Solar thermal resonant energy exchange desalination (STREED) for 24-hour, membrane-free, off-grid water treatment

Abstract Freshwater scarcity is a pressing global issue exacerbated by climate change and growing populations. Current desalination technologies all face limitations: reverse osmosis requires grid electrical power and specialized membranes, thermal desalination is inefficient, and membrane systems are prone to fouling. Here we introduce Solar Thermal Resonant Energy Exchange Desalination (STREED), a robust, membrane-free and efficient solar thermal desalination approach. Utilizing the principle of Resonant Energy Transfer, the distillation efficiency can be maximized by matching the heat fluxes between interacting air and water fluids. Dynamic tuning of the flow rates in response to varying solar intensities significantly increases efficiency, extending freshwater production over 24-hour/day. We predict week-long freshwater productivity increases of 70% with an average Specific Water Productivity (SWP) between ~3 and ~5 L/kWh, depending on available solar irradiation. STREED adapts to fluctuating solar inputs, offering a scalable solution for decentralized, off-grid water treatment, crucial for remote communities facing water scarcity.