# Radiative heat transfer
# Scope: Gray surface exchanging with large surroundings; absolute temperatures.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

emissivity = 0.9
area = 0.1 m^2
temperature = 350 K
surroundings = 293 K
stefan = 0.00000005670374419 W/(m^2*K^4)

heat := emissivity*stefan*area*(temperature^4-surroundings^4) [W]

check radiative heat target: heat >= 20 W

scenario alternative: emissivity = 0.72