Research On The Performance Of The Liquid Desiccant Air Dehumidifier

Liquid desiccant dehumidification is a technology using solution for airdehumidification, which has advantages of environmental protection and energyconservation by using non-polluting cycle working fluid for air handling driven byavailable waste heat, solar energy or other low-grade energy sources. As thegovernment has attached great importance to promote energy conservation policy indifferent fields, more and more scholars focus on the liquid desiccant technology, andvarious types of liquid desiccant units have been proposed in recent years. Althoughthe liquid desiccant technology has been applied in a number of industrial andcommercial situations, it still remains to be studied in the aspects of liquid carryingand operation strategies. Consequently this paper carried out the following studies:First, a new partitions core is setup for solving the problem of liquid carrying ofthe outlet air from dehumidifier/regenerator. In order to obtain the performance of thecore, the dehumidification and regeneration experiments were carried out on the airdehumidification/regeneration unit. The amount of liquid carrying from the newpartitions core was compared with that from wet curtain of5090. Thedehumidification/regeneration performance of the new partitions core and5090wetcurtain were also compared. Experimental results showed that, under the sameexperimental conditions, the amount of liquid carrying of the new partitions wasreduced by99.6%in dehumidifier and58%-87%in regenerator compared with that of5090wet curtain. As it turned out, the two new partitions could be a good solution tothe problem of liquid carrying. In the aspect of mass transfer performance, both thedehumidifier and regenerator with the new partitions performed better than the oneswith5090wet curtain. Compared with the5090wet curtain, the dehumidification rateand the volumetric mass transfer coefficient of the new partitions were increased by11%-22%and9%-42%respectively under the same experimental conditions. Inregenerator, the regeneration rate and the volumetric mass transfer coefficient of thenew partitions were increased by24%-38%and7%-36%respectively than that of the5090wet curtain. Second, in order to provide operational strategies for the unit, experimental studyof continuity was conducted on the basis of dehumidification and regenerationsemi-continuous experiments. Effect of the variety law on the dehumidification ratewas studied by the interaction of any two factors, such as solution regenerationtemperature, solution flow rate and concentration. The dehumidification rate formulawas fitted by the factors of solution regeneration temperature, solution flow rate,concentration. On the basis of the formula developed, the operation of the unit wasadjusted according to the dynamic parameters of outdoor air. The thermodynamicproperty of the unit was also analyzed under different regeneration temperatures.Finally, the flow field distribution of the new partitions inside the dehumidifierwas studied by simulation. The result showed that the air flow is more evenlydistributed within the new partitions core, which is favorable for mass transfer.Meanwhile, the reliability of the model was verified by comparing the simulationresults with experimental results, and this model could provide the basis for thestructure transformation of the dehumidifier.