1. What is a Radiative Heat Transfer Calculator?

Definition: This calculator estimates the heat transfer between two surfaces due to thermal radiation based on the Stefan-Boltzmann law.

Purpose: It helps engineers, physicists, and students calculate radiative heat exchange between objects at different temperatures.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Radiative heat transfer (Watts)
• \( \sigma \) — Stefan-Boltzmann constant (5.67×10⁻⁸ W/m²K⁴)
• \( \epsilon \) — Emissivity of the surface (0 to 1)
• \( A \) — Surface area (m²)
• \( T_1 \) — Hot surface temperature (Kelvin)
• \( T_2 \) — Cold surface temperature (Kelvin)

Explanation: The calculator computes the net radiative heat transfer between two surfaces based on their temperatures and material properties.

3. Importance of Radiative Heat Transfer Calculation

Details: Accurate calculation of radiative heat transfer is crucial for thermal system design, energy efficiency analysis, and understanding heat exchange mechanisms.

4. Using the Calculator

Tips: Enter the surface emissivity (default 0.9 for most materials), surface area, and both temperatures in Kelvin. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the Stefan-Boltzmann constant?
A: It's a physical constant (5.67×10⁻⁸ W/m²K⁴) that describes how much power is radiated by a black body per unit area.

Q2: What does emissivity represent?
A: Emissivity (0 to 1) measures how effectively a surface emits thermal radiation compared to an ideal black body.

Q3: Why use Kelvin for temperature?
A: The Stefan-Boltzmann law requires absolute temperature in Kelvin for accurate calculations.

Q4: What if T₂ > T₁?
A: The calculator will show a negative value, indicating heat transfer is in the opposite direction.

Q5: What's a typical emissivity value?
A: Common values are 0.9 for most surfaces, 0.95 for black paint, and 0.05 for polished metals.