## 4 Conclusions  
To better simulate and predict the performance of BIPV systems, this paper takes a step towards improving their performance ratio determination, focusing on the thermal  
Figure 8: Annual performance ratio heatmap for Stockholm for 2019 (based on CAMS and PVGIS irradiance data). Figure 7: Annual performance ratio heatmap for Madrid in 2019 (based on CAMS and PVGIS irradiance data). and angular power losses. Among the different parameters affecting the \(PR\), module temperature and the angle of incidence of irradiance are the most dependent on the BIPV application due to the varied module positioning. After reviewing and assessing the suitability of several models to simulate the temperature and angular performance of BIPV modules, the corresponding power losses were calculated for any module's positioning. The proposed methodology is easy to replicate and proposes polar heatmap graphs to estimate \(PR\) at the desired location for assessing at a glance the sensitivity of the system's efficiency to the tilt and azimuth angles, aiding in the development of BIPV designs. The estimated \(PR\) for the analysed case study in Madrid ranged between 0.74 for a north-oriented 60-degree-tilted module and 0.82 for a north-oriented vertical module. When considering other orientations, the majority of azimuth and tilt combinations show a \(PR\) of 0.77-0.80, with better behaviour towards the southeast than the southwest due to the effect of temperature losses that increase module temperature throughout the day. A comparison of the results of temperature (ranging from 0.89 to 1.00) and angular (0.83 to 0.97) power loss factors reveals that angular losses are more relevant than thermal losses for the analysed BIPV ventilated facade in Madrid. The same heatmap graphs developed for Stockholm indicate higher \(PR\) values overall, reaching 0.85 for vertical modules oriented north and showing values above 0.82 in most cases. These graphs also present a better north-south symmetry, given that the temperature impact is lower in colder locations. As can be expected, climatic conditions, latitude, and the modules' positions are the most influential parameters when analysing annual \(PR\) values. The methodology was validated by comparing modelled results (estimated \(PR\)) with in situ experimental measurements (experimental \(PR\)) for the case of a BIPV ventilated facade in Madrid. Future work evaluating this procedure in different locations and BIPV systems is advised to assess and refine the proposed methodology. The assessment of the most used cell temperature models has shown improvement in using dynamic temperature approaches, resulting in a more reliable estimation of the \(PR\). However, all the considered models have shown acceptable results for a BIPV ventilated facade if their fitting coefficients are adjusted with experimental local data. Power losses due to module temperature can be reduced by improving the backside ventilation of the modules, while surface anti-reflecting coatings and surface finishes can lower angular losses and, at the same time, reduce glare caused by BIPV modules. The visual information delivered in this paper constitutes a first step towards globally estimating the \(PR\) for BIPV applications at a pixel spatial resolution. A second step in the analysis should focus on local topology for specific buildings and the surrounding elements. The proposed methodology can be refined by delving into additional \(PR\) factors such as soiling and solar spectrum effects.