Thermal resistance 13 of multi-layer backfill method

Thermal resistance offered by the material in layer 3 along the flow path q1.

Symbol
$R_{q13}$
Unit
K.m/W
Formulae
$\frac{\ln{\left(\frac{2 \left(C_{1} \left(- a_{T} + c_{T}\right) + a_{T}\right)}{D_{o}} \right)}}{k_{3} \operatorname{atan}{\left(\frac{s_{T}}{a_{T}} \right)}}$
$D_{o}$