The research enabled us to test the system in different configurations such as different number of turbine blades, their distance to the turbine’s axis of rotation, the influence of the system’s inertia, different types of anchoring etc.
The obtained results show that the parameter which has the biggest influence on the amount of energy acquired by our device is the method of anchoring. When the axis of pendulum motion of the float is anchored more rigidly, we extract more wave energy. It is exceptionally important because if the float does not move back when the wave approaches, it can extract more kinetic energy. Moreover, waves should not lift the float with the column in order to extract more potential energy from waves.
The results of calculations for two methods of anchoring the float. Both configurations were calculated for 2-meters high waves and 10-meters float hull, measured when the float is straight in front of the approaching waves.Series 1 – Two anchoring cables on both sides of the float hull. Series 2 – Six anchoring cables, star-shaped arrangement. Generated power P = f(omega) Rotational speed of turbine n = f(omega) Driving torque on turbine Q = f(omega)
These types of anchoring are possible to apply at the Baltic Sea (high tide < 0.05 m). For the tides as high as several metres we have developed a different type of anchoring the system, for example using floating energetic platforms or floats. The first results of the research are very promising because the power of 2-meters high waves amounts to ca. 13 kW/m of crest length. Therefore, waves which crash against the 10-meters long float hull have the power potential of 130 kW. In star-shaped configuration of anchoring, generated power on turbine by our system amounts to 17 kW. Thus, the total efficiency amounts to 13%.
Below the comparison of several most characteristic parameters when the waves height is 2 meters. At equal weight with PELAMIS P1 prototype, WaveNRG produces almost 3 times more energy.
|System||Number of floating units||Length of float(s) (m)||Total weight (t)||Generated energy (kW)||Efficiency (%)|
|PELAMIS P1||1||120||750||153 *||10|