## 4 Conclusions  
In this work, the thermodynamic behavior of a double skin facade (DSF) and performance assessment in terms of pre-heating efficiency during the cold season and the dynamic insulation efficiency during the hot one is studied using an experimental measurement campaign in specific climate conditions of Romania. Experimental work was done on naturally and mechanically ventilated single-story DSF built on southwest facade of the INCERC Laboratory of Applied Research and Testing in Constructions in Iasi. During the hot season, three outdoor air curtain modes of ventilation were chosen: natural ventilation with lateral openings on the exterior glazing, forced ventilation with lateral openings, and natural ventilation combining lateral and vertical openings on the top of the channel. During the cold season, the lateral and vertical openings are closed, and the channel facade behaves like a thermal buffer between the building and the exterior air. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Day**} & \(v_{med}\) & \(T_{e}\) & \(T_{exh}\) & \(I_{t}\) & \(\dot{m}_{v}\) & \(Qr\) & \(Qs\) & \(Qi\) & \(Qinc\) & \(\varepsilon\) \\ \cline{2-10}  & **(m/s)** & (°C) & (°C) & **(W/m2)** & **(kg/s)** & **(W)** & **(W)** & **(W)** & **(W)** & **(\%)** \\ \hline
12 July 10:00 & 0.46 & 29.2 & 39.3 & 402 & 0.11 & 1096 & 878 & 123 & 2097 & **52.3** \\
12 July 15:00 & 0.43 & 26.9 & 37.9 & 14 & 0.10 & 1108 & 31 & 109 & 1247 & **88.8** \\
12 July 17:00 & 0.46 & 22.1 & 25.5 & 54 & 0.11 & 369 & 118 & \(-\)15 & 472 & **78.2** \\
13 July 12:00 & 0.44 & 27.4 & 40.9 & 550 & 0.10 & 1380 & 1201 & 139 & 2720 & **50.7** \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Dynamic insulation efficiency for the first ventilation mode (SET 1: 07 th–13 th July). \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Day**} & \(v_{med}\) & \(T_{e}\) & \(T_{exh}\) & \(I_{t}\) & \(\dot{m}_{v}\) & \(Qr\) & \(Qs\) & \(Qi\) & \(Qinc\) & \(\varepsilon\) \\ \cline{2-10}  & **(m/s)** & (°C) & (°C) & **(W/m2)** & **(kg/s)** & **(W)** & **(W)** & **(W)** & **(W)** & **(\%)** \\ \hline
16 July 13:00 & 0.62 & 25.7 & 32.3 & 610 & 0.14 & 953 & 1332 & 53 & 2338 & **40.8** \\
17 July 13:00 & 0.48 & 24.6 & 39.3 & 160 & 0.11 & 1641 & 349 & 123 & 2113 & 77.7 \\
18 July 10:00 & 0.45 & 23.4 & 38.4 & 442 & 0.11 & 1592 & 965 & 114 & 2671 & **59.6** \\
19 July 16:00 & 0.49 & 31.7 & 34.7 & 425 & 0.11 & 344 & 928 & 77 & 1349 & **25.5** \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Dynamic insulation efficiency for the second ventilation mode (SET 2: 14 th–20 th July). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Day**} & \(v_{med}\) & \(T_{e}\) & \(T_{exh}\) & \(I_{t}\) & \(\dot{m}_{v}\) & \(Qr\) & \(Qs\) & \(Qi\) & \(Qinc\) & \(\varepsilon\) \\ \cline{2-10}  & **(m/s)** & (°C) & (°C) & **(W/m2)** & **(kg/s)** & **(W)** & **(W)** & **(W)** & **(W)** & **(\%)** \\ \hline
23 July 10:00 & 0.38 & 19.8 & 22.4 & 207 & 0.48 & 1261 & 452 & \(-\)46 & 1667 & **75.6** \\
23 July 15:00 & 0.45 & 27.7 & 34.7 & 499 & 0.58 & 4087 & 1090 & 77 & 5254 & **77.8** \\
24 July 12:00 & 0.44 & 28.0 & 38.9 & 527 & 0.56 & 6177 & 1151 & 119 & 7447 & **82.9** \\
25 July 16:00 & 0.39 & 35.3 & 37.2 & 408 & 0.50 & 954 & 891 & 102 & 1947 & **49.0** \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Dynamic insulation efficiency for the third ventilation mode (SET 3: 24 th–30 th July). From the analysis of the measured data, the following considerations can be drawn. During the cold season, the buffer facade offers the possibility to ensure the partial or integral heating of the interior room for a solar radiation intensity higher than 100 W/m\({}^{2}\), when the temperatures inside the channel exceed the value of 20 \({}^{\circ}\)C with a difference of 14 \({}^{\circ}\)C relative to the exterior ones.