Air handling units: Purpose and Importance

Air handling units (AHUs) are essential components in many heating, ventilation, and air conditioning (HVAC) systems. They play a critical role in maintaining a comfortable and healthy indoor environment by circulating and filtering the air. AHUs are typically used in commercial and industrial buildings, hospitals, and laboratories. 

In this blog, we will discuss what AHU units are, their purpose, where they are used, the different parts of an AHU unit, and their importance.

What is an AHU Unit? 

An air handling unit (AHU) is a piece of mechanical equipment used to circulate, filter, and regulate the temperature and humidity of air in a building. An AHU unit consists of various components, including a fan, heating and cooling coils, filters, dampers, and controls. These components work together to provide conditioned air to the occupied spaces in a building.

What is the Purpose of an AHU Unit? 

The primary purpose of an air handling unit is to ensure that the air in a building is clean, comfortable, and healthy for occupants. AHUs are responsible for circulating and filtering air, which helps remove impurities and improve indoor air quality. Additionally, AHUs regulate the temperature and humidity of the air, which is crucial for maintaining a comfortable indoor environment.

Where do we use AHU Units? 

AHUs are used in a variety of applications, including commercial and industrial buildings, hospitals, laboratories, and data centres. These buildings typically have a high occupancy rate and require a constant supply of fresh air to maintain a healthy and comfortable indoor environment. Air handling units are also used in cleanrooms, which require a controlled environment with minimal contamination.

These systems are typically put in the basement, on the rooftop, or on particular building floors. Typically, they serve a specialised purpose and maintain the temperature in a specified area or zone in the building, like public toilets. Thus, it is not uncommon to find several air handling units around a building.

In some cases, like high-rise buildings, only one AHU room is situated on the rooftop. They supply the whole building and might lack an air duct. In these cases, the unit depends on air leakage, which is inefficient. At present, multiple smaller air handling units provide air in different zones to increase efficiency. Since the building is also more compact and air-tight, a return duct is not required to regulate the pressure inside the building.

What are the components of an AHU unit?

An AHU unit has various components that work together to provide conditioned air to a building. The following are the different parts of an AHU unit:

• Fan: The fan is the heart of an air handling unit. It is responsible for circulating air through the unit and distributing it to the occupied spaces in a building. Fans can be either centrifugal or axial, depending on the application.
• Heating and Cooling Coils: The heating and cooling coils are responsible for regulating the temperature of the air. These coils can be either hot water or steam coils for heating and chilled water or refrigerant coils for cooling.
• Filters: Filters remove impurities from the air, including dust, dirt, and allergens. There are several types of filters available, including fibreglass, pleated, and HEPA filters. The type of filter used will depend on the specific application.
• Dampers: Dampers are used to regulate the flow of air through the air handling unit. These dampers can be either manual or automated and can be used to adjust the temperature and humidity of the air.
• Controls: Controls are used to monitor and regulate the various components of an air handling unit. These controls can be either manual or automated and can be used to adjust the temperature, humidity, and airflow.
• Mixing Box: Mixing boxes are used to mix fresh air and return air to maintain a desired temperature and humidity level.
• Sound Attenuators: Sound attenuators reduce the noise level of the air passing through the air handling unit.

To Sum Up:

AHUs are critical components in HVAC systems that are used to circulate, filter, and regulate the temperature and humidity of air in a building. Air handling units are used in a variety of applications, including commercial and industrial buildings, hospitals, laboratories, and data centres. An air handling unit is made up of various components, including a fan, heating and cooling coils, filters, dampers, and controls. Each of these components plays a significant role in ensuring you breathe in purified air and lead a happy and healthy life.