## 3 Case Study
The hospital requires about 50% of the electric energy consumption, the second energy consumer is the swimming pool, while the other users require less than 7% each. Similar situations can be found for thermal and cooling demand, with the exception that cooling energy is not required by the schools, as in summer there are no students and the cooling plants have not been provided. The last row of Table 1 shows the sum of all power peaks, and is, as can be expected, greater than the total power peak by about 10%. The electric demand shown in the table does not account for the energy required by the compression chillers for the production of cooling energy. Figure 3 shows the trend of electric, thermal and energy demands for all buildings. It shows clearly that the trends are characteristic of tertiary sector users and also of a typical European continental climate, where during winter the thermal demand is higher than in summer period because of the need for space heating. During summer the thermal demand is only due to hot sanitary water demand, while there is a requirement of cold for space cooling. The electric energy is slightly higher during winter and lower in summer. This trend is related to the daylight hours, as during the summer there is a lower need of lighting. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{2}{c}{**ELECTRIC**} & \multicolumn{2}{c}{**HEATING**} & \multicolumn{2}{c}{**COOLING**} \\ \hline
**USERS** & **Year Dem.** & **Peak Power** & **Year Dem.** & **Peak Power** & **Year Dem.** & **Peak Power** \\ \hline  & (MWh) & (kWe) & (MWh) & (kWt) & (MWh) & (kWc) \\ Town Hall & 346,640 & 189 & 692,720 & 410 & 148,712 & 150 \\ Theatre & 852,208 & 270 & 908,648 & 655 & 457,688 & 458 \\ Library & 492,240 & 110 & 587,608 & 296 & 112,364 & 115 \\ Primary School & 73,808 & 54 & 979,468 & 591 & 0 & 0 \\ Retirement Home & 489,048 & 101 & 739,956 & 246 & 207,568 & 138 \\ Archive & 82,516 & 36 & 429,604 & 238 & 78,652 & 91 \\ Hospital & 3,284,416 & 628 & 7,884,141 & 1847 & 1,445,612 & 2087 \\ Secondary School & 303,668 & 148 & 2,301,980 & 2084 & 0 & 0 \\ Swimming Pool & 1,043,572 & 315 & 2,794,580 & 1425 & 297,416 & 435 \\ Total & 6,968,116 & 1717 & 17,318,705 & 7017 & 2,748,012 & 3048 \\ User Peak Power sum & & 1851 & & 7792 & & 3474 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: User energy demand data. The energy demand patterns of the hospital in winter and summer are shown in Figure 4, for two representative working days. The winter trend shows greater electric energy demand during the daylight hours due to a higher occupancy factor, a heating demand higher in the morning and in the evening and a very low cooling demand, which is required by the air conditioning system. In summer, the cooling demand is higher compared with the winter season and reaches a maximum at about 3 p.m., the electric demand is similar to that of winter, while the thermal demand employed as sanitary water is higher during daylight hours and lower during the night. Each building has different energy patterns which depend on the occupancy factor, thermal insulation, night lighting, etc. Figure 4: Hospital hourly energy demand patterns for a typical working day in winter (**top**) and summer (**bottom**). Figure 3: Trends of electric, thermal and cooling energy demands. The type and the size of the equipment which is part of the system superstructure must be appropriate to allow their integration, and proportionate to the user energy demands. All components considered in the optimization are commercially available and the prices have been obtained through a market survey. Two different kinds of components have been considered: fixed size components and variable size components. The optimal size/configuration of the energy system is obtained by defining the number of fixed size equipment installed and the size of variable size components (boilers, compression chillers, thermal storages). Table 2 shows the sizes of components which can be installed in the different units.