## 3 Results and Discussion
### Thermal Property of Treated PCM  
Dual-phase specimen 2 was homogenized into a liquid phase and evaluated by DSC. From the results in the previous section, single-phase specimen 2, marked as solid phase, contained a small amount of liquid phase. The thermogram of treated specimen 2 (Figure 4) showed clear differences from that of the as-received-single-phase specimen 2 (Figure 3b) under endothermic and exothermic processes. During the endothermic process, treated specimen 2 exhibited a distinct single peak, whereas as-received solid specimen 2 had two peaks (Figure 3b). The measured onset \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**PCMs** & **Process** & \begin{tabular}{c} **Onset Temp.** \\ (\({}^{\circ}\)**C)** \\ \end{tabular} & \begin{tabular}{c} **Peak Temp.** \\ (\({}^{\circ}\)**C)** \\ \end{tabular} & \
\begin{tabular}{c} **End Temp.** \\ (\({}^{\circ}\)**C)** \\ \end{tabular} &
\begin{tabular}{c} **Latent Heat** \\ **(J/g)** \\ \end{tabular} \\ \hline Specim 1 & & 26.6 & 31.3 & 43 & 157.3 \\ Specim 2 & & 27.2 & 31.1 & 43 & 176.8 \\ Specim 3 & & 23.6 & 28.9 & 44 & 146.0 \\ Specim 4 & & 28.9 & 33.8 & 45 & 161.0 \\ \hline Specim 1 & & \(-\)1.8 & \(-\)0.5 & \(-\)7.6 & 135.4 \\ Specim 2 & & \(-\)5.7 & \(-\)1.8 & \(-\)10.3 & 152.5 \\ Specim 3 & Exothermic & \(-\)4.0 & \(-\)1.6 & \(-\)9.5 & 131.0 \\ Specim 4 & & \(8.6\) & \(3.7\) & \(-\)6.4 & 50.7 \\ Specim 4 & & \(-\)11.7 & \(-\)11.0 & \(-\)20 & 106.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Thermophysical properties of PCMs under endothermic and exothermic processes. temperature, melting temperature, and latent heat were 26.9 \({}^{\circ}\)C, 31.9 \({}^{\circ}\)C, and 149.8 J/g, respectively, which were similar to the measured properties of as-received specimen 2 under the endothermic process. A similar degree of superheating was observed compared to the reference melting temperature. This implies that the degree of superheating is related to the state of the specimen at the first stage of DSC. Relatively high superheating was found in the following three specimens: specimen 1, which had a melting temperature lower than room temperature and was marked as liquid phase; as-received single-phase specimen 2, which was marked as solid phase and presumably had a small portion liquid; treated specimen 2, which had a homogeneous liquid phase. A liquid phase at the beginning could not be fully solidified in the first step of the DSC thermoprofile, as shown in Figure 2, which caused phase inhomogeneity during the endothermic process. This phenomenon is also related to the thermal diffusivity of the liquid phase, which is explained in the next section. During the exothermic process, treated specimen 2 showed two exothermic peaks of onset temperatures of 15.8 and \(-\)9.5 \({}^{\circ}\)C, solidification temperatures of 13.5 and \(-\)10.7 \({}^{\circ}\)C, and latent heats of 36.6 and 12.6 J/g. The supercooling was mitigated via homogenization, but not fully prevented. The exothermic peak temperatures of treated specimen 2 were very similar to those of specimen 4, which had a melting temperature distinguishable from the room temperature. Supercooling during the exothermic process can be caused by incongruent solidification behavior caused by phase segregation, low rate of nucleation, or the fast cooling rate of the DSC test. The multiple peaks that occurred under the exothermic process were also discussed by [PERSON] et al. [53]. They reported the thermophysical properties of fiber-containing PCM based on salt hydrates. The specimen was maintained at least 24 h at 293 K/45% relative humidity (RH) under full liquid phase prior to the DSC test at heating/cooling rates of 10 K/min. A single peak was observed under the endothermic process, but one major peak and two minor peaks were observed under the exothermic process. The incongruent solidification behavior of the materials based on salt hydrates was considered to be the cause of supercooling.