studying chimney and updraft dynamics today. im interested in potentially creating a flue diverted bench. or, a solid thermal mass ( in the shape of a bench ) where the chimney has two paths out. one direct, so that the chimney can be heated, creating draft even in cold weather, and then rediverted through a long run that passes through a heat capturing mass of brick and clay. the two chimney path method is used widely in Siberia where air gets so cold and dense in a chimney, you sometimes cant start a fire because the fire cant get enough draft to push the cold air out of the end of the chimney.