A heat recovery-based ecofriendly solar thermal-driven electricity/hydrogen/freshwater multigeneration scheme using LNG regasification: Energy, exergy, economic, and environmental (4E) analysis

The availability of ample solar energy resources holds significant importance for populated islands as it represents a vital avenue for ensuring sustainable energy provision while reducing reliance on external energy sources. The proposed system is designed to offer residential solutions, providing a promising answer to fulfill the varied energy requirements of modern islands. This innovative system integrates parabolic trough solar collectors, a cascaded organic Rankine cycle (ORC), a hydrogen production unit via electrolysis, and a water desalination system through membrane modules. By employing an optimized methodology, this system enhances the thermal efficiency of the proposed setup and enables island communities to access natural gas resources. A robust programming code has been crafted to comprehensively evaluate the system from the standpoints of energy, exergy, economics, and the environment. The system is engineered to accomplish a range of objectives, including the generation of 1.2 MW of electricity, meeting a cooling load of 460 kW, producing 9.7 kg/h of hydrogen, and supplying 33 kg/s of desalinated water. In addition, natural gas is delivered to the consumer network at a rate of 3.09 kg/s. The financial assessment, which includes the initial investment and ongoing maintenance, shows that the cost rate for the whole system is 142 $/h, with an estimated levelized cost of 33.2 Cent/m³ for fresh water. The findings of the environmental assessment indicate that the proposed system holds significant potential for mitigating carbon dioxide (CO₂) emissions, with a maximum reduction rate of 254 kg/h. This reduction in CO₂ emissions leads to a corresponding decrease in the CO₂ emission cost rate, estimated to be approximately 7 $/h.