# Assessment of Batteries' Contribution for Optimal Self-Sufficiency in Large Building Complexes
## 2 Materials and Methods
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Hotel 1** & **Hotel 2** & **Hotel 3** & **Hotel 4** & **Hotel 5** \\ \hline Waterpark & 1 & 1 & 0 & 0 & 0 \\ \hline Pool & 5 & 3 & 3 & 5 & 5 \\ \hline Bars & 6 & 3 & 3 & 3 & 6 \\ \hline Restaurant & 3 & 2 & 2 & 6 & 5 \\ \hline Gym & 1 & 1 & 1 & 1 & 1 \\ \hline Spa & 1 & 0 & 1 & 1 & 1 \\ \hline Jacuzzi & 1 & 0 & 0 & 1 & 1 \\ \hline Sauna & 1 & 0 & 0 & 1 & 0 \\ \hline Hammam & 1 & 0 & 0 & 0 & 1 \\ \hline Football field & 1 & 1 & 0 & 0 & 0 \\ \hline Tennis court & 2 & 0 & 0 & 1 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Facilities of all hotels. lower stars is the limited availability in facilities they provide compared to hotels with more stars, meaning that the annual consumption is also lower, with a textbook example being the comparison between Hotels 3 and 4. In Figure 2, the annual consumption per room is presented, reinforcing the previous argument. Exploring their monthly consumption within a year as well as their hourly maximum value, these hotels can be further compared and studied. Observing Figures 3 and 4 and comparing the area and the rooms of each hotel presented in Table 2, it is easy to conclude that the area and the number of rooms are not appropriate criteria for the consumption of each hotel. Taking into account the area and consumption as well as the maximum hourly value for each hotel, it is noticeable that it is not proportional to the area, but it depends on the facilities. Focusing on a smaller scale, the consumption is studied in a random week in August and  
Figure 3: Total energy consumption of the 5 hotels for each month of 2022. Figure 2: Yearly consumption per room. At this point, an algorithm is deployed to investigate a proposal scheme of photovoltaic system-battery storage coupling as a solution towards self-sufficiency for each hotel. The first step of the algorithm represents the compilation of different types of data, the hourly energy demand of each hotel for the year 2022, and the hourly production of a photovoltaic (PV) system located on the island of Crete. The use of these data yields the state of the storage system after each hour, along with the energy flows caused by the PV installation and the network's imports that contribute to load satisfaction. The next step is the calculation of annual quantities describing the system's efficiency, which are used to detect a possible correlation between the characteristics of each hotel (such as number of rooms, size), along with the capital expenditure needed for such an investment, and the decision variables of the model (the installed PV power and the storage capacity). The array of hourly demand contains elements that are symbolized as \(\mathrm{Load[i]}\), with \(\mathrm{i}\) being the number of hours since installation, and the normalized PV output as \(\mathrm{PV[i]}\), meaning that for hour \(\mathrm{i}\), the PV output \(\mathrm{PV_{out}[i]}\) is calculated using Equation (1):  
\[\mathrm{PV_{out}[i]}=\mathrm{PV_{power}}\times\mathrm{PV[i]} \tag{1}\]  
with \(\mathrm{PV_{power}}\) symbolizing the installed nominal power of the photovoltaic system. At the start of the algorithm's implementation, the storage system in each hotel is describing the behavior of the system for each hotel separately, for a time step of one hour, are calculated. Figure 4: Hourly maximum consumption for the 5 hotels in 2022. Figure 5: Consumption curve of a week (8–14 August 2022) for the 5 hotels. Initially, the discharge of the storage system installed to the system for each hour, \(\text{Storage}_{\text{out}}[\text{i}]\), is calculated as described in Figure 6.  
Afterwards, the total amount stored after each hour is computed (Figure 7). Figure 6: Computation of storage output after each hour. Figure 7: Computation of system storage for each hour. If both the PV output and available storage discharge do not cover the hourly amount needed, the facility relies on the network to satisfy the difference.