Investigation of Desalination System with Hybrid Solar/Electrical Heating Module

An integrated desalination system with a combination of electrical heating by power supply and solar heating by Fresnel lens with sun tracking system was investigated in this study. The experiments were carried out under the climatic conditions of Kaohsiung City (22°36’58” N, 120°18’47” E), Taiwan. With only solar heating by Fresnel lens, the temperature of the seawater is strongly dependent on the position of the seawater tray and climatic conditions, and seawater evaporation is not stable. To maintain the uniform evaporation of seawater, an electrical heating plate was also used to provide energy for the desalination process. The results indicate that there are two desalination processes: evaporation on the surface of the seawater and boiling inside the seawater. The production of distilled water is greatly improved with this solar/electrical desalination system, especially at boiling temperature. The results indicate that the energy efficiency and recovery efficiency of this desalination system increase rapidly as electrical power increases. In this study, the commercial energy efficiency of the system can reach 85%, and the recovery efficiency can approach 56.52%. Additionally, a higher annual productivity (6036 L) is obtained, and the cost per liter of distilled water is about 0.152 (US$/L).