Development of a Liquid Desiccant Air Conditioning System Using Ionic Liquids

LDACs (liquid desiccant air-conditioners) with heat pump can perform cooling dehumidification or heating humidification, and have high energy-saving and sterilization performance.Therefore, they are installed in hospitals, nursing homes, and food factories, where humidity control is required.However, LiCl (lithium chloride), a conventional humidity control liquid, is highly corrosive to metals, requiring the use of highly corrosion-resistant materials for the pipes and the heat exchangers.These lead to the problem that the manufacturing cost of the air conditioner increases.Therefore, we developed an inexpensive and compact LDAC by adopting a novel IL (ionic liquid) that does not corrode the metals commonly used in air conditioners.In this study, we evaluated the metal solubilities and sterilizing properties of the IL.Based on the physical properties of the IL, the humidity control module was improved for the purpose of downsizing and cost reduction of the unit.Moreover, we conducted a performance evaluation of the LDAC in the environmental test room under the condition in which temperature and humidity change rapidly in short period of time to simulate the condition of sudden showers of rain in summer.Test results showed that processed air was supplied at very stable level.