Research on enhancing deep dehumidification by constructing a double-effect synergistic process in an air-cooled desiccant dehumidifier

Abstract

Inherent properties of adsorption isotherm itself often restrict the dehumidification capacity of single desiccant. By leveraging the complementarities in the effective humidity range and regeneration temperature between silica gel and EMM-8, the dual desiccants dehumidifier with a double-effect synergistic process was established in this study to enhance deep dehumidification capacity. In order to explore its superiority, a numerical parametric study was conducted to compare dehumidification performance from a comprehensive view of energy and exergy between single silica gel and dual desiccants dehumidifiers via a validated numerical model. Results indicated that with a few exceptions, the dual desiccants dehumidifier is superior in the indices of dehumidification performance, and it is always able to easily reduce air humidity ratio to below the deep dehumidification threshold of 0.0062 kg/kg. Besides, at the regeneration air temperature of 90 °C, the minimum outlet air humidity ratio $Y_{a1,ad,out\_\min }$ and effective deep dehumidification time $t_{eff}$ reach 0.0024 kg/kg and 189s, achieving an air dew point temperature of minus 6 °C. Under the optimal cooling air flow arrangement, the moisture removal capacity $MRC$ and the second law efficiency $\eta$ reach their maximum of 0.0053 kg/kg and 0.167, respectively, with the dehumidification coefficient of performance $DCOP$ of 1.42.