Heat Gain through Partition, Floor or Ceiling Calculator

Heat Gain Formula:

\[ Q_{gain} = U_i \times SA_{Duct} \times CLTD \]

Heat Transfer Coefficient:

W/m²·K

Surface Area of Duct:

m²

Cooling Load Temp Difference:

Tolerance:

Heat Gain (W):

1. What is Heat Gain through Partition, Floor or Ceiling?

Definition: This calculator estimates the heat gain through building partitions, floors, or ceilings based on heat transfer coefficient, surface area, and temperature difference.

Purpose: It helps HVAC professionals and engineers determine cooling loads for proper system sizing and energy efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q_{gain} = U_i \times SA_{Duct} \times CLTD \]

Where:

\( Q_{gain} \) — Heat gain (Watts)
\( U_i \) — Heat transfer coefficient (W/m²·K)
\( SA_{Duct} \) — Surface area of duct (m²)
\( CLTD \) — Cooling load temperature difference (K)

Explanation: The heat transfer coefficient multiplied by surface area and temperature difference gives the heat gain through the structure.

3. Importance of Heat Gain Calculation

Details: Accurate heat gain calculation ensures proper HVAC system sizing, energy efficiency, and thermal comfort in buildings.

4. Using the Calculator

Tips: Enter the heat transfer coefficient, surface area, temperature difference, and optional tolerance percentage. All values must be > 0 except tolerance which can be ±.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical heat transfer coefficient?
A: Values vary by material, but common ranges are 0.2-0.5 W/m²·K for insulated walls and 1.5-3.0 W/m²·K for single-pane windows.

Q2: How do I determine the cooling load temperature difference?
A: CLTD depends on outdoor temperature, indoor setpoint, solar radiation, and thermal mass. ASHRAE provides standard values.

Q3: Why include a tolerance factor?
A: Tolerance accounts for uncertainties in input values and real-world variations (±5% is common).

Q4: Can this be used for cooling load calculations?
A: Yes, heat gain is a primary component of cooling load calculations for HVAC systems.

Q5: How does surface area affect heat gain?
A: Heat gain is directly proportional to surface area - doubling the area doubles the heat gain.