HVAC Systems

You can circumvent this issue using several methods:

1. Adjusting the Aspect Ratio

You can modify the duct's Aspect Ratio. Ideally, the preferred range is between 1:1 and 1:4. Exceeding a ratio of 1:4 leads to an unnecessary increase in:

• Material consumption (galvanized steel sheets).

• Insulation requirements.

• Heat loss through the duct surface.

This is clearly illustrated in the following figure, sourced from the Carrier Handbook - Air Distribution Chapter.

2. Modifying Dimensions within Velocity Limits

If adjusting the aspect ratio is not feasible and you must change one of the duct dimensions, you can reduce the required dimension. However, this must be done carefully to ensure that the air friction does not exceed allowable limits.

Keep in mind that reducing the area will:

• Increase air velocity.

• Increase noise levels.

You should always cross-reference the maximum allowable velocities in the ductwork using the following table, also found in the Carrier Handbook - Air Distribution Chapter.

I hope this explanation is thorough and addresses your question. Please let me know if you need any further assistance.