Effect of Degradation and Size Selection for the Photovoltaic System Installed in a Nearly Zero Energy Building in Tropical Climate

From the perspective of the energy transition, the diffusion of photovoltaic systems and the study of their energy performance considering climate change fulfil a crucial role. The aim of this paper is to evaluate the convenience of installing photovoltaic systems in a tropical climate considering the degradation of system performance and the polluting emissions scenario that would affect climate change in the short term (2030s), in the medium term (2050s) and in the long term (2080s). A calibrated model of an existing nearly zero energy building (nZEB), with residential use, is used as case study. It was simulated for the weather conditions of Santo Domingo, Dominican Republic, with the aim of analysing the building’s performance, considering different software for estimating photovoltaic production and considering different opportunities for system design and sizing. The results indicate that the annual producibility in the reference year is approximately 7900 kWh with a monthly difference between the hottest and coldest periods of the year of around 100–200 kWh. In terms of energy balance, the case study can be considered a Positive Energy Building (PEB) since the electrical generation exceeds the energy demand in each month. Finally, considering different system sizes, degradation of photovoltaic performance and the evolution of climatic conditions, the building can be classified as nZEB and as PEB for a satisfactory number of months