Design and development of wire-mesh packed bed liquid desiccant dehumidifier to reduce pressure-drop and carryover

Abstract

In response to the high air-pressure drop and desiccant carryover experienced in liquid desiccant-packed bed dehumidifiers, which adversely affect the room environment and system economics, this study explored various modified wire-mesh packed bed designs. It experimentally evaluated dehumidification efficiency, and thermal performance across different corrugated wire-mesh packings, introducing a new design for cost-effective moisture removal while reducing pressure drop and desiccant carryover. Three specially designed packings (P-1, P-2, and P-3) were tested against standard commercial options like Celdek (7090, 6090, 5090) and Mellapak 250Y, focusing on optimizing performance. At a constant optimal concentration of the desiccant solution, the effects of airflow rates (ma), solution flow rates (ms), and solution temperatures (Ts) on the performance of the system was analyzed. The findings indicated that P-1 performed better than others, particularly in terms of condensation rate (CR) and moisture effectiveness (εm). Specifically, it outperformed the acrylonitrile butadiene styrene (ABS) (benchmark) packing by 22.1 % and 8 % respectively at a solution concentration of 40 wt% and ma of 0.025 kg/s under ambient conditions of nearly 0.02921 kg/kg specific humidity and 31 °C temperature. Increasing the void fraction led to a reduction in air pressure drop while enhancing the wettability, and dehumidification efficiency. The packing, P-1, made of stainless steel (SS340) with 0.3 cm mesh was finally proposed to obtain better performance for dehumidification applications in buildings. Additionally, its potential to reduce air-pressure drop and desiccant carry-over can provide improved energy efficiency and enhanced air quality, making it a practical choice for sustainable building cooling solutions.