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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]

Water plays a significant role in the daily activities of the human population, and its overall consumption is increasing rapidly, due to the enhancement of living standards. Iran is located in the dry belt of the earth, and 70% of its area is arid and semi-arid. The desalination systems, which use fossil fuels in order to overcome the water crisis in Iran, are not ever sustainable due to available energy depletion and greenhouse gas emissions. This study investigated the design of an active solar water desalination system. Evaporation rate and diameter reduction of sprayed saline water droplets in a glass chamber were calculated by a verified mathematical model. The effect of key parameters, including nozzle type (long cone orifice, drilled steel orifice, sapphire orifice), nozzle size (outlet diameters of 0.9–1.1 mm), injection pressure (1–5 bar), temperature, relative humidity (20–60%) and pressure inside the glass chamber (4500–6500 Pa), on evaporation rates, were investigated by the mathematical model. The flow rates of produced vapor and inlet saline water were calculated as 0.003252 L/s and 0.0181 L/s, respectively, by considering favorable condition, such as injection pressure of 5 bar, nozzle size of 0.9 mm, relative humidity of 20% and pressure of 4500 Pa inside the glass chamber. Radiation intensity was calculated using Meteonorm 7 software for Tehran during a year, which was compared with meteorological data of Mehrabad airport station. [ABSTRACT FROM AUTHOR]