# A Sustainable Polygeneration System for a Residential Building
## 3 Results
### Performance Analysis  
Once the designs for each site and configuration have been presented, the results from the KPIs and the \(\mathrm{LCO_{x}}\) of each demand establish the best arrangement, with slight variations in the results according to the three sites analyzed. These results can be seen in the following Table 10. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**KPI Parameter** & **Location** & **A** & **B** & **C** & **D** \\ \hline \multirow{3}{*}{Primary energy saving ratio (PESR)} & 1 & 0.640 & 0.646 & 0.651 & 0.645 \\  & 2 & 0.648 & 0.654 & 0.658 & 0.652 \\  & 3 & 0.683 & 0.683 & 0.685 & 0.682 \\ \hline \multirow{3}{*}{CO\({}_{2}\) emissions saving ratio (CO\({}_{2,R}\))} & 1 & 0.720 & 0.726 & 0.733 & 0.728 \\  & 2 & 0.746 & 0.750 & 0.755 & 0.751 \\  & 3 & 0.778 & 0.778 & 0.781 & 0.779 \\ \hline \multirow{3}{*}{Total investment (\(\Pi_{\text{PS}}\), \(\xi\))} & 1 & 348,256 & 293,445 & 421,824 & 408,448 \\  & 2 & 338,021 & 286,710 & 394,825 & 390,299 \\ \cline{1-1}  & 3 & 477,903 & 398,157 & 519,016 & 517,594 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Performance analysis of the proposed configurations for each site. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Electricity Generator** & **Location** & **A** & **B** & **C** & **D** \\ \hline \multirow{3}{*}{PV} & 1 & 73.82 & 96.82 & 85.04 & 76.32 \\  & 2 & 72.66 & 95.34 & 85.38 & 77.00 \\  & 3 & 72.41 & 95.95 & 85.36 & 82.00 \\ \hline \multirow{3}{*}{PVT} & 1 & 31.22 & 8.56 & 20.27 & 28.82 \\  & 2 & 32.38 & 10.04 & 19.94 & 28.15 \\  & 3 & 32.73 & 9.46 & 19.97 & 23.23 \\ \hline \multirow{3}{*}{TEG in PVT} & 1 & 0.51 & 0.17 & 0.25 & 0.42 \\  & 2 & 0.5 & 0.17 & 0.23 & 0.40 \\  & 3 & 0.40 & 0.14 & 0.22 & 0.32 \\ \hline \multirow{3}{*}{TEG in BB} & 1 & 0.85 & 0.11 & 0.24 & 0.98 \\  & 2 & 0.88 & 0.13 & 0.23 & 0.98 \\ \cline{1-1}  & 3 & 0.57 & 0.16 & 0.22 & 0.72 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Gross electricity fraction obtained by each power technology. The analysis of the above table is detailed below, row by row. * From the point of view of the PESR, all configurations yield similar data (0.64-0.68), and the remaining is due to the net electricity balance in periods of higher demand than production. Zaragoza has the best PESR due to its higher demands, followed by Valencia and, finally, Almeria, with the lowest overall needs (see Table 3). * A similar pattern was found with CO\({}_{2}\) savings. All configurations and alternatives also show similar relative values to PESR. A higher value is found (0.72-0.78) since natural gas emission factors exceed the Spanish grid's electricity factor (see Table 6). In the economic analysis, the major findings are:
* The highest investment is found in option C, due to the largest solar field required and the SEAC cost. Option B requires the minimum investment. MED technology is, in general, expensive but used throughout the year. * However, electrically activated technologies (HP and RO) have better energy performances. The use of thermal energy displacing PV to PVTs is penalized electrically. In addition, a high number of operating hours of the boiler are needed to maintain the required temperature for MED (throughout the year) and SEAC (in summer). This makes the cost of pellet supply the most significant component of expenditure in the polygeneration installation, thereby reducing the annual savings significantly. * Thus, the highest annual savings was found with the B option (HP + RO), then option C is the second in this term (SEAC + RO), followed by A (HP + MED), and finally, D (SEAC + MED). * Therefore, by combining investment and annual savings, the order found according to the feasibility of configurations (measured in terms of the SPB) is relatively straightforward: option B is the best option (HP + RO), followed by option C (SEAC + RO), option A (HP + MED), and finally, option D (SEAC + MED).