IN-24-C019 - Experimental Evaluation of a Compact Liquid-Desiccant-Based Clothes Dryer System

Advanced clothes dryer systems utilizing vapor compression cycles often employ refrigerants with significant negative environmental impacts as the working fluids. In contrast, this study introduces a novel liquid-desiccant-based clothes dryer system, utilizing a liquid desiccant solution as the working fluid, free from global warming potential. Despite the environmental benefits, traditional liquid desiccant systems often suffer from bulkiness. This research addresses this issue by developing and testing a compact liquid-desiccant-based clothes dryer designed to match the footprint of commercially available dryer bodies. The foundational design elements encompass an absorber unit and an integrated desorber-condenser module engineered to occupy a reduced volume while delivering high drying performance. The dehumidifier module employs multiple parallel textured surfaces to efficiently capture moisture at elevated temperatures. The desorber-condenser module transfers the latent heat of the condensation process from the desorbed water vapor to the air entering the drum. The desorber-condenser module also serves as the site of thermal energy transfer between the heating element and the liquid desiccant solution. The energy efficiency and drying time of the proposed system have been analyzed under the DOE standard testing procedure at various operational conditions. The effect of desorber surface temperature was carried out under static conditions. It was found that with an increase in desorber surface temperature, Combined Energy Factor (CEF) and total drying time decrease. When the desorber surface temperature was kept constant throughout the drying process, a peak CEF of 5.67 lbm/kWh at a desorber operating temperature of 116°C and a minimum drying time of 33 min at a desorber operating temperature of 151°C were recorded. When the desorber surface temperature was dynamically varied from 155°C at a rate of 1°C/min, a CEF of 6.51 lbm/kWh and a drying time of 36 minutes were achieved. The results from the present study offer new ways to optimize the operating conditions of advanced liquid-desiccant-based drying systems.