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The relationship between urban geometry and microclimate is a relevant topic for both urban planning and urban climatology, as it significantly influences the thermal comfort of individuals. Urban geometry, shaped by building typology, has opposite effects for different seasons, satisfying a demand for compactness in summer, to secure protection from the sun, and openness in winter, to provide solar access.

The study presents a long term numerical analysis of the effect of height/width proportions on the thermal comfort of courtyard typology in Italy throughout the year. According to a detailed version of Koppen-Geiger classification, 6 Italian cities were selected as representative for each climate, excluding Alpine climates: Aosta, Milano, Campobasso, Firenze, Lecce, Catania. The assessment of thermal comfort is based on the Physiologically Equivalent Temperature (PET), calculated using the RayMan model. The input for the model are 30 years data on air temperature, vapour pressure, air velocity and cloud cover, with 3-h resolution, obtained from the meteorological station of each city.

The results of daily median analysis over the year and seasonal frequency analysis indicate that high height/width proportions appear to have a stabilizing effect over thermal comfort. This effect is favourable for both winter and summer season; being more conspicuous in summer than in winter, it benefits more the courtyards located in warm climates. (C) 2016 Elsevier Ltd. All rights reserved.