## 4 Dynamic Energy Simulations under Future Climate Conditions
### Building Energy Modelling under Future Climate Conditions
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Category** & \
\begin{tabular}{c} **Winter Operative** \\ **Temperature Range** \\ \end{tabular} &
\begin{tabular}{c} **Summer Operative** \\ **Temperature Range** \\ \end{tabular} \\ \hline I & \(\text{T}_{\text{operative}}\geq 21\)\({}^{\circ}\text{C}\) & \(\text{T}_{\text{operative}}\leq 25.5\)\({}^{\circ}\text{C}\) \\ II & \(20\)\({}^{\circ}\text{C}\leq\text{T}_{\text{operative}}<21\)\({}^{\circ}\text{C}\) & \(25.5\)\({}^{\circ}\text{C}<\text{T}_{\text{operative}}\leq 26\)\({}^{\circ}\text{C}\) \\ III & \(18\)\({}^{\circ}\text{C}\leq\text{T}_{\text{operative}}<20\)\({}^{\circ}\text{C}\) & \(26\)\({}^{\circ}\text{C}<\text{T}_{\text{operative}}\leq 27\)\({}^{\circ}\text{C}\) \\ IV & \(\text{T}_{\text{operative}}<18\)\({}^{\circ}\text{C}\) & \(\text{T}_{\text{operative}}>27\)\({}^{\circ}\text{C}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Indoor operative temperature ranges for comfort categories according to the UNI EN 16798-1:2019 [59] for residential buildings. detail, the operative temperature intervals for both the summer and winter periods were adopted to establish the percentage of the corresponding indoor environmental quality categories associated with each building configuration. In this specific case, only Categories II, III and IV were considered as the simulations were carried out for an existing building, and a normal level of expectation would be \"Medium\" (Category II), as recommended by the standard. Furthermore, the mean, minimum and maximum expected operative temperature was extracted for better comparisons. The indoor temperatures estimated for the building in its original state were assumed as baseline, and percentages of increments/decrements were calculated and are reported in the tables. The obtained categories are plotted from Figures 12-17 and the temperatures are summarised in Tables 4-9. The comparisons underline several variations which should be taken into account for further consideration of the effectiveness of DSF systems. The estimated summer performance of Double Facades could lead to a different distribution of future comfort levels due to the high levels of predicted global solar radiation. As highlighted in the previous section, the amount of monthly mean radiation expected for the years 2030, 2050 and 2070 is much more significant than actual conditions, and this could generate the worst comfort rates for various DSF typologies. Due to a high solar load, the Double Facade, in fact, becomes a heated element which continually emits accumulated heat. This element is much more sensitive to this phenomenon than the original building envelope because it is entirely made of glazed surfaces. While on the one hand the DSF acts as a heat damper, reducing the effect of solar load on the inner operative temperature, on the other it also tends to increase the number of hours for which higher temperatures are estimated and, consequently, leads to a lower level of comfort. A mechanical system should be introduced to improve the summer indoor environment and to enhance natural ventilation in case of extra loads, converting the DSF into a hybrid technology. In evaluating winter comfort rates (Figures 15-17), the general temperature increase predicted for the coldest months allows higher levels of expectation, and this was estimated for both the building's original state and its state after the DSF's installation. The discomfort rates under future conditions tend, in fact, to decrease, and this reduction assumes more significant values for DSF systems, ensuring better performances than those reachable by the reference building in its original state. Additionally, in this case, the DSF that allows the best indoor environment is the Multi-Storey variety, which is capable of guaranteeing the highest percentage with a better level of expectations. Moreover, it is interesting to note that the winter comfort level predicted for the year 2050 shows better values than 2070.