Introducing two practical wave energy conversion
designs: the Hanna Turbine known as a WETGEN (Wave Energy Turbine GENerator), U.S. Patent No. 8,358,026 and the
Hanna MultiDrive, a mechanical,
direct-drive power take-off (PTO), U.S. Patent No. 8,745,981. Both devices harvest energy from ocean waves by
means of the OWC (Oscillating Water Column) principle. OWC
technologies are the most mature and well-studied wave conversion systems in
the industry. For the
definition of an OWC, click
Engineers at Oregon State University (OSU) built a small working Hanna
Turbine. The device was tested with a bi-directional air flow.
Acting as an impartial third-party, the OSU College of Engineering issued a
final report that validated the Hanna Turbine in 2014.
Turbine improves upon the pioneering but inefficient Wells Turbine that was
invented over thirty years ago.
In contrast to the Wells, the Hanna Turbine uses asymmetrical airfoils with a lower angle of attack which creates more
lift and less drag. The design resists "stall", improves
self-starting and can function over a wider bandwidth with higher torque values.
It offers lower damping (restriction) to the bi-directional airstream due to a smaller
diameter hub and wider gaps between the high lift blades. Unlike the Wells, it drives
two generators - doubling the power output. Both generators are easily
accessable and operate in a dry environment. The Hanna Turbine is more versatile
than the Wells, offering three distinct power take-off designs to
meet job-specific applications. It can be scaled up to three meters (9
feet) in diameter. A 15cm (6 inch) diameter model can provide battery
charging power for small
autonomous research buoys.
wave energy devices operate in the open ocean. In comparison, both
Hanna technologies operate at sea but also can function as shore based
installations. They can be built into jetties or breakwaters and can be connected directly to the
grid. As an alternative, Hanna ocean based applications can be installed on tethered buoys, the legs of off
shore oil rigs, or on floating wind and wave harvesting platforms. Hanna
primary drives can also spin water pumps to
support desalination plants and other renewable energy technologies.
All completed EIR studies for existing shore based OWC installations have
resulted in FONSI (Findings of no Significant Impact). Hanna shore based
power plants will not interfere with maritime traffic, commercial fishing or
Most deep water designs are sealed up
and their generators are inaccesible at sea. To perform maintenance,
the sealed devices must be removed from the water and transported to shore.
Both of the Hanna PTO's avoid these costly O&R haulouts. Routine
maintenance at sea is possible through weather-tight hatches. No
generating components are immersed in water.
Videos of the
Hanna Turbine can be viewed on the WETGEN
You Tube channel. For a more detailed description of the Hanna
MultiDrive power take-off, click
HERE. Additional information
is posted on John Hanna's LinkedIn page or simply Google WETGEN.
To assure the responsible development and successful commercialization of both
technologies, the inventor seeks to assign 100% ownership of the patents
to an established manufacturer or developer.