Fox James wrote:Hi Nate, if you forward wind my video to around 2minutes you can see my version of a glass front J tube with airwash !
Glenn Herbert wrote:Welcome to permies, Nate. Sounds like you have already been studying rocket science
You say you like the simplicity of the J-tube over the batch box, but it sounds like you are introducing as much complexity as a batch box with doors and air washing glass. If you have a chamber large enough to load with a batch of larger logs, the geometry of the burn tunnel and riser goes away and you no longer have the turbulence of the fast right angle bend. To bring that back, you could make a constriction... like a batch box has.
A top loading firebox may be fine for starting; what happens when the first load burns down and you want to refill it while it is still hot? You will have a strong push for hot gases and smoke to go straight up into your face as you are loading. Draft will not overcome that for a large lid. A front door will have less of that issue.
Peter van den Berg spent literally years and many dozens of iterations with professional testing equipment to optimize the batch box design. I believe all of the issues you mention have been addressed in his work.
Fox James wrote:Nate, you should study the batchbox design as it is difficult to beat it on shear performance, the design is very well tested and proven.
Also look up Bell chambers as they are largly superseding piped systems.