Methods of harvesting water from air for sustainable buildings in hot and tropical climates

A rapid rise in demand for fresh and potable water every day has impacted global water resources that become an international matter of significant concern in keeping with the global population's fast growth. Although tropical countries receive abundant rainfall levels throughout the year, the lack of access and supply of clean water in many rural areas in this region considers an environmental challenge of this century. Atmospheric air represents a reservoir of clean water with an estimated quantity of 12,900 km3, while the amount of renewable fresh water on the planet is approximately 12,500 km3. Therefore, there is a need for new sustainable methods to provide a supplementary water supply for buildings. This research aims to examine passive methods and mechanisms of extracting water from ambient air that can be used in tropical buildings compared to rainwater harvesting systems. The methodology is based on a comprehensive review to explore the potential methods, challenges and opportunities for collecting atmospheric water on-site in the tropics. Analytical evaluation of approaches, mechanisms, systems' productivity and performance was conducted. The research results revealed two technical ways that would be effective to extract water from humid air, namely: regenerative solar desiccant/collector and dew water condensation systems. This study would help to shape the application of Atmospheric Water Generation (AWG) that is expected to be more cost-effective, sustainable and adaptable to tropical building applications.