31 August 2021

Paper No 023 – Membrane-based air dehumidification using organic ionic liquid desiccant – 13th IEA Heat Pump Conference, Jeju, Korea

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Membrane Ionic Liquid Desiccant Air Dehumidification (MILDAD) is a promising alternative to conventional
dehumidification systems that employ mechanical compressors and refrigerant-based cooling with evaporator
and condensing coils. However, its application has been limited due to high manufacturing and installation
cost, durability issues, concerns with corrosion due to leakage and salt carry over into the downstream air and
onto surfaces. This paper reviews substantial progress made with new systems based on combining advanced
ionic membranes that are pressure resistant, thin walled with high water permeability, and non-porous with
synthetic organic, non-crystalline ionic liquid desiccants. Alternative design configurations are discussed
comparing cross flow shell-and-tube membrane contactors employing ionic membrane tubes through which
ionic liquid desiccant air flows. Performance data for MILDAD prototypes is provided. Dehumidification of
the incoming supply airstream and regeneration into exhausted building air is demonstrated. The latent
effectiveness of the MILDAD system will be discussed along with some future steps to improve performance
of the system.