In order to find locations that maximise exposure to prevailing wind directions, while gaining improvements in performance caused by proximity to the building, the wind field around the building was modelled. This assessment aids the designer to select wind turbine technology that is appropriate and aesthetically suitable for the building whilst optimising their placement for maximum power generation.

The CFD model of the 100m tall building and the urban area in the immediate vicinity consisted of an area with dimensions of approximately 2.9km x 2.9km. A mesh of approximately 1.6 million volumetric cells was used. A realistic k-ε RANS turbulence model was applied with appropriate atmospheric boundary conditions. 

Model wind speeds and directions were picked based on annual average prevailing winds located at nearby meteorological stations. In order to determine the sensitivity of building locations to win speed and direction, numerous wind directions were modelled at representative wind speeds.

Horizontal-Axis Wind Turbine (HAWT)

The performance of a single HAWT was accessed. Using a commercial 20kW HAWT with two mast options of 13m and 20m (shown right with surface pressure contours) it was found that the 13m option outperformed the 20m option. Furthermore, it experienced 3% less turbulence as detailed below.

Vertical-Axis Wind Turbine (HAWT)

Another option for wind power generation is the siting of multiple VAWTs closer to the building to take advantage of the local speed-up of the wind caused as it moves around the building. VAWTs are less affected by turbulence and are omni-directional.

Modelling indicated that some locations on the building would be shielded. As seen in the table below, modelling a number of wind directions provides siting for these turbines to avoid shielding as well as allowing mast heights to be specified to achieve desired performance. In this example, placing a VAWT at the NE corner would produce no power during frequent southerly winds.