Multi-Level Design Optimization of Reverse Osmosis Water Desalination Powered via Photovoltaic Panels With Battery Storage

Author(s):  
Jihun Kim ◽  
Karim Hamza ◽  
Mohamed El-Morsi ◽  
Ashraf O. Nassef ◽  
Sayed Metwalli ◽  
...  

Reverse osmosis (RO) is one of the main commercial technologies for desalination of water with salinity content too high for human consumption in order to produce fresh water. RO may hold promise for remote areas with scarce fresh water resources, however, RO energy requirements being in the form of electric power have few options in such areas. Fortunately, scarce rainfall is often associated with abundant sunshine, which makes solar photovoltaic (PV) power an attractive option. Equipping a photovoltaic powered reverse osmosis (PV-RO) desalination plant with battery storage has an advantage of steadier and longer hours of operation, thereby making better use of the investments in RO system components, but the additional cost from including batteries may end up increasing the overall cost of fresh water. It is therefore of paramount importance to consider the overall cost-effectiveness of the PV-RO system when designing the desalination plant. Recent work by the authors has generalized the steady operation model of RO systems to hourly adjusted power-dispatch via a proportional-derivative (PD) controller that depends on the state of charge (SOC) of the battery, yet the operating conditions; namely pressure and flow for a given power dispatch were only empirically selected. This paper considers a multi-level optimization model for PV-RO systems with battery storage by considering a “sub-loop” optimization of the feed pressure and flow given power dispatch for a fixed RO system configuration, as well as a “top-level” optimization where the system configuration itself is adjusted by the design variables. Effect of the sub-loop optimization is assessed by comparing the obtained cost of fresh water with the previous empirically adjusted system for locations and weather conditions near the city of Hurgada on the Red Sea.

2014 ◽  
Author(s):  
Jihun Kim ◽  
Karim Hamza ◽  
Mohamed El-Morsi ◽  
Ashraf O. Nassef ◽  
Sayed Metwalli ◽  
...  

Reverse osmosis (RO) is one of the main technologies for water desalination, which can be used in locations with water resources that have high salinity content (such as saline ground water or seawater) to produce fresh water. Energy requirement for RO is less than other desalination processes, but is in the form of electric power, which can be scarce as fresh water in in remote areas not connected to the grid. Fortunately, many areas with fresh water shortage due to lack of rainfall have abundant sunshine. The combination of solar power and RO desalination is attractive, but remote areas usually requires small modular units, which favors photovoltaic (PV) solar energy harvesting. It is important to consider the net cost-effectiveness of the system when designing the PV-RO desalination plant. Adding battery storage to a PV-RO system has the advantage of steadier operation, but is an additional cost whose real benefit is only realized with a larger PV array that can harvest more energy during daytime. This paper compares the net unit cost of fresh water for realistic scenarios of PV-RO systems with and without battery storage. A multi-level optimization approach previously developed by the authors for time-variant power PV-RO systems is adopted; a “sub-loop” optimization determines the operating pressure and flow rate given a fixed system configuration and instantaneous power input, while an “outer loop” optimizes the configuration of the desalination plant. The sub-loop optimization is done via an enumeration approach, while the outer loop is optimized via a mixed real-coded genetic algorithm (GA). A demonstration study shows a batteryless system being approx. 30% more expensive per unit fresh water production than a fully optimized battery-backed system. However, most of the cost of a batteryless system is in initial investment, which with 7% less annual operating cost, can present a plausible design choice for remote areas.


Author(s):  
Jihun Kim ◽  
Karim Hamza ◽  
Mohamed El Morsi ◽  
Ashraf O. Nassef ◽  
Sayed Metwalli ◽  
...  

Fresh water availability is essential for the economic development in small communities in remote areas. In desert climate, where naturally occurring fresh water is scarce, seawater or brackish water from wells is often more abundant. Since water desalination approaches are energy intensive, a strong motivation exists for the design of cost-effective desalination systems that utilize the abundant renewable energy resource; solar energy. This paper presents an optimization model of a solar-powered reverse osmosis (RO) desalination system. RO systems rely on pumping salty water at high pressure through semi-permeable membrane modules. Under sufficient pressure, water molecules will flow through the membranes, leaving salt ions behind, and are collected in a fresh water stream. Since RO system are primarily powered via electricity, the system model incorporates photovoltaic (PV) panels, and battery storage for smoothing out fluctuations in the PV power output, as well as allowing system operation for a number of hours after sunset. Design variables include sizing of the PV solar collectors, battery storage capacity, as well as the sizing of the RO system membrane module and power elements. The objective is to minimize the cost of unit volume produced fresh water, subject to constraints on production capacity. A genetic algorithm is used to generate and compare optimal designs for two different locations near the Red Sea and Sinai.


Author(s):  
Hammad Siddiqui ◽  
Mariam Elnour ◽  
Nader Meskin ◽  
Syed Zaidi

Reverse Osmosis (RO) is an efficient and clean membrane-based technology for water desalination. This work presents a full-scale seawater reverse osmosis (SWRO) desalination plant simulator using MATLAB/Simulink that has been validated using the operational data from a local plant. It allows simulating the system behavior under different operating conditions with high flexibility and minimal cost.


1992 ◽  
Vol 25 (10) ◽  
pp. 299-318 ◽  
Author(s):  
J. A. Slim ◽  
D. G. Devey ◽  
J. W. Vail

The City of Port Elizabeth designed its main sewage treatment works with water reclamation in mind and, as the reverse osmosis process, in earlier pilot plant investigations, had shown promise in its ability to produce potable water from a sewage works tertiary effluent, a full scale tubular reverse osmosis (RO) plant was installed and operated for about 12 000 hours. The investigation showed that, although renovated water of high quality can consistently be produced under normal sewage treatment plant operating conditions, using existing plant operating personnel, frequent mechanical and instrument failures indicated the need for more reliable equipment. Feed flow to the plant averaged 25 475 1/hr with a product recovery rate of 67.5%. A 13% reduction in peak standard flux occurred, indicating that membrane fouling could be controlled within acceptable limits even though the feed received no pre-treatment other than rapid sand filtration and chlorination. No abnormal degradation of the membrane was indicated. The results obtained indicated that chemically the product was of good potable quality with the possible exception of the levels of ammoniacal nitrogen, phenols and organic pollution indicators. Bacteriological quality of the product was not satisfactory but this could easily be rectified by the provision of adequate post disinfection. Daphnia pulex toxicity tests indicated that the RO product was on occasion undesirable for human consumption. The total cost of the RO product was R l.86/kl. Although the tubular RO process has great potential for producing potable water from a tertiary sewage effluent without pre-treatment, a further stage of post-treatment is probably necessary to remove micro-pollutants.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Jian Wang ◽  
Xiaolong Wang ◽  
Aipeng Jiang ◽  
Shu Jiangzhou ◽  
Ping Li

A large-scale parallel-unit seawater reverse osmosis desalination plant contains many reverse osmosis (RO) units. If the operating conditions change, these RO units will not work at the optimal design points which are computed before the plant is built. The operational optimization problem (OOP) of the plant is to find out a scheduling of operation to minimize the total running cost when the change happens. In this paper, the OOP is modelled as a mixed-integer nonlinear programming problem. A two-stage differential evolution algorithm is proposed to solve this OOP. Experimental results show that the proposed method is satisfactory in solution quality.


RSC Advances ◽  
2021 ◽  
Vol 11 (43) ◽  
pp. 26800-26812
Author(s):  
H. Leelavathi ◽  
N. Abirami ◽  
R. Muralidharan ◽  
Helen P. Kavitha ◽  
S. Tamizharasan ◽  
...  

Accessibility of adequate safe and fresh water for human consumption is one of the most significant issues throughout the world and extensive research is being undertaken to resolve it.


Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 377
Author(s):  
Federico Leon ◽  
Alejandro Ramos-Martin ◽  
Sebastian Ovidio Perez-Baez

The water situation in the Canary Islands has been a historical problem that has been sought to be solved in various ways. After years of work, efforts have focused on desalination of seawater to provide safe water mainly to citizens, agriculture, and tourism. Due to the high demand in the Islands, the Canary Islands was a pioneering place in the world in desalination issues, allowing the improvement of the techniques and materials used. There are a wide variety of technologies for desalination water, but nowadays the most used is reverse osmosis. Desalination has a negative part, the energy costs of producing desalinated water are high. To this we add the peculiarities of the electricity generation system in the Canary Islands, which generates more emissions per unit of energy produced compared to the peninsular generation system. In this study we have selected a desalination plant located on the island of Tenerife, specifically in the municipality of Granadilla de Abona, and once its technical characteristics have been known, the ecological footprint has been calculated. To do this we have had to perform some calculations such as the capacity to fix carbon dioxide per hectare in the Canary Islands, as well as the total calculation of the emissions produced in the generation of energy to feed the desalination plant.


Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2772
Author(s):  
Vishwas Powar ◽  
Rajendra Singh

Plummeting reserves and increasing demand of freshwater resources have culminated into a global water crisis. Desalination is a potential solution to mitigate the freshwater shortage. However, the process of desalination is expensive and energy-intensive. Due to the water-energy-climate nexus, there is an urgent need to provide sustainable low-cost electrical power for desalination that has the lowest impact on climate and related ecosystem challenges. For a large-scale reverse osmosis desalination plant, we have proposed the design and analysis of a photovoltaics and battery-based stand-alone direct current power network. The design methodology focusses on appropriate sizing, optimum tilt and temperature compensation techniques based on 10 years of irradiation data for the Carlsbad Desalination Plant in California, USA. A decision-tree approach is employed for ensuring hourly load-generation balance. The power flow analysis evaluates self-sufficient generation even during cloud cover contingencies. The primary goal of the proposed system is to maximize the utilization of generated photovoltaic power and battery energy storage with minimal conversions and transmission losses. The direct current based topology includes high-voltage transmission, on-the-spot local inversion, situational awareness and cyber security features. Lastly, economic feasibility of the proposed system is carried out for a plant lifetime of 30 years. The variable effect of utility-scale battery storage costs for 16–18 h of operation is studied. Our results show that the proposed design will provide low electricity costs ranging from 3.79 to 6.43 ¢/kWh depending on the debt rate. Without employing the concept of baseload electric power, photovoltaics and battery-based direct current power networks for large-scale desalination plants can achieve tremendous energy savings and cost reduction with negligible carbon footprint, thereby providing affordable water for all.


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