Cableizer

Thermal emissivity wall material

The values are band-averaged infrared emissivities, recommended default plus a short plausible range appropriate for typical finishes (unpainted, as-built surfaces).

Note that surface finish, oxidation, painting, temperature and wavelength can change emissivity significantly.

Symbol
$\epsilon_{t}$
Related
$M_{tray}$
Tray material
Used in
$h_{rad,BA}$
Heat transfer coefficient radiation tray bottom—air [W/(K.m$^2$)]
$h_{rad,SA}$
Heat transfer coefficient radiation tray sides—air [W/(K.m$^2$)]
$h_{rad,TA}$
Heat transfer coefficient radiation tray top—air [W/(K.m$^2$)]
$K_{r}$
Radiation shape factor
Choices
MaterialValueRange
PE0.90.85 - 0.95
PP0.970.90 - 0.97
PVC0.940.90 - 0.97
Metal0.070.05 - 0.15
Alu0.050.03 - 0.10
StN0.230.15 - 0.30
StW0.280.20 - 0.35
Fibre0.920.88 - 0.95
Cem0.930.85 - 0.96