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🖋️ System Design

Diffusers/Grilles/Vents (Air Terminals)

Diffusers, Grilles, and Vents are components used for specifying flow rates in ventilation systems.

Adding Diffusers/Grilles/Vents

Adding Diffusers/Grilles/Vents

Choose from the six available options based on shape and orientation:

  • Square - Horizontal: A square diffuser placed on a horizontal surface like a ceiling.

  • Square - Vertical: A square diffuser placed on a vertical surface like a wall.

  • Rectangular - Horizontal: A rectangular diffuser placed on a horizontal surface like a ceiling.

  • Rectangular - Vertical: A rectangular diffuser placed on a vertical surface like a wall.

  • Circular - Horizontal: A circular diffuser placed on a horizontal surface like a ceiling.

  • Circular - Vertical: A circular diffuser placed on a vertical surface like a wall.

Placing Diffusers/Grilles/Vents

Step-by-step

  1. Move the selected Diffuser/ Grille/Vent around the workspace to preview its position.

  2. The Diffuser/ Grille/Vent will snap to the nearest duct for alignment. If snapping is undesired:

    - Hold CTRL to disable snapping.

    - Press M to match the closest System

    - Use Arrow keys to raise and dop the Height.

    - Use H to match the height of the connecting Duct .

  3. Left-click to place the Diffuser/ Grille/Vent.

    Adjust its position afterward by clicking and dragging it.

Diffuser Properties

General Properties:

  • Flow System: Assign the diffuser to the appropriate ventilation system (e.g., Supply Air).

  • Color: Customize the color for easier identification in your design.

Flow Rate Properties:

There are five options for adding the flow rate to a Diffuser/ Grille/Vent:

  • Manual: Manually choose a desired flow rate if not using h2x for flow calculations.

If you are not using h2x for ventilation flow rate calculations (by drawing the building footprint, etc.), then you will need to use this one.

  • Share Units: Distributes the building's total required flow rate evenly among all units.

Example:

Total building flow rate: 100 GPM

Diffusers: 4 

Flow rate per unit: 25 GPM each (even distribution).

  • Percentage: Allows you to set a specific percentage of the total building flow rate to allocate.

Example:

Total building flow rate: 100 GPM

Allocated percentage: 60% to Diffuser A, 40% to Diffuser B

Flow rate: Diffuser A = 60 GPM, Diffuser B = 40 GPM.

  • Room: Aligns with the specific flow rate required by each room.

Example:

Room A requires 30 GPM, Room B requires 20 GPM, Room C requires 50 GPM.

Flow rate aligns exactly with each room's requirement: Diffuser in Room A = 30 GPM, Diffuser in Room B = 20 GPM, Diffuser in Room C = 50 GPM.

  • Room Size: Matches the required flow rate of each room, and distributes any remaining building flow rate proportionally based on room area.

Example:

Total building flow rate: 120 GPM

Room A = 200 sq. ft., Room B = 200 sq. ft., Room C = 400 sq. ft., Room D = 400 sq. ft.

Base flow rate: Room A = 20 GPM, Room B = 20 GPM, Room C = 40 GPM.

The shared flow for Room D (40 GPM) was distributed proportionally: Room A = 10 GPM, Room B = 10 GPM, and Room C = 20 GPM.

Final flow rates: Room A = 30 GPM, Room B = 30 GPM, Room C = 60 GPM.

Shape and Dimensions:

  • Orientation: Set the airflow direction (horizontal or vertical).

  • Shape: Specify the diffuser’s shape (square, rectangular, or circular).

  • Width and Height: Enter the width and height dimensions.

  • Height Above Floor: Define the mounting height to suit the design layout.

Pressure Drop Properties:

  • Pressure Drop Method: Choose how pressure drop is calculated:

    • Zeta: Input a Zeta value, used to calculate the pressure drop based on flow and velocity.

    • Fixed: Input a fixed pressure drop.

Troubleshooting Diffusers/Grilles/Vents

  • Connection Issues:

    • Verify that the Diffuser/ Grille/Vent is correctly connected to the Duct system.

    • Semi-transparent ducts indicate disconnection.

  • Review Properties:

    • Ensure that Flow Rates, Dimensions, and Pressure Drop values are accurately input in the Properties tab.

    • Override defaults if necessary for specific design requirements.

  • Flow System Compatibility:

    • Confirm that the Diffuser/ Grille/Vent is assigned to the correct System (e.g., Supply Air).