## 2 Research Subject
### Collection and Evaluation of Energy Consumption  
Energy consumption has been derived through the acquisition and analysis of electricity supply bills. These energy demands arise from various sources within the livestock, including controlled mechanical ventilation and cooling systems, which ensure an optimal indoor microclimate for both the animals and the working staff. In addition, consumption is driven by lighting and electronic control systems, which maintain suitable environmental conditions for the livestock and support the overall management of operations. The energy consumption data are presented in Table 3. The table illustrates the monthly energy consumption in the current state scenario (SDF), where the livestock operates without renewable energy sources. Consequently, all electricity demand is met through the national energy mix supplied by the grid. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Energy Consumption** & **January** & **February** & **March** & **April** & **June** & **July** & **August** & **September** & **October** & **November** & **December** \\
**(Electricity)** & **January** & **February** & **March** & **April** & **June** & **July** & **August** & **September** & **October** & **November** & **December** \\ \hline Electricity bills [kWh] & 3503 & 3953 & 4714 & 4752 & 4671 & 6278 & 6931 & 6658 & 4566 & 3840 & 4247 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Monthly energy consumption in the baseline scenario (SDF) measured on the electricity bills—\(\mathcal{O}\) authors. Figure 8: Localization of the various sensors positioned in the case study to capture the environmental determinants necessary for assessing the actual climatic conditions—\(\mathcal{O}\) authors. The assessment of electricity consumption for the retrofit scenario (RIQ) was conducted by calculating the energy potentially generated by a fixed photovoltaic system installed on the building's roof, after assessing the load-bearing capacity of the roof to support the new photovoltaic system. For this analysis, the Photovoltaic Geographical Information System (PVGIS) was used, an online tool developed by the European Commission's Joint Research Center (JRC) to assess solar energy potential and photovoltaic (PV) system performance worldwide [60]. The results of this evaluation are presented in Figure 9 in terms of monthly energy output from fixed-angle PV systems and monthly in-plane irradiation. The calculation assumes the installation of 80 photovoltaic panels, each with a peak power of 410 W, evenly distributed between the southwest-facing (40 panels) and southeast-facing (40 panels) roof slopes. The analysis estimates an average annual energy production of 16,926 kWh for the southeast-facing slope and 16,385 kWh for the southwest. The productivity of the east pitch roof is slightly higher than that of the west pitch each month. The highest production occurs during the summer months, with a peak in June and July. In contrast, productivity is approximately one quarter of the summer values during the winter months of December and January. The results described above were assessed considering a system loss of 14% for both the east and west pitches, a change in output due to angle of incidence of 4.07% for the east pitch and 4.3% for the west pitch, spectral effects of 0.80 and 0.81, respectively, and temperature/low irradiance losses of 10.83% (east) and 11.12% (west), resulting in total losses of 25.85% for the east pitch and 26.26% for the west pitch. The assessment of monthly energy consumption for the retrofit scenario (RIQ) is presented in Figure 10, comparing it with the monthly data for the current state (SDF). This histogram highlights the natural reduction in energy consumption following the installation of the photovoltaic system. It should be specified that this refers to the consumption of electricity supplied by the grid. From January to April, the gap between the two scenarios progressively increases, peaking in April.