Mitigating urban heat island effect: Optimization metrics for road pavement based on entransy dissipation

Mitigating urban heat island (UHI) effect caused by high temperature of urban road, optimizing heat transfer design is essential for urban sustainability. Current design methods rely on experimental designs, which often depend on single metrics such as temperature and heat dissipation, neglecting their varying impacts on heat transfer performance. In this study, through the application of topology optimization technology, the pavements were optimized by temperature and heat dissipation, respectively. Based on the entransy dissipation theory, the variations in convection, surface radiation and heat conduction performance of optimized pavements were analyzed. The relationship between entransy dissipation, temperature and heat dissipation was discussed, and the optimization metrics of entransy dissipation were determined. The results indicated that pavement structure differed when temperature and heat dissipation were used as metrics. The heat conduction entransy dissipation of the upper layer (G_condup) of the pavement designed with temperature decreased, while the heat conduction entransy dissipation of the middle layer (G_condmid) and lower layer (G_condlow) increased. Conversely, the pavement designed with heat dissipation exhibited the opposite trend. A strong correlation was found between the temperature, heat dissipation and the entransy dissipation, with surface radiation entransy dissipation (G_radia) and G_condup having the most significant influence. Consequently, these were selected as the design metrics. The optimized pavement designed with entransy dissipation exhibited good cooling and heat dissipation performance.