Atmospheric water harvesting: emerging technologies to collect freshwater from air

Collecting freshwater from atmospheric moisture

 

A recent review paper ^[1] published in Applied Thermal Engineering by an international team of researchers from BRAC University, Bangladesh, and Swinburne University of Technology, Australia, examines the potential of atmospheric water harvesting (AWH) technologies to produce freshwater directly from moisture present in the air.

 

Conventional water production technologies include desalination, which removes salts from seawater, wastewater recycling, which treats used water for reuse, and rainwater harvesting. Although effective in many contexts, these approaches can be constrained by infrastructure requirements, energy consumption, environmental impacts, dependence on rainfall or geographical limitations. AWH offers a complementary, decentralised solution that does not rely directly on surface or groundwater resources, making it particularly attractive for remote, off-grid and disaster-prone regions.

 

The review identifies four main approaches to atmospheric water harvesting:

 

• Condensation-based systems, which use vapour-compression refrigeration or thermoelectric cooling to lower air temperature below its dew point, allowing water vapour to condense and be collected. These systems are particularly effective in humid climates but can require substantial energy input.
• Sorption-based systems, which use hygroscopic materials, such as desiccants or metal-organic frameworks (MOFs), to capture atmospheric moisture and subsequently release it through heating. They can operate under relatively low-humidity conditions, although thermal energy is required for regeneration.
• Radiative cooling systems, which exploit heat loss to the night sky to cool down surfaces and promote dew formation without electricity consumption, but generally provide limited water yields and depend strongly on weather conditions.
• Hybrid systems, which combine different harvesting mechanisms to improve efficiency and adaptability across varying climatic conditions, at the expense of greater system complexity and cost.

Recent advances and future perspectives

 

The review highlights how innovative sorbent materials, improved cooling technologies and renewable energy integration are expanding the potential applications of AWH. In particular, advances MOFs can capture moisture at relative humidity levels as low as 10-20%, while solar-powered systems offer opportunities for autonomous operation. The authors also examine recent experimental developments, including a solar-powered thermoelectric water harvesting system that demonstrated water production under real climatic conditions and met basic microbial safety requirements.

 

Despite these advances, energy consumption, equipment costs, variable water yields and the need for reliable water quality control remain important barriers to widespread deployment. The authors identify hybrid system development, improved materials, waste heat utilisation and the integration of machine learning and smart control systems as promising directions for improving performance and reducing costs.

 

Overall, the review suggests that atmospheric water harvesting could become an increasingly valuable complementary technology for decentralised freshwater production, particularly where conventional water supplies are limited or unreliable. As highlighted in the 60th IIR Technical Brief “The role of Refrigeration in the Global Economy, 3rd Edition” ^[2], refrigeration-based innovations such as AWH can contribute to the objectives of United Nations Sustainable Development Goal 6 (SDG 6) ^[3], which aims to ensure access to clean water and sanitation for all. Further technological development and real-world validation will be essential to improve the economic viability of these solutions and support their broader deployment.

 

For more information, the scientific paper is available in open access in Applied Thermal Engineering.

 

 

Sources:

[1] Saha, G., Imran, M. T., Shams, S. M., Khan, M. F. A., Azad, A. K. M. A. M., Imteaz, M. A. (2026). From air to water: science, technology, and future of atmospheric water harvesting (AWH). Applied Thermal Engineering 302 (2026) 132073. https://doi.org/10.1016/j.applthermaleng.2026.132073

[2] IIR (2025). The role of refrigeration in global economy. 3rd edition. 60th Technical Brief on Refrigeration Technologies. International Institute of Refrigeration (IIR), Paris. http://dx.doi.org/10.18462/iir.TechBrief.04.2025

[3] United Nations. Goal 6: Clean water and sanitation. https://jointsdgfund.org/sustainable-development-goals/goal-6-clean-water-and-sanitation