## 3 Results
### CFD numerical simulation
When the camera is 3 or 5 cm, a greater speed of the external air implies a reduction of the interior temperature of the camera when entering a greater volume of cold air. However, for a camera 10 cm thick, this phenomenon does not occur on the ground floor. Figure 6: Temperatures in the air chamber, according to the floor and the size of the chamber. Figure 7: Temperatures in the air chamber, according to wind speed and chamber dimension. The external air velocity (\(\times\)1) and the thickness of the air chamber (3 cm) were kept constant in Figure 8. The data was taken in the outermost part of the air chamber (inner face of the stone cladding). This figure compares the relative temperature and humidity values in the three floors of the building. When the temperature is lower and the relative humidity is higher, condensation can occur--liquid water that can affect the material, and which persists over time. In the case studied, the area to be analysed more closely is on the right side of the graph, coinciding with the horizontal joint of 15 mm between the ground floor and the first floor. Table 4 shows the variation in temperature and relative humidity for different thicknesses of the air chamber and the different floors of the building, comparing the speed of the soft (\(\times\)1) and moderate (\(\times\)3) air. The reduction in temperature is more pronounced on the ground floor, with air chamber thicknesses of 3 and 5 cm, up to 27% and 29%, respectively (Table 4a). Regarding relative humidity, the greatest increase occurs in floor 1, with a 1 cm air chamber, up to 29%. Also noteworthy is the 17% increase in the ground floor for the 3 cm air chamber (Table 4b). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{(**a**)} & \multirow{2}{*}{**Temperature**} & \multicolumn{6}{c}{**Air Velocity x1–x3**} \\ \cline{3-8}  & & **C1** & **C3** & **C5** & **C10** & **C25** \\ \hline \multirow{5}{*}{(**b**)} & Floor 2 & \(-\)20\% & \(-\)12\% & \(-\)17\% & \(-\)14\% & \(-\)13\% \\  & Floor 1 & \(-\)26\% & \(-\)26\% & \(-\)18\% & \(-\)18\% & \(-\)1\% \\  & Ground Floor & \(-\)2\% & \(-\)27\% & \(-\)29\% & \(-\)8\% & \(-\)8\% \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Temperature and Relative Humidity with variation of air velocity. Darker colour indicates the higher values. Figure 8: Comparison between relative humidity and temperature to locate possible condensation. Table 5 shows the variation of temperature and relative humidity by comparing different thicknesses of the air chamber for smooth (\(\times 1\)) and moderate (\(\times 3\)) air velocity. With a soft air velocity (\(\times 1\)), the temperature is drastically reduced if we compare the thickness of the air chamber of 3 cm with that of 1 cm, with up to a 47% reduction in plant 1 (Table 5a). When the air velocity was moderate (\(\times 3\)) this reduction in temperature increased to 60% with the same air chamber thicknesses (Table 5c). Regarding relative humidity, this increases to 96% if we compare the 3 cm chamber with the 1 cm chamber in plant 1 with the soft air velocity (\(\times 1\)) (Table 5b). For moderate air velocity (\(\times 3\)), the increase is not so sharp, but importantly, there was an up to 74% increase in relative humidity in the ground floor when comparing the 3 cm air chamber and the 1 cm air chamber (Table 5d). Figure 9 compares the temperatures of the air chamber as a function of height, in the interior part (next to the thermal insulation), in the central part of the chamber, and in the exterior part (interior area of the stone cladding). The analysis covers the chamber thicknesses analysed: 1, 3, 5 10 and 25 cm. In all cases, the 1-cm-thick air chamber keeps the temperature very high. In the inner part of the air chamber, the highest temperatures are reached with the 1, 3 and 25 cm chambers, with the lowest temperatures corresponding to the 5 and 10 cm chambers. In the central part of the chamber, the temperature is clearly reduced, as we increase the thickness of the air chamber.