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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.

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.

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.

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.

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.

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.

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.

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.

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.

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.