Evaluation of energy performance in buildings with flexible and semi-transparent photovoltaic integration

This paper examines how building envelope material and Building Integrated photovoltaic system (BIPV) integration affects the energy performance of a prototype office building which is located in a semi-arid and warm climate i.e. Peshawar Pakitan. In this study, a simplified single zone office model was developed using sketchup, openstudio and energyplus which serves as a controlled benchmark enabling comparison of three different envelope configurations including an ASHRAE based material as a reference case, a thermally insulated assembly and a simple lightwood structure. In the final lightweight wood structure, flexible PV modules were applied to the model for the opaque surfaces such as roof and walls while semi-transparent PV was modeled on the windows. The simulation results reveal that after applying the PV setup, the modules generated 2102.78 kWh annually which reduced the overall site energy from 3417 kWh to 1386 kWh lowering the net Energy Utilization Index (EUI) of the building from 255.36 to 103.60 kWh/m 2 . The simulation also shows that by integrating BIPV with the building, the average annual indoor temperature was also slightly decreased while maintaining year-round energy savings. Shading effect on the energy consumption and PV power generation was also analyzed by designing shading structures on the eastern and northern faces of the building. It has been found that shading decreases PV power generation and increases the net site EUI; however, the temperature and humidity remain almost constant. The building model used in the study is intentionally simplified and does not represent the full complexity of a large-scale building, however, it helps in providing a reproducible benchmark for isolating the impact of envelope material and the BIPV system under controlled conditions. The findings of the study reveal that for the selected prototype and climate, the building can considerably offset the building energy demand and can support further experimental and large-scale studies.