## 3 Results
### Summer Season  
The PCM phase change occurs rapidly during the summer season, even before 10:00 h. Figure 9b shows that the window with PCM presented a lower radiation transmission than that of clear double glazing because the PCM is solid during the first hours of the day. Generally, the short time that the phase change process takes is enough to control the solar gains because the solid PCM obstructs the passage of direct radiation during the morning hours. After the phase change is completed, the vertical radiation transmitted through the windows is equal for both the PCM and reference windows allowing diffuse radiation transmission when the sun is not in the field of view.  
The daily cooling energy consumption of HVAC in the PCM room was lower than the energy consumption in the AIR room for all the season (Figure 6) and for most of the daytime (Figure 9c). The total cooling energy savings in summer were 19.6% for two main reasons. First, solid PCM blocked direct solar radiation in the first hours of the day, reducing solar heat gains. Second, the PCM window reduced heat fluxes more than the double-glazed window (Figure 9e), decreasing the heat transmission by conduction through the window. In addition, the peak loads were noticeably lower in the PCM room during sunny days of summer (Figure 9c).  
Figure 11: Cont.  
Figure 7 shows that PMV and PMV* in the AIR room presented higher extreme values and greater quantities of values over 1.0 than in the PCM room all summer. This result reflects more moments with a warm and hot thermal sensation in the AIR room than in the PCM room. The quick phase change process in PCM glazing was enough to keep the values of the PMV and PMV* indices close to 0 in the PCM room under direct solar radiation on the facade (Figure 9f,g). This result was mainly due to the mean radiant temperature remaining close to the PCM melting temperature (Figure 9d). Mean radiant temperature was the primary source of higher values of PMV and PMV* because it was observed that mean radiant temperature peaks occurred at the same time as PMV and PMV* peaks.  
Regarding visual comfort, the DGP values of the PCM rooms were slightly higher than those of the AIR room (Figure 8). The main difference in DGP between the two rooms occurred during the early morning, and there were no noticeable differences in DGP the rest of the time (Figure 9h). Early in the morning, the DGP of the PCM room was higher because of interreflections of the direct radiation inside the PCM when it was changing phases. Inside the PCM, solar radiation was reflected and transmitted to the interior environment in different directions, producing high brightness and contrast between the window and the opaque surfaces. As a result, the glare source in the PCM room was even higher than that in the AIR room, where the glare source was the solar disk. This effect is shown in Figure 13, where the higher luminance values in the window of the AIR room are concentrated around the solar disk in the sky and not in the building surroundings. In the PCM room with the solid PCM, the higher luminance values are located in all the window areas regardless of whether there is the sky or another surrounding object in the field of view behind the window. This means that the glare source area and the DGP value are higher in the PCM window than in the double-clear glazed window during the morning.