Does the fresh air duct in geomantic omen belong to chimney?

does not belong to. The fresh air duct in geomantic omen is a ventilation duct, which is used to change the air and does not belong to the category of chimney. A chimney is a structure that provides ventilation for the hot smoke or smoke of a boiler, stove, stove or fireplace. Chimneys are usually vertical, or as close to vertical as possible, to ensure the smooth flow of gas and suck air into the so-called chimney combustion or stack effect. The space inside a chimney is called a flue. Chimneys may be found in buildings, steam locomotives and ships.