A Study of Liquid Desiccant System Performance

Desiccant systems have been proposed as energy saving alternatives to vapor
compression air conditioning for handling the latent load. Desiccants are classified as either
liquid or solid. The main components for a liquid desiccant system are the dehumidification and
regeneration towers. Use of liquid desiccant offers several design and performance advantages
over solid desiccant, especially when solar energy is used for regeneration. For liquid-gas
contact, packed towers with low pressure drop provide good heat and mass transfer
characteristics for compact designs.
This paper presents the results from a study of the performance of a packed tower absorber for
lithium chloride desiccant dehumidification system. A finite difference model was developed to
determine the packing height of the dehumidification towers. The finite difference model was
written in MATLAB language which is a suitable model to measure the optimum height of a
tower.
The paper also examines the effects of different design parameters on the height of a packed
tower using a mathematical model. The effects of air and liquid flow rates, air humidity,
desiccant temperature and concentration were reported on the packing height and humidity
effectiveness of the column. In conclusion the results of the present study are compared with
previous experimental studies.