Optimizing the amount of solution in packed liquid desiccant systems for sustained dehumidification

Abstract

Liquid desiccant dehumidification technology, driven by renewable energy, presents an energy-efficient solution to dehumidification. However, a large solution amount is always configured to extend the dehumidification process and address the unavailability of renewable energy. This is due to a lack of design guidance regarding the optimal desiccant solution amount. This study aims to address this gap by offering guidelines, with a particular focus on the dehumidification duration. Initially, a benchmark for the solution amount is defined for convenient quantification in further study. Then, a theoretical analysis of the dehumidification degradation process is conducted. Results reveal that dehumidification duration is primarily constrained by the temperature rise of the desiccant solution, rather than the solution amount. Consequently, a natural cooling unit, instead of mechanical cooling, is introduced to remove the temperature rise. Following this guideline, multiplying the benchmark for the solution amount can significantly extend the dehumidification duration from minutes to hours, while increasing it by tens of times can extend further to days. Furthermore, the solution amount can be reduced by over 90 % with the design guideline compared to the traditional method. This study paves a way to significantly reduce the solution amount and relevant costs for liquid desiccant dehumidification systems.