Influence of concentration difference between dilute cells and regenerate cells on the performance of electrodialysis regenerator

Abstract

Air-conditioning systems consume a large proportion of energy consumption in buildings, which leads to an important significance of energy-saving in air-conditionings. For liquid desiccant air-conditioning system, a new air-conditioning with good energy-saving potential, electrodialysis (ED) can be a reliable regeneration method, which cannot be affected by hot and wet air. In this paper, an ED regeneration experimental system was conducted to investigate actual effect of concentration difference between dilute and regenerate cells on the performance of ED regenerator. The results show that increase of concentration difference is harmful to performance of ED regenerator. Moreover, decrease of liquid desiccant flow rate in regenerate cells can be a solution to add concentration increase in regenerate cells even when concentration difference is big, but it is harmful to current efficiency of ED regenerator and COP of liquid desiccant air-conditioning system based on ED regeneration. On the other hand, as current efficiency and COP finally tends to be stable with the increase of current and concentration difference, the “final” current efficiency and COP may only depend on liquid desiccant concentration, the structure of ED regenerator and characteristics of membranes, which should be improved to optimize the performance of ED regenerator.