A wind energy converting system, comprising: - an airflow generating means comprising at least one air inlet and at least one air outlet; - a wind converting apparatus for the at least one air inlet or the at least one air outlet, preferably for the at least one air outlet, said wind converting apparatus comprising: - a sleeve configured for being arranged over one of the at least one air inlet or one of the at least one air outlet, said sleeve comprising a first opening placed around the one of the at least one air inlet or the one of the at least one air outlet and a second opening opposite thereof; - a helical propeller body rotatably arranged within the sleeve such that air circulating within the sleeve induces a rotation of the helical propeller body; - wherein a rotation axis of the helical propeller body substantially corresponds to an axis of a corresponding sleeve portion; - characterized in that the helical propeller body comprises at least one complete helix turn; - wherein an outer diameter of the helical propeller body is gradually increasing as seen in a direction of the air circulation from a first extremity of the helical propeller body facing the direction of the air circulation; and - an alternator connected to the helical propeller body and configured for converting the rotation of the helical propeller body into electricity. - an airflow generating means comprising at least one air inlet and at least one air outlet; - a wind converting apparatus for the at least one air inlet or the at least one air outlet, preferably for the at least one air outlet, said wind converting apparatus comprising: - a sleeve configured for being arranged over one of the at least one air inlet or one of the at least one air outlet, said sleeve comprising a first opening placed around the one of the at least one air inlet or the one of the at least one air outlet and a second opening opposite thereof; - a helical propeller body rotatably arranged within the sleeve such that air circulating within the sleeve induces a rotation of the helical propeller body; - wherein a rotation axis of the helical propeller body substantially corresponds to an axis of a corresponding sleeve portion; - characterized in that the helical propeller body comprises at least one complete helix turn; - wherein an outer diameter of the helical propeller body is gradually increasing as seen in a direction of the air circulation from a first extremity of the helical propeller body facing the direction of the air circulation; and - an alternator connected to the helical propeller body and configured for converting the rotation of the helical propeller body into electricity. - a sleeve configured for being arranged over one of the at least one air inlet or one of the at least one air outlet, said sleeve comprising a first opening placed around the one of the at least one air inlet or the one of the at least one air outlet and a second opening opposite thereof; - a helical propeller body rotatably arranged within the sleeve such that air circulating within the sleeve induces a rotation of the helical propeller body; - wherein a rotation axis of the helical propeller body substantially corresponds to an axis of a corresponding sleeve portion; - characterized in that the helical propeller body comprises at least one complete helix turn; - wherein an outer diameter of the helical propeller body is gradually increasing as seen in a direction of the air circulation from a first extremity of the helical propeller body facing the direction of the air circulation; and - an alternator connected to the helical propeller body and configured for converting the rotation of the helical propeller body into electricity.