JOHN CLARK HANNA
A previous version of this page described the Hanna Turbine, US patent 8,358,026. The Hanna Turbine is both a wave and tidal energy converter. The full Hanna patent has been acquired by an established tidal energy developer in the United Kingdom. The new owner and its partners enjoy a substantial economic and technical advantage over competing technologies. This is because the Hanna design has no gear box and uses fixed-pitch blades to harness cross-current tidal flows. Expensive variable pitch mechanisms are unnecessary. Its large diameter, multiple blade rotors efficiently extracts power from bi-directional tides. The simple Hanna drive line is key to the turbine's versatility and low O&M cost.
The following information describes another Hanna wave energy system that is available for acquisition.
THE HANNA MONO-RADIAL TURBINE IN OWC CONFIGURATION
In-house Proof of Concept testing has been successfully completed for the mono-radial design by Oregon inventor John Clark Hanna. The new radial power take-off (PTO) is a novel and exquisitely simple wave energy converter. From the exterior, the method of air intake appears to be self-evident. But inside the turbine's casement, there is a proprietary method of directing the air. The full force of the incoming air flows are efficiently harnessed to increase the rotational driving force.
Unlike common OWC (Oscillating Water Column) impulse turbines, the new Hanna PTO somewhat resembles a Pelton Wheel. It is a radial, self-rectifying air wheel that does not use valves, sensors or solenoids to help the rotor turn in one direction. Peripheral collector vanes help develop optimal momentum. The Hanna design uses a special air-cored, axial flux generator which avoids the magnetic resistance and drag that normally hinders a turbine's forward motion and torque.
The Hanna Radial Drive is versatile. It can also operate within a sealed closed loop system. The closed loop system has a balanced air flow in both directions. Unlike the OWC application, the closed-loop version is never exposed to corrosive salt water mist and the resulting marine slime that coats internal parts. The closed loop system can be miniaturized and is ideal for charging batteries on board small autonomous, extended mission research and data gathering buoys.
THE HANNA MONO-RADIAL TURBINE IN CLOSED LOOP CONFIGURATION
When operated as a full-size OWC-type converter, the design will generate utility-grade power from shore-based installations, surface buoys or fully submerged buoys that are out of sight from the shore. The subsurface buoy's excitation force is caused by the fluctuating pressure differentials created by passing waves above the structure and the relatively static pressure at the buoy's lowest point. To learn more about the proprietary subsurface buoy, contact John Hanna directly.
For information on another patented wave energy converter, a mechanical direct-drive PTO called the Hanna MultiDrive click HERE.