Design and simulation of a novel modular solar-regenerative solid desiccant dehumidification system

Desiccant wheels are widely used solid dehumidification systems that provide continuous operation and high moisture removal efficiency. However, they require heated air for regeneration, typically supplied by external sources such as electric or gas heaters, which increases overall system complexity. This research presents a novel modular solid desiccant dehumidification system that directly utilizes solar energy for regeneration, providing a compact and efficient design. This system features a blade-damper-shaped adsorption-desorption bed integrated with dual air channels, enabling the synchronization of dehumidification and solar-driven regeneration. The specially shaped carbon black-coated silica foams were employed as the desiccant. To fully evaluate the dehumidification performance of the novel system, a multiphysics simulation-based approach which combines the Linear Driving Force (LDF) model was adopted with different desiccant configurations: 20 mm and 5 mm block-shaped desiccants, and 5 mm and 2.5 mm fin-shaped desiccants. The transient simulation results reveal that the fin-shaped desiccant configurations yield significantly better dehumidification performance than the block-shaped ones, owing to the more substantial increase in effective contact surface area. In particular, the system equipped with the 2.5 mm fin-shaped desiccant achieved the best dehumidification outcome, reducing the humidity ratio to a minimum of 8.4 g/kg and attaining a peak moisture removal rate of 0.475 g/(m2·s). During regeneration, this configuration demonstrated a maximum regeneration temperature of approximately 70 °C under 1000 W/m2 solar irradiation. The system operates with a mode swapping every 80 min. The simulation results prove the feasibility of proposed modular solar-regenerative solid desiccant dehumidification system, which has potential to enhance the performance of DPC systems.