2 Urban wind energy potential: Impact of building arrangement and height

2

Urban wind energy potential: Impact of building arrangement and height

This chapter is submitted to a peer-reviewed scientific journal:

CFD assessment of wind energy potential for generic high-rise buildings in close proximity: Impact of building arrangement and height

Juan, Y.H., Rezaeiha, A., Montazeri, H., Blocken, B., Wen, C.Y., Yang, A.S.

Abstract: High-rise building complexes are of great importance for enabling sustainable urban development in large parts of the world. Earlier studies have indicated that high wind speed regions can be present along the passage between two high-rise buildings as well as above the roofs. At such locations, urban wind energy could be harvested by installing wind turbines between and/or above the roof of the buildings. However, the available wind energy potential around an array of generic high-rise buildings in close proximity has not yet been assessed for different building configurations. This paper conducts a detailed evaluation of the impacts of the building arrangement and height for a 2×2 array with a building height-to-street width ratio of 30 on the mean wind velocity and the wind energy potential along the passages between both upstream and downstream buildings as well as on their roofs. The following parameters are analyzed: (i) the passage width between the two upstream buildings (w), (ii) the streamwise distance between the upstream and downstream buildings (d), and (iii) the height difference between the upstream and downstream buildings (ΔH). The 3D steady Reynolds-averaged Navier-Stokes (RANS) equations are solved using the Reynolds stress model (RSM) turbulence model for closure. The CFD results are validated using wind-tunnel measurements of mean wind speed and turbulence intensity performed for the same building array. The results show elevated wind power density along the upstream passages for small w (= 0.15B), high d (= 0.6B), and equal building height (ΔH = 0). In contrast, comparatively high values of w, small d, and ΔH < 0 yield high wind power densities between the downstream buildings. Among the different wind turbine types considered, horizontally-mounted vertical axis wind turbines seem the most promising option for wind energy harvesting between the buildings.

Keywords: Urban wind energy; wind resource assessment; urban planning; urban physics; urban morphology; building arrangement