I have a shop - 24x36 that has a simple gable roof of low slope.

It's finished and insulated.

There is a small built in AC unit in one corner of the wall towards towards
the top. A custom opening has been created for this AC unit (it's window
type unit, but the opening is not a window).

I was thinking I might be able to simply remove the AC unit and make a
chimney fitting like this..

|
_ _ | (passes through the opening used for the AC in summer
|
|
(to stove)

I could set this up in the winter, and then switch back to the AC in the
summer.

Thoughts?

The alternative is to cut another hole in my wall, or ceiling/roof.