key to this is stopping the the burn when it gets to the bottom of the can. Otherwise the char that is left behind will burn from the bottom up leaving nothing but ash behind. If all you are after is heat no problem if you want the char you have to stop the burn. Hope this helps.
The top looks similar to something sold as “Magic Heat” but probably bigger.
Mine isn’t rigid enough and it would need to be run very slow to cut. Even hardwood I can’t go real deep or real fast.
Back in high school I did a tiny bit of metal spinning but haven’t tried to set up any way to do that myself. That’s a good idea though. My sawblade cover is working but I added a piece of felt (in addition to the stove rope) to help it seal better. So far that hasn’t gotten too hot.
Doing a little more studying, I still think my main problem was the moisture in the ashes but the raw wood even mixed with the charcoal was probably creating a lot of the moisture too. The last run had very little raw wood and it run pretty good.
I don’t regret trying the raw wood and it looks like I could get away with at least some less than perfect CHARCOAL but I don’t want to add a monorator hopper or all the heat exchangers that would be needed to use raw wood. Not on this one anyway.
I had already used some of the charcoal salvaged from the house furnace but this was what I was able to collect from a couple days without really trying. That should be enough for over an hour run time for the generator. The colder it gets here, the more charcoal I could potentially collect and purposely feeding smaller chunks of wood would speed up converting it into coals.
I’m not happy with how my cyclone is turning out so I think I’ll stick with the radiator I made and use the filter to collect any moisture like I have been doing. This down draft gasifier is starting to work about as good as the simple fire but holds more fuel and shouldn’t need as perfect of charcoal. It probably won’t hurt if a brand or even a tiny bit of raw wood slips in but the rocket fuel idea looks like it adds too much moisture if not some tar.