pipe thru the wall = I've never understood why anyone would cut a hole in a perfectly good roof. I built a dual wall pipe thru the wall. My stove pipe goes thru that. No worry of too much heat at the wall.
purpose of heat reclaimer = the temp difference below the reclaimer and above the reclaimer is 150 degrees. Works pretty good huh. If you look at it there are round tubes that go thru the box. Behind the box is a squirrel cage fan blowing air thru those tubes. Thus reclaimer. I'm using that 150 degree heat rather than letting it escape up the chimney. I built it.
shop ceiling height = 10ft at the eave, 12ft in the center. Vaulted ceiling. All steel building.
chimney pipe size = I used what I had. 1/4" wall steel pipe.
The actual temp drop from the top of the stove to the chimney going out the wall is 420F degrees. Even with that I'm a bit disappointed that my outside chimney pipe is still at 92F degrees. But it doesn't soot up so I guess losing that heat is work it.