Solar water desalination system

Solar humidification and dehumidification desalination

Solar humidification and dehumidification system follows the very basic natural water purification system (Kalidasa Murugavel & Srithar, 2011; Narayan et al., 2010). The principle of the solar humidification and dehumidification desalination (SHDD) system is basically the evaporation of salty water into an airstream and then the successive condensation of the air stream to collect pure water. Air can hold water molecules and this capacity increases with increasing temperature. For an increase of about 20°C in the temperature, there is an increase of around 400 gr water vapor per kg of dry air.

Fig. 9.3 presents an SHDD system integrated with a solar collector. The major segments of an SHDD system are a humidifier, a dehumidifier, and a solar collector as presented in Fig. 9.3 (Narayan et al., 2010; Nassar, Yousif, & Salem, 2007). Air passes through a solar air collector and gets heated. The warm dry air then enters into the humidifier and passes through the sprayed salty water and grabs water molecules. The heated humid air then flows through the dehumidifier where the water molecules get condensed to provide potable water.