The Energy Yield of Roof Mounted Wind Turbines

Abstract

The roof is a possible site for small wind turbines. This is a new but more and more accepted idea. Several Dutch companies in close cooperation with the Section Wind Energy of Delft University of Technology are busy with the design of small roof wind turbines at the moment. The important flow features for a wind turbine on the roof however are unknown. The common wind engineering knowledge is only focussed on extreme wind speeds in order to have a safe building. So, models to calculate the flow features on the roof, important for a wind turbine, have to be developed. This paper gives a first attempt to describe the flow features and guidelines necessary for siting of small wind turbines on the roof. They concern: the desirable height above the roof, the change of the undisturbed wind to the wind speed above the roof and the probability distribution of the wind speed above the roof. With use of the guidelines three example calculations are given to assist the reader in the calculation procedure.