Hybrid configuration of Darrieus and Savonius rotors for stand‐alone wind turbine‐generator systems

Abstract

SUMMARYThe suitable hybrid configuration of Darrieus lifttype and Savonius drag-type rotors for stand-alone wind turbine-generator systems is discussed using our dynamic simulation model. Two types of hybrid configurations are taken up. Type A installs the Savonius rotor inside the Darrieus rotor and Type B installs the Savonius rotor outside the Darrieus rotor. The computed results of the output characteristics and the dynamic behavior of the system operated at the maximum power coefficient points show that Type A, which has fine operating behavior to wind speed changes and can be compactly designed because of a shorter rotational axis, is an effective way for stand-alone small-scale systems.

The effect of the opening ratio and location on the performance of a novel vertical axis Darrieus turbine

“…Although, those methods do improve the self-starting ability of the Darrieus turbine, the Savonius-Darriues turbine seems the only one which has the simple structure, good ability of self-starting, and can meet the most of the requirements of the urban environment. According the researches of the Wakui, T., the highest C P of two kinds of SavoniusDarrieus turbine is about 0.204 and 0.231% [17], respectively. This is much lower than the C P of a normal Darrieus which is about 35% [18].…”

“…It limits the utilization of VAWTs, and no less to say the application in the urban environment. Thus, many approaches have been proposed to improve starting ability of the H-Darrieus, such as cambered airfoils [9,10], new airfoil profile [11], flexible blades or sails [8], variable pith blades [12,13], helical or Turby Darrieus [14,15], Savonius-Darrieus hybrid turbine [16,17] and so on. Although, those methods do improve the self-starting ability of the Darrieus turbine, the Savonius-Darriues turbine seems the only one which has the simple structure, good ability of self-starting, and can meet the most of the requirements of the urban environment.…”

Application and Economic Viability of Wind Turbine Installation in Lutak, Iran

“…The lift type vertical axis wind turbines (Darrieus wind turbine) performance prediction is a very complex task, since its blades move around the rotor axis in a three dimensional aerodynamic environment that lead to several flow phenomena, such as, dynamic stall [7], flow separation, flow wake deformations [8] and their natural inability to self-start. These issues can be overcome with the use of several more or less complex solutions, being one of them the development of a blade profile capable of making the wind turbines self-start [9].This paper focuses on presenting a methodology for the development of self-start capable Darrieus wind turbines with the improvement in the blade design and the integration of savonius device [10,11].…”

Self-start performance evaluation in Darrieus-type vertical axis wind turbines: Methodology and computational tool applied to symmetrical airfoils

“…In these environments the vertical axis wind turbines (VAWT) have several advantages over horizontal axis wind turbines (HAWT). Several solutions have been presented to overcome the Darrieus type VAWT inability to selfstart: use of a guide-vane [6], using a hybrid configuration of a Savonius VAWT (drag type wind turbine) and a Darrieus VAWT (lift type wind turbine) [7]- [9], use of mechanical system to optimize the blade pitch [10], [11], use of blades that change their form during operation [12], [13], or a specific blade profile capable of offering self-start capabilities to the wind turbine without extra components [14], [15].…”