# Performance-Based Evaluation of Courtyard Design in China's Cold-Winter Hot-Summer Climate Regions
## 3 Results of Performance Evaluation
### Results of Adjusting the Ecological Buffer Space of the Courtyard  
To study the impact of the buffer space on the ecological climate of a courtyard, this study simulated the indoor air operative temperature of the courtyard building without an air system to validate the natural indoor air operative temperature under improved and initial designs under different climatic conditions (winter and summer). The indoor air operative temperature can be the simple average of the indoor air temperature and the mean surface radiant temperature [45]. Also, this study simulated energy consumption in the initial and improved designs, and were evaluated if air-conditioning systems are applied to eliminate building loads under different climatic conditions (winter and summer). Comparative statistics of the daily natural average air operative temperature and air-conditioning load in the hottest month (July) and the coldest month (January) were presented for Room 1, Room 2, and Room 3, which are shown in Figures 11 and 12. Table 2 also summarizes the results of the average natural room air operative temperature, peak load, and total load of three rooms in summer and winter from the simulation. In summer, the improved design opens the ecological buffer space wide. As shown in Figure 11, Room 1 and Room 2 did not consider the ecological buffer effect in the initial design, and the indoor natural temperature in summer is higher than that of the improved design, which conducts an opening treatment to the buffer space. In the initial design, Room 1 connects to the corridor space, hallway, and other usable spaces. Its large-area glass curtain wall in the corridor space completely isolates the indoors from the outdoors, but creates a large air-conditioning load [46]. In the improved design, the ecological buffer space of the courtyard is adjusted to open the corridor space wide. Some buffer spaces are additionally built on the southern side of Room 1 and the effect becomes more obvious after improvements. The results show that at the beginning of the hottest month (from 1 st to 9 th July), the outdoor air temperature is relatively low, while the operative temperature results in the initial design and improved design are very close. On the remaining days, the improved design can reduce the temperature of courtyard around 1 \({}^{\circ}\)C. In winter, the improved design closes all ecological buffer spaces. Figure 13 shows, when ecological buffer spaces are closed in winter, the air in the buffer spaces would continuously heat up due to solar radiation, with a higher room temperature than that of the practice of partially open buffer spaces in the initial design. As shown in Table 2, results show that the maximum average natural room temperature in Room 1 can be reduced by about 1.8 \({}^{\circ}\)C in summer, and the minimum average natural room air operative temperature can be increased by about 1.1 \({}^{\circ}\)C in winter; while they are 1 and 1.2 \({}^{\circ}\)C in rooms 2 in summer and winter, respectively. For room 3, improved design can achieve both maximum operative temperature reduction in summer and minimum operative temperature increase in winter by 1 \({}^{\circ}\)C.  
Figure 10: The sectional plan of the wind speed contour in winter under the initial design (**top**) and improved design (**below**). Figure 11: The average nature temperature results for three rooms in summer for initial design, improved design, and outdoor air. Figure 12: The average nature temperature results for three rooms in winter for initial design, improved design, and outdoor air. Figure 13 shows the energy use for cooling, which indicates the improved design can reduce the energy use for cooling. Figure 14 shows that enclosing the buffer space in winter can achieve overall energy saving in the courtyard building. The peak cooling load and the total cooling load in summer in Room 1 are reduced by 12.4% and 25.09%, respectively; 35.7% of the peak heating load and 36.1% of the total heating load can be saved in winter.