## 3 Results and Discussion
### Influence of the Refrigerant Type
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{3}{c}{**Refrigerant Type**} & \multirow{2}{*}{**Parameter**} & \multicolumn{3}{c}{**Refrigerant Type**} \\  & **R-113** & **R-134a** & **R-32** & & **R-113** & **R-134a** & **R-32** \\ \hline Pdt (dPa) & 83.21 & 26.80 & 23.68 & Tdt (\({}^{\circ}\)C) & 34.50 & 17.97 & 11.82 \\ Ppump (W) & 27.9 & 12.3 & 14.3 & \(\overline{\text{T}}_{\text{cpu}}\) (\({}^{\circ}\)C) & 78.72 & 61.66 & 56.48 \\ EERp & 115 & 260 & 224 & \(\overline{\text{T}}_{\text{cpu}}\) (\({}^{\circ}\)C) & 79.50 & 62.97 & 56.82 \\ \(\overline{\text{t}}_{\text{con}}\) & 0.513 & 0.634 & 0.792 & Tdcpu (\({}^{\circ}\)C) & 0.78 & 1.31 & 0.34 \\ \(\text{dT}_{\text{sub}}\) of the first evaporator inlet & & & & & & \\ (\({}^{\circ}\)C) & 14.51 & 0.30 & 0.02 & \(\text{S}_{\text{cpu}}\)\({}^{2}\) & 0.08 & 0.34 & 0.02 \\ \(\text{dT}_{\text{sub}}\) of the condenser outlet (\({}^{\circ}\)C) & 0.78 & 0.06 & 0.02 & \(\text{S}_{\text{cpu}}\)\({}^{2}\) & 0.34 & 0.26 & 0.01 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Simulation results of the PCTCS using different refrigerants: R-113, R-134a, and R-32. Figure 9: Internal parameter distribution in the PCTCS using different refrigerants (R-113, R-134a, and R-32): (**a**) pressure and total pressure drop distribution; (**b**) thermodynamic quality and void fraction distribution; (**c**) temperature distribution; (**d**) heat transfer coefficient distribution. R-113 showcased the largest at 34.5 \({}^{\circ}\)C. The underlying rationale for this observation stems from the properties of R-32, a high-pressure refrigerant. Specifically, R-32 demonstrates the highest saturation pressure among the refrigerants studied and undergoes a less significant change in saturation temperature in response to pressure fluctuations. This characteristic inherently reduces the temperature disparity between the system's evaporation and condensation. Moreover, high-pressure refrigerants are typically characterized by higher boiling heat transfer coefficients, which further compress the temperature differential between the CPU temperature and the evaporation temperature of the refrigerant. The cumulative effect of these factors leads to a minimal Tdt for R-32. This finding is consistent with [PERSON]'s research [46], underscoring the general principle that refrigerants with higher pressure levels typically yield a decreased temperature differential. Notably, the temperature variance between the two CPUs was marginal across all PCTCS configurations using various refrigerants, signifying excellent CPU temperature uniformity. As is evident in the above analyses, these disparities in the various PCTCSs stemmed from the inherent variations in the physical properties of the refrigerants. In terms of overall PCTCS performance, the R-32 configuration stands out, followed by R-134a, with R-113 lagging. Practical implementation, nevertheless, ushers in distinct challenges. Specifically, the high operating pressure associated with the R-32 system introduces profound considerations for engineering deployment, operational dependability, and construction costs, especially considering the intricate network of piping and joints within the PCTCS. Additionally, crucial factors including toxicity, flammability, and cost necessitate careful evaluation. Therefore, the selection of an apt refrigerant becomes an essential determinant in optimizing the PCTCS's performance.