The impact of neighbourhood geometries on outdoor thermal comfort and energy consumption from urban dwellings: a case study of the Riyadh city, the kingdom of Saudi Arabia

The thesis addresses the contributions of urban geometry under hot-arid summer condition in the Riyadh City, Saudi Arabia, toward both; the development of comfortable microclimate conditions in outdoor spaces at pedestrian level, and energy consumption from urban dwellers. The urban geometry is described in this thesis by three variables, including building height to street width aspect ratios (H/w), sky view factor (SVF) at pedestrian level, and the solar orientations of the canyons. These three variables are used in this study to investigate their influence on the microclimate conditions and the associated outdoor thermal comfort and energy consumption from urban dwellers. The work intends to shed light on the existing geometries of different urban locations in Riyadh City and the associated thermal conditions, as well as the thermal perceptions and preferences of outdoor users. Therefore, integrated empirical studies that are composed of three original surveys are carried out, including a study of land surface temperature of Riyadh City, outdoor thermal comfort survey, and in situ microclimate measurements in different urban locations at neighbourhood scale and within urban canyons. Following that, microclimate and energy modelling are carried out on a number of hypothetical urban geometries that proposed according to the current buildings and planning regulations in the Riyadh City, i.e. building materials, opening ratios on building facades, buildings and streets layouts and minimum width of local streets. Yet, since the study measures the impact of scenarios modifications of urban geometry on the issues under investigation, thus, additional buildings heights and different setback aspect ratios have been added. The proposed hypothetical urban geometries investigated include various street aspect ratio (H/st.) equal to 0.5, 1, 1.5 and 2, and setback aspect ratio (H/sb.) equal to 0, 2, 4 and 8. The proposed urban settings that resulted from the combination of the various streets and setbacks aspect ratios are modelled on four different orientations, including EW, NS, NE-SW and NW-SE, and a total of 64 different urban geometries were evaluated