Experimental study on heat and mass transfer of a multi-stage planar dehumidifier

Removing excessive moisture from the ambient air by means of a selective membrane in the membrane-based dehumidifier has become a new emerging technology. The present study pertains to the experimental work on heat and mass transfer of a multi-stage planar membrane dehumidifier. Commercial Nafion 212 membranes are applied in this membrane dehumidification system because of the large selectivity. The operating conditions of inlet dry air are fixed to maintain at temperature of 27ºC and relative humidity of 0.1% while performing dehumidification tests. Attention is mainly paid to examining the effects of various temperature, relative humidity and flow rate of the wet side inlet air on performance indexes including the dehumidification rate (DR), dew point approach temperature (DPAT), pressure loss (ΔP), and pumping power (Ω) in planar membrane-based dehumidifiers. Measured results show that increasing inlet temperature, relative humidity and flow rate of humid air in the wet channel enhances performance indexes, that is, higher DR, DPAT, ΔP and Ω. In addition, the counter flow configuration in the dehumidifier provides better mass and heat transfer performance compared to parallel flow configuration.