It's a wood gassification stove. They do work, but like the "rocket stoves", they require constant attention to feed, and on start-up tend to puff back quite a bit. They work more or less like a car's catalytic converter, where very high temps in the "combustion chamber" burn the particulate contained in smoke.
I built several small models, and one larger unit I heated my shop with one winter. Frankly, more of a pain than it was worth because it wouldn't hold a fire long enough.
When it developed cracks, I replaced it with a masonary "mass storage" heater, a more conventional stove with a heat exchanger built into it, above the firebox, and plenty of mass to retain heat. My stove I now use weighs about 1000 lbs, and will hold the shop at livable temps all night. It burns "ordinary" size wood, and is very good at running a HOT fire.... My BIL has a bunch of ash growing on his place, so I bought some, mostly split, some smaller limbs, and this stove burns it ALL GONE with very little ash, and once hot, almost no visible smoke.
My current stove durng a test (before the firebox door hinges had been made/installed
The exposed firebrick in front kept leaking around the edges, as it doesn't expand as much as red brick when heated.
I slobbered a bunch of fireplace cement on it, but it didn't last.
recently I pulled those front firebricks and resealed them using high temp fireplace silicone (not shown) THAT worked because it stays flexible.
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