(173as) Hollow Fiber Membranes for Evaporative Cooling

Hollow fiber membranes are widely used as membrane contactors, for gas separations, and for filtration applications. Insight into the relationship between membrane parameters such as porosity, tortuosity, pore diameter, and membrane thickness can be used for the development of mathematical models for performance characteristics. Information is presented on a series of vacuum membrane distillation experiments conducted on a highly hydrophobic polypropylene hollow fiber membrane module. This data investigates the relationship between membrane parameters and the heat transfer that occurs throughout a module as driven by evaporation. Water fed through the lumen side of the polypropylene hollow fiber membrane module will evaporate through the pores of the membrane. Because of the nanometer pore size and hydrophobicity of the membrane, a liquid-vapor interface is suspended across each of the pores by the surface tension of the water. During experimental trials, heat transfer from the lumen water measured through the variation of flow rate and shell side pressure. Application of this data to a series of fluid and mass transfer models was used to evaluate heat rejection values. Future applications of this model will provide valuable information on heat transfer phenomena in hollow fiber membrane-based separations.