## 4 Verification
### Verification of PFD and Reliability Assessment Program
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Equipment**} & \multirow{2}{*}{**Assumptions**} & \multicolumn{4}{c}{**RPM Ratio**} & \multicolumn{2}{c}{**Efficiency Ratio**} \\  & & & **(Output/Input, No loss)** & & **(Output/Input)** \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Gears \\ Pulley \\ Gearbox \\ Shaft \\ H Pump \\ H Motor \\ \end{tabular} } & \(N_{1}\): 80–20, \(N_{2}\): 10, Efficiency: 98\% & 2.0–8.0 & 0.98 \\  & \(D_{i}\): 0.8–0.2 m, \(D_{o}\): 0.1 m, Efficiency: 97\% & 2.0–8.0 & 0.97 \\  & \(N_{1}\): 20, \(N_{2}\): 10, Gear efficiency: 98\%, Stage: 2 & 2.0 \(\times\) 2 = 4.0 & (0.98)\({}^{2}\) = 0.96 \\  & \(RPM\) ratio: 1.0, Efficiency: 100\% (No loss) & 1.0 & 1.0 \\  & \(RPM\) ratio: 2.0, Efficiency: 85\% & 2.0 & 0.85 \\  & \(RPM\) ratio: 2.0, Efficiency: 90\% & 2.0 & 0.90 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Assumptions and RPM ratio and efficiency ratio of input/output for each equipment. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{ \begin{tabular}{c} **PFD** \\ **(Secondary Energy** \\ **Conversion System)** \\ \end{tabular}  } & \multicolumn{4}{c}{**Stage**} \\ \cline{2-11}  & \(\mathbf{N}_{1}\) & \(\mathbf{N}_{2}\) & & & \(\mathbf{3}\) & & \(\mathbf{4}\) & & **Final** \\ \cline{2-11}  & \(\mathbf{(D_{1})}\) & \(\mathbf{(D_{2})}\) & \(\mathbf{\eta}\) & \(\mathbf{W_{r}}\) & \(\mathbf{W_{e}}\) & \(\mathbf{W_{r}}\) & \(\mathbf{W_{e}}\) & \(\mathbf{W_{r}}\) & \(\mathbf{W_{e}}\) & \(\mathbf{\eta}\) & \ \begin{tabular}{c} **RPM** \\ **(No Loss)** \\ \end{tabular}  \\ \hline \begin{tabular}{c} PFD 1 \\ (Gears–Shaft) \\ PFD 2 \\ (Gears–Shaft) \\ Gearbox–Shaft) \\ PFD 3 \\ (Gears–H \\ Pump–H Motor) \\ \end{tabular}  & 20 & 10 & 0.98 & 1.0 & 1.0 & - & - & - & - & 0.98 & 2.0 \\  & \(0.98\) & 4.0 & 0.96 & 1.0 & 1.0 & - & - & 0.94 & 8.0 \\  & \(0.98\) & 2.0 & 0.85 & 2.0 & 0.90 & - & - & 0.75 & 8.0 \\  & \(0.98\) & 2.0 & 0.85 & 2.0 & 0 terms of economics [48]. In terms of system performance, RPM increases gradually as the number of equipment-pieces in the system increases. Therefore, when using the conceptual design process in this study, it is essential to improve the design more cost-effectively by evaluating economic viewpoints such as CAPEX and OPEX related to the system efficiency in the early development stages of the system [49]. Finally, for the generators with different types of secondary energy conversion systems, it is judged that a more efficient design is possible if design is performed according to the conceptual design process suggested in this study. The process proceeds in the order of constructing the system based on the PFD derived through system analysis through IDEF0 while assessing the reliability of the constructed system using the performance formula of the equipment constituting the system. In addition, as in this study, if a hybrid system that applies both a mechanical system and a hydraulic system is designed based on reliability assessment using a DB of equipment, it is expected that a more seamless conceptual design and reliability assessment will be possible. However, since the expression of the performance formula varies depending on the equipment of the system, the efficiency curve or DB of the equipment must be constructed separately. In addition, the purpose of this study is to provide the basis for conceptual design based on reliability assessment through system analysis of the secondary energy conversion system, so it does not perform accurate reliability assessment based on a physical model considering the factors attributable to the efficiency of the system equipment. For example, in the case of a secondary energy conversion mechanical system with a pulley system, when assessing reliability based on a physical model, it should be modeled considering various deterioration factors such as belt characteristics and friction. However, in this study, factors affecting efficiency were not considered, and efficiency DB based on commercial products was used.