An air handling unit (AHU) in a centralized cooling system typically consists of several components, including heating and cooling coils, a humidifier, filters, and fans. The heating coil is usually connected to a hot water supply, while the cooling coil is connected to a chilled water supply. The humidifier adds moisture to the air to maintain a desired humidity level, while the filters remove airborne contaminants. The fans, which can be axial or centrifugal, move the conditioned air through the ductwork to the building spaces.