Humid air handling process is a key part of the air-conditioning system. Air handling units using liquid desiccant or desiccant wheel are the common air humidity control devices using desiccants. Based on the basic air handling process using desiccants

similarity between the dehumidification units using liquid desiccant and desiccant wheel is analyzed in present research. Uniformity coefficient ξ is used to describe the uniformity of the driving force between air and desiccants for heat and mass transfer

then to investigate the diversity between liquid desiccant dehumidification and desiccant wheel. It is found that

for the desiccant wheel

distribution of the driving force are relatively uniform throughout the whole wheel. As to the liquid desiccant process

the uniformity characteristic of the driving force is significantly influenced by the relative position of the inlet air and solution states. Only when the inlet air and solution states are along the iso-relative-humidity line

the distribution of the driving force is uniform

with a uniformity coefficient ξ close to 1. Analysis on different air handling processes indicate that the distribution characteristic of the driving force offers an effective guidance for constructing an optimized actual process for air dehumification.