In these systems, a desiccant removes moisture from the air, which releases heat and increases the air temperature. The dry air is cooled using either evaporative cooling or the cooling coils of a conventional air conditioner. Commercially available desiccants include silica gel, activated alumina, natural and synthetic zeolites, lithium chloride, and synthetic polymers. Desiccant systems can supplement conventional air conditioners, reducing the need for vapor-compression systems to operate for long cycles and at low temperatures in order to handle temperature and humidity. By working together, conventional cooling systems and desiccant systems can tackle the temperature and humidity loads separately and more efficiently.
Desiccant technologies have numerous current and potential applications.
Desiccants contribute to a drier, cleaner, more comfortable environment in schools, hospitals, hotels, office buildings, and stores of all kinds. Desiccant units are being tested in fast-food restaurants, schools, and elsewhere. To develop baseline data for schools in moderate and hot, humid climates, the researchers are studying four schools in the metropolitan Atlanta area and six in Georgia's coastal region. Some schools in the study have active humidity control and continuous ventilation systems, and some do not. The study will be used to develop recommendations and HVAC design considerations for improving IAQ in schools and other large buildings.