Humidity and cycle period effect on hygroscopic efficiency of desiccant coating heat exchangers with different desiccants.

This study used desiccants of silica gel and sodium polyacrylate respectively coated on fin and tube heat exchangers to enhance the absorption efficiency of vapor in the air. The respective cyclic switching times for dehumidification and regeneration processes of the dehumidification systems are investigated in order to find suitable switching times for further improving the operation efficiency of the system. In the system, the two desiccant coating heat exchangers are operated periodically in mass equilibrant states between the dehumidification and regeneration processes. The experimental results show that, while hot water of 60°C was supplied during the regeneration process, suitable cyclic switching times for both desiccants in different operation conditions were recommended in this study. When the inlet air relative humidity is 80%, in the case of sodium polyacrylate, a high COPth of 0.356 can be reached by adapting the corresponding recommendatory switching times in dehumidification and regeneration processes.