Simulating Wind Power Density around Buildings for Siting

A recent development in wind energy is to site small wind turbines on or near buildings. This approach has the advantages of generating power at the point of use, integrating energy generation with other land uses, and harvesting accelerated wind power enhanced by building geometry. Some of the initial studies, however, did not attempt to optimize the location of the turbine on the building and the power production results were disappointing.

This purpose of this study is to simulate the potential wind power density around buildings using high fidelity computational fluid dynamics (CFD). Our approach is to model flow around buildings using very fine scale meshing techniques and apply a Detached Eddy Simulation model, which blends Reynolds Averaged Navier Stokes (RANS) modeling in the surface layer where the mesh is the finest as well as in the far field with Large Eddy Simulation (LES) in the separated regions detached from the building and in its wake. By employing this DES technique with a highly refined grid around a building and varying the wind direction, we are able to produce maps of power density in the vicinity of the building.

This modeling approach is first applied to a cubical geometry for which we can validate the CFD results with field measurements. We additionally model a slant roofed building to study the power density around typical residential buildings. Finally, we study the power density in a DES simulation of an urban environment to determine the impact of upstream buildings on the power density of those buildings in its wake.

We find that the most convenient locations for wind turbines on buildings do not correspond with the locations with the maximum power densities. Thus, studies such as this one have the potential to inform the energy production community on best practices for siting building integrated wind turbines, as well as guiding the way toward designing buildings to directly integrate wind turbines in their design. The authors are currently working with architects and engineers to address these issues.