## 3 Results  
### Results of Historic Building Aeranics  
In order to understand the behaviour and air flows around the ancient building, as well as the effect of cross-ventilation inside the building, the results obtained in the various studies conducted with the use of computational fluid dynamics (CFD) are presented. Firstly, the results regarding the full street simulation are presented. This analysis has been conducted for a range of wind conditions and at different times of the day and night. However, the most representative case is presented here, at night and with the average air velocity obtained for the entire summer period. This case is representative because it corresponds to the period when windows are opened to facilitate cross-ventilation for cooling the rooms of the house. This is not a viable option during the day due to the high temperatures typically reached in the area. The streamline pattern shows the movement of the air around the dwelling and inside the courtyard (Figure 16). As can be seen, the previous building alters greatly the flow. In addition, for a better comprehension of the phenomenon, the \(\dot{m}\) (in kg/s) is obtained. It is noticeable that the amount of air entering the ground floor inside the courtyard is ten times smaller than that entering the upper floor. This means that significantly less air reaches the bottom of the courtyard, reassuring the previous statement. Apart from that, the pressure contour (Figure 17) gives the static pressure in the surroundings of the dwelling which is in a depression caused by the previous building. Wall pressure coefficients are obtained in the highlighted spots. Table 4 show the pressure coefficient on four points of the dwelling. Both analyses are of great significance as it provides insight into the direction of airflow within a building when windows are opened and cross-ventilation is initiated. In this instance, due to the configuration of the dwelling and its location, the air will enter through the windows in the courtyard and subsequently flow to the exterior through the windows in the rooms. With these pressure coefficients and Equation (2), the pressure difference between both windows of the upper floor is calculated: \(\Delta\)P = 0.301 Pa. Once the difference in pressure between the windows in the courtyard and the external windows has been established, it is possible to conduct a simulation to observe the airflow within the upper floor, given that the window with the highest pressure will be located in the courtyard. It can be assumed that an air flow with a temperature equal to that of the outside, will be established with a certain mass flow, which will be determined by the dimensions of the windows that will traverse the rooms, cooling them with a certain value of efficiency. The streamline pattern (Figure 18) shows the air movement through the floor and the recirculation formed in each room. As can be seen, the mass flow of the air entering through the three windows connected to the terrace is 1.08 kg/s, distributed 54% in room FF_R2 and 46% in room FF_R1. This distribution of the mass flow is caused by the architecture of the house itself, due to the position of the doors and windows. What is really important about this figure is that it clearly shows the position of the recirculations created in the rooms with sensors, with two vortices appearing in each room, one on each side of the jet of air that crosses the room. It should be noted that although different scenarios have been analysed, the figure shows the most interesting case at right, with the difference in pressures previously obtained. Figure 17: Static pressure contour of the full street simulation. Figure 18: Streamlines pattern of the upper floor. In addition to the flow pattern, Figure 19 shows the temperature map within the first floor of the building, demonstrating the steady-state conditions that prevail when cross-ventilation is occurring.