## 2 Architectural Models and Research Methods  
The research subject is the main control building of a substation located in Yichun City, Heilongjiang Province, China. It consists of a 10 kV equipment distribution room, a secondary equipment operation monitoring room, and other rooms. The main transformer is located outside. The building has a construction area of 293.02 m\({}^{2}\) and a total height of 5.00 m. Please refer to Figure 1 for the building plan. The red portion in Figure 1 represents the distribution of electrical equipment within the main control building of the substation. Currently, the building is equipped with a mechanical exhaust system for summer ventilation. The main HVAC systems comprise split air conditioning units for cooling in the summer and electric heating for warming in the winter. The diagram in Figure 2 illustrates the actual exterior wall structure of the building. Based on the physical properties and thickness of the wall materials, the exterior wall heat transfer coefficient was calculated to be 0.22 W/(m\({}^{2}\cdot\)K) using the GBSWARE2024 software. The thermal performance of the reference building in Table 1 was determined  
Figure 1: Substation main control building plan. based on parameters such as wall and window materials. The reference building's thermal performance was obtained according to the regulations for thermal transfer coefficients for doors and windows outlined in the \"Unified Standard for Energy-saving Design of Industrial Buildings\" GB51245-2017 [18]. The building's thermal performance complies with energy-saving standards. The heat load is calculated based on the principle of steady-state heat transfer, considering both heat loss and gain in the room. The focus of the heat load calculation is on heat loss. To achieve heat balance, the calculation includes heat lost through the enclosure structure, heat lost through the heating of cold air, and heat produced by equipment operation. According to Section 4.5.5 of the \"35 kV-110 kV Substation Design Code\" GB50059-2012 [19]: \"Distribution unit room, reactor room, and other electrical equipment rooms should have a mechanical ventilation system set up, and the indoor temperature should be maintained at no more than 40 \({}^{\circ}\)C in summer.\" According to Section 8.3.2 of the \"Technical Regulations for the Design of 220 kV-750 kV Substation\" DL/T5218-2012 [20]: \"The main control room, computer room, relay room, communication room, and other rooms required by process equipment of the substation should be equipped with air conditioning.\" The indoor temperature and humidity of the air-conditioned room should meet the process requirements, and the process has no special requirements. The design temperature in summer is 26 \({}^{\circ}\)C to 28 \({}^{\circ}\)C, the design temperature in winter is 18 \({}^{\circ}\)C to 20 \({}^{\circ}\)C, and the relative humidity should not exceed 70%. Generally, there is no backup for air conditioners. The working time of the substation is set by BESI, the energy consumption calculation software of GBWARE2024, and the indoor temperature is set at 20 \({}^{\circ}\)C in the heating season and 28 \({}^{\circ}\)C in the cooling season. The hourly temperature throughout the year is obtained by invoking meteorological parameters, with the highest temperature being 33.3 \({}^{\circ}\)C and the lowest temperature being \(-\)26.7 \({}^{\circ}\)C, as shown in Figure 3. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Name** & **Actual Building** & **Reference Building** & **Unit** \\ \hline Shape coefficient & 0.49 & 0.49 & \\ Roof heat transfer coefficient & 0.34 & 0.35 & W/(m\({}^{2}\cdot\)K) \\ Heat transfer coefficient of the outer wall & 0.22 & 0.35 & W/(m\({}^{2}\cdot\)K) \\ Thermal resistance of the surrounding ground & 3.76 & 1.10 & (m\({}^{2}\cdot\)K)/W \\ Heat transfer coefficient of the window & 0.9 & 0.9 & W/(m\({}^{2}\cdot\)K) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of heat transfer coefficients.