Water Desalination System Research Articles

A Review of the Water Desalination Systems Integrated with Renewable Energy

Water and energy are indispensable entities for any flourishing life and civilization. The water and energy scarcities have emerged due to the dramatic growth in the population, standards of living, and the rapid development of the agricultural and industrial sectors. Desalination seems to be one of the most promising solutions to the water problem; however, it is an intensive energy process. The integration of the renewable energy into water desalination systems has become increasingly attractive due to the growing demand for the water and energy, and the reduction of the contributions to the carbon footprint. The intensive investigations on the conventional desalination systems, especially in the oil-rich countries have somewhat overshadowed the progress and implementation of the renewable energy desalination (RED) systems. The economic performance evaluation of the RED systems and its comparison with conventional systems is not conclusive due to many varying factors related to the level of technology, the source of energy availability, and the government subsidy. The small RED plants have a high capital cost, low efficiency and productivity which make RED systems uncompetitive with the conventional ones. However, the selection of the small RED plants for the remote arid areas with small water demands is viable due to the elimination of the high cost of the water transportation, and the connection to the electricity grid. The purpose of this paper is to review the technology, energy, and cost of the recent available desalination systems and their potential to be integrated with the renewable energy resources. This review suggests that the solar still distillation (SD) system, which is simply a natural evaporation-condensation process, is the most practical renewable desalination technique to be used in the remote arid areas; however, a further research is required to enhance their performance and to increase the productivities of these systems.

Sustainable Membrane Distillation Coupled with Solar Pond

Abstract The necessity for fresh water is at the top of the international schema of serious issues. As the fresh water shortage becomes an issue, the application of desalination plants is rapidly rising on a large scale. Also, membrane technologies are gaining high importance for their great performance and their economic viability. Membrane distillation as a novel thermally-driven separation process can be adapted for water desalination, due to its simplicity and ability to couple with a sustainable source of energy. In this paper, study was conducted to develop a Sustainable Water Desalination (SWD) system by combining direct contact membrane distillation with solar ponds. A brief explanation of the solar pond concept and the concept of the membrane distillation (MD) system was illustrated. Additionally, the possibility of desalinating high saline water with zero brine discharge was investigated. Moreover, an alternative source of energy which is from the heat stored in the lower zone of the solar pond was investigated by using the combination of MD and salinity gradient solar pond (SGSP). In this work, the idea of using the surface of the solar pond as heat sink for the permeate water was considered, by introducing floating cooling pipes that are also acting as wave suppressors to reduce the surface mixing in solar pond caused by wind-driven currents. Furthermore, the present understanding and contribution to the research efforts to build a SWD technology system was analysed. In addition to the concept illustration, an indoor study was also conducted about the performance of MD with variation of the feed temperature. It concluded that as the feed temperature increases, the heat flux, mass flux, heat transfer coefficients and evaporation efficiency will increase as the temperature polarization coefficient decreases.

Combined Thermoelectric Power Generation and Passive Vacuum Desalination

Abstract This paper proposes a passive water desalination system combined with thermoelectric power generation. Desalination is achieved by reducing the saturation temperature of saline water through vacuum. The vacuum is generated using 5m of negative head (drop), which significantly reduces the boiling temperature of water. The thermoelectric generator unit (TEGU) uses four thermoelectric cells to generate electricity using Seebeck effect. The cold side temperature of TEGU is maintained by the reduced saturation temperature of saline water, and temperature for hot side can be provided by low grade heat source, e.g. solar, waste heat. The heat transfer through the system is a transient to steady state conduction, and theoretical calculations show that an absolute pressure of 50 kPa can be achieved in the system which reduces the saturation temperature to around 80 ° C. Thermal resistance and heat flow networks are used to validate fresh water output, evaporation, and condensation rates based on input heat. The objective is to achieve proof of concept through experimental model, and thermal analysis. Further research is directed into elimination of non-condensable gases in the system and use of passive condensation techniques to reduce energy input.

Performance improvement of a passive solar still in a water desalination

Using a solar energy in water desalination system is regarded as one of the most effective ways to resolve the problem of freshwater shortages in this world. Experimental and theoretical approaches were carried out to design and test multistage solar still. The experimental tests were conducted for five months in the city of Kirkuk, north of Iraq, at 43.39° longitudinal and 35.17° latitude. The performance requirement of the design is dependent on many factors such as circumstances, work and designation variables. Designating variables, mainly length, width, height and volume of each stage besides the number of all stages, are determined via theoretical analysis approach. The results obtained by both approaches have shown that there is a 10% deviation in still water productivity. Also, the results indicated that the minimum and maximum daily average of still water productivity is 1.7 and 3.8 kg. MATLAB software was employed to model and simulate the experimental processes of evaporation and condensation. The simulation model results were found to agree well with the experiments carried out in many other papers and studies. The test results reported that the system produces about 5 kg of clean water per day with 87% distillation efficiency and 26% of the overall efficiency due to heat losses in the system. Such system is not only promising, but can offer a new technology that can particularly be used in remote and rural areas. The theoretical calculations were compared with the experimental results, and there is a good agreement between the two .

Three-objective optimization of a novel triple-effect absorption heat transformer combined with a water desalination system

A novel triple-effect absorption heat transformer is proposed and compared with a most studied configuration of triple-effect absorption heat transformer and a modified form of it from the viewpoint of exergoeconomics. All systems are integrated with water desalination system to produced distilled water. Sensitivity analyses are performed to identify the influence on the systems’ performance of such decision parameters as the temperatures of evaporator, condenser, absorber and absorbing evaporators for all the configurations. Then a three-objective optimization is accomplished to specify the optimal design points for the purpose of minimizing the product unit cost and maximizing the exergy coefficient of performance as well as the distilled water mass flow rate. In this regard, the Pareto frontiers are plotted for all the systems. The results show that, under the optimized conditions, the exergy coefficient of performance and distilled water mass flow rate for the proposed configuration can be higher by 16% and 38% with respect to the corresponding values in the other two systems. In addition, it is observed that the maximum gross temperature lift in the proposed system is about 20–40% higher than those in the other systems.

Optimal Design of Water Desalination Systems Involving Waste Heat Recovery

Water desalination appears as an attractive alternative to provide fresh water in several parts of the world. However, this process is very expensive due to the high-energy consumption, and as consequence, significant pollution is produced due to the burning of fossil fuels that yield huge emissions of CO2. Furthermore, most of the desalination processes yield a lot of waste heat at low temperature, which can be recovered. Therefore, this paper presents an optimization approach for designing water desalination systems involving heat integration and waste heat recovery to reduce the desalination cost, energy consumption, and overall greenhouse gas emissions. The proposed approach accounts for the optimal selection of existing and emerging desalination technologies based on the heating and cooling requirements and incorporating waste heat recovery systems. The integration of the proposed systems provides power and thermal energy to the desalination task. Also, the proposed approach includes the optimal sele...

Geothermal sea water desalination system (GSWDS) using abandoned oil/gas wells

Nowadays, the water crisis has turned to be a major problem in all over the world. Fresh water shortage and energy intensive process are the reasons underlying water crisis. Seawater desalination can be a solution for the fresh water shortage, but this process needs plenty of energy. Abandoned oil and gas wells are useless geothermal heat sources which can be used as a heat source for water desalination. Abandoned oil wells are capable of providing valuable amount of heat without the necessity to drill expensive deep wells. In this paper, the results of numerical simulation of an abandoned oil well in the Southern part of Iran, in “Ahwaz oil field”, is used for simulation of multi-effect seawater desalination process which uses oil well as a heat source and can approximately produce 565m3/day of fresh water. There are thousands of abandoned oil/gas wells in Iran that can be used as a heat source for this desalination system. This innovative use of abandoned wells is capable of not only solving the fresh water issues in Southern part of Iran, but also leading the country to go through sustainable developments. The process is environmentally-friendly, and significantly reduces the production of emissions, that are considered to be one of the main challenges in conventional desalination systems.

Initial Study Of Potency Thermal Energy Using OTEC (Ocean Thermal Energy Conversion) As A Renewable Energy For Halmahera Indonesia

The Blue Energy is the one of renewable energy. Indonesia as a maritime country has many potention to implement this Blue energy, but it still an advance technology to convert this energy into the electricity. The concept of OTEC with Land Based System is to boost the cost effectiveness of ocean technology. OTEC Land based system which is integrated with the cooling system, water desalination systems, aquaculture, and agriculture. Geographically Halmahera district is located in the Eastern Province of North Maluku. Halmahera is the one of remote island in Indonesia that still lack of electricity. By processing the Argo Float data in 2013-2015 using ODV (Ocean Data View) software, shows the difference of ocean temperature in Halmahera sea surface the range is 29°C. In depth of 1000 m, the sea temperature ranging from 2°C. The Electrical potential of OTEC a long 55 km Halmahera beach are around 93,1% as potential source of OTEC technology. The electricity OTEC prediction is 5,12 MW. Capacity factor of OTEC is 0.857, means that Halmahera have electrical potential for applying OTEC for each year is 35,88 GWh/year.

Heuristic Optimization Techniques for Air Gap Membrane Distillation System

Heuristic approaches are proposed and implemented to optimize the air gap membrane distillation (AGMD) system for water desalination. A mathematical model to predict the permeate flux of the AGMD system was developed based on the analysis of heat and mass transfers within the module. The developed mathematical model is linked to two optimization algorithms, namely the ant colony optimization (ACO) and particle swarm optimization (PSO). These algorithms have been developed and employed to find the optimal set of variables for the maximum permeate flux of distilled water. The considered variables included feed water temperature, coolant water temperature, air gap width, feed flow rate, and coolant flow rate. The PSO provides comparatively better solution and is computationally less intensive. The differences between the optimum values of flux from the two techniques were found to be less than 3%. Effects of extending the limits (ranges) of different variables were considered.

Recycling brine water of reverse osmosis desalination employing adsorption desalination: A theoretical simulation

Intake, pretreatment and brine disposal cost of reverse osmosis sea water desalination systems represent about 25% of total cost of the desalinated water. The present study investigates effect of reverse osmosis brine recycling employing adsorption desalination on overall system desalinated water recovery. The adsorption desalination produces dual useful effects which are high quality potable water and cooling effect. Reverse osmosis desalination is simulated by engineering equation solver (EES). The brine leaving reverse osmosis system is fed to adsorption desalination system. The adsorption desalination is driven by a low temperature heat source such as solar energy. The adsorption desalination system has been simulated by MATLAB. Results show that the proposed combination system recovery increases and permeate salinity decreases. In addition to system performance improvements, a cooling effect is generated and can be utilized for cooling applications.

Techno-economic evaluation of forward/reverse osmosis hybrid system for saline water desalination

Techno-economic evaluation of forward/reverse osmosis hybrid system for saline water desalination

Feasibility study of an electrodialysis system for in-home water desalination in urban India

Poor quality of drinking water delivered to homes by state utilities, and a large reliance on brackish ground water resources in parts of urban India, has resulted in the adoption of in-home water treatment solutions. The only existing in-home water treatment solution capable of desalination is reverse osmosis (RO). However, existing RO products can recover only 25–50% of the feed water supplied as usable product water. In this study, an alternative solution that relies on electrodialysis (ED) was designed and experimentally shown to achieve a recovery of 80%, producing 12L/h of water at the desired salinity of 350ppm from a feed salinity of 3000ppm. The cost and size of the proposed system were also found to be comparable to existing in-home RO systems. In-home ED water treatment systems could compete with existing RO products while providing the advantage of improved water-conservation in water-stressed India.

Three-objective optimization of water desalination systems based on the double-stage absorption heat transformers

A new type of double-stage absorption heat transformer integrated with water desalination system is proposed and compared with four other types of absorption heat transformers i.e. a conventional type of double-stage and three different types of double-effect absorption heat transformers from the viewpoint of exergoeconomics, using Engineering Equation Solver software. Considering product unit cost, exergy coefficient of performance and mass flow rate of distilled water as objective functions, a three-objective optimization is performed to specify the optimal design point for all studied systems. The temperatures of evaporator, condenser, absorber and absorbing evaporator (low-pressure absorber for double-stage absorption heat transformers) are considered as decision variables and the related Pareto Fronts are plotted for all the studied cycles. The results show that the maximum gross temperature lift in the proposed type of double-stage absorption heat transformers is about 18–27% higher than that in other considered systems. Therefore, its evaporator temperature can be risen by up to about 120°C. It is also observed that, under optimized conditions, the exergy coefficient of performance however, is found to be the highest for the type in which there is no split for the absorber inlet an exit streams (type 3).

Simultaneous management and control on cost and time in the project development through fuzzy logic to risk management

Projects are a series of unique activities defined in order to achieve a unique goal. Before implementation, project activities to be conducted in future are predicted and the initial timetable of the project is prepared. Given the fact that future is vague and unclear, risks and uncertainties will inevitably exist in the implementation of projects because human is unable to precisely foresee the future. Projects are planned according to estimations obtained from little information about the future conditions of projects. Considering the fact that the planning involve uncertainty, time delays and costs imposed by uncertainties are unavoidable .Risk management is a project management standard used extensively. The effects of the risk of time and cost were simultaneously investigated in one of the huge, national projects in Iran, namely the water supply project from Persian Gulf to the mineral industries of south eastern Iran, which involves the largest water desalination system in the Middle East. Information pertaining to risk management was gathered, and fuzzy number theory, fuzzy logic, software, and information analysis and combination were employed. A model was put forward including 7 stages and 20 steps in SPSS, and MATLAB was also utilized in civil projects for increasing planning accuracy. The results differed from those of existing, traditional methods, such as the method of probability of occurrence * degree of impact, for risk management.

Experimental investigation of adsorption water desalination/cooling system using CPO-27Ni MOF

Although many adsorbent materials have been used in adsorption systems, only silica-gel was tested experimentally for desalination applications. This work experimentally and numerically investigates the use of CPO-27(Ni) an advanced Metal Organic Framework-MOF adsorbent material in a 1-bed adsorption system for water desalination and cooling applications. Operating parameters as switching time, half cycle time, evaporator and condenser water inlet temperatures were studied to investigate their effects on cycle water production and cooling. Moreover, a mathematical simulation model is developed, validated and used to predict cycle outputs at other operating conditions. Results showed that as evaporator temperature increases and condenser temperature decreases, cycle outputs increase. Also, it was shown that adsorption desalination cycles can work with condenser pressure lower than evaporator pressure as the cycle is an open loop one (i.e. no refrigerant is flowing back from condenser to evaporator). A water production of 22.8m3/tonne·ads/day was achieved using 40°C evaporator temperature, 5°C condenser temperature and 95°C desorption temperature. Similar water production can be achieved using 30°C condensing temperature but at 120°C desorption temperature. For space cooling applications (Tevap<20°C), cycle cooling produced was found to be 65Rton/tonne·ads. This work highlights the potential of using advanced MOF materials for water desalination/ cooling applications.

Water self-diffusivity confined in graphene nanogap using molecular dynamics simulations

Fundamental understanding of water confined in graphene is crucial to optimally design and operate sustainable energy, water desalination, and bio-medical systems. However, the current understanding predominantly remains in the static properties near the graphene surfaces. In this paper, a key water transport property, i.e., self-diffusivity, is examined under confinement by various graphene nanogap sizes (Lz = 0.7–4.17 nm), using molecular dynamics simulations with various graphene-water interatomic potentials (Simple Point Charge (SPC/E) and TIP3P water models). It is found that the water self-diffusivity nearly linearly decreases as the graphene-water interatomic potential energy increases at a given nanogap size. It also decreases as the graphene nanogap size decreases down to Lz = 1.34 nm; however, it shows the peak water self-diffusivity at Lz = 0.8 nm and then continues to decrease. The peak water self-diffusivity is related to the significant change of the overlapping surface force, and associated, nonlinear local water density distribution. The in-plane water self-diffusivity is higher up to nearly an order of magnitude than that of the out-of-plane due to the geometrical confinement effect by the graphene nanogap. The obtained results provide a roadmap to fundamentally understand the water transport properties in the graphene geometries and surface interactions.

Using PDMS coated TFC-RO membranes for CO2/N2 gas separation: Experimental study, modeling and optimization

Thin film composite (TFC) reverse osmosis (RO) membranes are semipermeable membranes that are utilized in water purification or water desalination systems. Discarding these membranes after end-of-life leads to environmental problems. Reusing old TFC-RO membranes is one way to solve this problem. For this reason, in this study, used TFC-RO membranes were coated with polydimethylsiloxane (PDMS) for CO2/N2 gas separation application. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was utilized to confirm the crosslinking of coated PDMS. The morphology of PDMS/TFC-RO membranes was characterized using scanning electron microscopy (SEM). The parameters that can affect performance of prepared membranes (N2 permeance and CO2/N2 selectivity) are concentration of PDMS solution, coating time, solvent evaporation time and curing temperature and time. Given that the used membranes don't have uniform surfaces, the first step of this study was to investigate the effect of the above mentioned factors on virgin membranes using fractional factorial design (FFD) of experiments. The results obtained showed that PDMS concentration is the most significant factor that has a negative effect on N2 permeance and positive effect on CO2/N2 selectivity. The reported CO2/N2 selectivity of PDMS membranes was 11–12, but this selectivity for prepared PDMS/TFC-RO membranes was in the range of 6.7–22.5. After determining optimum conditions, the gas separation performance of PDMS coated used TFC-RO membrane under these conditions was finally determined. The results showed that the used membranes had a better performance than virgin membranes.

A Review of the Hybrid Solar Chimney and Water Desalination Systems for Simultaneous Production of Electricity and Fresh Water

This paper provides an overview of the operation principles and characteristics of a novel solar energy sourced power generation system called solar chimney power plant (SCPP) or solar updraft tower (SUT). The discussion includes the physical concept, historical development, characteristics and operational feasibility, as deduced by previous researches and case studies. It also discusses the commercialization of this technology and the continuous efforts aimed at integrating SCPP with water desalination technologies (WDT). Consequently, the authors concluded that there is a significant prospect of integrating SCPP with liquid desiccant system (LDS) for the purpose of efficient simultaneous production of electricity and fresh water.

Weather forecasting for optimization of a hybrid solar-wind–powered reverse osmosis water desalination system using a novel optimizer approach

The optimum design for a stand-alone hybrid desalination scheme, able to fulfill the fresh water demand of a remote area located in Davarzan, Khorasan, Iran, is determined and investigated. The scheme consists of a reverse-osmosis desalination unit powered by solar and wind electricity production systems with battery energy storage. To predict the energy production, data from many weather stations are required, and a new forecasting strategy is proposed for weather related parameters (solar irradiance, wind speed, and ambient temperature). The system is implemented and tested using real data from northeastern Iran. To determine the optimal values of parameters for the hybrid renewable energy system that satisfy the load in the most cost-effective way (minimizing the life cycle cost and not exceeding the maximum allowable loss of power supply probability), the use of harmony search and a combination of harmony search with chaotic search is proposed. As an efficient heuristic, harmony search is easy to implement and can escape from local optima. The decision variables (number of batteries, total swept area of the rotating turbine blades, and total area occupied by the set of photovoltaic panels) are optimized using a harmony search-based chaotic search for the most cost-effective system.

Experimental study of a bubble basin intended for water desalination system

One new technique that can increase the water evaporation rate in the solar still is to generate air bubble through its base. The aim of this research work is to perform a design basis for a modified solar still using air bubbling through water layer and to determine the heat and mass transfer coefficients between air bubbles and water in the basin. An experimental test set-up was fabricated and assembled. The process consists of air bubbles passing through the base of the basin to the seawater under some experimental conditions of airflow rate, inlet air temperature and humidity, and water temperature and depth. Detailed experiments were carried out at various operating conditions. Within the studies ranges, the results indicate that the water vapor content difference is moderately affected by the water temperature and airflow rate but slightly affected by the water level. The heat and mass transfer coefficients were obtained experimentally and fitted in forms of empirical correlations. The statistical study has shown a good agreement between the model and the experimental measurements, with an average relative error not exceeding 20%.