Heat Transfer Rate (\( Q_r \)):

\[ Q_r = \epsilon \cdot \lambda \cdot A \cdot T^4 \]

Where:

• \( Q_r \) is the heat transfer rate, in watts (W).
• \( \epsilon \) is the emissivity.
• \( \lambda \) is the Stefan-Boltzmann constant, \( 5.7 \times 10^{-8} \) W/m²-°K⁴.
• \( A \) is the surface area, in square meters (m²).
• \( T \) is the temperature of the surface, in kelvin (°K).