Exergo-economic analysis of multi HDH system integrated with evaporative crystallizer for zero liquid discharge

This study investigates the feasibility of integrating a multi-stage humidification-dehumidification (HDH) system with an evaporative crystallizer for achieving zero liquid discharge (ZLD) in desalination processes. Exergoeconomic analysis is employed to assess the energy efficiency, economic viability, and exergy destruction of the integrated system. The study reveals that the gained output ratio (GOR) of the integrated system is approximately 1.121, which is lower than the GOR of the standalone HDH system (1.204), indicating the energyintensive nature of the crystallizer. The main result highlights that while the integration supports achieving ZLD, it comes at the cost of reduced energy efficiency and increased capital expenditure, emphasizing the trade-offs between sustainability goals and system performance. Capital costs analysis shows that HDH blocks account for $547,245, representing almost 92.18 % of the total cost, while the air heater and crystallizer contribute 35 % and 26 %, respectively, to exergy destruction. Furthermore, unit production cost analysis under various scenarios demonstrates potential cost reductions through the sale of produced salt and utilization of waste heat recovery mechanisms. Overall, the findings highlight the potential of integrated HDH systems with evaporative crystallizers for addressing water scarcity and environmental sustainability challenges. Further research in this area could lead to more efficient and cost-effective solutions for water desalination.