Microclimate Simulation and Optimization of Traditional Dwellings in Humid Subtropical Regions of China

Traditional dwellings in humid subtropical China contain climate-adaptive spatial elements, yet their outdoor thermal-comfort performance and passive optimization potential remain insufficiently quantified. This study examined three traditional Minnan mansions in Quanzhou, Fujian Province, to evaluate how courtyards, alleyways, recessed entrance spaces, and peripheral vegetation regulate summer outdoor thermal environments. Field microclimate monitoring, UAV photogrammetry, and ENVI-met/BioMet simulations were combined, and baseline models were validated using measured air temperature and relative humidity data. Single-element scenarios were developed for ground albedo adjustment, courtyard shading, alleyway green pergolas, recessed entrance shading, increased fengshui woodland density, and optimized woodland layout, followed by multi-element combined strategies. The results indicate that shading and vegetation-related measures reduced daytime heat stress primarily by limiting solar radiation exposure, improving near-ground thermal and humidity conditions, and modifying local wind fields. Combined strategies produced more stable UTCI improvements than individual interventions, with a maximum UTCI reduction of 7.5 °C. In contrast, high-albedo paving reduced local air temperature but could worsen UTCI by increasing reflected short-wave radiation. These findings provide quantitative support for low-intervention thermal environment optimization and climate-adaptive renewal of traditional dwellings in humid–hot regions.