The heat exchanger with not be part of the main body. It will be next to it, like a twin cylinder in height and width. All the filtration will also be on this side unit.
I did a lot of research on heat transfer, transfer rates, and materials... and have decided to spend the extra buck and go with 36 1/2" thin walled stainless pipes, each 36" long in either an open configuration, or (optionally) as a closed water heater for those who have water pressure, and want to use as a coolant.
The name of the game here is SURFACE AREA!!
For those who wish to air cool the pipes, I am positioning them so that 2-3 fans could take the waste heat from the outside core jacket as the poser source. I'm looking at both Stirling engine fans and thermoelectric. both would work, both would provide ample air flow, and both would utilize waster heat for power.
However, as nifty as that may (or may not) be, a water cooled approach is far superior.
It would kind of look like this (below), but upright, and the cooling tubes would only exist on the outside edge.
I am debating on whether or not to keep the shell on at all times, or to leave as optional... Open to the air would be more effective for air cooling, but "componentizing" the shell, as a "slip on" kind of thing would be difficult.
Multi-nozzle / multi-cyclone
More coming soon on the multi-nozzle idea... However, the main reason is so the air velocity at the nozzle tip can be configured to operate in a tight, predictable range. There is a direct correlation between combustion temperatures and air velocity. If I were to just have one big nozzle, I lose control... Better to "step" up the number of nozzles as the suction increases. (IMO)
Same with the cyclones. A cyclone is only effective within a certain gas velocity range... Too slow and your efficiency can drop to less than 50%. Too fast, and you're dealing with pressure drop, frictional heat, etc. Better to "step" up the number of cyclones as the gas demand dictates, so you are always in the 90%+ efficiency range. (IMO)
As for fuel processing, I really like Gary's charcoal processor. I also like the Thymark shredder:
However, these are expensive, and I think something similar to Gary's crusher would be cheaper to make, and just as effective.
The charcoal would drop down, and then at an angle, drop into a rotating trommel filter with a 1/8" mesh. Whatever falls through the mesh can be used as biochar (or whatever), and the sized char pieces would continue through and drop into a container. All this would be completely enclosed to control dust.
Because i plan on building a hand crank blower (with optional motor), I am trying to use that cranking mechanism for all three uses, just with different gear ratios. I.e. when you're cranking the char crusher, the trommel is also spinning.