Citation:
Abstract:
Compact cities increase their temperature under the effects of heat island and global climate change. Important literature addressed passive energy cooling and solar urban planning. However, to date little is known about the relevant planning variables for getting insolation and natural ventilation. Failures in planning have caused important overuse of air conditioning and, in lower income areas, high temperatures put serious risk on their population. This paper addresses this important topic grounded on the Barcelona’s urbanization theory of Cerdà (1860); who already based his planning under both, insolation and wind flow of the urban fabric. In this research we concentrate to analyse the consistency in his pattern of orienting the urban grid for getting better insolation and wind-flow. Methodologically, to study the urban grid orientation consistency with winds and solar radiation, LiDAR (Light Detection and Ranging) technology and wind data are used to obtain digital elevation surface and to calculate insolation and wind flow in the streets in the summer solstice (21st of June) and the winter solstice (21st of December). The results were contrasted by rotating the street grid 90 degrees north. We expect to confirm the following hypothesis. Firstly, streets are differently insolated depending on street grid orientation. Secondly, the height of the buildings project patterns of shadows in streets subject to the grid orientation. Thirdly, the direction of wind flow would enter differently to the city, depending on orientation of the urban solid. Finally, insolation and natural ventilation influence population comfort, health and decrease energy consumption creating a more sustainable urban environment, and improving quality of life.
Key words: Insolation, natural ventilation, Cerdà, Barcelona, compact city, LiDAR.