Comparative Analysis on Dehumidification Performance of KCOOH–LiCl Hybrid Liquid Desiccant Air-Conditioning System: An Energy-Saving Approach

Abstract

Conventional air conditioners (AC) operate on vapor compression refrigeration (VCR) technology, which is a heavy consumer of electricity, and the used refrigerants harm the environment. In humid and hot areas, a liquid desiccant AC system integrated with a VCR system has been proposed as a better alternative to traditional standalone VCR system, as it is an energy-efficient system that can remove latent air load, air pollutants from the processed air, and it is energy-saving. In this study, a hybrid liquid desiccant air conditioning (LDAC) system with a capacity of 5.5 kW was designed and developed by integrating these two different technologies, and the vapor pressure of potassium formate (KCOOH) solution at different solution temperatures and concentrations were monitored experimentally to determine the optimal concentration range. Moreover, a comparative study was conducted to analyze the dehumidification performance of lithium chloride (LiCl) and KCOOH solutions. Experiments are designed by using Minitab 19 software, which employs the design of an experimental technique through full factorial design by considering four variables, namely, type of desiccant, inlet air flow rate, inlet desiccant temperature, and inlet air humidity. To study and compare dehumidification characteristics of both solutions, three responses were considered, i.e., the coefficient of performance of a hybrid system, the heat load of dehumidifier, and specific humidity change. Experimental results revealed that 70% of KCOOH solution exhibited comparable vapor pressure to that of 36% LiCl solution. Additionally, the dehumidification ability of the KCOOH solution was better than that of the LiCl solutions.