Adaptive PCM-Enhanced Windcatcher (APEW): Integrating phase change materials with a literature-based windcatcher geometry for passive cooling in hot-arid climates

Windcatchers are established passive cooling systems in hot-arid regions; however, their ability to stabilize supply air temperatures under extreme summer conditions remains limited due to insufficient thermal buffering and incomplete nocturnal recovery. This study enhances their thermal responsiveness by integrating dual-layer encapsulated phase change materials (PCMs) into a multidirectional windcatcher based on previously validated design parameters from the literature, termed the Adaptive PCM-Enhanced Windcatcher (APEW). The novelty lies in airflow-coupled PCM placement with staggered melting points, embedded both within the windcatcher walls and directly inside the airstream, enabling convective discharge enhancement under limited diurnal temperature variation. A transient simulation framework was developed in DesignBuilder/EnergyPlus, employing the Conduction Finite Difference algorithm to model PCM phase-change behavior under peak summer conditions in Riyadh, Saudi Arabia. Two configurations were evaluated: (i) dual PCM layers within the wall assembly and (ii) a hybrid system combining wall-integrated PCM with airflow-interactive encapsulated PCM tubes. Results demonstrate a peak indoor air temperature reduction of up to 8.7 °C relative to the baseline case. The hybrid configuration achieved 21.7% cooling energy savings during peak summer operation and exhibited improved nocturnal discharge completeness, enabling sustained seasonal performance despite elevated nighttime temperatures. The APEW system presents a water-independent passive cooling strategy that strengthens latent heat utilization, enhances cyclic stability of PCM systems in desert climates, and reduces mechanical cooling, effectively demonstrating the potential of combining windcatcher ventilation with PCM-based thermal storage for passive cooling in hot-arid climates.