Now for my brain fart... What about an exhaust recirculation back into the burn chamber,
Allen. I like that concept. I think I know what you mean by the turbo concept but not in this situation. I'm thinking you mean to re-plum the exhaust into the feed chamber like a closed loop. I would think also that O2 would still need to be introduced also.
My shop is so leaky that it wouldn't hurt the human and cat if oxygen was taken from the room, but in a tight house, a way would have to be found to find more combustion air .
So, if there is just co2 coming from the flue and not combustible, why bother? Now my little brain is scrambled.
Paul, at fire out I use a plate of steel over refractory wool covering the firebox. Climbing up to the roof I can feel no heat coming out of the flue. Seems to work just fine. Over an 8 hour no burn my bench gives up maybe ten degrees.