Analytical Method for Estimating Energy Output of Small Wind Turbines Integrated in Urban Areas

Austrian Institute of Technology, Energy Department, Gieffinggasse 2, 1210 , Vienna, Austria

Abstract

This paper presents the development of the analytical approach for estimating the wind energy potential at locations around buildings in urban areas that are suitable for installing Small Wind Turbines (SWT). This development is performed in three steps. In order to analyze the flow pattern in a typical urban geometry, the first step consisted of a series of numerical simulations, where an assumed urban configuration (specified building size and respective distances between the buildings) was varied with an incremental value, and for each analyzed configuration different incoming wind conditions (different reference wind velocity) were incrementally imposed. In the second step the velocity profiles in the characteristic cutlines around the central building under investigation were extracted from the respective realizations of urban flow numerical solutions, and an analytical expression was derived approximating all extracted velocity profiles to fit the best an assumed flow pattern. The derived analytical expression was cross-plotted with the results of a fully three-dimensional realistic urban flow numerical solution, and the obtained matching level was satisfactory. Finally, using the derived expression, in the third step the estimation of SWT energy output was defined based on the average wind velocity information at given location and the related urban configuration characteristics.