Reduction of the Wind Resistance Exerted on the Convex Side of the Wind Cup in the Anemometer-Type Vertical Axis Wind Turbine

Abstract

Windmills are reliable source of renewable energy across the globe. Windmills or wind turbines are of two types, one is of the vertical axis and the other is of the horizontal axis. The design of a vertical-axis wind turbine (VAWT) is simpler than that of a horizontal-axis wind turbine (HAWT), making it cost-effective. HAWTs usually are much larger while VAWTs can be made as small as an anemometer, therefore these can be operated in low-speed winds. Instead of erecting a few big HAWTs in large fields, several relatively small VAWTs can be installed on buildings, TV towers, and streetlight poles, to generate power at a low scale. The best thing about VAWTs is, that these are all-weather machines; VAWTs run no matter which direction the wind is blowing. Despite many advantages, VAWTs are used less than HAWTs due to one major technical problem, air resistance. As the turbine rotates the concave side of the cup experiences a force on it and gets pushed and the system rotates. But the other cup which is also pivoted to the same axis moves in opposite directions. Although, this cup faces the wind on the convex side, still outstays the resistance of the wind. This resistance causes the turbine to slow down and the overall efficiency gets dropped. The experiments conducted in this research are aimed at increasing the efficiency of the same by reducing the wind resistance on the convex side of the wind cup. Simple one-way valves are used for lowering the resistance. A number of these valves are installed on wind cups which reduce the resistance to a significant level and increase the efficiency. This research demonstrates the potential of a one-way valve system as a cost-effective modification to optimize the performance of the anemometer-type VAWTs, contributing to the development of more efficient renewable energy  solutions.