Roof mounting site analysis for micro-wind turbines

Building-integrated micro-wind turbines are promising low-cost renewable energy devices. However, the take-up of micro-wind turbines in high density suburban environments is still very limited due to issues such as: a) low wind speeds; b) high turbulence intensity; and c) the perception of potentially high levels of aerodynamic noise generated by the turbines. The wind flow field above the roof of buildings in this environment is different to that over flat terrain or around isolated buildings. The effect of the local suburban topology on the wind speed and turbulence intensity fields in a given locality is therefore an important determinant of the optimal location of micro-wind turbines. This paper presents a numerical study of above roof wind flow characteristics in three suburban landscapes characterized by houses with different roof profiles, namely: pitched roofs, pyramidal roofs and flat roofs. Computational Fluid Dynamic (CFD) technique has been used to simulate the wind flow in such environments and to find the optimum turbine mounting locations. Results show how the wind flow characteristics are strongly dependent on the profile of the roofs. It is found that turbines mounted on flat roofs are likely to yield higher and more consistent power for the same turbine hub elevation than the other roof profiles.