## 4 EnergyPlus Simulation Results  
### Analysis of Energy Saving Rate in Different Climate Zones  
Figure 9 shows the influence of each technology on energy saving when compared with the base system using the Incheon weather file. When passive systems (Cases 1-5) were applied, the energy conservation rates were 5.2-15.4% when compared with the base system. In detail, when the U-value of walls was changed from 0.47 (Base) to 0.15 W/m\({}^{2}\)-K (Case 1), the energy conservation rate was 5.2%. When the infiltration rate was improved from 0.6 (Base) to 0.2 ACH (Case 2), the rate was 6.6%. When double low-e (Base) was replaced with double tinted low-e (Case 3) and triple  
Figure 8: Climate characteristics of the four regions (average monthly outdoor air temperature and relative humidity). low-e (Case 4), respectively, the conservation rates were 7.4 and 9.9%. When Venetian blinds were installed on the outside of double low-e (Case 5), the conservation rate was 15.4%. Up to 29.9-45.6% of the primary energy can be saved from the air-conditioning system and plant system (Cases 6-13). In detail, when the VAV system was applied (Case 6), 29.9% of the energy was saved compared to the CAV system. When an economizer system was applied to the VAV system in Case 7, 39.3% of the energy was saved. When applying ERV, which is a technology that utilizes ventilation (Case 8), 37.1% of the energy was saved. The application of VAV + UFAD system (Case 9) saved 42.9% of the energy. Furthermore, the active chilled beam and DOAS (Case 10) saved 47.6% of the energy when compared with the base case. Therefore, after changing passive and air-conditioning systems, the primary energy consumption was decreased from 464.1 (Base) to as low as 243.2 kWh/m\({}^{2}\). In the plant system alternatives, the absorption chiller-heater was replaced by the hot water condensing boiler and centrifugal chiller. When the efficiency of the hot water condensing boiler was improved from 0.8 to 0.9, or the COP of the centrifugal chiller from 4.0 to 6.0 (Cases 11 and 12), the energy saving rates were 25.6 and 33.4%, respectively. When both the hot water condensing boiler efficiency (0.8\(\rightarrow\)0.9) and the centrifugal chiller's COP (4.0\(\rightarrow\)6.0) were improved in Case 13, the energy efficiency was increased by 36.8%. Therefore, the primary energy consumption was decreased from 464.1 (Base) to as low as 293.4 kWh/m\({}^{2}\), considering the after-plant systems. When the plant system was changed from the base system to the GSHP (Case 14), 31.2% of the energy was saved. When the active chilled beam with the DOAS + GSHP was used (Case 15), 61.6% of the energy was saved. Therefore, the primary energy consumption was decreased from 464.1 (Base) in Case 14 to 319.3 kWh/m\({}^{2}\), and in Case 15 to 178.4 kWh/m\({}^{2}\). Up to 31.2-61.6% of the primary energy could be saved from the renewable energy alternatives. The primary energy consumption and energy saving rates of each technology in New Delhi, Minneapolis, and Berlin, when the same high-performance technologies in the 15 cases were applied as in Incheon, can be seen in Figure 11 (New Delhi), Figure 11 (Minneapolis), and Figure 12 (Berlin). Figure 10 shows each technology's contribution to energy saving when the weather data of the four regions were applied. The technologies that are effective in each climate region compared to Incheon are marked (New Delhi: red rectangle, Minneapolis: blue triangle, Berlin: sky blue circle). Figure 9: Primary energy consumption values and energy saving potential (%) in each technology—Incheon. Figure 10: Primary energy consumption and energy saving potential (%) in each technology (four regions). When Incheon and New Delhi's energy saving rates are compared, the cooling energy was greater than the heating energy in New Delhi, due to a high number of cooling degree days (CDD). Thus, the base model primary energy consumption in New Delhi was 513.2 kWh/m\({}^{2}\), which was higher than that of Incheon.