Evaluating the thermal-radiative performance of ENVI-met model for green infrastructure typologies: Experience from a subtropical climate

Microclimate knowledge has been intensively integrated into urban planning and design to improve the buildings' energy performance and outdoor thermal comfort. To assess the climatic mitigation strategies, numerical modeling is gaining higher relevance. ENVI-met, a microclimate model to simulate the complex surfacevegetation-atmosphere interactions in the built environment, is receiving increasing popularity. This study aims to systematically evaluate the thermal-radiative performance of the ENVI-met model based on its recent updates. First, a field measurement was conducted in a subtropical city. Thermal-radiative parameters were collected besides three green infrastructure (GI) typologies (i.e., green roof, green wall, ground tree) and three corresponding reference sites. Second, sensitivity tests were conducted for the inputs and settings of ENVI-met model, including new radiation module IVS (Indexed View Sphere), meteorological boundary conditions, materials settings, and output intervals. Third, the thermal-radiative performance of ENVI-met was compared among the six measurement sites, three output intervals, and nine microclimate variables, based on four evaluation metrics. The results showed that 1) recent updates of ENVI-met can improve the estimation accuracy, especially with IVS on, radiation forcing, and localized materials settings; 2) ENVI-met was capable of simulating the thermal-radiative performance of three GI typologies simultaneously; 3) mobile measurement can be used for ENVI-met validation, and 4) model evaluation results were sensitive to the metrics. Overall, this study emphasized proper validation for ENVI-met before applications, when full forcing and localized settings are essential. The strengths and limitations of ENVI-met were discussed and implications were provided for model developers and users.