Design, evaluation, and optimization of an efficient solar-based multi-generation system with an energy storage option for Iran’s summer peak demand

• Published in: Energy conversion and management Vol. 242; p. 114324
• Main Authors: Khani, Leyla, Jabari, Farkhondeh, Mohammadpourfard, Mousa, Mohammadi-ivatloo, Behnam
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 15-08-2021; Elsevier Science Ltd
• Subjects: Ammonia; Brackish water; Coastal zone; Cooling; Desalination; Design optimization; Energy efficiency; Energy storage; Exergy; Goswami cycle; Molten salt heat storage; Molten salts; Multi-generation; Multiple objective analysis; Optimization; Peak demand; Peak load; Performance evaluation; Pressure ratio; Seawater; Solar energy; Solar power; Solar radiation; Storage units; Summer; Superheating; Thermodynamics; Water crises; Water resources; Iran; Multi-generation; Molten salt heat storage; Desalination; Optimization; Goswami cycle; Solar energy
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2021.114324

•A novel freshwater, cooling, and power trigeneration system based on solar energy and molten salt storage is designed.•The proposed system aims to satisfy the water and power shortage in a southern city of Iran.•The performance of the system is evaluated under worst weather conditions in summer time.•The system is optimized in four different scenarios to identify optimum operating conditions.
In summer, the coastal areas of southern Iran suffer from the freshwater shortage and electricity instability. Meanwhile, this region benefits from the high intensity of solar radiation and the huge potential of brackish water resources. Hence, this paper designs a novel cooling, power and pure water trigeneration system for application in this area to mitigate its energy and water crisis. The proposed system is composed of a solar-based Goswami power and cooling production cycle and a multistage flash seawater desalination process. Moreover, a molten salt heating energy storage unit is used to prove its steady operation under uncertain sunlight condition. A comprehensive parametric study is provided to evaluate the system performance by changing the key variables. The numerical results demonstrate that increasing the pressure ratio from 6 to18 causes 3.3% leads to an increase in system efficiencies and minimum total products cost experiences at the pressure ratio of 12.6. Additionally, as the superheating degree increases from 0 to 10 K, the energy efficiency decreases but the exergy efficiency increases. When the ammonia concentration at the rectifier exit is increased from 0.965 to 0.995, the energy efficiency increases 5%, the exergy efficiency has a decreasing trend from 28% to 25.9%, and the minimum total products cost is 131.2 $/GJ. Furthermore, the exergy efficiency gains its maximum, the energy efficiency has a minimum value, and the total products cost grows with higher values of the minimum approach temperature. Finally, the system is optimized under four different scenarios to identify its best operating condition in each condition: three single-objective and one multi-objective optimization cases. The results of the multi-objective optimization are trade-offs between the ones for single-objective optimization cases. In this case, the net power of 12 MW, cooling capacity of 15.74 kW, and the freshwater of 4.72 kg/s are attainable.