Model validation and case study on internally cooled/heated dehumidifier/regenerator of liquid desiccant systems

Traditional dehumidifiers and regenerators of liquid desiccant systems often use packed columns supporting adiabatic heat and mass transfer between air and liquid desiccant. As new-style equipment, internally-cooled dehumidifiers can improve dehumidification performance due to restraining temperature increase of the desiccant. Similar to internally-cooled dehumidifiers, an idea of internally heating is imitated to put forward internally-heated regenerators. The uniform mathematical model for an internally cooled dehumidifier and internally heated regenerator was presented and validated by comparison of computation results with experimental data in this study. The case study focused on the parameters distribution comparisons of the internally cooled/heated dehumidifier/regenerator with adiabatic ones and demonstrated coupled heat and mass transfer behavior. The results show that the internally-heated regenerator can produce higher regeneration efficiency than the adiabatic one to produce better energy efficiency and eliminate the dehumidification possibility which would happen in adiabatic regenerators. The internally-cooled dehumidifier can also provide better dehumidification performance comparing with the adiabatic one; however its benefit would be not as good as the internally-heated regenerator. In addition, effect of the width of the air channel on internally cooled/heated dehumidifier/regenerator was discussed and the results can help the optimal design of this kind of dehumidifiers and regenerators. (C) 2008 Elsevier Masson SAS. All rights reserved.