High-efficiency humidification and cooling system via rotating sheet-type 3D capillary structures

The growing demand for energy-efficient thermal-humidity regulation in industrial and architectural applications has driven research into advanced evaporative cooling technologies. While direct evaporative cooling offers advantages such as simplicity, low energy consumption, and high efficiency, conventional systems face limitations including insufficient gas-liquid contact area, short water retention time, and restricted vapor diffusion due to static 2D packing designs. To overcome these challenges, this study introduces a dynamic cooling and humidification system based on rotating sheet-type 3D capillary structures (SCSs) fabricated via 3D printing. The SCSs consist of interconnected millimeter-scale cubic frames that leverage capillary action to form discrete water arrays, significantly enhancing water retention and evaporation duration. By integrating multiple SCSs on a rotating axis with forced airflow, the system achieves superior mass and heat transfer efficiency. Experimental results demonstrate that 30 pieces of SCSs attains a humidification capacity of 416 g/h and cool water from 80 °C to 14 °C within 15 min. Compared to conventional 2D structures, they demonstrated approximately twice the humidification performance at ambient temperature and over 30 % higher coefficient of performance (COP) at 80 °C cooling. The system's structural adjustability, combined cooling-humidification performance, and operational adaptability present a promising solution for sustainable thermal management with reduced energy consumption, offering significant potential for industrial and environmental applications.