Recent Developments in Liquid Desiccant-Based Cooling Systems

The conventional vapor compression air conditioning systems remove moisture from the air by cooling to a very low temperature. This dehumidified air is then reheated to an appropriate supply temperature for occupants comfort. These two processes of excessive cooling and reheating of process air remarkably increase the air conditioning load. To avoid the excessive waste of energy an alternative way to achieve desired moisture reduction is the use of liquid desiccant dehumidification system in which a desiccant material absorbs moisture from the humid air. Thermal energy is used to regenerate the desiccant material and cycle continues. A good desiccant should have better moisture absorption capability and lower temperature of regeneration. Different types of new desiccant materials with high dehumidification performance have been proposed in past few years. These materials have the potential to improve the performance of liquid desiccant cooling systems because of lower heat input required for regeneration. In this article, liquid desiccant cooling systems have been discussed from variety of aspects including the need of liquid desiccant technology as an alternative way of cooling, working of liquid desiccant cycle, as well as developments of this technology. The research indicated that the technology of liquid desiccant cooling has a great potential of energy saving and providing human thermal comfort conditions in hot and humid climatic conditions with the utilization of alternative energy resources.