The role of urban design in enhancing the microclimate and thermal comfort in warm-humid Dar es Salaam, Tanzania

Due to the complexity of the outdoor environment, urban design patterns considerably affect the microclimateand outdoor thermal comfort in a given urban morphology. Parameters such as building height and orientation,spaces between buildings, plot coverage, etc influence the microclimate in terms of solar access, shade, windspeed and direction. In warm-humid Dar es Salaam, the consideration of microclimate and outdoor thermalcomfort in urban design has received little attention although the urban planning authorities try to develop thequality of planning and design. The main aim of this study is to investigate the relationship between urban design,urban microclimate and outdoor comfort in four different areas in the city of Dar es Salaam, during the wet anddry seasons. This investigation is mainly based on microclimate simulations using ENVI-met and differentexisting urban morphologies are climatically and thermally studied including low, medium and high rise buildings.Parameters such as Mean Radiant Temperature (MRT), wind speed and Physiological Equivalent Temperatureindex (PET) are presented as thermal maps to highlight the strengths and weaknesses of the existing urbandesign in the city. The study illustrates that the areas with low-rise buildings lead to higher MRT values than the areas with high-rise buildings. The results also show that the use of dense trees helps to enhance the thermal conditions, but it might negatively affect the wind ventilation in the outdoor spaces. This study provides a set of guidelines on how to develop the existing situation from microclimate and thermal comfort perspectives. Such guidelines will help architects and urban designers to increase the quality of outdoor environment and demonstrate the need to create better urban spaces in harmony with microclimate and thermal comfort