Urban geometry and electrical energy consumption in a tropical city

Urban climate and its heat islands phenomena are comprehensively studied nowadays. Yet, many topics on this subject remain important issues to be examined. Urban climate has a high variability and it is generally warmer and less windy than rural climate. The former depends on many characteristics such as topography, regional wind speed, urban morphology and many other factors. Considering the urban canopy layer, i.e, the air contained within urban street canyon, its radiation budget depends on thermal characteristics of the materials and of the geometry of the surroundings. Buildings trap energy reducing the urban long wave heat loss and generating the urban heat island. Among the main aspects causing the urban heat island are the physical characteristics and the spatial relationships of urban features. They have a direct influence on the thermal performance of buildings. The less a surface has visibility to the sky, the slower its cooling ability. Therefore, a thermal parameter called sky view factor (SVF) is one of the main heat island causes. Heat islands present their highest intensity in specific times of the day and they might have significant influence on cities’ energy consumption, however, there are only relatively few works dealing with their relationship. As shown by Santamouris et al. (2001) and Williamson and Erell (2001), there is not only a reduction on heating energy consumption, but also an increase on cooling load of buildings related to the spatial distribution of the urban heat island. Hence, this thermal phenomenon cannot be neglected on thermal analyses of cities. Taking into account those relevant points of the urban thermal environment, a research project named CEU (which in Portuguese stands for “Consumo de Energia Urbano”, or Urban Energy Consumption) is being undertaken at the State University of São Paulo in Bauru, Brazil. The CEU Project studies the relevance of urban geometry on the electrical energy consumption of medium sized cities, seeking the identification of patterns of urban energy consumption for urban planning purposes.