Air humidification–dehumidification for a water desalination system using solar energy

This paper presents a theoretical study of a solar desalination system with humidification–dehumidification which is a promising technique of production of fresh water at small scale (few m3/d). A general model based on heat and mass transfer balances in each component of the system was developed and used to optimize the system's non-dimensional characteristics. The daily production of fresh water depends on the ratio between the salt water and the air mass flow rates. It was shown that, if this ratio is continuously adjusted for optimum performance, it is possible to produce more than 40 L of fresh water daily per square meter of solar collector surface on a typical July day in Tunisia. Annual performances for open and closed air loop systems are also presented.