Influence of height ratio in groups of buildings of unequal height on micrositing of urban-SWTs

Roof-mounted small wind turbines (SWTs) in groups of buildings is an efficient method to expand urban wind energy. In order to 1) identify the value of the height ratio lambda (lambda = h/H, where h is the average surrounding building height and, H is the target building height) at which the influence of surrounding buildings on wind is minimized and 2) confirm the optimal location and installation height for roof-mounted SWTs in groups of buildings of unequal heights, we assess wind velocity and turbulence intensity above rooftops over five groups of buildings of unequal height by computational fluid dynamics (CFD). The rooves of low-rising buildings are not ideal installation locations for SWTs due to the high installation height needed to make them effective. The influence of surrounding buildings on wind behavior above the roof of the tallest building in a group of buildings of unequal height can be neglected when lambda <= 0.6. Therefore, the tallest building in the building group with lambda <= 0.6 should thus be considered an isolated building when micrositing SWT placement using CFD. This finding can be used to use CFD methods to simulate wind behaviors in urban environments.