# Computational Modeling of Passive and Active Cooling Methods to Improve PV Panels Efficiency
## 3 Results and Discussion
### Passive Method  
In this method, direct holes were made in the PV panel, as described in the modeling section. To analyze the behavior of the PV panel, the physics modules of turbulent fluid flow, heat transfer, and radiation were used. Figures 4 and 5, and Table 5 show the results obtained for the temperature variation, which are compared with the temperature behavior of the standard PV panel. Figure 4: Temperature distribution for the PV panels in \({}^{\circ}\)C: (**a**) standard; (**b**) perforated. Figure 4 shows a diagram of the temperature distribution in the cell, for standard and perforated PV panels; and Table 5 shows the different values of temperature reached by the standard panel (Stand. PV Panel Temp. ), the perforated panel (Perf. PV Panel Temp.) and their difference (Diff. Stand. PV Panel--Perf. PV Panel), considering a variation in ambient temperature (Amb. Temp.). Comparing the temperature values presented in Table 5, an average reduction of 4.46 \({}^{\circ}\)C can be observed for the perforated module compared to the standard module, with a minimum variation of 1.45 \({}^{\circ}\)C, and a maximum of 6.06 \({}^{\circ}\)C.  
Figure 6 shows the behavior of the wind as it passes through the solar panels. More turbulence flow can be seen for the perforated panel compared to the standard panel. In this way, the operating temperature of the perforated panel is reduced, since any turbulent fluid works as a passive diffuser. This situation is confirmed with the results obtained for the boundary layer of the panels (Figure 7). In this figure, it is observed that the difference in the shape of layers is caused by the holes in the perforated panel. Figure 5: Temperature of the PV panels for different hours of the day: standard (**red**), perforated (**blue**) and ambient temperature (**black**). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Time** & **Amb. T. (\({}^{\circ}\)C)** & **Std. Panel (\({}^{\circ}\)C)** & **Perf. Panel (\({}^{\circ}\)C)** & **Diff. Std.—Perf.** \\  & & & & **Panel (\({}^{\circ}\)C)** \\ \hline
6:00 & 26.12 & 27.90 & 26.45 & 1.45 \\
7:00 & 26.65 & 35.77 & 31.32 & 4.45 \\
8:00 & 27.55 & 39.15 & 34.75 & 4.40 \\
9:00 & 28.36 & 42.44 & 37.23 & 5.21 \\
10:00 & 29.85 & 47.97 & 42.41 & 5.56 \\
11:00 & 31.16 & 52.62 & 47.92 & 4.70 \\
12:00 & 31.86 & 67.70 & 62.36 & 5.34 \\
13:00 & 31.78 & 67.34 & 62.60 & 4.74 \\
14:00 & 30.98 & 63.07 & 57.01 & 6.06 \\
15:00 & 30.17 & 57.94 & 52.33 & 5.61 \\
16:00 & 29.37 & 49.41 & 45.50 & 3.91 \\
17:00 & 28.45 & 42.08 & 38.80 & 3.28 \\
18:00 & 27.69 & 34.14 & 30.90 & 3.24 \\ Prom. & 29.23 & 48.27 & 43.81 & 4.46 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Temperature values of the PV panels for different hours of the day (standard—perforated). Finally, Table 6 shows the results in the output power of the PV panels modeled in this section, for which the mathematical model of the PV panel implemented in Matlab was used. These data were taken during sunny hours when the panel was exposed to the greatest radiation, from 10 a.m. to 3 p.m. With the perforated panel, a higher power output was achieved due to the improvements obtained in the operating temperature in relation to the standard panel. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Time** & **Std. Panel (W)** & **Perf. Panel (W)** & **Diff. Std.—Perf.** \\  & & & **Panel (W)** \\ \hline
10:00 & 67.61 & 71.29 & 3.68 \\
11:00 & 63.98 & 67.61 & 3.63 \\
12:00 & 50.16 & 55.71 & 5.55 \\
13:00 & 50.76 & 55.37 & 4.61 \\
14:00 & 54.80 & 60.44 & 5.64 \\
15:00 & 59.65 & 64.41 & 4.76 \\ Prom. & 57.83 & 62.47 & 4.65 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Power values of the PV panels for different hours of the day (standard—perforated). Figure 6: Wind speed (m/s) and flow lines on the panels: (**a**) standard; (**b**) perforated. Figure 7: Boundary layer of the wind in the PV panels. (**a**) Standard panel in vertical position; (**b**) standard panel with 45\({}^{\circ}\) tilt angle; (**c**) perforated panel with 45\({}^{\circ}\) tilt angle.