Exergy destruction comparison of facial area ratio on dehumidification performance of the rotary desiccant wheel system under conventional and deep dehumidification

Abstract

The rotary desiccant wheel has been extensively applied for humidity control in air conditioning systems, and it is also capable of deep dehumidification processes in various areas. The differences in the exergy destruction characteristics of the desiccant wheel between deep dehumidification and conventional dehumidification were still unclear. This study conducted numerical investigations to illustrate the impact of operating parameters, especially the facial area ratio, on the transfer exergy destruction and the mixing exergy destruction of the desiccant wheel components. The results revealed that the desiccant wheel with a facial area ratio of 1 has a higher exergy efficiency in conventional dehumidification due to low transfer and mixing exergy destruction. However, it shows a lower exergy efficiency than that of 3 under the deep dehumidification depth when operated at a high regeneration air humidity ratio. In the deep dehumidification process, the mixing exergy destruction caused by the distribution inhomogeneity of temperature and humidity ratio becomes a prominent factor to influence the exergy efficiency along with the transfer exergy destruction. It is concluded that the efficient design of the desiccant wheel dehumidification system highly depends on the dehumidification depth, the operating parameters, and the proper facial area ratio.