Passive evaporative cooling performance of building walls under typical wind-driven rain of hot-humid climates

Abstract

Passive evaporative cooling is an effective technique for reducing building energy consumption in hot-humid areas; however, the underlying hygrothermal performance of building ​walls​ under ​wind-driven rain​ remains poorly understood, hindering the practical application of this technique ​in​ climate adaptability. To address these key issues, this study employs the All-element Climate Simulation Cabin (ACSC) platform to simulate ​climatic​ conditions, investigating the impact of ​rainfall exposure​ on the daily variation in evaporative cooling on vertical building surfaces, i.e., sintered-porous-brick and white-tile. The findings reveal that white-tile walls display better thermal lag under clear conditions than sintered-porous-brick walls, whereas ​the latter​ performs better under rainy conditions. Moisture migration from wind-driven rain enhances wall evaporative cooling, particularly evident in sintered-porous-bricks, which achieve a temperature reduction of 1.45°C sustained ​for​ 48–84 h. Differences in water absorption properties between materials influence cooling duration, lasting approximately one day for white-tiles and up to three days for sintered-porous-bricks. Additionally, extending rainfall exposure from 3 to 6 h doubles the effective cooling duration. This research provides valuable insights into climate-adaptive and energy-efficient building design and establishes a reliable experimental methodology for exploring building-climate interactions.