Experimental investigation on LiCl-KCOOH blend for enhancing hybrid liquid desiccant–vapour compression system performance

Conventional vapour compression system (VCS) consumes a substantial amount of energy to maintain human thermal comfort, while its inability to control humidity precisely has led to the exploration of alternative cooling technologies. Among all alternative cooling technologies, the liquid desiccant system (LDS) has gained attention as an energy-efficient and sustainable solution offering precise humidity control. The performance of LDS is strongly influenced by the desiccant type, with desiccant blends demonstrating superior moisture absorption compared to single desiccants. Among these, a blend of lithium chloride (LiCl) and potassium formate (KCOOH) shows promising dehumidification performance with reduced corrosion potential, yet remains underexplored. This study investigates the optimal blend ratio of LiCl-KCOOH through experimental analysis within a hybrid liquid desiccant vapour compression (LDVC) system. The research compares the dehumidification performance of this blend against a pure LiCl solution, employing an optimal mixture design technique to develop empirical correlations for key performance parameters. These correlations were validated using analysis of variation (ANOVA) analysis. The influence of the liquid-to-gas ($L/G$) ratio on dehumidifier performance and the economic feasibility of the desiccant blend were also examined. Results reveal that the optimal blend comprises 37 % LiCl and 18 % KCOOH, enhancing the moisture removal rate ($\dot{\text{MRR}}$) and dehumidification effectiveness (${\epsilon }_{\text{DEH}}$) by approximately 12.3 % and 10.5 %, respectively, under hot and humid conditions. The primary contribution of this paper is the identification of the optimal desiccant blend composition of LiCl-KCOOH and the development of empirical models to evaluate the dehumidification performance of a hybrid LDVC system using this blend.