Emerging energy efficient thermally driven HVAC technology: Liquid desiccant enhanced evaporative air conditioning

Thermal cooling using low-grade energy resources such as solar energy, waste heat, biomass is one of the key solutions to the environmental degradation and fast depletion of primary energy resources. Liquid desiccant-based evaporative cooling is an environment-friendly and cost-effective alternative to the conventional air-conditioning systems due to its energy-saving potential. The idea of a liquid desiccant evaporative cooling system is to combine liquid desiccant dehumidification with an evaporative cooling system in order to advance the overall system performance and to utilize clean and renewable energy resources. In this chapter, desiccant-enhanced evaporative cooling systems have been discussed from variety of aspects including background and need of alternative cooling systems, concept of desiccant-based evaporative coolers, system configurations, as well as developments of technology. The research indicates that the technology of liquid desiccant-based evaporative cooler has a great potential of providing human thermal comfort conditions in hot and humid climatic conditions at the expense of less primary resources of energy as compared to conventional cooling systems. Furthermore, recent developments for liquid desiccant dehumidifiers and evaporative cooling technology along with future view of research in the field of desiccant cooling technology have been presented.