An Air Handling Unit (AHU) is the heart of a central air conditioning system that conditions and circulates air within large buildings by treating both fresh and recirculated air to control temperature, humidity, and air cleanliness before distributing it through ductwork. AHUs contain components like fans, filters, heating and cooling coils, and dampers to achieve specific indoor air quality and comfort levels for commercial, industrial, and large residential spaces.

Functions of an AHU

• Air Collection:AHUs take in outside air and, depending on the building's needs, can also mix in air returned from the rooms via a mixing chamber.

• Air Cleaning:Filters remove dust particles, bacteria, and other contaminants from the air. High-efficiency filters like HEPA can also be used.

• Temperature Control:Heating and cooling coils are used to adjust the air temperature to the desired level.

• Humidity Control:AHUs regulate the moisture content in the air to maintain a comfortable indoor environment.

• Air Circulation:A fan within the AHU pushes the conditioned air through a network of ducts to the building's various zones.

• Air Distribution:Ducts then distribute the air throughout the building and return it to the AHU to continue the cycle.

Key Components

• Casing: The outer structure of the unit, often made from GI sheets and an aluminum frame.

• Fan & Motor: Powers the air circulation system.

• Heating/Cooling Coils: Heat or cool the air passing through them.

• Filters: Remove particulates from the air.

• Dampers: Control the ratio of fresh, recirculated, and exhaust air.

• Heat Recovery Exchanger: An optional component that transfers heat between exhaust and incoming air to save energy.