Development and experimental study of a novel plate dehumidifier made of anodized aluminum

Abstract

The falling film dehumidifier is a key component in the liquid desiccant cooling system (LDCS). However, the most commonly used metals, such as steel and aluminum, can hardly resist the erosion of liquid desiccant. It greatly limits the fabrication of compact dehumidifiers and hinders the promotion of LDCS. The present study introduced a novel falling film dehumidifier which was made by the metal of anodized aluminum. Experiments were carried out to compare the dehumidification performance between ordinary aluminum dehumidifier and anodized one. The influences of air temperature, mass flow rate, inlet humidity and solution temperature, mass flow rate, temperature on dehumidification performance were identified. The results showed that the anodized aluminum could alleviate the erosion significantly. In addition, with the surface treatment by anodizing, the contact angle of lithium chloride solution decreased from 85.2° on an ordinary aluminum plate to 43.1° on an anodized one. Accordingly, the wetting area on the plate dehumidifier increased from 0.143 m2 to 0.178 m2 with a 24.5% increment at certain operating conditions. Both the absolute moisture removal and dehumidification effectiveness increased in various degrees for anodized dehumidifier compared with the ordinary type. The relative increments could reach up to 50.6% and 36.7% under certain conditions respectively. The newly introduced anodized aluminum dehumidifiers can not only alleviate the plate corrosion but also improve the dehumidification capability due to smaller surface contact angles, which can be promisingly applied in LDCS.