Cost Optimization of a Solar Humidification-Dehumidification Desalination System Augmented by Thermal Energy Storage

Solar-powered water desalination is one of the promising approaches for addressing fresh water scarcity in the Middle-East, North Africa, and areas of similar climate around the world. Humidification-dehumidification (HDH) is a scalable, commercially-viable technology that primarily utilizes thermal energy in order to extract fresh water from a high salinity water source. Because of inherent variability and uncertainty in solar energy availability due to daily and seasonal cycles, solar-powered HDH desalination systems may benefit from installing thermal energy storage (TES). TES can allow higher utilization of the installed system components and thus reduce the overall lifecycle cost of fresh water production. This work presents a configuration for a HDH desalination system augmented by TES. The system is optimized using Genetic Algorithms (GA) for minimum total annual cost (TAC) per unit volume of produced potable water while satisfying a preset potable water demand. The optimum results for the same location and cost function are compared with results from a previous system which does not have TES. The comparison shows a considerable reduction in potable water production cost when TES is utilized in addition to the benefit of smaller variation in water production across the day.