Proof of Concept of the Regeneration Part in a Novel Desiccant-Based Atmospheric Water Generator

Earth atmosphere holds a vast amount of water that can be considered a reliable freshwater resource. The desiccant-based atmospheric water generator comprises a basic humidification-dehumidification (HDH) system that uses a liquid desiccant solution instead of saline water and a desiccant-based air dryer. This paper focuses on the regeneration part of the desiccant-based atmospheric water generator. An experimental study is conducted on this part, which is a desiccant (lithium bromide)-heated open-air HDH cycle with brine recirculation. The system is designed and implemented in a controlled setting to investigate the effect of various system operating parameters, including desiccant-to-air mass flowrate ratio, cooling water mass flowrate, desiccant temperature, and cooling water temperature on the system performance indices. Performance is assessed based on the system freshwater recovery ratio, gain output ratio (GOR), and freshwater productivity. This study presents an innovative method by integrating humidification-dehumidification as the regeneration process within the atmospheric water generator to showcase its practicality. Results indicate an optimum desiccant-to-air mass flowrate ratio at which maximizes the system recovery ratio, productivity, and gain output ratio (GOR). Higher desiccant-to-air mass flowrate ratio and top (heating) temperatures lead to increased freshwater production rate, GOR, and freshwater recovery ratio. Lower bottom (cooling water) temperatures and higher cooling water flowrate enhance the system's performance.