This study explores the enhancement of charging performance in a triplex-tube latent heat thermal energy storage system (TTHX) by integrating longitudinal fins and alumina nanoparticles in phase change materials (PCMs). Numerical simulations are conducted to systematically examine the influence of fin length, thickness, number, and orientation, alongside the impact of nano-enhanced PCMs (NEPCMs) to identify optimal configurations for improved charging performance. The results show that incorporating fins accelerates the melting process, with thinner, more numerous fins providing the greatest enhancement. The optimal configuration, consisting of 64 fins with a reduced thickness of 125 µm, achieved an 86% reduction in charging time compared to the baseline case without fins. While adding nanoparticles to the PCM further improved heat transfer, concentrations exceeding 4% led to a decline in the system's overall thermal storage capacity. Among the PCMs studied, RT80-HC outperformed RT82 due to its higher latent heat of fusion and narrower phase-change temperature range. Additionally, horizontal fin configurations demonstrated a slight advantage by increasing the solid–liquid interface area, further enhancing melting efficiency. This study provides a comprehensive analysis of fin optimization and NEPCM integration in TTHXs, offering a better insight into maximizing thermal energy storage performance. The findings contribute to the development of more efficient latent heat thermal energy storage systems, supporting advancements in renewable energy utilization.

Severe water scarcity in recent years has magnified the economic, social, and environmental significance of water stress globally, making optimal planning in water resources necessary for sustainable socio-economic development. One of the regions that is most affected by this is the Sistan region and its Hamoun wetland, located in south-east Iran. Water policies are essential to sustain current basin ecosystem services, maintaining a balance between conflicting demands from agriculture and the protection of wetland ecosystems. In the present study, a multi-objective optimization model is linked with the Water Evaluation and Planning (WEAP) software to optimize water allocation decisions over multiple years. We formulate and parameterize a multi-objective optimization problem where the net economic benefit from agriculture and the supply of environmental requirements were maximized, to analyze the trade-off between different stakeholders. This problem is modeled and solved for the study area with detailed agricultural, socio-economic, and environmental data for 30 years and quantification of ecosystem services. By plotting Pareto sets, we investigate the trade-offs between the two conflicting objectives and evaluate a possible compromise. The results are analyzed by comparing purely economic versus multi-objective scenarios on the Pareto front. Finally, the disadvantages and advantages of these scenarios are also qualitatively described to help the decision process for water resources managers.