Pioneer Solar Water Desalination System: Experimental Testing and Numerical Simulation

Abstract

A pioneer system of solar water desalination was constructed, tested and numerically simulated for moderate latitudes, Cairo 30 °N. The humidification/dehumidification (HD) process is considered in this system. The salt water is heated by either solar energy or/and auxiliary heater before injection inside an insulated desalination chamber using an air atomizer. The air is supplied into a condenser by a 0.4 kW blower and later on it pulls hot salt water up through the atomizer from an insulated tank. By this idea the air is preheated inside the condenser and is used as a water pump. The flashing water is evaporated and condensed simultaneously above the condenser surface. A 2.39 M2 flat-plate solar collector is used to heat the salt water existed in an insulated tank. The tank opening is closed by the chamber one. By this way the salt water is circulated naturally inside the solar water heater where it is forced inside the desalination chamber. A numerical simulation of the considered system was developed and validated. It was provided a mathematical model of each system component. The system was successfully tested using either solar or/and auxiliary energies. It can produce about 36 liter daily of purified water where the using of solar energy alone can obtain about 12 liter on clear days. To visualize the heat and mass transfer inside the chamber temperature and humidity distribution were measured. The annual and monthly performance of the system is presented. In addition an empirical equation of the distilled water quantity is obtained versus the incident solar radiation. Moreover, economic study was provided and it is found that one liter of distilled water can cost about 0.2 US$ using the considered system. Key words: Solar desalination; Air atomizer; Air condenser; Thermosiphon; Humidification/dehumidification; Numerical simulation