## 3 The Case Study
### Structural Design and Building Envelope Characteristics  
The loadbearing structure is LSF (Figure 5), on which six steel sheets are welded and used as removable landing gears, which are then used to transfer forces to the ground (Figure 4). The wall has a single layer of vertical steel studs every 600 mm, while in exceptional situations where additional stiffening is needed, or for load bearing purposes, the gap between two vertical studs is 300 mm. In case of floor studs, the gap between two studs is 380 mm, while the gap between the roof studs is 480 mm (Figure 5). These distances were determined in a structural analysis, taking into account ultimate limit states and especially serviceability limit states, which was dominant due to the limit of maximum deflections of the glazing, technical systems installed, and aesthetics (cracking of internal surfaces, etc.). Non-combustible thermal insulation (mineral wool) is placed between vertical (wall) and horizontal (floor and roof) steel studs, while continuity of thermal insulation is maintained by adding additional thermal insulation to both the external and internal side of the walls, roof, and floor. Different physical-mechanical properties of mineral wool insulation are required depending on the building envelope element in which it is installed (filling between steel studs, external insulation in the ventilated air cavity, additional thermal insulation layer under gypsum plasterboards). Depending on this, and in consultation with the manufacturers, different types of mineral wool insulation were selected (stone or glass wool). All characteristic layers of opaque building envelope elements are shown in Figure 6. \begin{table}
\begin{tabular}{c c} \hline Net floor area, \(A_{k}\) [m\({}^{2}\)] & 14.75 \\ \hline Gross floor Area, \(A_{f}\) [m\({}^{2}\)] & 22.35 \\ \hline External surface area of the building envelope, \(A\) [m\({}^{2}\)] & 118.96 \\ \hline Heated building gross volume, \(V_{e}\) [m\({}^{3}\)] & 69.73 \\ \hline Heated air volume, \(V\) [m\({}^{3}\)] & 35.84 \\ \hline Shape factor,\(f_{0}\) [m\({}^{-1}\)] & 1.71 \\ \hline \end{tabular}
\end{table} 
Table 1: Geometric characteristics of the MUZA. Figure 4: View of the main facade of the MUZA constructed with the LSF system. Figure 5: Load bearing steel structure of the MUZA: **left—**numerical model, **right—**realized structure. Figure 6: MUZA’s opaque envelope assemblies. Two sliding doors are placed on the main and back facade, respectively, and are characterized by triple glazing with low-e coating, argon filling, and PVC profile. On the main facade, larger sliding doors (3.7 \(\times\) 2.2 m) have external and internal safety glazing (precaution measures due to the facts that the MUZA will be publicly used and frequently transported). Calculated thermal transmittance for larger sliding doors is \(U_{w}\) = 0.83 W/m\({}^{2}\)K (\(U_{g}\) = 0.6 W/m\({}^{2}\)K, \(U_{f}\) = 1.1 W/m\({}^{2}\)K, \(g_{z}\) = 0.60), and \(U_{w}\) = 0.97 W/m\({}^{2}\)K (\(U_{g}\) = 0.7 W/m\({}^{2}\)K, \(U_{f}\) = 1.3 W/m\({}^{2}\)K, \(g_{z}\) = 0.70) for smaller sliding doors (2.3 \(\times\) 2.2 m), respectively. As it was expected that large transparent elements on a building with a small useful floor area and indoor air volume would lead to overheating issues and thermal discomfort, three levels of shading were foreseen:  
1. _Window shutters on both sliding doors acting as a lateral shading_--during transport, they are closed, and their primary function changes to protecting the glazing from mechanical damage caused by external factors (rocks, birds, etc.). 2. _Venetian blinds on larger sliding doors_--motorized blinds can be manually controlled through a central unit, but they can be programmed to start shutting down automatically when solar radiation is too strong, or at sunset. 3. _Self-load bearing textile overhang on larger sliding doors_--this can be easily removed and installed when needed.