## 3 Analyzing Systems Improvement Programs
### Minimize the Power Consumption of the Device
The carbon emissions during the operational phase of the building should be determined based on the energy consumption of different types of systems and the carbon emission factors of different types of energy. The total carbon emissions per unit building area (\(C_{M}\)) during the operational phase of the building should be calculated according to the following formula:  
\[C_{M}=\frac{\left[\sum\limits_{i=1}^{n}\left(E_{i}EF_{i}\right)-Cp\right]y}{A} \tag{7}\]  
\[E_{i}=\sum\limits_{j=1}^{n}\left(E_{i,j}-ER_{i,j}\right) \tag{8}\]  
where \(C_{M}\) represents the carbon emissions per unit area during the operational phase of the building (kgCO\({}_{2}\)/m\({}_{2}\)), \(E_{i}\) denotes the annual consumption of the \(i\)th energy type in the building (units/year), \(EF_{i}\) stands for the carbon emission factor of the \(i\)th type of energy, \(E_{ij}\) represents the consumption of the \(i\)th energy type by the \(j\)th type of system (units/year), \(ER_{ij}\) is the amount of the \(i\)th energy type provided by renewable energy systems for the \(j\)th type of system (in units per year), \(i\) refers to the type of terminal energy consumption in the building (including electricity, gas, and oil), \(j\) denotes the type of energy system in the building (including HVAC and lighting), \(Cp\) represents the annual carbon reduction amount of the building's green space carbon sink system (kgCO\({}_{2}\)/year), \(y\) is the design life of the building (in years), and A is the building area (m\({}^{2}\)). Table 8 presents the total CO\({}_{2}\) emissions during the operational phase of the building over its lifecycle (50 years). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Type** & **Cooling/Heating Load (kWh/Year)** & **Electricity Consumption (kWh/Year)** & **Carbon Emission Factor (kgCO\({}_{2}\)/kWh)** & **Carbon Emission (tCO\({}_{2}\)/Year)** \\ \hline Air source heat pump & 19,426 & 10,792 & & 6.2 \\ heating system & 19,426 & 19,426 & 0.5703 & 11.1 \\ Heating system for & 2524 & 841 & & 0.5 \\   electric heating & - & 2746 & & 1.6 \\   Cold supply system & - & 21,900 & & 12.5 \\   Illuminating system & - & \multicolumn{1}{c}{Total} & 20.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Building operational carbon emissions. Figure 13: Comparison chart of monthly heat consumption, cooling consumption, and electricity generation. The energy consumption during the operational phase of the research object mainly comes from electricity, and the emission factor for the electricity grid is selected based on the data released in February 2023 by the Ministry of Ecology and Environment in the notice \"Regarding the Management of Greenhouse Gas Emission Reports for Power Generation Enterprises for the Period of 2023-2025.\" The average emission factor for the national electricity grid in 2022 was 0.5703 kg CO\({}_{2}\)/kWh. From Table 8, it can be observed that the heating system using an air source emits 4.9 fewer tCO\({}_{2}\) per year compared to the electric heating system. Over the 50-year lifecycle of the building, the carbon emissions per unit area during the operational phase of the building are 1638 CO\({}_{2}\)/m\({}^{2}\).