Innovative modeling and simulation of membrane-based dehumidification and energy recovery equipment

Membrane-based dehumidification is a promising solution for building applications because of its low cost and limited energy consumption. Developing an efficient and cost-effective open-source code simulation tool is important for optimizing and evaluating such devices in HVAC applications. This paper describes a physics-based model, which accounts for the fundamental heat and mass transfer between a humid-air vapor stream on the feed side and a flowing stream on the permeate side of a membrane. The developed model comprises two mass transfer submodels—a microstructure model and a performance map model—and adopts a segment-by-segment method for discretizing heat and mass transfer governing equations for flow streams on the feed and permeate sides of a membrane. The model can simulate dehumidifiers and energy recovery ventilators with parallel-flow, cross-flow, and counter-flow configurations, and the predictions compare reasonably well with the measurements. The model was used to evaluate the effect of membrane microstructure parameters and membrane surface deflection factors, as well as to investigate the performance of combined dehumidification and energy recovery exchangers. The model and C++ open-source codes are expected to become a fundamental tool in analyzing future membrane-based dehumidification systems.