Influences of the mixed LiCl-CaCl 2 liquid desiccant solution on a membrane-based dehumidification system: parametric analysis and mixing ratio selection

Bai, Hongyu; Zhu, Jie; Chu, Junze; Chen, Xiangjie; Cui, Yuanlong; Yan, Yuying

Abstract

The membrane-based liquid desiccant dehumidification system has high energy efficiency without the traditional liquid system carry-over problem. The performance of such a system strongly depends on solution's temperature and concentration, which have direct relationship to the solution surface vapour pressure. Compared with the pure liquid desiccant solution, the mixed liquid desiccant solution has lower surface vapour pressure, better system performance and lower material cost. In this paper, the performance of a flat-plate membrane-based liquid desiccant dehumidification system with the mixed solution (LiCl and CaCl2) is investigated through theoretical and experimental approaches. A mathematical model is established to predict the system performance, while the electrolyte non-random two-liquid (NRTL) method is applied to calculate the mixed solution properties. The influences of the solution mixing ratio, temperature Tsol and concentration Csol are evaluated, and it is found that the regeneration heat Qreg can be dramatically reduced by either applying a high concentration solution or increasing CaCl2 content in the mixed solution. Compared with the pure LiCl solution system, the mixed solution system COP can be improved up to 30.23% by increasing CaCl2 content for a 30% concentration solution. The optimum mixing ratio varies with the solution concentration. For the mixed LiCl-CaCl2 solution, the system highest COPs appear at the mixing ratios of 3:1, 2:1 and 1:1 for 20%, 30% and 40% concentrations respectively.

Citation

Bai, H., Zhu, J., Chu, J., Chen, X., Cui, Y., & Yan, Y. (2019). Influences of the mixed LiCl-CaCl 2 liquid desiccant solution on a membrane-based dehumidification system: parametric analysis and mixing ratio selection. Energy and Buildings, 183, 592-606. https://doi.org/10.1016/j.enbuild.2018.11.038

• Journal Article Type: Article
• Acceptance Date: Nov 19, 2018
• Online Publication Date: Dec 1, 2018
• Publication Date: Jan 15, 2019
• Deposit Date: Nov 19, 2018
• Publicly Available Date: Dec 2, 2019
• Journal: Energy and Buildings
• Print ISSN: 0378-7788
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 183
• Pages: 592-606
• DOI: https://doi.org/10.1016/j.enbuild.2018.11.038
• Keywords: dehumidifier, membrane, COP, mixed solution
• Public URL: https://nottingham-repository.worktribe.com/output/1282507
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0378778818332043?via%3Dihub
• Additional Information: This article is maintained by: Elsevier; Article Title: Influences of the mixed LiCl-CaCl2 liquid desiccant solution on a membrane-based dehumidification system: Parametric analysis and mixing ratio selection; Journal Title: Energy and Buildings; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.enbuild.2018.11.038; Content Type: article; Copyright: © 2018 Elsevier B.V. All rights reserved.