Experimental study of dynamic characteristics of liquid desiccant dehumidification processes

Abstract

Liquid desiccant dehumidification is an effective method of removing moisture from the air for air conditioning in built environments. The dehumidifier is a critical component where coupled heat and mass transfer between the desiccant solution and the air occurs. Understanding the dynamic characteristics of the dehumidifier is essential to develop controllers and operation strategies for the liquid desiccant hybrid air-conditioning systems. This article presents an experimental study of the dynamic heat and mass transfer characteristics of a counter-flow packed-type liquid desiccant dehumidifier. Experiments were carried out to investigate the dynamic responses of the outlet air and desiccant solution to various changing inlet conditions. In addition, the influences of typical configuration and operation parameters on the dynamic dehumidification process were analyzed. The results indicate that the settling time of the dynamic process decreases with the air and solution flow rates while increases with the packing height. The experimental results also show that the outlet air humidity ratio stabilizes sooner than the outlet air temperature during the dynamic process. The time constants of the heat and mass transfer processes were obtained, which are valuable to controller design.