Energy is an essential ingredient of socio-economic development and economic growth. Renewable energy provides a variable and environmental friendly option and national energy security at a time when decreasing global reserves of fossil fuels threatens the long-term sustainability of global economy. The integration of renewable resources in desalination and water purification is becoming increasingly attractive. This is justified by the fact that areas of fresh water shortages have plenty of solar energy and these technologies have low operating and maintenance costs. In this paper an attempt has been made to present a review, in brief, work of the highlights that have been achieved during the recent years worldwide and the state-of-the-art for most important efforts in the field of desalination by renewable energies, with emphasis on technologies and economics. The review also includes water sources, demand, availability of potable water and purification methods. The classification of distillation units has been done on the basis of literature survey till today. A comparative study between different renewable energy technologies powered desalination systems as well as economics have been done. The real problem in these technologies is the optimum economic design and evaluation of the combined plants in order to be economically viable for remote or arid regions. Wind energy technology is cheaper than the conventional ones, and used extensively around the world. The slow implementation of renewable energy projects especially in the developing countries are mostly due to the governments subsides of conventional fuels products and electricity. The economic analyses carried out so far have not been able to provide a strong basis for comparing economic viability of each desalination technology. The economic performances expressed in terms of cost of water production have been based on different system capacity, system energy source, system component, and water source. These differences make it difficult, if not impossible, to assess the economic performance of a particular technology and compare it with others. Reverse osmosis is becoming the technology of choice with continued advances being made to reduce the total energy consumption and lower the cost of water produced.

A review of renewable energy technologies integrated with desalination systems

Thermodynamic and economic considerations in solar desalination

http://iraniansciencedirect.persiangig.com/document/error%20analysis/5143.pdf

Analysis of an innovative water desalination system using low-grade solar heat☆

In a simple horizontal or inclined basin type solar still, the basin receive solar radiation through the transparent cover, heats the water to evaporate, hot saturated air rises, vapour condenses at the cool lower surface of the glass cover, slides down and is collected using a drain. In a single effect still, the latent heat of condensation is exhausted as waste. In multi effect still, the heat of condensation of the previous effect is utilized in the next effect to heat the water. This article reviews the different methods tried by different researches to improve the productivity of multi effect solar still.

A review of different methods to enhance the productivity of the multi-effect solar still

Solar still is an ideal source of fresh water for both domestic and agricultural aspects. It is one of the most important viable applications of solar energy. The simplest and most proven type of solar stills is the single basin type, but its thermal performance is limited. Many research papers were presented where different methods were performed to improve the productivity of single basin solar stills. In this paper, a review of different designs of solar stills was presented particularly the double, triple and multi-effect solar stills, vertical stills, tubular type solar stills, finned and corrugated stills, and stepped type solar stills. A detailed cost analysis for different configurations was presented. The various parameters affecting the performance of the considered designs of solar stills were outlined. The daily productivity of the double basin solar still is on the average 36% higher than that of the single basin still. The inverted absorber triple basin solar still gives a substantially higher yield than double and single basin inverted absorber solar stills. An optimum area of the vertical still absorber was found to be 3.5 m2. From the results obtained for the tubular solar still it was concluded that with cooling air flow, the production increased by about 32.8%, and with cooling water flow, it further increased by about 59% more than the system without cooling. A maximum increase in productivity of about 98% was achieved for stepped solar stills when fins, sponge and pebbles were used. The maximum productivity of stepped solar still was obtained with tray depth and width of 5 and 120 mm, which is about 57.3% higher than that of the conventional still.

L.K. Jha

Papers

A double-basin solar still coupled to a collector and operating in the thermosiphon mode