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, healthier, more comfortable environment in schools, hospitals, hotels, office buildings, and stores of all kinds. ORNL is testing and rating desiccant systems in the laboratory. Liquids wash the air and cleanse it of bacteria, microbes, and other unhealthful contaminants. Prior to the testing at NREL, manufacturers had no way of comparing wheels or of knowing their performance level. Advancements in desiccant material and equipment design have improved performance and reliability and have reduced the cost of desiccant equipment.