## 4 Verification of Zero-Energy Building Integrated Planning Methodology
### Verification According to S/V Ratio and Solar Panel Installation  
In order to compare and analyze the energy consumption and energy production according to the S/V ratio of the building, a standard building to compare the difference in energy production and demand according to the S/V ratio change was modeled, as shown in Figure 6, using TRNSYS [16]. The small office of DOE was modeled by modifying it to have the same volume and different S/V ratios, as shown in Table 6. In order to realistically consider the energy consumption and energy production calculation of the simulation model, the heat transmission rate of the building energy conservation design standard was applied, as shown in Table 7. Table 8 shows the indoor cooling and heating setting conditions for the simulation. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Case**} & **Width** & **Depth** & **Height** & **Ratio of Lateral to** & **Floor Area** & **Surface** & **Volume** & **S/V Ratio** \\  & **[m]** & **[m]** & **[m]** & **Longitudinal Length [-]** & **Area** & **Volume** & **S/V Ratio** \\ \hline
1 & 11.6 & 11.6 & 11.6 & 1.0 & 134.6 & 807.3 & 1560.9 & 0.52 \\
2 & 16.1 & 16.1 & 6.02 & 1.0 & 259.2 & 906.1 & 1560.4 & 0.58 \\
3 & 40.0 & 10.0 & 3.9 & 4.0 & 400.0 & 1190.0 & 1560.0 & 0.76 \\
4 & 22.6 & 22.6 & 3.1 & 1.0 & 510.8 & 1298.1 & 1562.9 & 0.83 \\
5 & 30.0 & 20.0 & 2.6 & 1.5 & 600.0 & 1460.0 & 1560.0 & 0.94 \\
6 & 38.0 & 19.0 & 2.1 & 2.0 & 722.0 & 1690.2 & 1559.5 & 1.08 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: S/V ratio modification of small office. Figure 6: Simulation model for energy analysis by TRNSYS: (**a**) energy consumption model; (**b**) energy production model. The simulation revealed that the annual energy consumption is affected by the S/V ratio, as shown in Figure 7. For buildings of the same volume, the smaller the outer envelope area, the smaller the energy requirement. Therefore, in zero-energy building planning, it is necessary to reduce the envelope area as much as possible. The design of the building is decided under comprehensive considerations such as the client's demand, aesthetic point of view, and site constraints, but in order to achieve a zero-energy building, a design with the lowest S/V ratio should be selected from among various design candidates. Energy production was calculated assuming that solar panels are installed on 50% of the roof area. As the floor area gradually increases from case 1 to case 6 as the S/V ratio changes, the solar panel installation area of the roof is also increased. The annual energy production is affected by the S/V ratio, as shown in Figure 7. For buildings of the same volume, the energy production increases as the roof area among the envelope areas increases. In the case of a building in which solar power is applied as a renewable energy source, the change in the energy consumption and the energy production occurs at the same time according to the change in the S/V ratio. Therefore, when planning a zero-energy building, it is necessary to determine the S/V ratio from an optimal solution point of view rather than determining the shape of the building based on one of the criteria of energy consumption or energy production. As a result, as shown in Figure 7, in terms of final energy requirements based on the sum of energy consumption and energy production,