The second generation of the solar desalination systems

In Solar Energy Laboratory, Mechanical Engineering Department, Faculty of Engineering & Technology—Sebha University, an investigation has been conducted of the productivity of solar desalination system working on the basis of evacuation. Solar energy intensity has been concentrated by means of concave mirror, which reflects the sunrays to the focus of the concave, where the still is located. The apparatus has been designed and fabricated in our laboratory, the experimental model consists of elliptical, metallic container (to resist the imposed outer pressure) located in the focus of concave reflector. The still works under vacuum of 562.5 torr (25 kPa absolute) to reduce the normal boiling point of the income water. A condenser has been used to condense the outlet vapor—and working as a water trap—before interring the vacuum pump. The experiment was carried out during the period from 15 April to 15 May 2003. The water productivity of the offered still was found about 20 l/d per unit area of the reflector. The experimental results showed a significant improvement of the productivity of desalinized water, about 303% compared with the other thermal solar stills. Moreover, the increase of the performance ratio is about 900% more than the roof-type desalination solar systems. These results encourage us to adopt the offered procedure to manufacture large-scale solar desalination plants to provide the rural regions with drinkable water.