## 4 EnergyPlus Simulation Results
### Analysis of Energy Saving Rate in Different Climate Zones
When the VAV + underfloor air distribution (UFAD) system was applied in New Delhi, 13.3% (56.2 - 42.9%) more energy could be saved compared to Incheon, and the cooling energy saving rate (63.8%) and fan energy saving rate (75.5%) were significant. When the applicability of the UFAD system in the hot climate was evaluated, the UFAD \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{3}{*}{\begin{tabular}{c} **Conservation** \\ **System** \\ \end{tabular} } & \multirow{3}{*}{**Classification**} & \multicolumn{2}{c}{**Incheon**} & \multicolumn{2}{c}{**New Delhi**} \\ \cline{3-6}  & & \begin{tabular}{c} **Primary Energy** \\ **Consumption** \\ **(kWh/m2)** \\ \end{tabular} & \begin{tabular}{c} **Energy Saving** \\ **Rate** \\ \end{tabular} & \begin{tabular}{c} **Primary Energy** \\ **Consumption** \\ **(kWh/m2)** \\ \end{tabular} & \begin{tabular}{c} **Energy Saving** \\ **Rate** \\ \end{tabular} \\ \hline \multirow{3}{*}{Base} & Total & 464.1 & \multirow{3}{*}{-} & 513.2 \\  & Heating & 126.5 & & 76.3 \\  & Cooling & 198.7 & & 287.1 \\  & Fan & 76.8 & & 75.2 \\ \hline \multirow{3}{*}{\begin{tabular}{c} High Efficiency \\ SHGC Window \\ \end{tabular} } & Total & 418.4 & 9.9\% & 431.1 & 16.0\% \\  & Heating & 118.8 & 6.1\% & 67.7 & 11.2\% \\  & Cooling & 172.8 & 13.1\% & 215.8 & 23.4\% \\  & Fan & 70.5 & 8.2\% & 65.8 & 12.5\% \\ \hline \multirow{3}{*}{\begin{tabular}{c} External Venetian \\ Blind \\ \end{tabular} } & Total & 392.5 & 15.4\% & 379.6 & 26.0\% \\  & Heating & 112.0 & 11.5\% & 64.8 & 15.1\% \\  & Cooling & 159.7 & 19.6\% & 180.9 & 38.4\% \\  & Fan & 63.7 & 17.1\% & 65.1 & 13.5\% \\ \hline \multirow{3}{*}{\begin{tabular}{c} VAV System \\ \end{tabular} } & Total & 325.4 & 29.9\% & 325.9 & 36.5\% \\  & Heating & 103.1 & 18.5\% & 60.9 & 20.2\% \\  & Cooling & 157.0 & 26.1\% & 199.5 & 31.6\% \\  & Fan & 52.7 & 70.5\% & 20.9 & 72.2\% \\ \hline \multirow{3}{*}{\begin{tabular}{c} High Efficiency \\ Cooling System \\ \end{tabular} } & Total & 319.3 & 31.2\% & 300.7 & 41.4\% \\  & Heating & 72.2 & 27.8\% & 59.9 & 21.4\% \\  & Cooling & 137.0 & 41.8\% & 123.5 & 56.9\% \\  & Fan & 62.8 & 31.4\% & 48.2 & 35.9\% \\ \hline \multirow{3}{*}{\
\begin{tabular}{c} VAV + ERV \\ (Energy Recovery \\ Ventilation) \\ \end{tabular} } & Total & 289.6 & 39.3\% & 249.9 & 51.3\% \\  & Heating & 74.7 & 40.9\% & 39.0 & 48.8\% \\  & Cooling & 118.8 & 40.2\% & 122.6 & 58.7\% \\  & Fan & 29.6 & 61.5\% & 25.3 & 66.4\% \\ \hline \multirow{3}{*}{
\begin{tabular}{c} VAV + UFAD \\ \end{tabular} } & Total & 243.2 & 42.9\% & 224.6 & 56.2\% \\  & Heating & 79.5 & 41.8\% & 42.5 & 44.3\% \\ \cline{1-1}  & Cooling & 89.4 & 44.8\% & 105.0 & 63.8\% \\ \cline{1-1}  & Fan & 23.6 & 63.8\% & 18.4 & 75.5\% \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Breakdown of the energy consumption and saving rate (comparison of Incheon and New Delhi). was able to save more energy than the CAV system, and provide better thermal comfort for the occupants [43]. In addition, the UFAD can save more energy than the CAV system in terms of annual energy consumption and peak load. Thus, the UFAD is effective in hot and humid climate regions [44; 45]. Table 7 shows the details of the energy saving rates when the high-performance technologies were applied to Minneapolis (Cold humid zone_6A), in comparison with the Incheon climate (Mixed zone_4A). The energy saving rate of the high-R insulation wall was 8.0% (\(13.2-5.2\%\)) more than the rate of Minneapolis when compared with the base case. The heating energy showed the highest reduction rate of 15.8%. In a related study performed in hot and cold regions, this indicated that the insulation performance is more effective in cold climates than in hot climates [46]. Analysis of the insulation thickness on energy performance also suggested that increasing the insulation in hot weather is not as effective at increasing the energy efficiency [47]. The energy saving rate of the high U-value window was 7.4% (\(14.7-7.4\%\)) more in Minneapolis than in Incheon.