## 3 Results and Discussion
It can be seen that there is a relationship between the type of day and the performance with which the set of panels and the inverter works, ranging from mean values slightly below 0.75 for L1 days, which are those with the lowest performance, to mean values close to 0.9 for H2 days, which are the types of days on which there is a higher average \(PR\) value. The greatest dispersion of \(PR\) values within the different groups occurs on L1 days, indicating that a greater heterogeneity of the days selected by the algorithm was obtained within this group. With regard to the behaviour of the set of modules and inverter, it can be observed that on H days, the performance of their operation was similar on the three types of days, regardless of the irradiance fluctuations that occurred. Within the M days, the performance of M3 and M2 days were similar to each other, despite the differences in the fluctuations of the daily irradiance profiles in these two groups, and both were slightly higher than the performance of M1 days. The same was true for L days, in which the \(PR\) values of the L2 and L3 days were similar to each other, and higher than those of the L1 days, which corresponded to lower irradiance values. It is noteworthy that H1 and M1 are not the days with the best average \(PR\) within the categories of H and M days respectively, but it was found that days with passing clouds, and therefore with fluctuations in production, had better average performance ratio than clear sky days or days with fewer transitions. To see the reason for this behaviour, Figure 11 shows the average daily efficiency of the PV modules obtained for the days on each group. Figure 11 shows that, although the production of energy in the modules is proportional to the irradiance received by them, the efficiency with which the modules transform solar radiation into electricity varied depending on the type of day, such that, on L1 days, modules worked with an average efficiency of 12%, and on H2 days, which are those with the best average efficiency of the panels, had average values close to 14%. It can be observed that in this H2 group, there was less dispersion of the average efficiency of the module from one day to another within the same group. It can be seen that, in general, the days with the lowest module efficiency corresponded to L days. Within the subcategories, the efficiency improved from L1 to L2 and L3, as the total daily irradiance increased. Within these types of days, the variability or dispersion of the results within the same group was  
Figure 4.6 Average daily efficiency of PV modules in the clusters L1, L2, L3, M1, M2, M3, H1, H2 and H3. greater, which indicates, as already mentioned, the heterogeneity of patterns that may exist within these subcategories. The behaviour of the efficiency of the PV modules improved for days with medium irradiance. However, it is worth noting that within the M1, M2 and M3 groups, there was no better performance on the days with lower fluctuations (M1), but, contrary to what might be expected at first, on M3 days, which had higher fluctuations, the average efficiency was higher, even taking into account that, for the three types of days, M1, M2 and M3, the total daily irradiance is within the same range of values (Figure 9). With respect to the behaviour of the modules on H days, the average efficiency value was slightly higher than on M days, but a similar behaviour appeared with respect to the presence of fluctuations. Although the best efficiency results, above 15%, were found on some H1 days, in general, the average module efficiency was higher on H2 days, which had more fluctuations in irradiance, than on H1 days. The best average efficiency value was found on H2 days, as on H3 days there was a small decrease, but the average efficiency was still slightly higher on H3 than on H1 days. It is difficult to make a comparison of the results obtained with those found in previous research, since irradiance profiles are highly dependent on geographical location.