1. What is Cooling Air Flow Rate Calculation?

Definition: This calculator determines the required air flow rate (in CFM) needed to remove a specific heat load given a temperature difference.

Purpose: It helps HVAC engineers and technicians properly size cooling systems and ventilation requirements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Air flow rate (cubic feet per minute, CFM)
• \( Q_{btu} \) — Heat load (British Thermal Units per hour, BTU/h)
• \( \Delta T \) — Temperature difference (°F)
• 1.08 — Constant combining air density and specific heat

Explanation: The formula calculates how much air needs to be moved to remove the specified heat load given the temperature difference between supply and return air.

3. Importance of Air Flow Rate Calculation

Details: Proper air flow calculation ensures efficient cooling, prevents equipment overheating, and maintains optimal system performance.

4. Using the Calculator

Tips: Enter the heat load in BTU/h and the temperature difference in °F. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the 1.08 constant in the formula?
A: It's derived from the product of air density (0.075 lb/ft³) and specific heat (0.24 BTU/lb-°F), multiplied by 60 to convert from hours to minutes.

Q2: What's a typical ΔT for air conditioning systems?
A: Most systems are designed for ΔT of 18-22°F, but this can vary based on system design.

Q3: How do I find the heat load (Q_btu)?
A: Heat load can be calculated from equipment specifications, room dimensions, or measured with appropriate instruments.

Q4: Does this formula work for both heating and cooling?
A: Yes, but the temperature difference should always be positive (warmer to cooler).

Q5: What if I need to calculate in metric units?
A: You would need to use different constants for calculations in °C and kW.