Conference Paper Session 7: Presentation 2: Optimization of the Desiccant Dehumidifier and Regenerative Evaporative Cooling System in Hot and Humid Areas (TA-23-C038)
Optimization of the Desiccant Dehumidifier and Regenerative Evaporative Cooling System in Hot and Humid Areas (TA-23-C038)
Presenting Author: Yanling Zhang, the School of Professional Education and Executive Development,The Hong Kong Polytechnic University, Hong Kong
Author: Hao Zhang, the School of Professional Education and Executive Development,The Hong Kong Polytechnic University, Hong Kong
Author: YI Chen, College of Marine Equipment and Mechanical Engineering Jimei University, Xiamen, China
Author: Hongxing Yang, The Hong Kong Polytechnic University, Hong Kong
Author: Chun Wah Leung, the School of Professional Education and Executive Development,The Hong Kong Polytechnic University, Hong Kong
Optimization of the desiccant dehumidifier and regenerative evaporative cooling system in hot and humid areas Abstract
In recent decades, global building energy consumption has proliferated, especially in hot and humid areas, of which air conditioning (A/C) accounts for about 50%. Incorporate a liquid desiccant dehumidifier (LDD) into the indirect evaporative cooling (IEC) system is a solution to break the regional restriction of IEC and is widely applicable to various climate regions by taking the advantage of decoupling treatment of cooling and dehumidification. This liquid desiccant cooling system (LDCS) is a promising energy-saving and emission-reduction scheme and is expected to be an alternative to conventional mechanical cooling systems in hot and humid areas. One of the problems it faces is the complexity of the system. This paper aims to establish a new simulation-based LDCS and propose strategy optimization of its operating parameters. The adaptability in a hot-humid region is tested. A newly developed internally cooled LDD is used in the system, which can apply the system return air as the cooling air source. More components are connected within this system, placing higher demands on operational and maintenance optimization. For a system with many influencing parameters, sensitive analysis and multi objectives optimization were used in the optimization and assessment of the potential and performance of the system. The orthogonal test was employed for the sensitive analysis in this study, and five critical parameters (temperature, relative humidity, inlet air velocity, the concentration of the desiccant, and return air ratio) were optimized based on the response surface model. The system coefficient of performance (COP) is used as the optimization objective. The case study in hot and humid regions demonstrated the regional capability of the LDCS system. The results illustrated that the system COP using the newly proposed system increased from 4 to 8.01 compared to the traditional MVCR system. During the months with higher humidity and moderate temperature, the system runs with low wind speed (1.5m/s) and high desiccant concentration (45%) can significantly improve the COP (8.3%) and meet the dehumidification demand. The proposed system may facilitate the application of IEC and LDD and guide the monthly operational mode of the system in hot and humid areas.
Learning Objectives:
• Provide an overview of the concept of liquid desiccant cooling system (LDCS) and its potential to replace traditional mechanical vapor compressor refrigeration (MVCR) systems in hot and humid areas.
• Apply the optimization strategy of the operating parameters of LDCS to increase its system cost of production (COP).