Unacceptable environmental pollution from the fossil fuel energy sources is increasing the demands on green energy concept and developing alternative solutions and has encouraged the international community to employ clean and renewable energy sources such as wind energy. Among different types of wind turbines, Savonius vertical axis in spite of its fascinating advantages including low rotational speed and noise, self-start capability, and independency relative to wind direction has gained less attention in industry due to low energy conversion efficiency. This paper investigates the insertion of a one-way opening valve on the three-blade Savonius wind turbine to reduce generated negative torque on convex side of the blade. Position, size, opening direction, and the opening angle limitation are defined as design parameters and 17 different scenarios in five main categories based on these parameters are modeled, simulated, and analyzed. Concluding, unlimited counter-clockwise large valve in position III exhibits 14% improvement in performance, which is promising.