Performance investigation and exergy analysis of a novel recirculated regenerative solid desiccant dehumidification system

Vapor compression dehumidification (VCD) is limited by the wet-bulb temperature, which results in high-energy consumption, especially in enclosed hot and humid spaces. An improved recirculated regenerative solid desiccant-vapor compression (RRSD-VC) hybrid dehumidification system was proposed to achieve highly efficient dehumidification in enclosed cabins, such as those in marines, spacecraft, and underground shelters. An experimental study of the RRSD-VC system was carried out to analyze the dehumidification characteristics and exergy performance. The results indicate that the regenerative airflow ratio (γ) was the most crucial performance indicator of the proposed system. The system moisture removal capacity (D_tot) increased with decreasing precooling temperature and increasing regeneration air temperature, and the highest D_tot was obtained when the optimal γ was reached. The exergy efficiency of the RRSD-VC system (η_ex) was inversely proportional to γ. Therefore, a balance of high dehumidification capacity and low energy consumption could be maintained in the system design. Moreover, η_ex could be improved by 55.7% when the electric heating was replaced by heating with waste heat recovered from the engine exhaust gas for air regeneration. The results of further parametric analysis showed that the RRSD-VC system was more adaptable than the VCD system to hot and humid conditions.