# Temperature duct outer surface

This is the temperature of the outer surface of a duct or a riser/J-tube.

With crossing heat sources, a temperature rise of $\Delta\theta_{0x}$ applies at the hottest point.

Symbol
$\theta_{de}$
Unit
°C
Formulas
 $\theta_{di}-T_{4ii} n_{cc} W_t+\frac{T_{4ii} W_{duct}}{2} n_{cc}$ cables in duct $\frac{W_{tot} T_{st} T_{sa}+\theta_t T_{sa}+\theta_{at} T_{st}}{T_{sa}+T_{st}}$ cables,heat sources or PAC/GIL in ventilated tunnel $\theta_{di}-T_{4ii} n_{cc} W_t$ cables in trough, in channel $\theta_e$ heat sources in trough, in channel $\theta_a+v_4 \Delta \theta_p+\left(1-v_4\right) \Delta \theta_x+n_{cc} W_{tot} v_4 T_{4\mu}$ PAC/GIL buried in duct $\theta_{di}-T_{4pii} W_{sum}$ air-filled pipe with objects
Related
$\Delta \theta_{0x}$
$\Delta \theta_p$
$\Delta \theta_x$
$T_{4\mu}$
$T_{sa}$
$T_{st}$
$\theta_a$
$\theta_{at}$
$\theta_{di}$
$\theta_e$
$\theta_t$
$W_{duct}$
$W_{sum}$
$W_{tot}$
Used in
$\alpha_{st}$
$\Delta \theta_s$
$\mathrm{Gr}_{ext}$
$I_c$
$\mathrm{Ra}_{ext}$
$T_{4iii}$
$T_{sa}$
$T_{st}$
$\theta_c$
$\theta_{di}$
$\theta_{film}$
$\theta_{gas}$
$\theta_{tm}$
$W_{conv,ext}$
$W_{rad,ext}$