## 4 Results
### Phase II  
The results of campaign 5 (painting of the opaque envelope with reflective paint and natural cross ventilation by wind action for 24 h) are shown in Figure 15. The highest temperatures always occurred in the cell without the passive cooling measures (cell C2). In the cell where cooling measures were applied (cell C1), 5.1 \({}^{\circ}\)C of cooling was obtained. The results also showed that the greatest temperature difference between the two cells occurred  
Figure 12: Variation of external and internal temperature in cells C1 and C2 during one week of campaign 2 (application of a low-emissivity reflective film in the attic). Figure 13: Variation of external and internal temperature in cells C1 and C2 during one week of campaign 3 (natural cross ventilation by wind action). during the day, with an average of 2.5 \({}^{\circ}\)C. During the night, this difference did not reach 1.0 \({}^{\circ}\)C, thus presenting an average for the 24 h of the day of 1.7 \({}^{\circ}\)C of cooling. When the opaque envelope painted with reflective coating was associated with natural cross ventilation by the wind action only at night (campaign 6), the results obtained did not differ significantly from those of campaign 5, with a mean difference between the two cells of 1.6 \({}^{\circ}\)C. It was also possible to verify that there was a slight increase in temperature differences during the day, with an average difference of 2.8 \({}^{\circ}\)C, since, with ventilation disabled when outside temperatures were higher, the entry of warmer air coming from outside was avoided. In this campaign, the maximum difference obtained between the two cells was 5.0 \({}^{\circ}\)C (Figure 16). Figure 14: Variation of external and internal temperature in cells C1 and C2 during one week of campaign 4 (painting the opaque envelope with reflective paint). Figure 15: Variation of external and internal temperature in cells C1 and C2 during one week of campaign 5 (painting of the opaque envelope with reflective paint and natural cross ventilation by wind action for 24 h). The association of the opaque envelope with reflective painting with natural ventilation by the chimney effect in cell C1 (campaign 7) also showed good results (Figure 17), since in cell C1 measured temperatures were, on average, 1.8 \({}^{\circ}\)C lower than in cell C2. These differences were very similar to those obtained in campaigns 5 and 6 for the night period (0.8 \({}^{\circ}\)C) and slightly higher for the day period (3.1 \({}^{\circ}\)C on average and 5.6 \({}^{\circ}\)C of maximum difference). These results demonstrate a greater effectiveness of natural ventilation by the chimney effect compared to cross ventilation by the wind action, since it occurs even when the wind speed is practically null. Figure 16: Variation of external and internal temperature in cells C1 and C2 during one week of campaign 6 (painting of the opaque envelope with reflective paint and natural cross ventilation by wind action during the night period). Figure 17: External and internal temperature variation in cells C1 and C2 during one week of campaign 7 (opaque envelope with reflective painting and natural ventilation by chimney effect for 24 h). Table 3 summarizes the results obtained in the seven experimental campaigns carried out. When applied individually, opaque envelope with reflective painting proved to be the most effective of the techniques. Cross ventilation by wind action for 24 h showed an average temperature difference of 0.6 \({}^{\circ}\)C between cell C1 (where the technique was implemented) and cell C2. However, its effectiveness is greater at night, with the average difference increasing to 0.8 \({}^{\circ}\)C. The results using the reflective painting showed an average temperature difference between the two cells (C1 against C2) of 1.1 \({}^{\circ}\)C, increasing to 1.5 \({}^{\circ}\)C if only the daytime period was considered.