Energy and exergy analysis for advanced air-conditioning: Comparative evaluation of electrodialysis and aerodynamic thermal methods in liquid-desiccant reconcentration

A comprehensive exploration into the efficiency thresholds of electrodialysis (ED) and conventional aerodynamic thermal (AT) methods for reconcentrating high-concentration solutions is absent in current discourse. To address the gap, this study undertakes explicit derivations and experimental investigations to discern the divergences in energy and exergy performances between these two methods. The experimental results reveal that the ED method exhibits 6.9 times higher energy output/input ratio than the AT method, yet its exergy efficiency is 2.1 times lower in the baseline scenario due to the oversight of spent solution restoration costs. Moreover, the exergy loss of each component is identified by comparing the maximum exergy efficiency with the experimental exergy efficiency. These results help pinpoint measures to address significant exergy loss in key components, thereby boosting system performance. For the ED method, innovation and advancement in membrane technology and materials should be prioritized due to the significant limitations imposed by imperfect membranes. While for the AT method, utilizing renewable energy sources like solar energy to power the heater can greatly enhance system efficiency, considering that exergy loss within the heater is the primary limiting factor.