Rooftop wind turbine airflow dynamics

Many building owners, from individuals with single family homes to corporations that manage skyscrapers, are looking at ways to increase their energy efficiency. This could mean cutting down on the energy used by the building, but it could also mean integrating renewable energy generation into the building to offset some of that energy usage.

Hu et al. employed wind tunnel tests to evaluate the dynamics of vertical-axis wind turbines (VAWTs) mounted on building rooftops.

While VAWTs are uncommon in large-scale wind projects, they are perfect for perching atop buildings. Their design has no directionality, making them more efficient under constantly changing wind conditions. In addition, the ability to locate their mechanical parts at the base of the turbine lowers maintenance costs.

While putting VAWTs on roofs makes theoretical sense, there is little guidance on how to install these turbines for the best effect.

“There is relatively limited research on the wake characteristics of typical VAWTs on flat roofs and optimizing the installation locations and initial capacities for distributed power generation,” said author Xiangjun Wang.

To address this, the authors used their wind tunnel data to determine the effect of the turbines on wind speeds and turbulence intensities, the impact of different installation locations and wind directions on the flow field, and the probability distribution of the wake as a result of installing rooftop turbines.

“The findings of this study will provide valuable insights for the optimal placement of VAWTs, wind resource assessment, and utilization of wind energy on rooftops,” said Wang.

Source: “Experimental study on rooftop flow field of building based on the operation of vertical-axis wind turbines,” by Jiafeng Hu, Xiangjun Wang, Hua Yang, and Bin Huang, Journal of Renewable and Sustainable Energy (2024). The article can be accessed at https://doi.org/10.1063/5.0205549 .