Modeling, simulation and experimental validation of a pad humidifier used in solar desalination process

Water is an extremely important commodity for the improvement of arid and semi-arid environments. As for the water production technology, desalination techniques based on either thermal or membrane separation methods such as multi-stage flash, multi-effect, vapor compression and reverse osmosis are only reliable for large capacity ranges of 100-50,000 m³/ day of freshwater production, inefficient from the view point of energy consumption and generally coupled to fossil fuel sources that have a negative impact on the environment. Hence, for the improvement of these regions it is necessary to shift from fossil fuel usage to some environmentally friendly energy source, such as solar energy, as it is available abundantly in such environments. The aim of the present paper is to study numerically and experimentally a pad humidifier used in a seawater solar desalination unit based on humidification-dehumidification principle. The pad humidifier dynamic modeling is based on various heat and mass balance equations. The effect of operating parameters on the pad humidifier characteristics has been investigated. To validate the computer program, a comparison between the experimental and theoretical results was conducted, and a good agreement had been obtained.