Motor-driven chimney draft system

A motor-driven chimney draft system comprising:

• a flue gas inlet for receiving a flow of flue gases,
• a flue gas outlet for discharging the flow of flue gases,
• a flue gas compartment delimited by a flue gas compartment wall, the flue gas compartment being in fluid communication with the flue gas inlet and with the flue gas outlet,
• a motor compartment delimited by a motor compartment wall, the motor compartment housing a motor having a motor shaft extending through the motor compartment wall and through the flue gas compartment wall, the motor shaft carrying an impeller situated in the flue gas compartment for driving the received flow of flue gases in a flow direction from the flue gas inlet to the flue gas outlet,
• wherein the flue gas compartment wall and the motor compartment wall are arranged at a distance from and facing each other so as to define an air space oriented vertically therebetween and closed downwardly, the air space having a plurality of openings along a periphery of the air space at two opposite vertical sides and in an upward direction, allowing ambient air to flow through the air space from thermally induced natural convection, wherein the air space is separated from the flue gas compartment by the flue gas compartment wall,
• such that the motor shaft, and thereby the motor, is cooled by the air flow through the air space both during operation of the motor and when the motor is inactive.