## 4 Results of the Optimizations
### Complete Distributed Generation Solution
\begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & \begin{tabular}{c} **Environmental** \\ **Solution** \\ \end{tabular} & \begin{tabular}{c} **Isolated** \\ **Solution** \\ \end{tabular} & \begin{tabular}{c} **Distributed** \\ **Generation** \\ **Solution** \\ \end{tabular} & \
\begin{tabular}{c} **Distributed** \\ **Generation Solution** \\ **with Central Unit** \\ \end{tabular} &
\begin{tabular}{c} **Complete** \\ **Distributed** \\ **Solution** \\ \end{tabular} \\ \hline DHN pipes (n\({}^{\circ}\)) & - & - & 9 & 8 & 8 \\ DCN pipes (n\({}^{\circ}\)) & - & - & - & - & 4 \\ Central pipe size (kW) & - & - & - & 6323 & 4980 \\ ICE (kW) & - & 1840 & 2290 & 1840 & 1840 \\ MGT (kW) & - & 0 & 0 & 0 & 0 \\ BOI (kW) & 5241 & 984 & 0 & 3408 & 1954 \\ ABS (kW) & - & 735 & 0 & 1620 & 1435 \\ HP (kW) & - & 980 & 2380 & 1120 & 1890 \\ CC (kW) & 3474 & 1763 & 1759 & 1056 & 250 \\ PV panels (kWp) & - & 225 & 134 & 225 & 225 \\ ST panels (m\({}^{2}\)) & - & 0 & 734 & 0 & 0 \\ TS (kWh) & 6973 & 15,016 & 8553 & 0 & 0 \\ CS (kWh) & 0 & 0 & 0 & 0 & 0 \\ Central ICE & - & - & - & 0 & 0 \\ Central BOI & - & - & - & 0 & 0 \\ ST field (m\({}^{2}\)) & - & - & - & 23,585 & 21,764 \\ Central TS (kWh) & - & - & - & 173,935 & 169,926 \\ Operating cost (0\(\&\)/y) & 2473 & 1080 & 1284 & 1025 & 1045 \\ Total investment cost (kF/y) & 1267 & 4020 & 3968 & 8248 & 8114 \\
**Total annual cost (kF/y)** & **2622** & **1604** & **1746** & **1792** & **1785** \\
**Reduction wrt conv. solution** & **-** & **38.8\%** & **33.4\%** & **31.7\%** & **31.9\%** \\
**Total annual emissions (t/y)** & **6497** & **5427** & **4940** & **3846** & **3827** \\
**Reduction wrt conv. solution** & **-** & **16.2\%** & **24.0\%** & **40.8\%** & **41.1\%** \\ \hline \hline \end{tabular}
\end{table} 
Table 17: Total optimal annual energy magnitudes (MWh)—complete distributed generation solutions. \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & **Environmental** & **70\% Env.** & **30\% Env.** & **Economic** \\ \cline{2-5}  & **Optimization** & **Opt.** & **Opt.** & **Optimization** \\ \hline ICE electricity & 726 & 5807 & 8510 & 10,412 \\ MGT electricity & 0 & 0 & 0 & 0 \\ PV panels electricity & 239 & 239 & 239 & 239 \\ Bought electricity & 8671 & 2858 & 1283 & 226 \\ Electric user demand & 6968 & 6968 & 6968 & 6968 \\ CC electricity & 78 & 54 & 34 & 51 \\ HP electricity & 2035 & 610 & 604 & 607 \\ Sold electricity & 501 & 1257 & 2411 & 3234 \\ ICE thermal energy & 1057 & 8313 & 12,241 & 15,187 \\ MGT thermal energy & 0 & 0 & 0 & 0 \\ BOI thermal energy & 0 & 112 & 63 & 527 \\ HP thermal energy & 3974 & 820 & 916 & 1054 \\ ST panels thermal energy & 17,520 & 16,771 & 13,612 & 6711 \\ Thermal user demand & 17,319 & 17,319 & 17,319 & 17,319 \\ ABS thermal energy & 0 & 2077 & 2431 & 2560 \\ Wasted thermal energy & 4436 & 5930 & 6753 & 3439 \\ CC cooling energy & 234 & 162 & 101 & 153 \\ ABS cooling energy & 0 & 1377 & 1594 & 1676 \\ HP cooling energy & 2537 & 1227 & 1074 & 933 \\ Cooling user demand & 2748 & 2748 & 2748 & 2748 \\ Wasted cooling energy & 0 & 4 & 8 & 5 \\ \hline \hline \end{tabular}
\end{table} 
Table 18: Summary of the different compromise solutions obtained for the different configurations considered. As mentioned before, the 70% environmental optimization has been identified as the best compromise for the Complete distributed solution. Figure 16 shows its optimal configuration: the layout of the DHCN is shown together with the size of the components installed in each site. The DCN connects sites 2, 5, 6 and 1, and a single pipe connects site 7 to 9. The layout of the DHN is very similar to the one shown in Figure 14 for the distributed generation solution integrated with the central solar system, while the component sizes installed in each production unit are slightly changed. These differences are consequence of the additional operation options allowed by the adoption of the DCN. Nevertheless, in the evaluation of the optimization results, we have to keep in mind that the MILP problems have been optimized with a gap equal to 1%.