Urban Climate and Building Energy Performance in Compact Cities in Mediterranean Climate

Cities in the Mediterranean basin are characterised by compact and dense urban fabric, leading to a strong night-time urban heat island (UHI) intensity which increases thermal discomfort and building energy use in summer. This chapter reviews several experimental and numerical studies investigating the UHI intensity in representative Mediterranean cities, discussing the limitations and suitability of different approaches based on the purpose of the analysis (i.e. outdoor thermal comfort or building energy efficiency). Some recurrent urban climate characteristics are highlighted, such as the importance of urban morphology and sea breeze, the range of the daytime and night-time UHI intensity and its seasonal variability. Case studies of Rome and Barcelona are used to present modelling approaches to integrate urban climate in building energy performance. The complexity of the urban climate modifications in this context and their net energy impact on buildings are discussed considering UHI intensity, mutual shading between buildings, urban surface temperatures and wind speed in urban canyons. The last section is dedicated to urban and building design strategies for heat management in Mediterranean cities, including effective UHI mitigation measures and flexible passive cooling design strategies for buildings.