Palácio dos Biscainhos, Braga.
This “flue” is nothing less than the whole meat smoking room. Sausages and other meats would be placed at the hooks shown on the top photo, and be smoked from a firepit below. The small holes in the wall, and the roof itself, would let the smoke out. The wonderful iron structure lifts the tiles so there is an air gap at the junction with the walls. Needless to say, the kitchen has been cleaned and no curing has been done in a while!