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. <EOS>