Numerical investigation of a novel phase change materials integration method in windcatchers for enhanced thermal performance in hot and dry climates

The depletion of natural resources, global warming, and the rising cost of fossil fuels are among the major challenges faced by modern societies. Buildings consume more than 40% of global energy, and ventilation, cooling, and heating account for over 60% of that consumption. This has increased interest in passive cooling approaches that can reduce both energy use and greenhouse gas emissions. One promising option is using phase change materials (PCM) for thermal storage, especially when combined with natural ventilation systems such as windcatchers, which are already widely used in many regions. In this study, a single-sided windcatcher integrated with PCM chambers was numerically investigated in ANSYS Fluent using the enthalpy method, and several chamber geometries were compared. For an inlet air condition of 35°C at 1 m s^-1, the flat PCM configuration reduced the outlet temperature by about 3°C, while cylindrical chambers initially achieved a 5 to 6°C reduction, but the cooling effect weakened rapidly with time. By adding fins to improve heat transfer, the inverted triangular finned cylindrical PCM chamber showed the best overall performance, providing a 5 to 6°C reduction while keeping the outlet temperature more stable for up to 2500 s. Compared with the flat chamber case, the inverted triangular finned design produced an outlet air temperature that was about 2°C lower under the same conditions. The results indicate that integrating 30 kg of RT21HC PCM within optimized finned chambers can noticeably improve the cooling effectiveness of windcatchers and offers a compact passive solution suitable for hot and dry climates. The findings demonstrated that integrating PCM chambers with inverted triangular fins inside a single-sided windcatcher significantly enhances its thermal performance. This configuration provided the highest and most stable reduction in outlet air temperature compared to flat, simple cylindrical, and other finned geometries, highlighting its potential as an efficient passive cooling solution for hot and dry climates.