Investigation of the efficiency of VAWTs at different wind speeds

Abstract

This paper presents results from an experimental and numerical study of different lift-based and drag-based vertical axis wind turbines (VAWTs). One of the main disadvantages of vertical axis wind turbines is the low efficiency and inability to self-starting at low wind speeds. The task of the study is to determine an efficient geometry of the turbine runner, which can generate higher power at the lowest wind speeds. A comparison has been made of the cut-in speed, rated speed, efficiency, and the self-starting capabilities. This work proposes an aerodynamic scheme for wind turbine runners, which can operate relatively more efficiently at low and variable winds. The presented results favour the selection of a wind turbine for operation in conditions of weak and variable wind. The experiments were conducted in the Laboratory of Hydro Power and Hydraulic Turbomachinery (HEHT Lab) at the Technical University of Sofia.