New perspective version of Bi-Darrieus wind turbine

There are a great variety of wind turbine constructions but by their principle of operation they are divided into three main types - sail (Savonius wind power unit), propeller and airfoils (Darrie wind turbine). At present, propeller -type wind -turbines are the most widely spread. They are produced on a commercial level in many countries. Other conditions being equal, the power produced by wind power unit (WPU) is proportional to the area being swept around by a wind wheel. Therefore, Megawatt propeller -type wind turbines have blades with the length of 40 and more meters. Only aircraft works with a highly -qualified personnel and corresponding equipment can produce such long blades of a specific shape. Of high interest have become airfoil wind turbines (Darrie WPU) lately. They are of a simpler construction and have a quite high wind power utilization factor ( ξ =0.45). In spite of the fact that this is a good index of WPU efficiency, the workers of al-Farabi Kazakh National University have developed a new version of a wind turbine which allows increasing 1.3- 1.6 times the value of this coefficient. This apparatus is named a Bi -Darrie unit. This paper presents the description of a Bi - Darrie unit, the principle of its operation and the possibility of increasing the wind power utilization factor. Also, the results of testing an acting laboratory model in an aerodynamic tunnel and a full -length apparatus are reported. Video films are attached to the paper. Key words: wind turbine, the blade, wind energy utilization coefficient