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Seawater desalination can be an attractive alternative to ensure a secure source of water. However, the energy requirements for that process are high and can be a problem, mainly in isolated areas. Renewable energies are the best way to supply the energy needs, because can be available near the desalination plants and avoid environmental/availability problems associated with fossil fuels. In this paper two forms of renewable energies particularly suited for desalination are described: wind power and wave power. [ABSTRACT FROM AUTHOR]

Indirect solar desalination systems consist of a conventional desalination unit coupled to a solar conversion system, unlike systems as solar stills that integrates in the same device the desalination and the energy conversion processes. They are among the most developed systems of renewable energy-powered desalination. Their most significant possibilities of development in the near future are assessed in this paper. Particular emphasis is given to the efficiency of such systems since their cost mainly depends on the maturity of the technology and the production scale, factors which may change in the future in favour of more efficient systems. Considerable research has to be conducted on the technologies that have never been coupled before as they could be reliable and cost-effective options. [ABSTRACT FROM AUTHOR]

The ADU-RES co-ordination action is an EC funded project that aims to bridge the gap between successful R&D work and commercial applications of small desalination systems powered by renewable energy. This paper reviews installed units in order to define the state of the technology. Ninety-one plants were identified and sixteen of them were reviewed for their technical and economical performance. The examined units desalinate brackish or sea water and employ different technologies including: solar thermal distillation, wind energy or photovoltaic panels (PV) combined with revere osmosis (RO) as well as mechanical vapour compression driven by wind turbines. It was found that the technology has made significant progress over the past years. Still, cost-effective solutions have to be developed especially for the scaling of the membranes caused by the intermittent operation or the corrosion because of the high-temperatures. Also the energy efficiency and the controlling of the systems have to be further developed. The first products are in the market and will improve through competition and experiences resulting from implementation in real conditions for long periods. [ABSTRACT FROM AUTHOR]

The hybrid process of seawater desalting couples the reverse osmosis with the multi-stage flash process. The hybrid process is usually planned to improve the performance of MSF and reduce the cost of desalted water. In this paper, we propose to apply a cogeneration system using a Refuse Derived Fuel to supply energy to this plant. Many researchers investigated the hybridization of RO and MSF technologies from different points of view. The present work is a trial to contribute in these efforts to throw more light on practicability of the hybridisation design through an optimization study, that is able to calculate the minimum water cost as function of the most important MSF plant parameters. [ABSTRACT FROM AUTHOR]

The supply of fresh water is becoming an issue of increasing importance in many areas in the world. In arid areas potable water is very scarce and the lives of people in these areas strongly depend on the amount of available water. Seawater desalination requires large amounts of energy and if this energy is produced by fossil fuels it will harm the environment. Therefore, renewable energy sources coupled to desalination offer an attractive solution. Considerable research is under way to optimise the matching of renewable energy technologies with the corresponding desalination technologies and especially to reduce the energy required per unit volume of fresh water produced. The present paper gives emphasis to the following technologies: 1) RO powered by PV and 2) Solar collectors for powering RO through a Rankine cycle. These systems are reviewed and recent developments are presented. Finally the economics of the systems are analysed and overall figures of the present fresh water cost are given. [ABSTRACT FROM AUTHOR]

In recent years, membrane technology has become increasingly significant and has been widely used in desalination. Some membrane processes, such as reverse osmosis and electrodialysis are used commercially while others such as membrane distillation are still in the research and development stages. This study reviewed the current status of a number of solar thermal and solar PV technologies that can be coupled with water membrane-based desalination processes. Solar systems have the potential to power membrane-based desalination plants but still cannot compete favorably with fossil fuel based energy desalination. Nevertheless, these systems remain a valid option for small scale units in remote areas. [ABSTRACT FROM AUTHOR]

EasyMED, a new MED process constructed with plates has shown good performances for desalination of salted water in laboratory. In order to prove the reliability of this process in real conditions, a three effects evaporator was operated in La Spezia (Italy). This unit is composed of three effects in series and five cells in parallel and is heated by hot water at about 75°C. 3 m³/day of high quality distillate with conductivity lower than 20 μS/cm was obtained. The overall heat transfer coefficients between heating water and seawater falling film reached 1400 W/m².°C whereas the coefficient between condensing vapour and evaporating seawater is about 4000 W/m².°C. The influence of the heating fluid temperature and the heating fluid flowrate is studied. The results were used to design a teneffects industrial unit producing about 150 m³/day. The potential application of solar heat collectors to supply thermal energy to this MED plate process is studied. [ABSTRACT FROM AUTHOR]

The purpose of this document is to explain the principle of a commercial Solar Still developed by Wilfried Rosendahl, Germany. It explains the practical and decentralized application of such as system and the experience over many years of operation. [ABSTRACT FROM AUTHOR]

New membrane distillation modules and desalination systems were developed which are completely powered by solar energy for standalone operation. The membrane distillation modules with heat recovery function need about 100 kWh of thermal energy per m³ of high quality distillate (conductivity as low as 20μS/cm measured). Four ‘compact systems' with a capacity of about 100 litres/day and a larger ‘two loop system' with a capacity of about 1000 litres per day were installed recently. [ABSTRACT FROM AUTHOR]

Recent years have seen a large number of newly developed pilot projects for solar desalination based upon a variety of technological approaches. This paper explores the possibility of moving into direct installation and practical application of small to medium sized off-grid hybrid (solar, wind) powered Reverse Osmosis desalination systems using commercially available energy optimized equipment from the maritime, yachting and off-shore sectors. The focus is on exploring the feasibility of implementing this technology for remote applications in rural settings of developing countries. Various systems including an actual application are presented, as well as energy options and operational problems described, keeping appropriate technology requirements in mind. Some economic considerations are included. [ABSTRACT FROM AUTHOR]

Seawater desalination is one of the most promising fields for the application of solar thermal energy due to the usual coincidence, in many places in the world, of water scarcity, seawater availability and good levels of solar radiation. During the 90s the Plataforma Solar de Almería (PSA) carried out a research project that successfully demonstrated the technical feasibility of solar seawater desalination using parabolic-trough solar collectors coupled with a conventional multi-effect distillation unit. In spite of significant achievements in the process energy efficiency, by the development and implementation of a double-effect absorption heat pump, the technology could not compete in cost reduction with conventional thermal distillation or reverse osmosis processes. In 2002, the R&D European Project AQUASOL was initiated at the PSA in order to improve the existing solar thermal desalination technology. This paper describes all these experiences along with a detailed description of the AQUASOL desalination system, currently under evaluation at the PSA. [ABSTRACT FROM AUTHOR]

Solar driven desalination systems based on evaporation of sea water and subsequent condensation of the generated steam have been investigated worldwide for many years¹. Starting from simple but sophisticated solar stills working very reliably and self sufficient on small scale drinking water production in the range up to 0.5 m³ per day, improved concepts have been realized mainly at a research level up to now. The main tasks in term of efficiency of such concepts were the reduction of specific energy consumption and by that requested solar aperture area per cubic meter of water produced daily. One of the concepts is the Multiple Effect Humidification (MEH) method. The enclosure comprising heat and mass transfer is separated from the solar collectors for heat supply of the process. Evaporation and condensation surfaces are oriented to enable continuous temperature stratification along the heat and mass transfer process, resulting in small temperature gap to keep the process running. Most of the energy afforded in the evaporator is regained in the condenser keeping the energy demand on a very low level of less than 120 kWh/m³. Such systems have been available as an industrial product since November 2005. A demonstration system was installed and commissioned in Jeddah/Kingdom of Saudi-Arabia. [ABSTRACT FROM AUTHOR]

This communicating article reviews desalination by solar still, and the recent studies on the solar still systems. The review includes basic principle of solar distillation, and also the quality of distilled water. A classification of the solar still systems was made in order to explain the types of solar still systems. General mathematical modeling methodology of solar stills and some mathematical modeling studies are given. The efficiency and performance of the solar still system are also given and discussed. [ABSTRACT FROM AUTHOR]

Energy and water have always been a central element of the insular condition due to their territorial, environmental and economic implications. The interdependence water-energy is increasingly evident on islands, and sometimes it even leads to a single management system for both. It is a determining factor in present development models. This paper describes the main issues of present and future water and energy policies in Sicily. A new Energy Master Plan will soon be adopted by the Regional Government which will increase the use of Renewable Energies (RE) encoure private investors. A special Bureau for Water Management plans to increase the capacity and efficiency of desalination plants already operating in Sicily as there are many areas with old distribution networks and scarce water resources. RE and desalination should be investments for the future and for private enterprises. Economic support is available both for RE electricity generation and for energy saving projects in general. An economic analysis of some possible applications of RE for desalination is presented. In the cases simulated we show how economic obstacles could be overcome. [ABSTRACT FROM AUTHOR]

The efficacy of desalination device based on using direct osmosis method has been examined. The device with productivity of 1 m³/hr consists of solar batteries with power of 500 W, water pretreatment unit on the base of fibroid sorbents, water disinfection device with specific power consumption of 0,1 Wh/m³ and desalination device with power of 450 W. Due to the financial support of UNESCO in March, 2005 the pilot device with productivity of 1 m³/hr was installed in Turtkul village of Aral Sea Region to remove salts from brackish water with a total concentration of about 17 g/l. [ABSTRACT FROM AUTHOR]

Desalination has become one of the water supply sources in most of the countries in the Middle East and North Africa region. All MENA countries lie in the Sunbelt region and have the space needed for solar technologies. However, utilization of solar energy in desalination is still limited in the MENA region. The success of implementing solar technologies in desalination depends on the progress made in converting solar energy into electrical and thermal energy, as the process of desalination depends on these types of energies. Realizing that desalination is a major consumer of energy and starting to use solar technologies in desalination will increase the demand on these technologies, so making it possible to go for mass production of PV cells, collectors and solar thermal power plants. This would lead eventually to a reduction in cost of these technologies. On the other hand, energy consumption by desalination processes has been reduced significantly in recent years. This means that if solar technologies are used, less PV modules and area for collectors would be needed for each cubic meter of water produced. [ABSTRACT FROM AUTHOR]

The solar potential of Bulgaria as well as opportunities for its utilisation through both thermal and photovoltaic installations is presented in this paper. The present solar power usage and ideas for energy efficiency and utilisation of renewable energy sources are shown. The fresh water resources of this country are estimated compared with the resources of other European countries and eventual future need of desalination is discussed in the work. [ABSTRACT FROM AUTHOR]

Morocco is characterised by a semi arid climate and the decrease of the available surface water has a strong impact on the renewable resources of ground water. Without additional unconventional water sources, the water deficit will keep growing, even if more dams are built in the future, since they alone will not mobilise more water by capita. The obligation to use other non conventional water resources such as desalinated water or waste water reuse and the need for a more rigorous policy of water management and planning becomes a necessity. However Morocco has a large potential of wind and solar energy sources that could be used in the sea water desalination. The paper presents the experiences of the use of renewable energy sources in desalination in Morocco and an economic analysis of wind powered desalination in the south of Morocco. [ABSTRACT FROM AUTHOR]

Supported by MEDRC and the CEC, European experts in desalination, renewable energy and computational analysis in scientific collaboration with partners from Jordan and Algeria are transforming the computational systems analysis environment RESYSproDESAL into a capacity for feasibility assessment analyses on de-central water and power supply, integrating renewable energy in MENA countries. [ABSTRACT FROM AUTHOR]

The subject of this paper is to optimize the operating parameters of an actual solar desalination plant in operation and maximize its annual water production. The plant is located in Abu Dhabi, UAE, it consists of a field of evacuated tube collectors, a heat accumulator of the thermallystratified type and a multiple-effect seawater (MES) evaporator of the vertical stack type. A simulation program "SOLDES" was used to find the influence of each of the selected operating parameters on plant production. Solar radiation and other weather data for Abu Dhabi were used in the simulation runs. The results of the program were validated against the actual plant data and the agreement was found to be good. The selected plant operating parameters found to have an effect on plant water production were the heating water flow to the evaporator, the collector bypass valve open temperature and the frequency of monthly collector cleanings. The aim is to maximize monthly water production by setting these operating parameters to their optimum values. For this purpose monthly correlation equations were established by running the program at different values of each parameter and using the least square technique. The resulting monthly second-degree polynomial were optimized using the steepest ascent method. [ABSTRACT FROM AUTHOR]

The south Mediterranean area is suffering from lack of drinking water. However, brackish water is abundant in these regions. Desalination of such water can be a solution to provide the needs of the local populations (less than 10 m³/day). Different solutions for brackish water desalination have been developed and many prototypes have been built and tested. Bourouni et al. (1999) developed a water desalination plant based on Aero- Evapo-Condensation Process (AECP). A prototype was built and tested in the region of Kebili in the south of Tunisia. A geothermal brackish water source was used to feed the unit. Promising results were found, since the cost of water was reduced to 1.2 USD per cubic meter of fresh water (Bourouni et al, 1999). The present study shows that the geothermal source can be replaced by solar preheated water. [ABSTRACT FROM AUTHOR]

Water desalination technologies and their possible coupling with solar energy were evaluated. The topic has a remarkable interest especially for the countries located within the Southern Mediterranean belt, generally characterized by vast arid and isolated areas with practically no access to electric power from the national grid. Economic factors being one of the main barriers to the diffusion of solar devices so far, an attempt was made to estimate water production cost for two different solar desalination systems: reverse osmosis and multiple effect evaporation process driven by photovoltaic and solar thermal energy, respectively. The results, obtained for plants with a capacity varying between 500 and 5,000 m³/d, were compared to the values relevant to a conventional desalination system. [ABSTRACT FROM AUTHOR]

The aim of our research is to develop humidification-dehumidification desalination technique for arid regions that are suffering from shortage of potable groundwater. The specific objective of the current study was to present a methodology to predict operation of a solar powered desalination unit using the Solar Multiple Condensation Evaporation Cycle principle. The corresponding dynamic models developed from the thermal energy and mass balances represent better the real behavior of the system and can be used to investigate the effect of various parameters on the performance of the desalination unit. Suitable modular software is developed to provide adequate computational facilities for simulating, sizing, designing and optimizing this kind of desalination unit. [ABSTRACT FROM AUTHOR]

The status of process modelling systems is outlined here along with the description of a dynamic model for the analysis and prediction of multistage flash desalination units. Several different operating conditions describing the operations of a solar powered MSF unit were simulated in order to investigate the model capabilities and potential for simulating real plant operations. The model is compared to full scale plant data and to more accurate data from a laboratory scale experimental unit. Results show how an example of the new generation of modelling tools allows us to solve the complex model for many disturbances introduced to the desalination system. The model contains ordinary differential equations with sharp changes in operating conditions which have been known to cause problems to many modelling systems. [ABSTRACT FROM AUTHOR]

for enhancing water supplies schemes in arid lands featuring an appropriate technology for solar energy use in the irrigation field. The present paper introduces the effect of water cost production on crops yields and these are then incorporated in the financial balance. It shows that the water desalination use in irrigation could be profitable for farmers, particularly for produce of high commercial value. The solar desalination in irrigation is only worthwhile if higher crop production is adopted and assuming a high qualification of farmers. However, further technical development and lower investment costs are needed for solar desalination concepts in order to get water costs down to levels competitive to more conventional desalination methods. The work was motivated by the increasing awareness of the need [ABSTRACT FROM AUTHOR]

Combining renewable solar energy and desalination would generate a sustainable source of fresh water as well as energy. This combination is highly valued as it limits and reduces air pollutant emissions and green house gases generated by combustion of fossil fuels. Increase in energy demand during the first half of this century is expected to continue, which makes the cost of renewable solar energy highly competitive against fossil fuels. Desalination has been relied on to provide fresh water for large cities and countries across the world. The desalination industry continues to grow in countries in arid regions. Various aspects of solar desalination processes, solar energy, and conventional desalination are discussed. Scenarios for combination of existing units with renewable energy are evaluated. The paper also includes a brief review of a number of novel cycles for combining solar energy and desalination. [ABSTRACT FROM AUTHOR]