Stefan-Boltzmann Law calculates the radiation energy of a subject surface. All objects with temperature above absolute ZERO radiate energy. The Stefan-Boltzmann equation is:
P = εAσT4
Where:
P: Radiation Energy
ε: Emissivity of the Surface. Check emissivity table below of common materials.
A: Surface Area, in m^2.
σ: Stefan-Boltzmann Constant, σ=5.67 × 10-8 W/m2•K4
T: Absolute Temperature
Emissivity Table of Common Materials (Click to add)
| Name | Temperature ( ̊C ) | Emissivity |
| Water | 38 | .67 |
| Ice, Smooth | 0 | .97 |
| Snow, Granular | -8 | .89 |
| Wood (Oak, Planed) | 38 | .91 |
| Soil Surface | 38 | .38 |
| Silk Cloth | 20 | .78 |
| Cotton Cloth | 20 | .77 |
| Sand | 20 | .76 |
| Limestone | 38 | .95 |
| Glass, smooth | 0-93 | .92-.94 |
| Granite | 21 | .45 |
| Concrete | 0-1093 | .94 |
| Clay | 20 | .39 |
| Brick, red, rough | 21 | .93 |
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