The impact of building façade materials toward outdoor thermal comfort and urban heat island: A case study for ENVI-met building environment simulation

Abstract The built environment contributes 40% of energy demand and 37% of CO2 emissions globally. Its planning and management are vital for achieving SDGs. Rising urban temperature, driven by urbanization and population growth, worsens the urban heat island effect and reduces urban thermal comfort. Evaluating the urban environment is crucial to create thermally comfortable spaces that can also lower the energy use. Currently most urban building facades are mainly composed of materials that easily absorb solar radiation and later release the accumulated energy in the form of heat, further deteriorating the urban thermal comfort. This study aims to simulate the impact of building façade materials to the urban air temperature (AT) and the physiological equivalent temperature (PET). Materials that could potentially decrease the urban temperature can be identified. To build a detailed simulation model and collect meteorological data as the simulation input, this study utilized drone and temperature sensors. The 3D model created from the drone survey is imported to ENVI-met software for simulation. The measured temperature of the urban environment by sensor is used as the simulation input and simulation validation. Four scenarios assuming specific building façade materials (concrete, wood, glass and steel) were applied for simulation. Among the selected materials in the simulation glass has the lowest maximum AT (34.54°C) followed by concrete (34.59°C), steel (34.62°C) and wood (34.63°C). This might be caused by the albedo and thermal characteristics of the selected materials. Expanding this research to cover a greater variety of materials and climate conditions could inform the future urban and city planning aimed at mitigating extreme microclimates such as the UHI effect.