Thermal impact of the orientation and height of vertical greenery on pedestrians in a tropical area

At the beginning of the 21st century, increasing amount of greenery in urban areas has been a priority for many urban planners following a social and environmental demand of the population. Many sustainability benefits can be attributed to urban green infrastructures. In this study we focus on analyzing the impact of vertical green systems (VGSs) on outdoor climate variables and thermal comfort by means of modelling techniques (ENVI-met v.4.3). The study is carried out in a courtyard surrounded by high-rise buildings in the hot and humid tropical climate of Singapore. Results show that weather conditions have a significant influence on the outdoor thermal performance of VGSs. Thermal comfort perception can be reduced by one category (e.g. from hot to warm) close to the façade depending on the geographic orientation of the VGS. Finally, this study shows that thermal benefits for pedestrians are provided mainly by the lowest meters of the VGS. Green elements above 6 meters in the facade reduce significantly the impact at pedestrian level. Results provide an insight to the implementation and dimensions of VGSs as urban infrastructure to improve the outdoor thermal environment, particularly in the tropical urban environment.