## 3 Results and Discussion  
### Analysis of the Experimental Bench  
We investigated a wide range of frequencies in the fans' motors of the evaporative condenser. The volumetric flow rate of air through EC varied from 4.16 m\({}^{3}\)/s with successive reduction until the magnitude of 0.66 m\({}^{3}\)/s. Table 1 shows the values obtained for the electricity consumption in the refrigeration system (compressor and fans of condenser) and condensation pressure in the EC after the measurements on the experimental bench. The results showed that it is not necessarily beneficial for the refrigeration system to maximally reduce the magnitude of condensation pressure. For higher frequencies, there was a more significant gain of electric consumption in the fans driven motors than the reduction in consumption for to the lowest compression ratios in the compressor. On the other hand, for the lower frequencies, despite the lower consumption in the fans' driven motors, the global consumption of the system (compressor and fans motors) was not reduced due to the augmentation of the power demand in the compressor. It is worth mentioning that parameters, such as thermal load and wet bulb temperature, were not used in the strategy of control of the developed algorithm and definition of operation frequency. Therefore, we used electric power for the logic control, which was the performance indicator considered in the refrigeration system. This parameter was chosen due to the commonly transient behavior of the ambient conditions and variation of thermal load by the product to be cooled, which makes difficult the use of other parameters as ambient information. \begin{table}
\begin{tabular}{c c c c} \hline \hline \begin{tabular}{c} **Frequency** \\ **(Hz)** \\ \end{tabular} & \begin{tabular}{c} **Volumetric Flow Rate of** \\ **the Air (m\({}^{3}\)/s)** \\ \end{tabular} & \
\begin{tabular}{c} **Consumption CP +** \\ **EC (kW)** \\ \end{tabular} &
\begin{tabular}{c} **Condensation** \\ **Pressure (bar)** \\ \end{tabular} \\ \hline
50 & 4.16 & 3.19 & 10.53 \\
45 & 3.74 & 2.92 & 10.59 \\
40 & 3.22 & 2.66 & 10.72 \\
35 & 2.80 & 2.50 & 10.92 \\
30 & 2.42 & 2.36 & 11.08 \\
25 & 2.04 & 1.81 & 10.58 \\
20 & 1.59 & 1.85 & 11.42 \\
15 & 1.14 & 2.41 & 13.22 \\
10 & 0.66 & 2.51 & 14.44 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Electricity consumption of the experimental bench. The results showed that the lowest volumetric flow rate of the air, \(Q=0.66\) m\({}^{3}\)/s, led to a power consumption of \(P=2.51\) kW. As the volumetric flow rate increased, the power consumption reduced up to the minimum magnitude of 1.81 kW for \(Q=2.04\) m\({}^{3}\)/s. From this point, the augmentation in the magnitude of \(Q\) led to an increase in electricity consumption up to the maximum magnitude of \(P=3.19\) kW, obtained when \(Q=4.16\) m\({}^{3}\)/s. The optimal volumetric flow rate of air was obtained for \(Q=2.04\) m\({}^{3}\)/s. This point of operation represented the condition where thermodynamic equilibrium (removing the unnecessary magnitude of thermal load out of the refrigeration system) and compression ratio that minimizes the consumption of the refrigeration system (compressor and fans of evaporative condenser) were obtained. The reason for this behavior was that for a volumetric flow rate of air above \(Q=2.04\) m\({}^{3}\)/s, there was a more significant gain of electric consumption in the fans' driven motors than the reduction in consumption due to the lowest compression ratios in the compressor. On the other hand, for a volumetric flow rate of air lower than \(Q=2.04\) m\({}^{3}\)/s, despite the lower consumption in the fans' driven motors, the global consumption of the system (compressor and fans motors) was not reduced due to the augmentation of the power demand in the compressor. This behavior occurred with the increase in the compression ratios and decrease in efficiency of the compressor for the lowest magnitudes of frequency of the control system.