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

Don't belong. The fresh air duct in geomantic omen is a ventilation duct, which is used to exchange air and does not belong to the category of chimney. Chimney is a structure that provides ventilation for the hot flue gas of 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 can be found in buildings, steam locomotives and ships.