Darrieus Meets Wells In New IHC Unit’s Wave Rotor


Ecofys is Dutch renewable energy and climate policy consultancy that has developed a Wave Rotor tidal energy device.

IHC Merwede, a Dutch company that focuses on design and construction solutions for the maritime sector, recently acquired the Wave Rotor technology.

The Wave Rotor technology enables IHC Merwede to launch a fully integrated system to generate electricity using tidal energy. The technology will be managed by a newly established company called IHC Tidal Energy.

In contrast to most tidal turbines, the Ecofys Wave Rotor is vertically oriented, allowing the device to convert power from tidal currents and wave motion directly into electricity.

Ecofys owned at least two international patent applications relating to its Wave Rotor technology:

    • International Patent Publication No. WO 2010/062170, entitled “An Apparatus for Harvesting Energy From a Body of Water and a Method” (‘170 Application)

  • The object of both applications is to provide an improved wave power device whose energy efficiency is increased considerably, thus reducing the costs of the energy.

    The ‘133 Application is directed to a tidal device that marries two types of rotor blades. More particularly, the device includes a Darrieus rotor having at least two Darrieus rotor blades, and a Wells rotor having at least two Wells rotor blades, wherein the Darrieus rotor and the Wells rotor are rotatable about a common axis.

    The device comprises three Darrieus rotor blades (101) and three Wells rotor blades (102). The Wells rotor blades are attached at their distal ends to a central axle (104), which is connected to a generator (105) for generating electricity.

    According to the ’133 Application, combining both Darrieus and Wells rotor blades achieves a higher conversion efficiency than than a wave power device having only Darrieus rotor blades or only Wells rotor blades.

    The ‘170 Application describes a similar device having both Darrieus and Wells rotor blades.

    The device (100) comprises three Darrieus rotor blades (101) hingeably connected near the distal ends of the Wells rotor blades (102). The proximal end of each Wells rotor blade connects to the central axis (104), which is connected with a generator (105) to generate electricity.

    The Darrieus blades (101) are arranged in a longitudinal direction and are connected at second points by connecting arms (122) to a lower point on the central axis.

    The second connections between the connecting arms and the central axis are rigid connections, and are preferably shorter than the Wells rotor blades that connect the first points of the Darrieus blades with the central axis.

    According to the ’170 Application, the device has an improved capability of handling varying loads because it is rigid to such an extent that the driving forces exerted on the Darrieus rotor blades are transferred to the central axis effectively, yet bending moments in the rotor blades are reduced, in particular near the transition of the Darrieus rotor blades to the connecting arms.

    With the newly acquired technology, IHC Merwede will further secure its position as a major maritime sector player, particularly in the renewable market.

    Article by Jeff Woodley, a contributor to Green Patent Blog. Jeff is a summer associate at McKenna Long & Aldridge and is currently in his final year at the University of California, Los Angeles School of Law. He received his undergraduate degree in Economics also from the University of California, Los Angeles.

    Article appearing courtesy Green Patent Blog.



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