On the application of a membrane air-liquid contactor for air dehumidification

This paper deals with a new approach to absorption air-handling systems working with liquid desiccants. A hydrophobic synthetic membrane, permeable to vapour but not to liquid, acts as a porous barrier between a hygroscopic solution and moist air. The results of a first series of experiments performed on a microfibre polyethylene membrane are presented and discussed in relation to an analytical model developed to analyse non-isothermal vapour flux through a hydrophobic membrane. Theoretically analysis is carried out to study the influence of different parameters affecting vapour mass Aux through the membrane. The results show that considerable vapour flux can be exchanged to/from a liquid desiccant and an air stream through the membrane, suggesting the feasibility of using compact-membrane absorber and desorber units in air handling. Furthermore, membrane contactors can achieve energy saving by performing desiccant reactivation at moderate temperatures (310-330 K).