A review of desiccant evaporative cooling systems in hot and humid climates

The use of air conditioning systems has seen considerable growth in the last few decades all over the world, especially in commercial buildings. However, it has shown to have adverse effects on the environment as well as increased energy consumption in buildings. Thus, there has been extensive research to identify alternatives to conventional vapour compression air conditioning systems. Desiccant evaporative cooling (DEC) is one such encouraging system, yet research into its use is still at an initial stage and it needs to be investigated further. In this paper desiccant-based evaporative cooling systems are reviewed, focusing mostly on the solid-based desiccant. The study presents one-stage and two-stage dehumidification, and direct and indirect evaporative cooling for application in hot and humid climates. The review has identified that solid-based desiccant evaporative cooling systems have high potential for use in hot and humid weather. Basic desiccant direct evaporative cooling systems having greater effectiveness in term of output temperature compared to indirect types, but any enhancement in the basic system such as use of an indirect/direct type resulted in a more efficient system. Different system configurations also showed that two-stage systems performed better and displayed lower supply temperatures and humidity ratios compared to the one-stage system.