Theoretical and experimental study of cascade solar stills

Most part of Iran is dominated by arid and semi-arid areas due to low annual rainfall. The need for production of fresh water from brackish water is considerably high, especially in dry regions. In this study 1 month daily-based experimental data from a solar still site has been reported. The technical and operational problems of this site which finally contributed to the total cease of the site are described. Then a detailed analysis is investigated on progress of a prototype which constructed in order to solve the site's problems. The results of 1 month of experimental data of the final design showed that the last prototype could be used to solve the current problems of the site. The average fresh water production for the modified cascade solar still is around 6.7 lit/day m(2), which shows 26% increase in compare to the initial site's units. The conductivity of the produced distilled water reduced to 10-20 mu S/cm which is an acceptable range in the solar still science. Moreover, a mathematical model is proposed to simulate the modified still. The model results and experimental data show a significant increase in the fresh water production in compare with the initial site's stills. (C) 2013 Elsevier Ltd. All rights reserved.