Experimental study on a horizontal tube falling film evaporation and closed circulation solar desalination system

A specifically designed solar desalinization system with a solar collector (about 2.01 m2 in area) has been developed and tested under practical weather conditions. In this system, a considerable fraction of the latent and sensible heat is successfully recycled and utilized for preheating the feedstock and recycling air via a condensation cavity and heat exchangers. The thermal performance of the system is greatly improved because of the falling film evaporation technology used. As a result, the yield is about two to three times more than that of a conventional single basin type solar still under the same conditions. The transient-state performance of the system, the relationships with the solar radiation, the operating temperature, the feedstock flow rate and the productivity are presented. Other factors influencing the freshwater are also discussed.