Performance analysis of a quasi-counter flow parallel-plate membrane contactor used for liquid desiccant air dehumidification

• A quasi-counter flow parallel-plate membrane contactor (QFPMC) is used for liquid desiccant air dehumidification.
• A two-dimensional steady-state heat and mass transfer mathematical model is developed.
• Compared to a cross-flow parallel-plate membrane contactor (CFPMC), the performances in the QFPMC are deteriorated.
• The solution channel pressure drop is increased.

A quasi-counter flow (combined counter/cross-flow) parallel-plate membrane contactor (QFPMC) is proposed and employed for liquid desiccant air dehumidification. The air and the liquid desiccant streams, in a quasi-counter flow arrangement, are separated by the selectively permeable membranes, which only allow the permeations of heat and water vapor while preventing other gases and liquid desiccant from permeating. A two-dimensional steady-state mathematical model is developed to study the performances in the QFPMC used for liquid desiccant air dehumidification. A finite difference method is employed to solve the equations governing momentum, heat and mass transports. The pressure drop, sensible cooling and dehumidification effectiveness are then obtained. An experimental work is conducted to validate the results. It can be found that compared to a cross-flow parallel-plate membrane contactor (CFPMC), the cooling and the dehumidification effectiveness of the QFPMC used for liquid desiccant air dehumidification are deteriorated by approximately 5–29% and 2–13%, respectively. Further, the solution channel pressure drop is increased by about 0.15–4.84 times.