Effect of the Shadings Pattern and Greenery Strategies on the Outdoor Thermal Comfort
Résumé
Abstract—The outdoor thermal comfort is influenced by the perception and satisfaction of the pedestrians, especially in hot and arid climates. Accordingly, the researchers look for the appropriate methods to reduce the Urban Heat Island and thus to enhance the outdoor thermal comfort level of pedestrians. However, there is limited research conducted on the outdoor thermal comfort in hot and arid climate. This work is an investigation study conducted in an urban area (Haifa Street) in Baghdad city, characterized by an arid climate with very high temperatures in summer season reaching 50℃. This study focuses on investigating possible mitigation strategies to ensure how we could improve the thermal comfort at pedestrian level for an urban area with intricate Western design (high–rise buildings, a large spacing between the buildings, asymmetrical canyon geometry, and lack of vegetation). We created four different scenarios to assess the role of vegetation elements such as trees, grass, and different shading patterns. The evaluation was performed in the hottest day in summer. For each scenario, the mean radiant temperature, specific humidity, air temperature, and wind speed distributions have been analyzed using ENVI-met software. Thermal comfort is assessed using the PET thermal index (Physiological Equivalent Temperature) and Predicted Mean Vote (PMV). The results reveal that the PET index can be reduced to 10.4 ℃, the temperature can be decreased of about 2.4℃ and PMV to 3. The study shows how the urban factors such as the aspect ratio, vegetation cover, shadings, and geometry of the canyon are crucial elements that urban planners and municipalities have to take into account, especially for new urban developments.