Three-fluid membrane contactors for improving the energy efficiency of refrigeration and air-handling systems

This paper concerns an innovative three-fluid membrane contactor able to exchange both sensible heat and latent heat with the process air. A condensing/evaporating refrigerant (first fluid) exchanges heat with a second fluid (water/liquid desiccant) flowing over the outer surface of hydrophobic membrane capillaries, inside which the process air flows (third fluid). In this study, bench tests were carried out with either distilled water or saturated KCOOH solution as the desiccant. Water at a controlled temperature was used to simulate the refrigerant-phase change across the component. A theoretical model of the component yielded predictions that displayed good agreement with the experimental results.Ways of improving the enthalpy effectiveness of the component are discussed, as are applications in refrigeration plants and hybrid air-conditioning systems (vapour-compression cycles plus liquid desiccants). This new component raises very interesting applicative opportunities; though fairly compact, it can improve the energy efficiency of refrigeration and air-handling systems.