## 3 Experimental Setup
### Measuring Instruments  
Experimental measurements included the electrical power, ambient temperature, flow rate, water temperature at the cooling system outlet and inlet, and wind speed. The power absorbed by the electrical resistance was measured with a digital wattmeter type \(PX120\) from \(MATRIX\)[45]. The ambient temperature was measured with a Testo 400 measuring instrument [46] and a T-type thermocouple. The flow rate was measured with a flow sensor type \(OF10 ZAT\) from \(AICHITOKEI\)[47]. Water temperatures were measured by a T-type thermocouple and distributed in the secondary system to measure the temperature at the water inlet/outlet. The wind speed was measured with a Testo 400 measuring instrument [46] and a Pitot tube. These devices were periodically calibrated to ensure traceability of measurements. All instruments were synchronised and all data were captured every 10 (s). Table 2 shows the characteristics of the measuring instruments used in the tests (see Figure 9).  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**Parameter** & **Apparatus** & **Specifications** \\ \hline Wind speed & Testo 400 & Measurement range: 0/40 (m/s) \\  & & Precision/resolution: 0.5 (\%) \\  & Pitot tube & Measurement range: 0/40 (m/s) \\  & & Uncertainty: 0.5 (\%) \\ Ambient temperature & Testo 400 & Measurement range: \(-\)40/150 (\({}^{\circ}\)C) \\  & & Precision/resolution: 0.1 (\({}^{\circ}\)C) \\  & Thermocouple & Measurement range: \(-\)40/150 (\({}^{\circ}\)C) \\  & & Uncertainty: 0.1 (\({}^{\circ}\)C) \\ Flow rate & AICHITOKEI & Measurement range: 0.35/5 (L/min) \\ Water temperature & Thermocouple & Precision/resolution: 2 (\%) \\  & & Measurement range: 0/85 (\({}^{\circ}\)C) \\  & & Uncertainty: 0.0625 (\({}^{\circ}\)C) \\ Electrical power & PX120 & Measurement range: 0/1000 (W) \\  & & Precision/resolution: 1 (\%) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Characteristics of the measuring instruments used in the tests.  
Figure 8: Photograph of the thermal subsystem.  
Any sources of error in the experiments conducted need to be taken into account to estimate the overall uncertainty associated with the measurements and to then detect inferences from the experimental results. An uncertainty analysis was performed for this reason. [PERSON], et al. [48] identified the different sources of error that can influence the uncertainties of experimental parameters, such as the methodology of the experiments, the calibration of the test rig, the random fluctuation of the instruments used, and the accuracy of observation. The root mean square method was used to determine the measurement uncertainties [49]:  
\[e_{R}=\left[\left(\frac{\partial f}{\partial x_{1}}e_{1}\right)^{2}+\left( \frac{\partial f}{\partial x_{2}}e_{2}\right)^{2}+\ldots+\left(\frac{\partial f }{\partial x_{n}}e_{n}\right)^{2}\right]^{\frac{1}{2}} \tag{4}\]  
where \(e_{R}\) is the overall uncertainty associated with the measurement, \(f\) is the given function of the measurement, and \(e_{1}\), \(e_{2}\),..., \(e_{n}\) are the measurement uncertainties of the related measured parameters. Table 3 shows the uncertainties of the parameters used in this study.  
Some authors consider experiments to be of high precision for uncertainties when below 2% [50] or 3% [48]. According to the results shown in Table 3, the experiments can be considered as highly accurate.