Numerical and experimental study on the regeneration performance of a liquid desiccant system coupled with rotating packed bed and vacuum

Abstract

High moisture load generated during the air quality control process introduces a considerable energy consumption, liquid desiccant air-conditioning system has some constrains during the application although it provides an opportunity to save energy. Therefore, a novel regeneration system of liquid desiccant coupled with rotating packed bed (RPB) and vacuum technique was proposed in this study. A numerical model of RPB was developed and validated in order to characterize the heat and mass transfer process during the regeneration and correlate to its performance, furtherly, an experimental rig was built to study its feasibility of RPB application in regenerators. To facility the investigation, the moisture removal rate was introduced to evaluate the regeneration performance and thereafter the effects of three key factors, rotating speed, regeneration pressure and initial concentration of liquid desiccant, were investigated accordingly. The results show that the moisture removal rate increases with the rotating speed for which the maximum of 17.395 g·L-1·min−1 was reached; meanwhile it decreases with the regeneration pressure and initial concentration of desiccant, among which the concentration has a greater impact on moisture removal rate. Compared to traditional packed bed regenerators, the rotating packed bed can significantly enhance the heat and mass transfer rate. In overall, the proposed system can reduce the energy consumption by 10.6%, the regenerate performance was improved significantly, and the feasibility of proposed system was verified to prompt its application.