Experimental and theoretical analysis of liquid desiccant dehumidification process based on an advanced hybrid air-conditioning system

Abstract

This paper presents the characteristic study of the air dehumidification process using liquid desiccant with low-temperature and low-concentration. Experiment research was conducted with an advanced liquid desiccant system driven by heat pump, and experimental data was acquired with the variation of the parameters of the inlet air and desiccant solution. During the experiment, LiCl solution was used as the liquid desiccant, while the temperature of the desiccant solution was lower than 20 °C and the mass concentration of the desiccant solution was kept below 0.33. In order to describe this special air dehumidification process, the classical NTU-Le model was modified upon the parameter ranges of the air and desiccant solution in this study. Furthermore, a new method for determining the coupled heat and mass transfer coefficients between air and desiccant solution was developed. With this method, heat and mass transfer correlations were derived from the experimental data to predict the performance of this special air dehumidification process. Based on these studies, an additional experiment was carried out to validate the accuracy of the corrected NTU-Le model, as well as the new evaluation method and the new heat and mass transfer correlations. Finally, the effects of the inlet thermophysical properties of air and desiccant solution on the performance of the dehumidifier were investigated. In addition, the real-time performance of the new hybrid system under a typical summer condition was analyzed.