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Water and energy are two inseparable issues that play an important role in human life. The oceans are massive resources of water, but the main problem is their high salinity. Solar desalination systems have been considered as a suitable solution to solve the problem of water deficit and to overcome the environmental problems caused by the conventional water desalination plants. One of the important points in raising the efficiency of solar water desalination systems is increasing the evaporation rate in a system with specified dimensions. The direction of the spraying of seawater in the chamber is one of the effective parameters in elevating the discharged rate of vapor in solar desalination systems. In this study, the effects of other parameters including injection pressure, nozzle outlet diameter, nozzle type, and relative humidity inside the chamber were investigated in both upward and downward injection directions by a mathematical model. The results of the model indicated variations in the rate of vapor generation in upward and downward directions. Also, the effects of other important parameters were studied including injection pressure (in the range of 1 to 5 bar), outlet diameter of the nozzle (in the range of 0.9 to 1.1 mm), type of nozzle (long cone orifice, drilled steel orifice, and sapphire orifice) and relative humidity (within the range of 20% to 60%). Overall, the results indicated increased vapor production at an injection pressure of 5 bar, nozzle outlet diameter of 0.9 mm, long cone orifice nozzle, a relative humidity of 20%, and upward direction. [ABSTRACT FROM AUTHOR]

In this study, the evaporation of injected water droplets, as one of the most important parts of the solar desalination system, was investigated. Elevating the evaporation rate is considered as one of the important points in increasing the efficiency of solar water desalination systems. The effective parameters on evaporation rate and reduction of the droplets’ diameter, which were sprayed in the chamber were investigated using the mathematical model. It should be noted that the effects of different factors mean environmental conditions inside the chamber, such as relative humidity and pressure, as well as the primary conditions of the droplet, including temperature, injection pressure, and initial diameter, were also considered. In this study, the information about a droplet inside the glass chamber in a downward direction at injection pressures of 1, 3 and 5 bar, inlet temperatures of 60°C, 65°C and 70°C and nozzle outlet diameters of 1.1, 1.0 and 0.9 mm was investigated by considering three types of long cone orifice, drilled steel orifice and sapphire orifice nozzle at different relative humidity and pressure values in a glass chamber to determine the favorable conditions for evaporation of saline water and freshwater production. Increasing the availability of freshwater by producing a high-flow rate of vapor is known as the most important achievement in solar water desalination systems. Finally, the best condition for producing freshwater was obtained at the injection pressure of 5 bar, the inlet temperature of 70°C, and the nozzle outlet diameter of 0.9 mm with a discharge coefficient of 0.9. [ABSTRACT FROM AUTHOR]