An air handling unit also referred to as an AHU, is a system of various components housed in a large, accessible box-shaped unit called a module. The module houses the appropriate ventilation requirements for the air-conditioning, purifying, or renewing of the air in an indoor space.

AHUs are commonly installed on the rooftop of buildings and the air is circulated through ducts to each of the rooms in the building.

WHAT IS THE PURPOSE OF AN AIR HANDLING UNIT?

An air handling unit is responsible for the proper ventilation of the interior of a building using outside air. In addition, it performs the carries out the following functions:

• Filtration of the air that reaches the interior of the building using air purification filters
• Control of the quality of the air that reaches the interior of the building
• Control of the air temperature inside the building so that the ambient temperature remains at the desired level at all times
• Monitoring and controlling the interior humidity

Air handling units are designed to control the air quality in areas where there is little to no natural ventilation combined with a high number of occupants at any given time. These areas include but are not limited to:

• Convention centers
• Conference halls
• Shopping malls
• Restaurants
• Hotels
• Office buildings
• Apartment buildings

Additionally, air handling units can be used in applications that require high levels of hygiene such as:

• Laboratories
• Pathology labs
• Hospitals
• Intensive care units
• Operating theatres
• Clean rooms
• Medical manufacturers

WHAT COMPONENTS MAKE UP AN AIR HANDLING UNIT AND HOW DO THEY WORK?

• Air Intake: Through the air intake component, an AHU collects air from outside and treats it before distributing it throughout the building
• Filter: This component is used to filter out airborne particles such as bacteria, viruses, dust, pollen, odor, and other air pollutants. The type of filter fitted into the AHU will depend on the air purity requirements of the building
• Fan: The fan is an electromechanical system that pushes the air from the AHU to the ducts that are responsible for the distribution of the filtered air
• Heat exchangers: These components transfer temperature between two fluids which are separated by a solid barrier
• Cooling coil: The cooling coil serves to cool the air that passes through it. This process causes condensation which is collected in a condensation tray
• Silencer: Air handling units can be quite noisy, and the silencer deals with this issue so that it does not disturb the occupants
• Plenum: This is empty space in which the air flow is homogenized