## 2 Methodology
### Sensitivity Study  
A sensitivity study was designed to attest the impact of the windows and the opaque envelope on the energy demand in museums for two different climate control strategies for the case of Lisbon. Four solutions for the windows' thermal transmittance, four solar heat gain coefficients and four solutions for the thermal transmittance of the opaque envelope were analyzed through the use of a sensitivity study to correlate all the hypotheses, performing a total of 128 simulations. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Building** & **Materials** & **d [m]** & \(\lambda\) [W/m.K] & \(\rho\) [kg/m\({}^{3}\)] & **C [J/kg.K]** \\ \hline \multirow{3}{*}{Walls Outside \(\rightarrow\) Inside} & \multirow{2}{*}{\begin{tabular}{c} Lime mortar \\ Mortared \\ limestone \\ \end{tabular} } & 0.03 & 0.70 & 1785 & 850 \\  & & 0.84 & 1.76 & 2122 & 850 \\  & & 0.03 & 0.70 & 1785 & 850 \\ \hline \multirow{3}{*}{Celling Outside \(\rightarrow\) Inside} & \multirow{2}{*}{\begin{tabular}{c} Wooden \\ layer \\ Concrete \\ Time mortar \\ \end{tabular} } & 0.02 & 0.15 & 740 & 1400 \\  & & 0.25 & 1.70 & 2322 & 850 \\  & & 0.03 & 0.70 & 1785 & 850 \\ \hline \multirow{3}{*}{Floor Outside \(\rightarrow\) Inside} & \multirow{2}{*}{\begin{tabular}{c} Lime mortar \\ Concrete \\ Wooden \\ layer \\ \end{tabular} } & 0.03 & 0.70 & 1785 & 850 \\  & & 0.25 & 1.70 & 2322 & 850 \\  & & 0.02 & 0.15 & 740 & 1400 \\ \hline \multirow{3}{*}{Windows} & \multirow{3}{*}{\
\begin{tabular}{c} Double-glazed aluminum \\ frames \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} U\({}_{\text{w}}\) = 3.63 W/m\({}^{2}\).\({}^{\circ}\)C \\ \end{tabular} } & \multirow{3}{*}{SHGC = 0.38} \\  & & & & & \\ \end{tabular}
\end{table} 
Table 2: Assemblies and respective material properties used in the model [45; 46]. \begin{table}
\begin{tabular}{c c} \hline \hline
**Visitors’ Impact** & \\ \hline Average occupancy & 10 visitors/h (open hours) \\ \hline \multirow{3}{*}{Sensible heat} & 88 W/(person.h) (60\% emitted by radiation and 40\% by convection) [42; 47] \\ \cline{2-3}  & 39 W/(person.h) (converted into 61 g/(person.h) according to [42; 47] \\ \hline CO\({}_{2}\) generation rate & 34 g/(person.h) [42; 48; 49] \\ \hline LPD (lighting power density) & 4.8 W/m\({}^{2}\)[32] \\ \hline Ventilation & \\ \hline Open hours & 456 m\({}^{3}\)/h of fresh air [42; 49] \\ \hline Night period & 61 m\({}^{3}\)/h of fresh air [42; 50] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Internal gains and ventilation used in the model [42; 48; 49; 50]. As regards the opaque envelope, four different scenarios of thermal transmittance were evaluated: the first one considering the original wall with no thermal insulation (U = 1.36 W/m\({}^{2}\).\({}^{\circ}\)C); the second case considering the use of 2 cm of thermal insulation (mineral wool) and a plasterboard of 1.5 cm (U = 0.77 W/m\({}^{2}\).\({}^{\circ}\)C); the third scenario considers a thermal insulation layer with 6 cm (U = 0.43 W/m\({}^{2}\).\({}^{\circ}\)C); and the fourth and last scenario considers a thermal insulation layer with 10 cm (U = 0.30 W/m\({}^{2}\).\({}^{\circ}\)C). For the windows, the U\({}_{\rm w}\) values were estimated according to CIBSE Guide A [51]: 6.01 W/m\({}^{2}\).\({}^{\circ}\)C for single-glazed and aluminum frames without thermal cut; 3.63 W/m\({}^{2}\).\({}^{\circ}\)C for double-glazed with an air layer of 6 mm and aluminum frames with 4 mm of thermal shear; 2.55 W/m\({}^{2}\).\({}^{\circ}\)C for double-coated glazes (\(\varepsilon\) = 0.2) with an air layer of 12 mm and aluminum frame with 12 mm of thermal shear; and 1.53 W/m\({}^{2}\).\({}^{\circ}\)C for double-coated glazes (\(\varepsilon\) = 0.05) with an argon layer of 16 mm and PVC frames with three hollow chambers. The use of windows with 1.4 \(\times\) 2.0 m\({}^{2}\) and a ratio of 0.185 between the frame area and the total area were considered.