Efficient, simple, and cost-effective approaches to mitigate shortages of freshwater are much needed today. Humidification and dehumidification (HDH) desalination systems are particularly well suited for small and distributed installations that can treat high salinity waters which are often found deep underground or associated with produced water. HDH systems however can be relatively inefficient when equipped with conventional heat exchangers. The installation of a direct contact packed bed in a HDH system is simple and can improve its performance significantly. Recent studies in HDH systems have been performed on counterflow direct contact condensers within a packed bed. The goal of this work is to perform a detailed study of crossflow direct contact condensers within a packed bed. Crossflow configuration is simple to install in larger units, the liquid supply and exhaust approach is also less complicated compared to counterflow systems. A two-dimensional mathematical model has thus been developed to estimate the performance of the system. The model is based on the balance of mass and energy. The resulting differential equations are solved numerically to predict the temperature of the water, air, and packed bed. Optimization was done using a genetic algorithm to find an optimized dimension of the packed bed domain to achieve the highest water production for a given volume A lab scale experimental setup has been built up to validate all results. In addition, the impact of geometry changes in the packed bed shape and flow directions were studied. A two-dimensional mathematical model was adopted to model condensers with new geometries. Computational results show that a wedge-shaped crossflow direct contact condenser can be 10-12 percent more effective than a regular rectangle cuboid-shaped packed bed condenser, square-shaped crossflow condenser. In addition, a compact cylindrical design of a crossflow HDH system configuration has been proposed, modeled, and its performance is presented.
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