Experimental studies on savonius-type vertical axis turbine for low marine current velocity

Renewable energy resources need to be explored to maintain and meet energy demand and replace the slowly depleting fossil fuels.  Malaysia, surrounded by sea with long coastlines, is poised to exploit the potential of this energy. This research work aims at designing a suitable device to extract energy from Malaysian sea current.  Malaysia’s ocean has a low current velocity averaging 0.56 m/s, which is below the working velocity of presently available current energy devices.  To overcome this velocity limitation, a Savonius-type Vertical Axis Marine Current Turbine (VAMCT) design was proposed.  The experiment to measure the torque of a Savonius-type turbine, which hitherto has been used for wind energy application, is presented in this paper.  The laboratory experiment was carried out in the towing tank facility in Marine Technology Laboratory at Universiti Teknologi Malaysia.  The Savonius model was attached to the towing carriage and current flow was simulated by moving the carriage in still water. The results show that turbine with double stacking rotors each with two paddles and overlap ratio of 0.21 give the best performance.