Development and performance evaluation of a liquid desiccant air conditioning system with hybrid electrodialysis and thermal regeneration

Liquid desiccant air conditioning (LDAC) systems have gained increasing attention due to the improved energy performance and reduced environmental impacts. This paper presents an LDAC system using electrodialysis (ED) as well as low grade heat generated from a hybrid photovoltaic thermal and evacuated tube (PVT-ET) collector for liquid desiccant regeneration. As ED regenerator is a key component in the proposed system, a modified mathematical model is used to simulate the mass transfer of the ED stack. The performance of the model was validated using the experimental data generated based on a lab-scale experimental setup. It is shown that the model predicted concentration of the solution in the regenerated tank matched well with the experimental data. Compared to the LDAC systems using conventional thermal regeneration, the proposed ED system can regenerate the LiCl liquid desiccant solution at a low temperature. The regeneration process can also be operated during night-time. The whole system simulation using TRNSYS showed that the outlet concentration of the spent solution in the thermal regenerator was in the range of 26.87-26.97% (wt/wt). The concentration of the regenerated solution at the ED outlet can be maintained at 29.99% (wt/wt).