Theoretical and experimental analyses of a novel recirculated regenerative rotary desiccant wheel dehumidification system

The high humidity environment in the submarine cabins results in high energy consumption of the air conditioning system. Moreover, the removal of the hydrogen contained in the air, which constitutes a threat to crew’s safety, generates a huge amount of heat. It is of particular significance to reduce the humidity of the air efficiently, through recovery of the waste heat in the dehydrogenation process. Therefore, a novel recirculated regenerative desiccant wheel dehumidification system is proposed in the present work for submarine air-conditioning. The dehumidification rate was optimized through an appropriate proportion between inlet and recirculating air flows. Theoretical modeling and experimental study were carried out to explore the optimal dehumidification performance at different working conditions. The influence of process air parameters (including temperature and humidity), regeneration air parameters (including bypass ratio and regeneration air temperature) and rotary desiccant wheel parameters (including rotation speed and air flow ratio) were analyzed. It was found that the dehumidification rate could be effectively improved compared to sea water direct cooling. It increased with increasing regeneration air temperature and temperature drop. There was an optimal bypass ratio for the system, around 55%-70%, to obtain the highest dehumidification rate. The ratio increased with the regeneration air temperature. There existed an optimal rotary speed (approx. 12 r·h^-1) and optimal air flow ratio (approx. 70%). Overall, the feasibility of the proposed system was validated and the dehumidification characteristics at various working conditions were demonstrated to prompt its application.