## 4 Discussion and Conclusions
### Discussion
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Design** & **50 cc/min 0.66 V** & **200 cc/min 0.22 V** & **200 cc/min 0.52 V** & **200 cc/min 0.82 V** \\ \hline
3 & 160.2 & 0.125 & 17.33 & 1811 \\
4 & 168.4 & 0.125 & 17.35 & 2092 \\
5 & 168.7 & 0.125 & 17.35 & 2127 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Total current for different designs under various operating conditions (mA). [PERSON] [34] proposed that the external power generation and energy efficiency were considered as indices for PEM performance. The main results established in this work: five designs with different channel shapes and gas flow patterns, were simulated numerically using computational fluid dynamics (CFD). Using this approach, it was possible to conceive of, detail, and analyze each design. The electrical current distributions of the two different serpentine channels with square or rounded flow bends were tested. We can mention some studies that we relied on to arrive at our results. [PERSON] [35] utilized a two-phase, multicomponent, transient, and three-dimensional model for simulating the performance of the PEMFC. In the first step, the best longitudinal catalyst loading distribution was found. In the second step, several lateral distributions were superimposed on the noted longitudinal catalyst loading distribution, and the performance of the PEMFC was evaluated for each distribution. Numerical results showed 3.1% enhancement for the longitudinal catalyst loading distributions. [PERSON] [36], through simulation, was able to detail the cell current density response to a step-change in cell voltage. By studying bipolar plates with different flow channel configurations, through computational modeling of fluid dynamics, a comparison was able to made of the pressure drop characteristics for different flow channel designs. The results showed that with a greater number of parallel channels and smaller sizes, a more effective contact surface area can be achieved along with a decrease in pressure drop. The correlations of these coefficients of the input region will be useful for the fuel cell simulation model. [PERSON] [37] analyzed different geometry configurations of collective flow plates using CDF and found for microchannels with different cross-section geometries, the detachment time, detachment diameter, and the removal time of water droplets increased in this sequence: triangle < trapezoid < rectangle with a curved bottom wall < rectangle < upside-down trapezoid. The detachment time for semicircle channel was longer than the rectangle, while its detachment diameter was smaller and the removal time shorter than the rectangle. [PERSON] [38], by simulating the flow channels, better uniformity in the current density distribution along the width of the cell could be attained. In other cases, the researchers showed real applications mainly for the automotive sector in hybrid vehicles or applications in the electronics industry such as telephony, computing, and instruments for research and development [33]. [PERSON], using ANSYS (r) v14, simulated the behavior of the relevant variables in a fuel cell (pressure, volume, mass flow) in eight different geometry configurations in bipolar plates. More uniform results were obtained in a geometry configuration with grooves [39], and the simulation reduced the time for laboratory-scale experimentation. In our own case, we carried out an application at the laboratory level applying polymeric materials for the manufacture of bipolar plates and the construction of a stack, achieving results similar to those obtained in commercial fuel cells, our contribution resulted in a decrease in the number of components (screws), since the manufactured cells were sealed with the same material as the bipolar plates. In most of the cases mentioned, the study was limited to the simulation of the plates and their different geometries [39].