Design and development of hybrid vertical axis turbine

Power from wind or water current can be extracted using a horizontal or vertical axis turbine. Vertical axis turbines are capable of extracting power from wind or water current regardless of the direction of flow. A hybrid turbine consists of two types of turbines on a same shaft. Such a design exploits good features of two turbines. This paper presents the design of a hybrid turbine based on a straight bladed Darrieus (lift type) turbine along with a double step Savonius (drag type) turbine. Four bladed Darrieus rotor is placed on top of a Savonius rotor. The hybrid vertical axis turbine has much better self-starting characteristics and better conversion efficiency at higher flow speeds. The hybrid turbine is built and tested in variable speed water currents. This turbine design can also be used as a wind turbine. This paper presents the system design and performance test results of the hybrid turbine. The designed hybrid vertical axis turbine will be used to generate power at the sea floor for an instrumentation system.