The function of the wind turbine is to extract energy from the wind. The wind is flowing air, which has speed and therefore kinetic energy. When the wind flows through the wind turbine blades, part of the kinetic energy is transferred to the wind turbine to make it rotate. The wind turbine gains energy, and the wind loses energy, so the wind speed after flowing through the wind turbine will slow down. This article explains the calculation methods of wind energy and wind turbine power and efficiency, and provides a video to make it easier to understand.
This article introduces the efficiency comparison of various wind turbines, including common vertical axis wind turbines(Savonius and Darrieus) and typical three-blade horizontal axis wind turbines. Among them, the Savonius turbine is a drag type wind turbines, and the Darrieus wind turbine and the three-blade horizontal axis wind turbine are both lift-type. The efficiency comparison chart of various wind turbines and related videos are shown below. If you want to understand what the Savonius and the Darrieus wind turbines are, please refer to => Basic principles and types of Vertical Axis Wind Turbines.
According to the literature, the Darrieus vertical axis wind turbine characterized by high efficiency but it is difficult to be self-starting. I couldn’t understand when I first came into contact with it. Since high efficiency means that it has torque, why can’t it start by itself? Later I realized that its efficiency must appear at a higher speed (similar to the high gear of a car), As for how high the speed should be? Usually 2~6 times faster than wind speed. This puzzles me even more, because the wind turbine is driven by the wind, why can it revolve faster than the wind speed? It seems that an experiment must be done, seeing is believing …
Due to the need for environmental protection and the fight against global warming, the development of renewable energy is urgent. In addition to solar energy, wind energy has attracted the most attention. In order to use wind energy, mankind has invented Wind Turbine for centuries. The wind turbine can convert wind energy into the rotating mechanical energy, and the torque generated by its main shaft can be used to drive a load, such as a generator or a water pump, for power generation or irrigation. According to the direction of the rotation axis, wind turbines can be divided into two types: horizontal axis and vertical axis.