Enhancement of Solar Desalination Still Productivity Using Flash Evaporation (Dept.M)

A solar desalination system with flashing chamber is experimentally investigated. The main objective of the present study was lo improve the performance of a traditional single slope solar still through a design modification using step-wise water basin instead of flat basin and coupling the solar still with a spray water system. These modifications can increase the solar still capability to capture more solar energy. The effect of using the spray system for seawater is investigated experimentally at different spray water velocities, and flow rates on the productivity and efficiency of the solar still. It was found that the productivity and performance of the system were significantly positive dependent on both the mass flow rate of the impure water and the linear speed of the nozzles holder. They increase slightly with the using of a porous medium in basin of the still as a heat storage sink. There is an optimum mass flow corresponding to the holder linear speed with respect to both thermal efficiency and distilled water production. The unit daily productivity reaches 6.7 L/m2.day and the average daily thermal efficiency reaches 77.35%. The maximum accumulated productivity is obtained at 250 rpm.