## 6 Conclusions  
In this study, the ventilation characteristics of a typical office room with different window-opening forms under CV and SV were studied. The ratio of the ventilation rate to the absolute value of thermal sensation was used to evaluate the natural ventilation performance. The main conclusions drawn are as follows. 1. For CV, on the windward side, the maximum value of the wind pressure coefficient of different window types does not appear at 0\({}^{\circ}\) (360\({}^{\circ}\)), but under the symmetrical condition of 22.5\({}^{\circ}\) (337.5\({}^{\circ}\)); there is a similar situation on the leeward side, where the minimum value of the coefficient appears in the symmetrical conditions of 157.5\({}^{\circ}\) (202.5\({}^{\circ}\)). 2. For CV and SV, the discharge coefficient increases with the increase in window opening, and the full opening of the sliding window has the highest discharge coefficient, which is 0.68 and 0.52, respectively. For medium and small openings, the discharge coefficient of the bottom-hung window opening inwards is the highest under CV, whereas that of the top-hung window opening inwards is the highest under SV. 3. Based on the evaluation of the ventilation performance of different window-opening forms, it is concluded that the sliding window with a full opening has the best ventilation performance under CV, with a ratio of 1293.26, whereas the ventilation performance is the best under SV when the opening of the top-hung window opening inwards is 45\({}^{\circ}\), with a ratio of 51.97. In general, the two types of top-hung windows have better ventilation performance under the two ventilation modes. The results of this study are useful for designers when selecting window types and designing windows with opening restrictors for office buildings. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**CV**} & \multicolumn{3}{c}{**SV**} \\ \cline{2-7}
**Window Types** & **Ventilation** & **Thermal** & **Ratio** & **Ventilation** & **Thermal** & **Sensation (\({}^{\circ}\)C)** & **Ratio** \\  & **Rate (m3/h)** & **Sensation (\({}^{\circ}\)C)** & **Rate (m3/h)** & **Sensation (\({}^{\circ}\)C)** & **Ratio** \\ \hline SW-1/3 & 858.12 & 1.85 & 464.40 & 71.52 & \(-\)1.64 & 43.69 \\ CWI-15\({}^{\circ}\) & 952.16 & 1.90 & 501.14 & 86.31 & \(-\)2.03 & 42.52 \\ CWO-15\({}^{\circ}\) & 814.04 & 2.01 & 405.00 & 98.56 & \(-\)2.45 & 40.23 \\ THWI-15\({}^{\circ}\) & 1428.25 & 1.93 & 740.03 & 133.86 & \(-\)2.78 & 48.15 \\ THWO-15\({}^{\circ}\) & 1451.76 & 1.70 & 853.98 & 127.24 & \(-\)2.77 & 45.94 \\ BHWI-15\({}^{\circ}\) & 1572.25 & 2.00 & 786.13 & 119.14 & \(-\)3.00 & 39.71 \\ BHWO-15\({}^{\circ}\) & 1069.71 & 1.79 & 597.60 & 135.54 & \(-\)3.09 & 43.86 \\ SW-2/3 & 1472.33 & 1.71 & 861.87 & 138.90 & \(-\)3.31 & 41.98 \\ CWI-30\({}^{\circ}\) & 1384.16 & 1.77 & 782.01 & 138.12 & \(-\)2.88 & 47.96 \\ CWO-30\({}^{\circ}\) & 1378.29 & 1.79 & 769.99 & 143.16 & \(-\)3.28 & 43.65 \\ THWI-30\({}^{\circ}\) & 1789.71 & 1.72 & 1040.53 & 172.01 & \(-\)3.56 & 48.32 \\ THWO-30\({}^{\circ}\) & 1751.51 & 1.73 & 1012.43 & 162.48 & \(-\)3.32 & 48.94 \\ BHWI-30\({}^{\circ}\) & 1901.39 & 1.84 & 1033.36 & 158.60 & \(-\)3.72 & 42.63 \\ BHWO-30\({}^{\circ}\) & 1316.57 & 1.80 & 731.43 & 155.81 & \(-\)3.60 & 43.28 \\ SW-1 & 2004.25 & 1.55 & 1293.26 & 203.94 & \(-\)4.17 & 48.93 \\ CWI-45\({}^{\circ}\) & 1613.39 & 1.80 & 896.33 & 167.76 & \(-\)3.47 & 48.35 \\ CWO-45\({}^{\circ}\) & 1625.14 & 1.76 & 923.38 & 168.51 & \(-\)3.80 & 44.34 \\ THWI-45\({}^{\circ}\) & 1822.04 & 1.76 & 1035.25 & 188.14 & \(-\)3.62 & 51.97 \\ THWO-45\({}^{\circ}\) & 1895.51 & 1.63 & 1162.89 & 170.79 & \(-\)3.32 & 51.44 \\ BHWI-45\({}^{\circ}\) & 1892.57 & 1.66 & 1140.10 & 179.72 & \(-\)4.14 & 43.41 \\ BHWO-45\({}^{\circ}\) & 1498.78 & 1.76 & 851.58 & 173.79 & \(-\)3.76 & 46.22 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Ratios of the ventilation rate to the absolute value of the thermal sensation for different window-opening forms. **Author Contributions:** Conceptualization, Y.W., Y.Y., T.Y. and Q.B.