Optimization of the Liquid Desiccant Cooling Systems in Hot and Humid Areas

Abstract

Air-conditioning systems in hot and humid regions account for over 50% of total energy usage. Integrating an indirect evaporative cooling (IEC) and a liquid desiccant dehumidifier (LDD) as the liquid desiccant cooling system (LDCS) presents an energy-saving and emission-reducing solution to replace traditional mechanical vapor compression refrigeration (MVCR) systems. This integration overcomes the regional limitations of IEC in hot and humid areas. The newly developed LDCS uses exhaust air as the working air source and solar energy as the heat source for desiccant solution regeneration. This study aims to develop an empirical model for the outlet parameters of the LDCS, propose an optimization strategy for its operating parameters, and assess the potential and energy performance through parameter analysis and multifactor optimization. By conducting sensitivity analysis and optimizing six critical parameters based on a response surface model (RSM), the system outlet temperature, relative humidity, and coefficient of performance (COP) are improved as the optimization objectives. The regional capability is demonstrated in three selected hot and humid cities. The results indicate that the LDCS can significantly increase the COP by 57.3%. Additionally, it can meet the dehumidification demand when operating with 25% of the air extracted in the RIEC during months with high humidity and temperature. This study will facilitate the application of IEC and LDD technologies, guide the design and operation scheme of the system, and promote energy-saving and emission-reducing solutions in hot and humid regions.