## 3 Results and Discussion
### Thermal Performance Measurements  
To evaluate the thermal performance of the test samples, the upper environmental chamber was subjected to an 8 h heating phase, followed by an 8 h cooling phase. Figure 15 displays the temperature curve of the environmental chamber and the temperature curves measured at the lower surface of the samples, specifically the surface within the testing room of each sample, namely gypsum boards GB/OD@CCF-10 and GB/OD@CCF-30 and the reference gypsum board (GB).  
In the first 45 min of heating, the rate of temperature increase (RTI) of the GB/OD@CCF-10 and GB/OD@CCF-30 samples is identical to that of the reference sample, and at this point in time, the temperature is 28 \({}^{\circ}\)C. After this point, the phenomenon of phase change of the stabilized PCMs begins as time passes. The absorption of the required heat for the n-octadecane change from solid to liquid is depicted by the decrease in the RTI of the two samples and the appearance of a \"plateau\" in their temperature curves (phase change zone). Interestingly, the duration of this plateau in each sample is obviously related to their different paraffin loading. In GB/OD@CCF-10, the phase change zone extends to 90 min, while in GB/OD@CCF-30, it extends to 135 min. When all the paraffin has become liquid, a brief sharp increase in the RTI of the two samples compared to that of the reference sample is observed, followed by a smoothing of these rates and their equalization with the reference. The difference in the absolute temperatures of the two samples compared to the reference is also noteworthy. GB/OD@CCF-10 has a difference of approximately 2 \({}^{\circ}\)C, and GB/OD@CCF-30 has a difference of approximately 7 \({}^{\circ}\)C, highlighting the effect of the loading percentage on the effectiveness of the advanced gypsum board to maintain a lower temperature within a space. The response of the samples to the subsequent sudden cooling of the environmental chamber confirms the positive effect of the higher paraffin content on the properties of the gypsum board. The rate of temperature decrease of the GB/OD@CCF-30 sample is noticeably lower than that of the GB/OD@CCF-10 sample in the phase change  
Figure 15: Thermal performance curves comparing gypsum board samples loaded with 10% and 30% OD@CCF to the reference gypsum board, GB.  
zone. Furthermore, the final temperature of GB/OD@CCF-30 is approximately 2 \({}^{\circ}\)C higher than that of the reference.  
The temperature curves of the indoor spaces of the test rooms are shown in Figure 16 along with the temperature curve of the environmental chamber. Specifically, the temperature variation is recorded in the environmental chamber and in the test rooms (indoor temperature) of the reference cement board (CB) and the cement board CB/OD@CCF-30, respectively.  
As the temperature of the environmental chamber increases, a difference in the rate of temperature increase (RTI) is observed between the reference sample (CB) and the CB/OD@CCF-30 sample. This difference, evident near 28 \({}^{\circ}\)C, can be attributed to the thermal energy absorbed by the CB/OD@CCF-30 sample for the phase change of the stabilized PCM from solid to liquid. Notably, the phase change zone stabilizes the temperature in the test room around 28 \({}^{\circ}\)C for approximately 3 h, unlike the reference cement board (CB) test room temperature, which steadily rises to around 33 \({}^{\circ}\)C during the same period. Subsequently, after about 5.5 h, the RTI in both rooms becomes similar. The absolute temperature difference between the two rooms remains constant at approximately 2.3 \({}^{\circ}\)C. It is evident that the cement board with stabilized n-octadecane has the capability to keep the room cooler for a longer period compared to the plain reference cement board.