Effective transient thermal resistance in the earth for daily load:

This is equivalent to the thermal resistance $T_4et$. for a transient period $\tau$ of 24 hours. It is calculated and used when a weekly and/or yearly load factor is given.

Symbol
$T_{\mathrm{4d}}$
Unit
K.m/W
Formulae
$\frac{\rho_{\mathrm{4}}}{2 \pi} \ln{\left (\frac{D_{\mathrm{x}}}{Do_{\mathrm{d}}} \right )}$
Related
$D_{\mathrm{x}}$
$Do_{\mathrm{d}}$
$\pi$
$\rho_{\mathrm{4}}$
$T_{\mathrm{4et}}$
Used in
$T_{\mathrm{4\mu}}$