Wind tunnel and numerical study of multi-storey vertical axis wind turbines with different configurations
Authors: Malge Abhijeet M. , Pawar Prashant Maruti 
Published: March 2021

Purpose
Three different configurations of vertical axis wind turbines (VAWT) were fabricated by changing the storey height and their orientations. The purpose of this study is to find the effect of storey height and orientation on the performance of wind turbines. The multistory VAWT has three storeys. The first configuration had increased middle storey height, with 0–90-0 orientation of blades. Wherein the second turbine had equal storey heights. The third configuration had increased middle storey height with 0–120-240 orientation of blades. The blades were tested numerically and experimentally.

Design/methodology/approach
In this research work, prototypes of innovative multistory VAWT were built with different configurations and orientations. Three configurations of three-storey VAWT were fabricated by varying the height of storey of turbines. The orientations were made by keeping the storeys orthogonal to each other. Multistory VAWT was tested numerically and experimentally. ANSYS Fluent was used for computational fluid dynamic analysis of VAWT. K-epsilon model was used for numerical analysis of wind turbine. Experimentation was carried out in a wind tunnel for different tip speed ratios (TSR).

Findings
The three configurations of innovative multistory VAWT were tested numerically and experimentally for different TSR. It has been found that the VAWT with equal storey height had a better performance as compared to the other two configurations with increased middle storey height. The power coefficient of equal storey height VAWT was about 22%, wherein the power coefficient of turbines with reduced upper and lower storey height was between 5%–8%.

Research limitations/implications
The research work of multi-storey VAWT is very novel and original. The findings of the research will contribute to the existing work done in the field of VAWT. This will help other researchers to have insight into the development of multistory VAWT. The effect of storey height and configuration of multi-storey VAWT is studied numerically and experimentally, which concludes that the performance of equal storey is superior as compared to other configurations.

Practical implications
The multi-storey concept of VAWT was developed to counter the problem of wind direction. The blades of each storey were arranged orthogonal to each other. This helped to harness wind power irrespective of the direction of the wind. This will make the VAWT more sustainable and financially viable for domestic use.

Social implications
The turbines are specially designed for remotely located housed in rural areas where the power grid is not yet reached. Users can install the turbine on their rooftop and harness wind power of 100 W capacity. This will help them to make their life easy.

Originality/value
This research work is very original and first of a kind. The multistory concept of the wind turbine was checked for the effect of storey height and orientations of blades on its performance. Different configurations and orientations of the vertical axis were designed and developed for the first time.