Catálogo de publicaciones - libros

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.

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.

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.

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.

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.

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.