Solar energy utilization in water production from humid air

Water recovery from atmospheric air is introduced as a beneficial solution for providing remote regions with fresh water. This system depends on extraction of water vapor from atmospheric air by using desiccant material. The desiccant material (calcium chloride solution) absorbs water from humid air during night time then, it evaporates the absorbed water during the day time by solar energy. The evaporated water condensates on the solar collector sides and the condensed water droplets are collected. A mathematical model for the regeneration process is introduced for theoretical study. The new model presents 15% improvement in theoretical results compared with other published models. This work aims to evaluate the effect of different operation conditions (initial desiccant concentration, initial mass of solution and host materials) on the system performance characteristics (system efficiencies, evaporation rate and water productivity). Moreover, the simulation model investigates the system performance for different Egyptian weather conditions (spring and summer). The total produced water, which could be obtained in spring, is about 3.02 l/(day·m2) in Alexandria.