ASSESSMENT OF A SUITABLE SITE IN A HILLY TERRAIN FOR WIND POWER GENERATION

Abstract

The energy in the wind together with its effect on a building in a region have been an area of active investigation and research for the purpose of harnessing the power in the wind and providing safety to the buildings from the damage caused by wind induced disasters. The wind speed over a region is dominated mostly by the terrain and topographic features. The presence of hills and escarpments causes acceleration and speeds up the wind velocity near their crests, causing an increase in the estimated wind energy potential. Similarly, the flow in a hilly terrain induces a different pressure distribution pattern around buildings and structures situated there as compared to those situated in a flat terrain. The present work reports an experimental study made for determining velocity speed ups, topography factors, and carrying out measurements of pressure coefficients on various zones of a gable roof building model of a roof slope of 25°, over different locations of the terrain and thus computing changes in estimated wind energy potential and comparing the various topographic factors (k3) and pressure coefficients thus obtained with the existing standards/codes. The experiments have been performed on a hilly terrain model of a scale of 1:500 with a low rise building model of a scale of 1:100 placed over different locations on the hilly terrain model. The approaching terrain to the hill has been considered as an "exposed open terrain with few or no obstructions and in which the average height of any object surrounding the structure the structure is less than 1.5m" defined as terrain category 1 by the Indian Standard Code (IS: 875, part — 3, 1987). The change in the estimated wind energy potential has been computed for different locations. Comparison of design pressure coefficients is made with existing Indian Standard Code (IS: 875, part — 3, 1987) and comparison of topographic factors is made with various wind codes. From the experimental study it has been found that the estimated wind energy potential increases at locations above the upper half of the hill, and the design pressure coefficients in most of the locations are found to be higher than those found for flat terrains and those given in codes.