*2.7. Monitoring and Communication*

To analyze and assess the performance of the system, it is recommended to collect data regarding the generated PV power. When this data is analyzed over a certain period of time, it can help to schedule maintenance for the installation (cleaning, testing, and a comparative analysis). Furthermore, peer-to-peer communication can be beneficial to detect fault scenarios, as will be discussed in detail in Section 4.

#### *2.8. Technical Room Space and Cable Management—Case Study EnergyVille*

The required technical room space (including technical shafts) for the BIPV installation needs to be minimal. This requirement is mainly valid for installations in densely populated areas where the price per square meter is elevated. Integrating the electronics and the cables is beneficial for this criterion. As already discussed under Section 2.4, using an AC or DC bus that runs along the modules can greatly simplify the cable managemen<sup>t</sup> of the system.

To evaluate the technical room space, a case study has been carried out. Figure 4 shows the EnergyVille research institute building, located in Genk, Belgium. This building has a BAPV capacity of 369.15 kWp installed on the roof of the building, occupying a surface of 3326.17 m2. The PV strings are connected to the grid via 23 string inverters of 8.5 and 20 kVA, requiring an inverter room of, approximately, 100 m3.

The southern façade of this building has a strong potential for a façade BIPV installation due to its southern orientation and the absence of nearby obstacles. The available surface allows a peak power installation capacity of 97.8 kWp. Considering that each panel covers a surface of 1.63 m<sup>2</sup> and the available surface is around 531 m<sup>2</sup> (already disconsidering the occupied area by the windows) and taking into account that the partial shading deteriorates the energy generation by 10–13% [53], the estimated peak power of the southern façade is around 85 kWp. If a BIPV structure is installed and connected via local micro-converters, the installation leads to an increase of about 25% of the installed renewable generation while it does not require additional room space.

**Figure 4.** The EnergyVille building located in Genk, Belgium with 369.15 kW of peak PV installed on the roof.

#### **3. Evaluation of the Electrical Installations for BIPV**

The objective of this section is to give an overview of the possible installation methods to electrically interconnect BIPV modules. A discussion on the advantages and disadvantages of each system will be provided. The following criteria are considered: monitoring, modularity, engineering effort, immunity against AC disturbances, immunity against partial shading, and reliability. The interconnection of BIPV modules to the AC grid or DC backbone, shown in Figure 1, leads to several options that will be explored. Figure 1a,b show the interconnection of BIPV modules directly to the AC grid, while Figure 1c,d represents the possible configurations to interconnect the BIPV modules to a DC microgrid.

Regarding the connection from the PV voltage level to the AC grid (single or three-phase) string inverters are often used [70–72]. The BIPV modules are connected in series, and the string is connected to one inverter. Micro-inverters, where each PV panel has its own low power inverter, are another possibility to connect the panels directly to the AC grid [73–75].

To guarantee immunity against AC disturbances, the BIPV modules can be connected via DC power optimizers to an LVDC grid (bipolar or unipolar), as shown in Figure 1. In this type of grid connection, two options are highlighted: a series operation of power optimizers and a parallel operation of power optimizers.

The systems abovementioned have strengths and weaknesses that will be presented considering the predefined criteria in this paper for a BIPV electrical installation. Table 1 presents this overview.
