Heat and mass transfer characteristics of a dehumidifier using an ionic liquid for a liquid desiccant system

We studied an air-liquid contactor that uses an ionic liquid as the absorptive solution, in the context of employing liquid desiccant systems for air humidity control. Most liquid desiccant systems use a packed column air-liquid contactor with lithium chloride as the absorptive solution. One of the advantages of using ionic liquids is that some of them are not corrosive towards aluminum or copper. Provided that an air-liquid contactor with ionic liquid can achieve the same or higher performance than a packed column air-liquid contactor, this component can be constructed from metal which allows it to be redesigned to improve the system performance. Therefore, the ultimate purpose of this study is to evaluate the potential of an aluminum-fabricated air-liquid contactor which uses an ionic liquid as the working fluid, and to design a system that can both dehumidify and regenerate the absorptive solution more effectively. In addition, the associated heat, mass and momentum transfer phenomena, were studied to clarify the performance of the air-liquid contactor. An experimental air-liquid contactor apparatus using an ionic liquid was used to measure temperature, concentration, mass flow rate, pressure, and humidity. By adjusting temperature, humidity, and air flow velocity, it was found that the air-liquid contactor using an ionic liquid showed comparable dehumidification performance as the lithium chloride system. This suggests the feasibility of an air-liquid contactor made of metal; such a contactor can be redesigned to further improve its performance.