1. What is Volumetric Flow Rate?

Volumetric flow rate (Q) is the volume of fluid that passes through a given cross-sectional area per unit time. In HVAC systems, it represents the amount of air moving through ducts and is crucial for proper ventilation and climate control.

2. How Does the Calculator Work?

The calculator uses the volumetric flow rate equation:

Where:

• \( Q \) — Volumetric flow rate (m³/s)
• \( A \) — Cross-sectional area of the duct (m²)
• \( v \) — Air velocity through the duct (m/s)

Explanation: The equation calculates the volume of air passing through a duct per second by multiplying the duct's cross-sectional area by the air velocity.

3. Importance of Air Flow Rate Calculation

Details: Accurate air flow rate calculation is essential for designing efficient HVAC systems, ensuring proper ventilation, maintaining indoor air quality, and optimizing energy consumption in buildings.

4. Using the Calculator

Tips: Enter cross-sectional area in square meters (m²) and air velocity in meters per second (m/s). Both values must be positive numbers. For circular ducts, calculate area using \( A = \pi \times r^2 \).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical air velocity in HVAC ducts?
A: Typical velocities range from 2-5 m/s for low-velocity systems and 6-12 m/s for high-velocity systems, depending on application and noise considerations.

Q2: How do I measure duct cross-sectional area?
A: For rectangular ducts: width × height. For circular ducts: \( \pi \times (\text{diameter}/2)^2 \). Ensure all measurements are in meters.

Q3: Why is air flow rate important in HVAC design?
A: Proper air flow ensures adequate ventilation, maintains comfort levels, prevents moisture issues, and ensures efficient operation of heating and cooling systems.

Q4: What units are commonly used for air flow rate?
A: Common units include m³/s, m³/h, CFM (cubic feet per minute), and L/s (liters per second). This calculator uses SI units (m³/s).

Q5: How does duct size affect air flow rate?
A: Larger ducts with the same velocity will have higher flow rates. Smaller ducts require higher velocities to achieve the same flow rate, which increases pressure drop and noise.