Abstract
Humidifiers are devices which increase the humidity of air or a carrier gas. They are used increasingly in a variety of applications such as heating, air conditioning, ventilation and desalination. The packing humidifier is the key component in solar desalination systems based on humidification and dehumidification principle. This paper focuses on developing a heat and mass transfer correlations for two types of natural packing, Thorn tree and palm leaves, used in solar desalination system. A mathematical model is developed for the packing humidifier based on heat and mass transfer balances. Several experimental tests were carried out on a test bench of an evaporation chamber, to determine the different heat and mass exchange coefficients at the contact surface of the two types of packing with the moist air. The effects of water and air mass flows are analyzed. It is shown that the heat and mass transfer coefficients increases with the increase of water and air mass flows. Correlations of mass and heat transfer coefficients are developed for each type of packing and compared with that given by the literature. Results show that the palm leaves are more efficient than the thorn trees. The developed correlations can be used to predict the packing size and the water and air outlet conditions of the packing humidifier.