9 Air Distribution Systems Explained

Key Concepts

1. Ductwork

Ductwork is the network of tubes or channels that distribute conditioned air throughout a building. It consists of supply ducts that carry cooled or heated air from the HVAC system to the living spaces and return ducts that bring air back to the system for reconditioning.

Example: In a residential home, ductwork runs through the attic or basement, connecting the central air conditioner to each room.

2. Registers and Grilles

Registers and grilles are the outlets and inlets for air in a duct system. Registers are used for supply air, while grilles are used for return air. They are typically installed in walls, floors, or ceilings and can be adjusted to control airflow.

Example: A living room has a supply register on the wall that blows cool air into the room and a return grille in the ceiling that pulls air back to the HVAC system.

3. Air Handling Units (AHUs)

Air Handling Units are mechanical systems that control and distribute air as part of an HVAC system. They typically include a blower, heating or cooling elements, filter racks, sound attenuators, and dampers. AHUs are crucial for maintaining indoor air quality and comfort.

Example: In a commercial building, an AHU is located in the mechanical room, responsible for circulating conditioned air throughout the office spaces.

4. Diffusers

Diffusers are devices that distribute air evenly into a room. They are designed to create a comfortable airflow pattern and prevent drafts. Diffusers come in various shapes and sizes and are often adjustable to control the direction and volume of air.

Example: A restaurant uses ceiling diffusers to evenly distribute conditioned air throughout the dining area, ensuring a comfortable environment for patrons.

5. VAV (Variable Air Volume) Systems

Variable Air Volume systems adjust the volume of air supplied to each zone based on demand. This allows for energy savings by reducing airflow when cooling or heating is not needed. VAV systems are commonly used in large commercial buildings.

Example: An office building uses a VAV system to adjust the airflow to each office based on the number of occupants and the current temperature, optimizing energy use.

6. CAV (Constant Air Volume) Systems

Constant Air Volume systems maintain a constant airflow rate regardless of the heating or cooling demand. These systems are simpler but less energy-efficient compared to VAV systems. CAV systems are often used in smaller buildings or older installations.

Example: A small retail store uses a CAV system to provide a consistent airflow throughout the store, ensuring a steady temperature regardless of the number of customers.

7. Dampers

Dampers are devices used to control the flow of air in a duct system. They can be manually or automatically operated and are essential for balancing the airflow in different parts of the building.

Example: In a multi-zone HVAC system, dampers are used to direct airflow to specific areas, such as closing off unused rooms to save energy.

8. Air Filters

Air filters are components that remove contaminants from the air before it is distributed throughout the building. They are crucial for maintaining indoor air quality and protecting the HVAC system from dust and debris.

Example: A hospital uses high-efficiency particulate air (HEPA) filters in its HVAC system to ensure that the air in patient rooms is free from harmful particles.

9. Zoning Systems

Zoning systems divide a building into different temperature zones, each controlled by its own thermostat. This allows for more precise temperature control and energy savings by heating or cooling only the occupied areas.

Example: A large home is divided into three zones: the bedrooms, the living room, and the kitchen. Each zone has its own thermostat, allowing the occupants to set different temperatures for each area.