## 4 Results and Discussion
### Limitations and Adaptations of the Standalone Dehumidification System  
This section will discuss the limitations and adaptations of HPDS and DWDS, aiming to indirectly demonstrate the necessity of an HDS. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{2}{c}{**Exhaust**} & \multicolumn{4}{c}{**Air Supply**} & \multicolumn{4}{c}{**Drying Time/d**} \\ \hline \multirow{3}{*}{**Temperature/\({}^{\circ}\)C**} & \multirow{3}{*}{**RH/100\%**} & **Moisture** & & **Moisture** & **Leakage** & **Leakage** \\  & & **Content/g** & **Temperature/\({}^{\circ}\)C** & **RH/100\%** & **Content/g** & **Rate** & **Rate** \\  & & **kg\({}^{-1}\)** & & & **kg\({}^{-1}\)** & **x = 0** & **x = 0.005** \\ \hline \multirow{8}{*}{18.3} & \multirow{8}{*}{80} & \multirow{8}{*}{10.3} & 30 & 3.9 & 257.6 & 348.5 \\  & & & 35 & 4.55 & 286.7 & 387.4 \\  & & & 40 & 5.21 & 323.9 & 438.1 \\ \cline{1-1}  & & & 45 & 5.87 & 372.1 & 503.3 \\ \cline{1-1}  & & & 50 & 6.52 & 436.1 & 589.9 \\ \cline{1-1}  & & & 55 & 7.18 & 528.4 & 714.5 \\ \cline{1-1}  & & & 60 & 7.84 & 670.1 & 905.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Drying time of the main cable. Figure 10: Schematic diagram of air leakage in the main cable. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{2}{c}{**Summer Cases**} & \multirow{2}{*}{**Supply Air**} & \multicolumn{2}{c}{**Operation Strategy**} & \multirow{2}{*}{**Energy**} & \multirow{2}{*}{**SMER**} \\ \hline \multirow{3}{*}{**Temperature/\({}^{\circ}\)C**} & **Moisture** & **Moisture** & **Evaporation** & **Regeneration** & **Consumption/kW** & **/kg kW\({}^{-1}\) h\({}^{-1}\)** \\  & **Content/g kg\({}^{-1}\)** & **Content/g kg\({}^{-1}\)** & **Temperature/\({}^{\circ}\)C** & **Temperature/\({}^{\circ}\)C** & **Temperature/\({}^{\circ}\)C** \\ \hline
38 & 34.36 & 18.44 & 24.00 & & 2.248 & 3.39 \\
36 & 30.64 & 16.63 & 22.60 & & 1.884 & 3.56 \\
34 & 27.29 & 14.38 & 20.80 & & 1.769 & 3.50 \\
32 & 24.28 & 12.52  
For HPDS, the evaporation temperature should be greater than 0 \({}^{\circ}\)C to avoid freezing. Three indicate outlet air status with a temperature of 7.5 \({}^{\circ}\)C, RH of 100% and moisture content of 6.5 g kg\({}^{-1}\) is in Figure 11. This shows that the HPDS can only reduce the moisture content to 6.5 g kg\({}^{-1}\). Pass three to draw an iso-moisture content line intersecting the line with 45% RH at five, and the temperature of five is 20 \({}^{\circ}\)C. This indicates that the minimum inlet air temperature of HPDS to meet the main cable air supply requirements is 20 \({}^{\circ}\)C. Therefore, when the inlet air condition is located in areas 3-4-5-6, the HPDS cannot meet the air supply requirements of the main cable. Figure 12 shows the inlet and outlet status of the DWDS. One and two are the inlet and outlet air of the dehumidification process, and three and four are the inlet and outlet air of the regeneration process. Table 6 lists the parameters for each status. Two is the intersection of the iso-enthalpy line of the dehumidification process inlet air and the iso-RH line of the regeneration process inlet air. Four is the intersection of the iso-enthalpy line of the regeneration process inlet air and the iso-RH line of the dehumidification process inlet air. Therefore, the air outlet state of the dehumidification process should fall in areas 1-2-3, and the air outlet state of the regeneration process should fall in areas 1-3-4. For the desiccant wheel, the change in air moisture content can be described by Equation (29). \[\frac{Y_{a^{\prime}}-Y_{a}}{Y_{b}-Y_{b^{\prime}}}=\frac{1}{3} \tag{29}\]  
Figure 11: Limitations and adaptations of a standalone dehumidification system. Figure 12: The state of the inlet and outlet air for the desiccant wheel dehumidification system. Therefore, the maximum dehumidification capacity is one-third of the maximum desorption capacity, that is, 30.3/3 = 10.1 g kg\({}^{-1}\). The moisture content corresponding to lines 7-8 is the lowest outlet moisture content of the DWDS.