Experimental Research on Regeneration Characteristic of ED Regeneration for Lithium Bromide Desiccant Solution with High Concentration: Operating Condition and Electrode Solution

• Main Authors: Qing Cheng, Han Wang
• Format: Article
• Language: English
• Published: MDPI AG 2020-09-01
• Series: Energies
• Subjects: liquid desiccant; regeneration; electrodiaalysis; LiBr; electrode solution
• Online Access: https://www.mdpi.com/1996-1073/13/18/4733

Electrodialysis is regarded as a novel liquid regeneration method, and the regenerated solution can satisfy the dehumidification requirements even in a hot and humid environment. LiBr solution is an important choice for a liquid desiccant air conditioning system due to its great dehumidifying ability, so it is necessary to conduct experimental exploration of the regeneration characteristics of ED regeneration for LiBr solution. In this paper, the effects of solution concentration, circulation flow rate, current and electrode solution on the performance of the electrodialysis regeneration system were studied by constructing an experimental electrodialysis regeneration system. The results show that growing the starting concentration of the LiBr solution adversely affects the regeneration characteristics of the electrodialyzer and of the air conditioning system dehumidified by the solution. Under test conditions, as the initial concentration of LiBr solution increased from 45% to 55%, the performance coefficient (COP) of the system decreased from 2.12 to 1.05. When the dehumidification requirement is met, the initial concentration of the LiBr solution should be reduced. Increasing the circulating flow rate can improve the regeneration performance of the electrodialyzer and the capability of the air conditioning system dehumidified by the solution, but excessively increasing the circulating flow rate will decrease the regeneration performance of the electrodialyzer and the performance of the air conditioning system dehumidified by the solution. Increasing the current can increase the concentration of the LiBr solution in the regeneration cells in a short time, but it will reduce the regeneration performance of the electrodialyzer and the characteristic of the air conditioning system dehumidified by the solution. The current needs to be minimized when meeting regeneration requirements. With the growth in the flow rate of the electrode solution, the regeneration performance of the electrodialyser decreases continuously.