Characteristic investigation of static liquid desiccant dehumidification process by molecular dynamics

Liquid desiccant dehumidification has been prevalent in recent years for air conditioning with the superiority of energy saving. The microscopic details of dehumidification processes should be obtained to deepen the understanding of the mechanism and then to promote the development of this technology. In this paper, the dehumidification processes under different gas densities and temperatures were simulated by molecular dynamics. The energy characteristic and trajectory of the water molecule absorbed by liquid desiccants were reported. The interactions of different components on the water molecule were further analyzed. Results show that the barrier caused by nitrogen and oxygen is weak. When the water vapor molecule moves just close to the liquid-gas interface from the air, the attraction of Bromide ions ranks first, followed by that of water molecules in solution and that of Lithium ions. It is also found that with an increase in the gas density, the interactions produced by denser nitrogen molecules on every water vapor molecule are not necessarily larger, which may give guidance to investigate mechanisms of dehumidification under higher pressures. In addition, higher pressures may significantly enhance the dehumidification under high temperature conditions in terms of the net absorbing rate.