# Sustainable Modularity Approach to Facilities Development Based on Geothermal Energy Potential
## 2 Materials and Methods
### Architectural Model  
_Boundary Conditions and Calculation Methodology_  
Following the principles of modular design, modules of the same footprint (5.5 \(\times\) 10 m) were used for both wellness and spa/medical facilities and utility spaces (heated and unheated). To enhance functionality and energy efficiency of the study model, balneotherapy units were grouped in pairs with a small joint space to access interior and exterior facilities. Heated auxiliary spaces were designed as combinations of 2-4 modules, while unheated modules may be placed along the northern side of the connecting corridor in a manner that enables efficient service and easy access. Figure 8 presents three development stages. Figure 7: Model for modular wellness facilities with optional hospitality and medical facilities. 1. an initial stage, with a small number of units and basic utility spaces (475 m\({}^{2}\), 2 \(\times\) 2 units for balneotherapy);
2. an intermediate stage, conceived as an extension of the initial stage (737 m\({}^{2}\), 3 \(\times\) 2 units for balneotherapy), and
3. high-capacity stage, (988 m\({}^{2}\), 4 \(\times\) 2 units for balneotherapy). Stage 1 (Figure 8a) comprises of 4 balneotherapy units _Mb1-Mb4_ with 3 additional utility modules _Mu1-Mu3_ for reception, changing rooms, office, examination room and cafe, and an unheated module _Mt1_ as the mechanical room. Stage 2 (Figure 8b) is conceived as an expansion of Stage 1 with 2 added balneotherapy units _Mb5-Mb6_, an additional utility module _Mu4_ and an additional technical module _Mt2_. The third stage (Figure 8c) presents a further extension with balneotherapy modules _Mb7-Mb8_, additional utility module _Mu5_ and technical module _Mt3_. An overview of the basic data for all three stages is given in Table 2.  
In terms of energy performance, two different approaches to building the thermal envelope were explored:  
1. base case, designed to comply with national regulations--EPC class C structure, with all envelope components meeting the mandatory _U_-values (thermal transmittance coefficient) thresholds; and
2. enhanced performance case, with _U_-values of thermal envelope components designed in accordance with Passive House standards. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Development Stage** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Balneo Units** \\ **(Heated)** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Utility Units** \\ **(Heated)** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Utility Units** \\ **(Unheated)** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Utility Units** \\ **(Heated)** \\ \end{tabular} } & \multicolumn{2}{c}{\begin{tabular}{c} **Urr Heated** \\ **(Heated)** \\ \end{tabular} } & \multicolumn{2}{c}{\
\begin{tabular}{c} **Net Heated** \\ **Area** \\ \end{tabular} } & \multicolumn{2}{c}{
\begin{tabular}{c} **Total Useful** \\ **Area** \\ \end{tabular} } \\ \cline{2-10}  & **pcs.** & **(m\({}^{2}\))** & **pcs.** & **(m\({}^{2}\))** & **pcs.** & **(m\({}^{2}\))** & **pcs.** & **(m\({}^{2}\))** & **(m\({}^{2}\))** & **(m\({}^{2}\))** \\ \hline
**1. Initial phase** & 4 & 220 & 3 & 165 & 1 & 55 & 2 & 17 & 18 & 420 & 475 \\ \hline
**2. Extended** & 6 & 330 & 4 & 220 & 2 & 110 & 4 & 34 & 43 & 627 & 737 \\ \hline
**3. High capacity** & 8 & 440 & 5 & 275 & 3 & 165 & 7 & 59 & 49 & 823 & 988 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Development stages—an overview of basic data. Figure 8: Three development stages for balneotherapy facility: (**a**) Stage 1 with 4 balneotherapy units, (**b**) Stage 2 with 6 balneotherapy units, and (**c**) Stage 3 with 8 balneotherapy units. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Component** & \begin{tabular}{c} **U\({}_{max}\) [W/(m\({}^{2}\)\(\times\) K)]** \\ **National 1** \\ **EnerPHit 2** \\ \end{tabular}  & \multicolumn{2}{c}{**Base Case**} & \multicolumn{2}{c}{**Enhanced Case**} \\ \hline External wall & & & & \\ \hline \multirow{6}{*}{