Lagrangian drifters are a low-cost easy-to-deploy solutionsfor sea monitoring.Theyare versatile and easy to maintain units that monitor the ocean while passively following the surface currents.Drifter’s autonomy has become a challenge these last years and the focus has been centred in PV solutions. Nevertheless, at some latitudes and atmosphericconditions,solar irradiation may be slight and other sourcessuchas the motion of the ocean wavescouldbe explored.Consequently, akineticenergy harvester...
Lagrangian drifters are a low-cost easy-to-deploy solutionsfor sea monitoring.Theyare versatile and easy to maintain units that monitor the ocean while passively following the surface currents.Drifter’s autonomy has become a challenge these last years and the focus has been centred in PV solutions. Nevertheless, at some latitudes and atmosphericconditions,solar irradiation may be slight and other sourcessuchas the motion of the ocean wavescouldbe explored.Consequently, akineticenergy harvester (KEH) has been developed for oceanic undrogued drifter applications.First, simulations of the motion of a spherical drifterhavebeen performed at different sea environment usingOrcaFlexsoftware. Resultshelpto understand the accelerationsand forces applied on the drifter where the KEH device will be placed.Second, the energy harvester device has been designed.A3D scheme is shown at Figure 1. As a result of the interaction with the waves, the drifter, which contains the KEH, rotates with a pitching, roll and yaw motion. Then, the proof mass, which tries to maintain the vertical positionof the KEHby the gravity effect, rotates in relation with the drifter thanks to the gimbal arms. Thisgenerates a torque along the axis thatthrough thegear system gets to the flywheel. There, the rotational movement is accumulated and then transmitted to the micro generator responsible for converting the torque into electrical power.Thanks to the one-way gear system, the generator only turns in one direction.Finally, a testof the KEHhas been performed in a water tank,simulating waves of10 cm high and 3 second period,achievingto generate 0,3 mW in continuous operation.
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