Modelling and performance evaluation of a novel disk-type liquid desiccant air dehumidifier with no film flow

Abstract

A liquid desiccant air dehumidifier (LDAD) with both high efficiency and low desiccant carryover is of vital significance to indoor environment. However, the instability introduced by desiccant film flow tends to deteriorate the droplets entrainment in product air and remains to be solved. In this study, a novel disk-type liquid desiccant air dehumidifier with no film flow (DLDAD) was developed to radically eliminate the apparent desiccant film flow. The distribution and refreshing of liquid desiccant on wetted surface is realized by the rotation of the disks rather than the film flow of liquid desiccant. The performance of DLDAD was numerically evaluated under varied dehumidifier parameters, including stage number, immersion depth, rotation speed and air and solution parameters. The results show that an increase in the stage number can increase dehumidification performance, ensuring the air outlet humidity ratio below 10 g/kg. The dimensionless immersion depth of 0.4 and the rotation speed of 3 r/min are suggested for better dehumidification performance in this case. Increasing solution concentration or decreasing solution temperature can effectively reduce the air outlet humidity ratio. All these results can support the structural design and practical application for LDADs with higher efficiency and lower desiccant carryover in the future.