## 4 Results and Discussion
### Effects of Air Supply Angle on Thermal Environment  
Based on the thermal comfort distribution analysis above, there are a number of points that are worthy of discussion. For instance, based on the PMV, the dining room was included in the comfortable area, whereas the living room and kitchen were slightly hot. This contradicts the results based on the EDT, which indicate that the living room and kitchen were comfortable, whereas the dining room was out of the comfort zone. Upon investigation of the temperature distribution in Figure 5a, an area with a poor cooling effect could be observed in the lower left corner of the living room. As is apparent from the EDT distribution in Figure 8b, the dining room showed a low EDT, where the formation of a jet-like airflow originating from the supply location was noticeable. [PERSON] et al. [21] reported improving the EDT distribution in a space by adjusting the discharge angle of a standing type air conditioner. Herein, an attempt was made to simultaneously solve the two problems mentioned above by changing the supply angle of the cooling air. [PERSON] et al. [21] reported generally good results when the discharge angle was adjusted upward. Herein, the numerical analysis was first conducted for the case of discharging 45\({}^{\circ}\) upward by controlling the exit guide vane (see Figure 7b). The corresponding results are presented in Figure 9. Looking at the airflow distribution shown in Figure 9a, the cooling air was supplied more evenly to the cooling space than it was in the airflow distribution shown in Figure 7a, which was supplied perpendicular to the discharge port's surface. Meanwhile, in the EDT distribution shown in Figure 8b, a value of at most \(-1.7\) was recorded in the dining room due to the high-velocity airflow. In Figure 9b, the velocity distribution in the case of supplying the cooling air vertically from the discharge surface, and that of supplying it at a \(45^{\circ}\) upward angle, were compared at a height of \(1.1\) m. As can be seen from the two velocity contour plots in Figure 9b, the high-speed area that existed in the dining room (red-to-yellow color) was removed when the cooling air was supplied at a \(45^{\circ}\) upward angle, as shown on the right. Furthermore, from Figure 9b, it can be qualitatively expected that the EDT would be improved by removing the high-speed region. However, finding the optimum discharge angle would require a quantitative index that can evaluate the thermal comfort in the entire cooling space. To quantitatively compare the improvement of the local thermal comfort distribution, the air diffusion performance index (ADPI), which describes the percentage of the comfort zone that satisfies the EDT index [21], was used herein. When evaluating thermal comfort based on ADPI, the ratio of the area wherein the EDT lies between \(-1.7\) and \(1\) is considered, as this is the comfort range of the cooling area. If it is more than \(80\%\) of the space, then thermal comfort is secured. For the calculation of ADPI, Equation (5) was applied in the calculation of the EDT, for the velocity distribution in Figure 9b, to find the area where the EDT is out of the comfort zone. The zone of discomfort obtained through this analysis is shown in Figure 10.  
Figure 10a shows the discomfort zone when the cooling air was supplied perpendicular to the discharge port's surface. In this case, the discomfort area was determined based on the EDT in a large area centered on the dining room with a jet flow. When the cooling air was supplied at an upward angle of \(45^{\circ}\), as indicated in Figure 10b, most of the discomfort areas, which existed widely in the dining room, disappeared. Instead, a discomfort zone was observed locally in the living room and kitchen. To compare the change in thermal comfort according to the change in the discharge angle in each space, the ADPI values for the living room, kitchen, and dining room were calculated, along with the average of the total cooling area.