## 2 Materials and Methods
### Computational Fluid Dynamics (CFD) Simulation
Load-bearing walls are usually very thick in this type of ancient dwelling, so it can be assumed that the thermal inertia is high so the boundary condition will include an imposed temperature equal to the mean temperature of the dwelling (T\({}_{\text{imp}}\)), whereas thinner walls are considered to lack this property, thus using an adiabatic wall condition. On the other side, from the results of the previous simulation, it will be obtained that the direction of the flow across the dwelling is from the courtyard to the street, so the inlet boundary condition is set as \"pressure inlet\" in the windows facing the courtyard, where the gauge total pressure value corresponds to the value of \(\Delta\)P calculated previously while the pressure gauge in the pressure outlet is set to zero in the windows facing the street. The floor plan with boundary conditions marked is shown in Figure 15.  
Ultimately, the configuration of the Fluent environment is analogous to that of the previous iteration, exhibiting only a few modifications. The initial step is to enable the energy equation, which is necessary for the simulation to perform temperature calculations. It is not evident which turbulent model is the most appropriate in this context. Nevertheless,  
Figure 14: Upper floor dimensions. Figure 15: Upper floor plan with boundary conditions. the utilisation of SST k-\(\Omega\) has been evidenced to yield favourable outcomes. The remaining configuration parameters remain unchanged from the previous iteration. Upon completion of the simulation, several results of interest are obtained. Firstly, the flow streamlines within the first floor provide insight into the location of the vortex formed within the rooms, despite the two-dimensional simplification. This is crucial for a more comprehensive grasp of the flow dynamics across the rooms, thereby facilitating the pre-determination of optimal sensor placement within the rooms. It is imperative to situate the sensors in locations shielded from the primary air jets to ensure the consistency of measurements. Subsequently, the total air mass flow rate entering the floor is determined, as well as the percentage of this entering each room. Subsequently, a final three-dimensional simulation of the room of interest is conducted. The room was modelled as a cube, with the door designated as the pressure inlet and the window facing the street designated as the pressure outlet. It can be assumed that the value of the inlet is equivalent to \(\Delta\)P (the pressure in the external windows) as the pressure loss on the corridor is negligible. The boundary conditions for the floor and room walls are set as temperature-imposed walls (T\({}_{\text{imp}}\)), in accordance with the aforementioned explanation. The ceiling is set as an adiabatic wall, given that it is not thick enough to be classified as otherwise. With this, it is expected to obtain numerical results about ventilation rate and temperature reduction efficiency. The first parameter is very important for the design of outdoor acclimatization strategies, which can be defined as an approximation of the number of times the air within a given zone is completely renewed in a period of time. This is named air renewal rate (ACH) and can be calculated with the airflow mass rate (\(\dot{m}\)) entering a room following Equation (3). \[ACH\;[\text{ren/h}]=\frac{\dot{m}[\frac{\text{kg}}{8}]\cdot 3600[\frac{\text{g}}{ \text{h}}]}{\rho[\frac{\text{kg}}{\text{m}^{3}}]\cdot A[\text{m}^{2}]\cdot 1[ \text{m}]} \tag{3}\]  
On the other hand, temperature reduction efficiency (\(\varepsilon\)) is a key point of this study, as it presents a novel approach to obtain the relation between the total air entering a space (\(\dot{m}_{nom}\)) and the part of it that actually participates in the heat dissipation (\(\dot{m}_{ef}\)) as it interacts with hot surfaces and cools them, increasing its own temperature in the process.