Abstract
We have focused on the novel desiccant dehumidification system, which is operated under isothermal condition by using heat exchanger as a desiccant unit. In this system, thermal energy generated by adsorption phenomena is removed by flowing heat exchanging fluid during dehumidification process, resulting that it is expected to achieve a large amount of dehumidified water by promotion of adsorption. In this study, a fundamental investigation was performed to estimate overall mass transfer coefficient of water vapor on silica-gel, which controls the dehumidification rate of the system, under isothermal condition. Adsorption experiments were isothermally conducted using copper tube coated with silica-gel on the inner wall under various air velocity, thickness of adsorbent and humidity of inlet air conditions. The overall mass transfer coefficient was determined by fitting experimental result with numerical one. As a result, it was found that overall mass transfer coefficient increased with increasing air velocity and decreasing thickness of silica gel coated. In addition, the mass transfer coefficient of water vapor was formulated as a function of Reynolds number and thickness of adsorbent.
