## 5 Results and Discussion
### Comprehensive Evaluation of Ventilation Performance of Different Window Types  
According to the description of the temperature and wind sensitive area of ANSI/ASHRAE Standard 55-2013, a 1.1 m height plane (head height of a human when sitting) in the room was selected for ventilation comfort analysis [43]. Figure 9 shows the velocity field and velocity vector of each window under the two ventilation modes. In the plan of the room, the exterior window of the room is located on the left. For CV, the influence range of the airflow is small under the three opening angles for CWO and BHWI, whereas the influence range for SW, THWI, and BHWO is large. The airflow influence range for CWI and THWO is small only under a small opening.  
Furthermore, the neutral temperature, average thermal sensation, and the proportion of thermal sensation interval of different window-opening forms of the z = 1.1 m plane of the room were calculated according to the method described in Section 3.3. For CV,  
Figure 9: Velocity field and velocity vector diagram of seven window types under (**a**) CV and (**b**) SV.  
the outdoor temperature was set to 25 \({}^{\circ}\)C according to the outdoor monthly average temperature during the experiment. For SV, the outdoor temperature was 10 \({}^{\circ}\)C, the same as that set in the simulation process. The average thermal sensation and proportion of thermal sensation intervals under the three opening angles of the two ventilation modes are shown in Figure 10.  
Figure 10: Average thermal sensation and proportion of thermal sensation interval: (**a**) small opening for CV; (**b**) medium opening for CV; (**c**) large opening for CV; (**d**) small opening for SV; (**e**) medium opening for SV; and (**f**) large opening for SV.  
It can be observed that, for CV, the average thermal sensation of the seven window types is within the comfort zone under the three opening degrees. The comfort of the THWO is the best under a small opening, and the comfort of the seven window types is similar under the medium opening. The comfort of the SW is the best under a large opening. For SV, the average thermal sensation of the seven window types is beyond the range of the thermal comfort zone under medium opening and large opening. The comfort of the SW is best under a small opening.  
To evaluate the ventilation performance of the different window-opening forms comprehensively, the ventilation rate for CV (Q) and SV (Q') of each window type was obtained by CFD simulation. Figure 11 presents a comprehensive comparison of the ventilation rate and thermal comfort of the z = 1.1 m plane under different conditions. As can be observed from Figure 11, SW-1 (the full opening of the sliding window) has the maximum ventilation rate under the two ventilation modes. The thermal sensations of the two ventilation modes are not close to 0 or equal to 0. The thermal sensations of the seven window types are similar under CV, and the thermal sensations of windows with large openings are worse than those with small openings under SV.  
Figure 11: Comprehensive comparison of ventilation rate and comfort: (**a**) CV and (**b**) SV.  
The ratios of the ventilation rate to the absolute value of the thermal sensation for different window types are listed in Table 8. It can be seen that SW-1 has the best ventilation performance under CV, with a ratio of 1293.26, and THWI-45\({}^{\circ}\) has the best ventilation performance under SV, with a ratio of 51.97. In summary, THWI and THWO have better ventilation performance under the two ventilation modes.