Water and energy crises are major challenges in many places of the world. The lack of drinkable water is often intensified in arid regions. Fortunately, this is generally accompanied with abundant sources of solar energy which can be used to drive desalination and water treatment systems. Solar powered humidification-dehumidification desalination systems (HDH) have attracted much attention in recent years [1-5]. The basic idea of solar-driven HDH systems is that when hot salt water is exposed to hot dry airflow, a specific quantity of vapour can be extracted by the dry air. Fresh water is retrieved by humid air condensation in a cooling coil in the dehumidifier section. Thus, the basic components of HDH cycle include a heat source, air humidifier and dehumidifier. Nafey [6] carried out an experimental investigation of HDH processes using a solar water heater and a solar air heater to heat the water and the air streams, respectively. Air humidification was carried out using an induced fan cooling tower. Orfi [7] presented a theoretical study of a HDH solar desalination system. The seawater was preheated in the dehumidification condenser and then heated in the solar collector before entering the humidification chamber. Antar [8] experimentally investigated an air-heated HDH desalination system with single-and two-stage heat recovery systems.

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