An efficient energy harvesting (EEH) water vehicle is disclosed. The base of the EEH water vehicle is fabricated with rolling cylindrical drums that can rotate freely in the same direction of the water medium. The drums reduce the drag at the vehicle-water interface. This reduction in drag corresponds to an increase in speed and/or greater fuel efficiency. The mechanical energy of the rolling cylindrical drums is also transformed into electrical energy using an electricity producing device, such as a dynamo or an alternator. Thus, the efficiency of the vehicle is enhanced in two parallel modes: from the reduction in drag at the vehicle-water interface, and from capturing power from the rotational motion of the drums.

A wind turbine with a tower; a nacelle supported by said tower; at least one unit to be cooled and arranged in the tower or the nacelle; a tower mounted heat exchange structure arranged outside the nacelle and tower; and a circuit facilitating a flow of a fluid medium between the at least one unit and the heat exchange structure. To improve thermal convection with the ambient space, the heat exchange structure comprises a set of panels mutually angled and extending outwards from the tower such that a flow of ambient air can pass transversely trough the panels and thereby cool the unit.

The tower comprises: a wall having an orifice for accessing the interior of the tower, and an outer surface defined by generatrices; and a reinforcement frame joined to the tower in the orifice zone, and comprising least two parts joined one to each other. Each part has a mid-plane that is parallel to at least one generatrix, the mid-planes of at least one pair of adjacent parts forming an angle other than 180 therebetween. It enables the obtention of a frame more conformed to the curvature of the tower, combining savings in the material of said frame, greater optimisation of the resistance of the tower and reduced stress concentration.

A wind turbine is described which comprises a tower, a nacelle mounted to the top of the tower, and a rotor mounted to the nacelle. The rotor comprises two or more blades mounted to a central hub. The hub supports two or more annular pitch bearings associated respectively with the two or more blades. Each pitch bearing defines a bearing plane inclined at a first angle with respect to a horizontal plane when the respective blade is oriented in a downwardly direction in alignment with the tower. Each pitch bearing is spanned by a hub plate; and a work platform integral with or mounted to the hub plate lies generally in a plane at a second angle to the horizontal plane when the respective blade is oriented in a downwardly direction in alignment with the tower, which second angle is less than the first angle. The work platform provides a substantially horizontal platform for use by maintenance personnel when installing or servicing components in and around the hub.