Professor Hsing-Sheng Chai and colleagues in Taiwan proposed to investigate the performance of a parallel system of four Savonius wind rotors with a solar panel deflector. The work is published in peer-reviewed Journal of Renewable and Sustainable Energy.
Since emphasis has been placed on renewable energies to protect the world from unwanted pollution, Chai and colleagues also join other research groups in improving savonius wind turbine which was used to generate energy. The savonius is a drag-type wind turbine, where the blades are the only driving force which the wind drag act. The rotational speed of the rotors and the relationship between the tip-speed ratio TSR and power coefficient Cp are to be considered.
According to the research team, to improve the performance of savonius wind rotors, they placed a series of rotors in a line, with a fixed distance between them, with each one rotating at a specific phase angle. The team in their view to improve the performance of 3 Kw integrated wind and solar system, they considered the number of blades, the wind velocity, the height of the rotor, and the blade overlap ratio. A system of four two-bladed savonius wind rotors in parallel matrix was constructed. The team employed a computational fluid dynamics software, Fluent, to analyze the flow fields then compared the simulations to their own experimental data.
They experienced magnus effect as each rotor absorbed momentum from other rotors during rotation, and is responsible for the additional rotation of the downstream rotor and the periodic coupling of local flow between the two rotors, enhancing the performance of the overall system. They found that the higher the wind velocity the better the performance of the system. The TSR values at the slopes of the simulation and experimental curves differ, this is because in simulations, the rotational speed of the wind rotors and inlet wind velocity are fixed values. A fast rotating wind that wind will easily passes through wind rotors, thereby causing Cp to decrease as a result of the wind not doing significant work on the rotors, said the research team.
This study experimentally tested novel four Savonius rotor system with a solar panel so as to improve the system performance and they were able to generate 14.55kWh of power per day at an efficiency of 21.7%. The results of this study show that the two-bladed configurations have better performance than the three-bladed ones, except with respect to the starting torque.
Hsing-Sheng Chai1, Chang-An Chen2, Chiun-Hsun Chen2, Novel Plant Development for a High Performance 3 Kw Integrated Wind and Solar System, Journal of Renewable and Sustainable Energy 8, 045302 (2016).Show Affiliations
- General Education Center, Aletheia University, 32 Zhenli St., Danshui Dist., New Taipei City 251, Taiwan, R.O.C.
- Department of Mechanical Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 300, Taiwan, R.O.C
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