1. What is the Heat Transfer Equation?

The heat transfer equation (Q = 1.08 × CFM × ΔT) calculates the amount of heat transferred in British Thermal Units (BTU) for air moving through a system. The constant 1.08 accounts for the specific heat of air and conversion factors.

2. How Does the Calculator Work?

The calculator uses the heat transfer equation:

Where:

• \( Q \) — Heat transfer in BTU
• \( CFM \) — Airflow in cubic feet per minute
• \( \Delta T \) — Temperature difference in °F
• 1.08 — Conversion factor (0.075 lb/ft³ × 0.24 BTU/lb-°F × 60 min/hr)

Explanation: The equation calculates how much heat is being added or removed based on airflow and temperature difference.

3. Importance of Heat Transfer Calculation

Details: Accurate heat transfer calculation is crucial for HVAC system design, sizing equipment, and evaluating system performance.

4. Using the Calculator

Tips: Enter CFM (airflow) in cubic feet per minute and ΔT (temperature difference) in °F. All values must be valid (CFM > 0, ΔT > 0).

5. Frequently Asked Questions (FAQ)

Q1: What does the 1.08 constant represent?
A: It combines air density (0.075 lb/ft³), specific heat of air (0.24 BTU/lb-°F), and conversion from hours to minutes (60 min/hr).

Q2: When is this equation most accurate?
A: For standard air conditions at sea level (29.92 in Hg, 70°F, 50% RH). Adjustments may be needed for other conditions.

Q3: Can this be used for both heating and cooling?
A: Yes, the equation works for both heating and cooling applications.

Q4: What are typical CFM values?
A: Residential systems typically range from 400-2000 CFM, while commercial systems can be much higher.

Q5: How does altitude affect the calculation?
A: At higher altitudes, air density decreases, so the constant should be adjusted (1.08 × (actual air density/0.075)).