In Thailand, the average wind speed is relatively low, approximately with 2-3 m/s at height of 20 m;therefore, Vertical Axis Wind Turbines (VAWTs) are chosen to be installed because those wind turbines are designed to yield just acceptable performances on mechanical works at not high wind speeds.However, standalone VAWTs are not sufficient for the most effective wind power conversion, so it isnecessary to invent a wind booster that can improve performances of VAWTs in order to overcome the limitation of harvesting energy with low availability at low wind speeds.
There are a few relevant researches in attempting to improve performances of VAWTs at low speed
conditions. Takao, M., et al [1] developed an air flow controlling device called a “directed guide vanerow”. This straight-bladed mechanism is inherently constrained due to the design; it can capture a wind stream only in a single direction of a VAWT. Chong, W.T., et al [2] developed omnidirectional guide vanes, which can greatly increase power output of a VAWT. Also, Pope, K.,et al introduced numerical analysis to determine operating angles of stator vanes for a VAWT.Although those devices can capture wind in all directions, proper arrangements of guide vanes are not concerned for best practice in those studies. Additionally, Ohya, Y. and Karasudani, T.developed a shrouded horizontal axis wind turbine system called “Wind-lens turbine”. It can be learnt that wind can be speeded up by a shaped passage even though the design is not applicable to VAWTs.In this study, a wind booster is developed in order to improve angular speed of the VAWT which leads to increase in mechanical power generated from the VAWT. By using specially-designed guide vanes, the wind booster can control flow direction and accelerate wind from any directions in order to yield effective impacts to VAWT blades.