Japan's NKK Designs Wave Energy Power Generation System

The technical staff of NKK's Tsu Research Laboratories has worked out the basic design of a dolphin type, wave energy absorption/ power generation system permitting 100 percent absorption and effective use of ocean wave energy.

Masato Hiraki, NKK New York general manager, said the major components of the system are a dolphin, connecting rod (arm), floating body and two generators.

The floating body rolls and heaves due to w a v e - e x c i t i ng forces, thereby generating relative revolving movements of the floating body and the connecting rod, and of the connecting rod and the dolphin. In this instance, revolutions are amplified by the use of gears.

The revolving movements are used as driving forces for power generators. In this manner, wave energy can be completely absorbed and concurrently used as driving forces for power generation.

Experiments using a scale model were conducted recently in public at Tsu Research Laboratories 60 m x 3 m x 1.5 m test basin. In the experiments, designed wave energy of 90 watts was applied to a floating body measuring 3 m x 1 m x 0.5 m. It was confirmed that wave energy was completely absorbed, resulting in the complete elimination of waves, and some 70 watts was recovered as electric energy. The margin of 20 watts was mechanical loss. Research will be continued on generation systems and structural analysis of the dolphin prior to offshore experiments.

In addition to power generation, the system can be utilized to provide pump driving power for desalination equipment and equipment for absorbing uranium in the sea. The system enables complete elimination of waves, thus providing suitable sites for fish farming, offshore recreation and port facilities.

Details of the experimental results will be announced at the 13th Symposium on Naval Hydrodynamics to be held in October in Tokyo.

NKK (Nippon Kokan) is Japan's second largest steelmaker and only integrated steelmaker/ engineer-constructor / shipbuilder.

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