Theoretical and experimental study of a pad humidifier used in a seawater desalination process

This paper presents an experimental and theoretical study of a pad humidifier used in a new multi-stage solar desalination process in operation in Tunisia. The experimental operation of the humidifier is presented in terms of temperature, relative and absolute humidity, and the quantity of evaporated water for different climatic and working conditions. A global simulation of the pad humidifier is presented. The Newton–Raphson method was used to solve the conservation equations. A comparison between theoretical and experimental results is also presented.

The present investigation carried out on an operating pilot plant tested the pad humidifier. The experimental operating parameters of the humidifier are presented in terms of temperature, relative and absolute humidity, and quantity of evaporated water during a representative sunny day. The air was slightly saturated at the exit of the humidifier, independent of the climatic conditions; the air temperature was somewhat greater than the water temperature at the outlet of the humidifier during a sunny day. The numerical study shows good agreement with the experimental reading. The computer calculations also gave the heat and mass transfer coefficients that are comparable with existing ones from the literature. Acknowledgments The authors thank the European Commission for financial support in the framework of INCODC and the Tunisian Ministry of Higher Education, Scientific Research and Technology in the framework of Contrat de Programme. The INCO- DC Project No. IC18-CT98-0265 is entitled, Development and optimization of a new process for desalination of seawater by means of solar energy (SOLDES).