## 2 Materials and Methods
### Building Information Modeling (BIM)  
The baseline building model, with conventional insulation, was developed using Autodesk Revit after evolving the 2D CAD drawing file to 3D BIM object, with a total floor area of 205.87 m\({}^{2}\) and a net conditioned area of 184.96 m\({}^{2}\). Figures 10 and 11 show the ground and first-floor plans including rooms' spaces division of the studied building, respectively. All spaces were identified in the software based on American Society of Heating, Refrigerating and Air-Conditioning Engineers ASHRAE standards integrated in [54], considering the occupancy type of each space inside the building, as illustrated in Table 2, which summarizes the sensible and latent heat gains, the lighting and power load densities, the infiltration flow rate, and the occupancy schedule. In the context of this study, the building is characterized as a well-sealed construction, featuring an average infiltration flow rate of 0.19 L/s\(\cdot\)m\({}^{2}\), as detailed in Table 2. Converting this value to 0.23 air changes per hour (ACH), considering a floor height of three meters, is noteworthy. Subsequently, spaces were categorized into thermal zones based on HVAC system characteristics and space boundary conditions. The modeling process for the reference design was facilitated within the Revit BIM environment, utilizing user-friendly tools that allow for the creation of custom object families by modifying default libraries. Analytical surfaces, space types, and solar analysis were the primary objects employed in energy modeling. Figure 10: Ground-floor plan. Moreover, Autodesk Revit employs the cumulative insolation method to conduct solar analysis on the building, considering solar information from sunrise to sunset throughout the year, based on available weather data for the specified location. In Amman city, for example, the results reveal that solar radiation reaches 1818 kWh/m\({}^{2}\) on the roof and certain sections of the southern facade, while the remainder of the building receives approximately 980 kWh/m\({}^{2}\), as illustrated in Figure 12.  
Regarding the thermal properties of the external building elements, such as walls, floors, and roofs, they were assessed by calculating their U-values and thermal capacities, considering the materials used in their construction. Accordingly, the characteristics of the main envelope components for the reference building model are summarized in Table 3.  
Since this paper focuses on the use of PCMs integrated into the exterior walls for thermal energy storage in terms of energy efficiency, Table 4 summarizes the thermal properties of the external wall layers arranged from the exterior to the interior side, along with Figure 13, which visually reveals the layers of the exterior wall for the reference building model. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Room Destination**} & **Sensible** & **Latent** & **Lighting** & **Power** & **Infiltration Air** \\  & \multicolumn{2}{c}{**Heat Gain**} & & **Load Density [W/m\({}^{2}\)]** & **Flow [L/s\(\cdot\)m\({}^{2}\)]** \\ \hline Bedrooms & 73.27 & 45.43 & 11.95 & 5.81 & \\ \hline Living room & 80.59 & 80.59 & 22.60 & 5.81 & \\ \hline Corridor & 73.27 & 58.61 & 11.84 & 5.81 & \\ \hline Guest room & 73.27 & 45.43 & 11.84 & 5.81 & \\ \hline Kitchen & 73.27 & 58.61 & 12.92 & 16.15 & \\ \hline Dressing room & 73.27 & 58.61 & 6.03 & 5.81 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Conditioned spaces characteristics (occupancy schedule \(-\) residential/24 h), adapted from [54]. Figure 11: First-floor plan. Figure 12: Solar analysis of the building model in Amman city.