Two slight variations on this system occur when process air is recirculated or vented. This is sometimes referred to as a hybrid system since it combines the components of a vapor-compression system with a desiccant system. This allows the system to meet both sensible and latent cooling loads. The desiccant system removes the latent load while the vapor compressor system meets the sensible load. A combination of heat exchangers and a vapor compression system meet the sensible load requirement.
Energy is saved since no overdrying or reheating is required.
The vapor compression system required is reduced in size because the latent cooling load is processed under the desiccant system. Both types of desiccant cooling systems operate on the same physical concepts. Heat Exchanger - The air leaving the desiccant wheel is further cooled in a heat exchanger. The heat is lost to the air on the regeneration side of the system. Humidifier - A second evaporator cooler creates a sensible cooling effect prior to the air stream discharging to the space.