Numerical modeling of a rotary desiccant wheel using super absorbent polymer for air dehumidification

The desiccant wheel (DW) is a widely installed desiccant dehumidification component in buildings due to its flexible design, quick response, and ability in indoor air quality enhancement. Recent studies in advanced desiccant revealed that the super absorbent polymer (SAP) possesses over six times better water vapor uptake ability than the most used silica gel. The application of SAP is significantly promising in promoting energy savings in air dehumidification in buildings. The objective of this study is to preliminarily investigate the overall dehumidification performances of a rotary DW using SAP. A transient numerical model using silica gel as a desiccant was developed and validated. The performance of different DW settings was predicted by the verified model and the experimentally tested isotherm. Modeling results indicate that compared with the silica gel-based DW, the SAP-based DW has 4-38% and 4-28% improvements in moisture removal capacity (MRC) and regeneration specific heat input (RSHI) in studied cases, respectively. The deployment of SAP-based DW can enhance both amount of dehumidification and operation energy saving. The model can furtherly guide the design and control optimization.