## 3 Results and Discussion
### DIALux(r) Analysis Results  
As stated in the methodology described in Section 2, four model classrooms were selected as representative of the different types of poorly illuminated classrooms, three of which were in building A and one was in building B (see Figure 6):  
* A-005 (medium-sized classroom model)
* A-016 (smaller classroom model)
* A-038 (large classroom model)
* B-306 (classroom with the worst lighting result in building B)  
The heterogeneous classroom sizes in building A prompted the selection of a higher proportion of cases from this building. In contrast, the classrooms in building B are much more homogeneous with regard to their geometry. To get a better idea of the current status of the illumination levels in the selected classrooms (in addition to the results from Table 1), the percentage distribution of the individual desks with regard to the measured illuminance, \(E_{m}\), was plotted (see Figure 7). This histogram clearly indicates the poor lighting conditions in the building A classrooms. Before analyzing any possible improvement, the current situation of the selected classrooms was simulated as accurately as possible using DIALux(r). As shown in Figure 4, the geometry and conditions of the classrooms were simulated, including the furnishings and position of all luminaires. Finally, the attenuation of these luminaires was adjusted to bring the results of the simulation as close as possible to the measurements taken (see Table 2 for the average and maximum values of measured and simulated lighting on the desks and blackboards in the selected classrooms). Figure 8 compares the illumination from the testing campaign, \(E_{m}\), and the DIALux(r) simulation, \(E_{dl}\), on each individual desk. The quality of the correlation between the two results can be appreciated compared to the ideal simulation indicated by the continuous line included on the graphs. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Classroom** & \(\begin{array}{c}A\\ \text{[m^{2}]}\end{  
Figure 6: Pictures of classrooms A-005 (**a**), A-016 (**b**), A-038 (**c**), and B-306 (**d**) selected for this study as representative of all classrooms at the _Escuela Tecnica Superior de Ingenieria Aeronáuttica y del Espacio_ (ETSIAE) at the _Universidad Politécnica de Madrid_ (UPM). Figure 7: Percentage distribution of the individual desks with regard to the measured illuminance, \(E_{m}\), in the classrooms selected for this study (A-005, A-016, A-038, and B-306). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **Classroom** & \(E_{\text{an},dk}\) **[lx]** & \(E_{\text{max},dk}\) **[lx]** & \(E_{\text{an},b}\) **[lx]** & \(E_{\text{max},b}\) **[lx]** & **UGR** & **UGR** \\  & & & & & & **(Average)** & **(max)** \\ \hline  & A-005 & 133 & 168 & 224 & 242 & - & - \\ Current & A-016 & 112 & 152 & 112 & 120 & - & - \\ Case & A-038 & 132 & 166 & 246 & 275 & - & - \\  & B-306 & 293 & 478 & 456 & 509 & - & - \\ \hline  & A-005 & 133 & 187 & 222 & 237 & 24 & 25 \\ Current & A-016 & 135 & 157 & 113 & 118 & 18 & 20 \\ Case & A-038 & 129 & 205 & 243 & 256 & 24 & 25 \\ Simulation & B-306 & 295 & 509 & 467 & 501 & 21 & 23 \\ \hline  & A-005 & 148 & 202 & 235 & 249 & 23 & 24 \\ Case 1 & A-016 & 152 & 176 & 126 & 132 & 17 & 19 \\  & A-038 & 141 & 218 & 254 & 265 & 23 & 25 \\  & B-306 & 311 & 531 & 483 & 520 & 21 & 23 \\ \hline  & A-005 & 304 & 403 & 431 & 451 & 23 & 25 \\ Case 2 & A-016 & 213 & 340 & 354 & 360 & 23 & 25 \\  & A-038 & 267 & 372 & 413 & 440 & 23 & 25 \\  & B-306 & 973 & 1088 & 974 & 1044 & 22 & 24 \\ \hline  & A-005 & 536 & 698 & 570 & 795 & 13 & 19 \\ Case 3 & A-016 & 614 & 686 & 593 & 696 & 16 & 19 \\  & A-038 & 506 & 809 & 555 & 745 & 14 & 19 \\  & B-306 & 564 & 855 & 527 & 581 & 15 & 19 \\ \hline  & & & & & & & \\ \end{tabular}
\end{table}