## 4 Results and Discussion
### Repeatability and Comparison with Literature Data  
Thermal conductivity values of W, EG, PG, EG:W 50:50, \(n\)-C\({}_{14}\), and \(n\)-C\({}_{16}\) at the temperature range 283.15 to 333.15 K, with a 10 K temperature step, were determined for \begin{table}
\begin{tabular}{c c c} \hline
**Corrections** & \(1\delta T_{1}1\) **(K)** & \(1\delta T_{1}1\)**/\(\Delta T_{\text{exp}}\) (\%)** \\ \hline \(\delta T_{1}\) & \(2.5\times 10^{-4}\) & \(1\times 10^{-2}\) \\ \(\delta T_{2}\) & \(1.2\times 10^{-4}\) & \(4\times 10^{-3}\) \\ \(\delta T_{4}\) & \(2.5\times 10^{-13}\) & \(1\times 10^{-11}\) \\ \(\delta T_{5}\) & \(1.7\times 10^{-9}\) & \(7\times 10^{-8}\) \\ \(\delta T_{7}\) & \(2.4\times 10^{-12}\) & \(1\times 10^{-10}\) \\ \(\delta T_{9}\) & \(2.2\times 10^{-10}\) & \(1\times 10^{-8}\) \\ \hline \end{tabular}
\end{table} 
Table 2: Contribution of each \(1\delta T_{1}1\) in Equation (7), averaged for the different fluids (W, EG, PG, EG:W 50:50 vol% mixture, \(n\)-C\({}_{14}\), and \(n\)-C\({}_{16}\)) at 303 K.  
Figure 3: Percentage deviations between \(\Delta T_{\text{exp}}\) data and \(\Delta T_{\text{reg}}\) determined by Equation (6) from the different tests (\(\bullet\) Test 1, \(\blacktriangle\) Test 2, and \(\blacksquare\) Test 3) as a function of time at different heat flux per unit lengths, \(\dot{q}\), for (**a**) water, (**b**) ethylene glycol, (**c**) propylene glycol, (**d**) ethylene glycol:water 50:50 vol%, (**e**) \(n\)-tetradacane, and (**f**) \(n\)-hexadecane. the three independent tests following Equation (6). The obtained values were compared to each other in Figure 4, obtaining deviations less than 3% for all the checked fluids over the entire temperature range. An average repeatability level of 0.58% over the studied temperature range and in the thermal conductivity range 0.130 to 0.700 W m\({}^{-1}\) K\({}^{-1}\) can be established. This repeatability value is in agreement with the deviations of the experimental temperature rise with respect to the ideal one established in Figure 3 and discussed in the last section. It is noteworthy that the deviations for the different fluids do not show temperature dependence. The scattering of values shown in Figure 4 confirms that the device and the operation mode are reliable from the repeatability point of view. The previous averaged results for W, EG, PG, EG:W 50:50, and \(n\)-C\({}_{14}\) were compared for each temperature and fluid with available literature values [37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49], as shown in Figure 5. The minimum and maximum deviations obtained are, respectively, 0.010% and 2.6% for W [37]; 0.70% and 6.6% for EG [43, 40, 41, 42, 43]; 2.2% and 5.8% for PG [43]; 0.20% and 4.3% for EG:W 50:50 [44, 45, 46]; and 2.1% and 7.4% for \(n\)-C\({}_{14}\)[47, 48, 49]. It must be pointed out that there is not an agreement in literature data of EG:W 50:50 that reaches deviations between the reported references [44, 45, 46] up to 3.3%. Consequently, this contributes to the scattering of deviations plotted in Figure 5d. The maximum deviations with respect to the studies by [PERSON] et al. [44] and [PERSON] and [PERSON] [45] are 2.9% and 3.6%, respectively, while the maximum deviation with respect to [PERSON] [46] is \(-\)4.4%. This last result contradicts the general tendency observed for the rest of the studied fluids (\(\lambda_{\text{exp}}>\lambda_{\text{lit}}\)). Some systematic discrepancies with no temperature-dependence between our experimental data and literature values can be identified in Figure 5. Thus, an average deviation of 1.1% is obtained for W, while 4.0% is reached for EG. Accordingly, with the deviations of the two mentioned fluids, the average deviation for EG:W 50:50 vol% is 2.1%. Due to the similar nature of the PG with regard to the EG, the average deviation of this fluid is similar, reaching 4.6%. It must be taken into account that the highest deviation is found for \(n\)-C\({}_{14}\) alkane, with an average deviation of 4.8%.