Optimized geometric design of internally cooled dehumidification plates

Efficient humidity control is essential for reducing cooling energy consumption in buildings, and the performance of internally cooled liquid desiccant systems depends strongly on the geometry of the dehumidification plate. This study examined how protrusion spacing, height, and shape influence falling film behaviour and coupled heat and mass transfer based on numerical simulations. The analysis combines numerical simulation with the field synergy principle to clarify how geometric features reorganize near-wall flow structures. The results show that an intermediate spacing of 5 mm and a protrusion height of 1 mm yield the highest moistureremoval performance, providing up to a 17 % increase relative to a flat plate. Among all geometries examined, the isosceles triangular protrusion most effectively enhances transfer by strengthening downward sweeping vortices and reducing local synergy angles. Increased air velocity, inlet humidity ratio, and solution concentration weaken synergy, whereas a higher solution flow rate improves film stability and promotes transfer. This work advances previous efforts by quantitatively linking surface geometry, organized vortex structures, and synergy metrics within a unified mechanistic framework. The findings offer practical, design-oriented guidance for developing high performance dehumidification plates and improving the energy efficiency of liquid desiccant cooling systems.