Heat and Mass Transfer Characteristics of Desiccant Polymers

Abstract

Desiccant-enhanced air conditioning equipment has exhibited both the capability to improve humidity control and the potential to save energy costs by lowering the latent energy requirement of the supply air stream. The resulting increasing popularity of desiccant-enhanced air conditioning systems has sparked new interest in the search for a better, more efficient desiccant material. The ultimate goal of this research was to develop a material that, when applied to an existing air-to-air heat exchanger, would achieve the necessary heat and mass transfer in a single process, thus transforming a sensible heat exchanger into a total enthalpy exchanger.

This study focuses on the development and determination of appropriate polymeric desiccant materials for use in different heat and mass transfer applications. Various candidate materials were initially studied. It was decided that polyvinyl alcohol best met the pre-determined selection criteria. After the focus material was chosen, numerical models representing two heat and mass transfer applications were created. One-dimensional numerical models were developed for the performance studies of a rotary wheel total enthalpy exchanger. A two-dimensional numerical model was developed for the performance studies of a fixed plate total enthalpy exchanger as well. Material characterization tests were performed to collect material property information required by the numerical models.

Sensible, latent, and total efficiencies gathered from both the rotary wheel total enthalpy exchanger and the fixed plate total enthalpy exchanger models indicate potential uses for some candidate polyvinyl alcohol materials.