1. What is a Duct Sizing Calculator?

Definition: This calculator determines the cross-sectional area of ducts needed for HVAC systems based on air flow rate and velocity.

Purpose: It helps HVAC professionals and engineers design efficient ductwork systems for heating and cooling applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( A \) — Duct cross-sectional area (m²)
• \( Q \) — Air flow rate (m³/s)
• \( V \) — Air velocity (m/s)

Explanation: The flow rate is divided by velocity to determine the required duct area for proper air distribution.

3. Importance of Proper Duct Sizing

Details: Correct duct sizing ensures efficient airflow, proper system performance, energy efficiency, and noise reduction in HVAC systems.

4. Using the Calculator

Tips: Enter the air flow rate in m³/s and desired velocity in m/s (default 2.5 m/s for residential systems). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical air velocity for residential systems?
A: Typically 2.5-5 m/s for supply ducts and 1.5-3 m/s for return ducts in residential applications.

Q2: How do I convert CFM to m³/s?
A: Multiply CFM by 0.00047194745 to get m³/s (1 CFM = 0.00047194745 m³/s).

Q3: What velocity should I use for commercial systems?
A: Commercial systems often use higher velocities (5-10 m/s) depending on the application and noise requirements.

Q4: How does this relate to duct diameter?
A: For circular ducts, diameter can be calculated from area using \( D = 2 \times \sqrt{A/\pi} \).

Q5: What about rectangular ducts?
A: The area calculation is the same, but you'll need to choose appropriate width and height dimensions that multiply to the required area.