Heat removed by the air in the tunnel, at the point z in the cable route, which is equal to $C_{av} \frac{\partial \theta_{at}(z)}{\partial z}$.

Symbol
$W_{\mathrm{a_{\mathrm{z}}}}$
Unit
W/m
Formulae
$\frac{N_{\mathrm{c}} N_{sys} W_{\mathrm{tot}} \left(T_{\mathrm{e}} + T_{\mathrm{t}}\right) + \theta_{\mathrm{a}} - \theta_{\mathrm{at_{\mathrm{z}}}}}{T_{\mathrm{a}} + T_{\mathrm{e}} + T_{\mathrm{t}}}$
Related
$N_{\mathrm{c}}$
$T_{\mathrm{a}}$
$T_{\mathrm{t}}$
$\theta_{\mathrm{a}}$
$\theta_{\mathrm{at_{\mathrm{z}}}}$
$W_{\mathrm{tot}}$
Used in
$\theta_{\mathrm{o_{\mathrm{z}}}}$
$\theta_{\mathrm{t_{\mathrm{z}}}}$