Experimental study of a multiple-effect humidification solar desalination technique

The object of this research is to experimentally investigate the principal operating parameters of a new desalination process working with an air multiple-effect humidification-dehumidification method. A test set-up was designed and constructed to carry out and optimize this technique. The main parts of the present set-up consist of a heat equipment device (heat exchanger), a spray humidifier and a dehumidifier system. This equipment was used to simulate the seawater desalination process experimentally with an eight-stage air solar collector heating-humidifying system. The outlet temperature of the air solar collector was correlated for use in the desalination process as a solar heating device. The operating conditions studied were: ratio of water to dry air mass flow rate through the system, humidifier inlet absolute humidity, dry air mass flow rate through the system and solar irradiation or humidifier inlet air temperature. The experimental results obtained were used to put stress and correlate the influence of the different operating conditions on the behavior of the eight-stage air heating-humidifying desalination process. The ratio of water to dry air mass flow rates was optimized, precisely 45%. The value of dry air mass flow rate through the system can be also varied with solar radiation in order to have a maximum of humidity content at the end of the system and though working in an adiabatic humidification process.