Water Current Turbines for River Applications - Alaska Energy ...

WCT Evaluation3.3.6 Flutter VanesNRCan-06-01071Oscillating Cascade Power System - ARNOLD COOPER HYDROPOW ER SYSTEMS (USA)Technology: In the Arnold Hydroelectric Power System or Oscillating Cascade Power System (OCPS),the hydrofoils are long, straight, non-varying in width and symmetrical (see figures below). They arearranged in parallel and in foursomes such that the blades are allowed to move towards and away fromeach other in a mirroring fashion. The interaction between the blades is quite complex in that the pitchof the blades is varied and the blades are alternatively attracted and then repulsed by the adjacent bladesuch that an oscillating motion is created. The gearing translates this back and forth motion intorotational energy for a generator. The pitch of the blades may be forced mechanically via the gearing ormay be naturally induced by the unstable path of the water. The blades can be arranged vertically orhorizontally to best fit the stream cross section. The efficiency of the system is not known. In a verticalblade arrangement the generator and gearing could be situated easily above water which has greatadvantages for accessibility during maintenance and in reducing the complexity and number of waterseals. The need for bearings at the far end of the blades would be dictated by the length and flexibilityof the blade.Laboratory tests have shown that a typical 7.32m x 3.05m x 0.91m module in a 3.05 m/s flow willproduce about 200 kW and 60 percent efficiency in conversion of kinetic hydro energy into electricpower.Application: Shallow water NTR’s, tidal areas, and manmade channels. The system can be made tooperate easily in reverse for tidal applications.Stage of Development: Prototypes have been built and run in flow tank settings. Presently, changes arebeing made to replace the complex gearing with some other technology, possibly hydraulics. Nocommercial units have been built to date.Verdant Power Canada ULC 33