Energy efficient design of internal cooling liquid desiccant dehumidification system based on useful exergy evaluation

This study presents a numerical model for an internally cooled liquid desiccant dehumidification system, specifically designed to optimize energy efficiency in high temperature and humidity environments. Utilizing exergy analysis, the performance characteristics of the system are evaluated, and energy-saving strategies tailored for these challenging conditions are identified. The impact of key component parameters, such as dehumidification and regeneration mass transfer coefficients, on energy consumption is thoroughly investigated. The results show that higher heating and cooling exergy demands are prevalent in humid climates compared to dry conditions. Furthermore, enhancing the dehumidification mass transfer coefficient significantly reduces energy consumption, surpassing the benefits achieved by increasing the regeneration coefficient. Optimal design values of 20 g/(m²·s) for dehumidification and 15 g/(m²·s) for regeneration mass transfer coefficients are recommended, alongside a maximum heat transfer coefficient limit of 120 W/(m²·K). With these optimal parameters, the water cooling exergy, solution heating exergy, and solution cooling exergy can be reduced by 10.1 %, 44.3 %, and 65.8 %, respectively. This research contributes valuable insights into the optimization of liquid desiccant systems, offering practical design guidelines for enhancing energy efficiency specifically in high temperature and humidity climates.