Energy balance and photovoltaic integration in positive energy buildings. Design and performance in built office case studies

This paper analyses the current definition of positive energy building (PEB) and a selection of both NZEB and PEB built projects with real monitored data, discussing their design features and potential for achieving positive energy balance. The research aims to assess an optimal ratio between photovoltaic (PV) area and achieved self-sufficiency ratios in office buildings. The study shows that most of the buildings' PV systems have an area equal to 10-20% of the total building's net floor area. Buildings that have PV to area ratio from 13% to 20% are self-sufficient from 100% to 150%. PV installation in the facades results decisive for reaching positive energy balance. The relation of the PV system installed on the facade to PV system on the roof is from 50% to 57% for the studied buildings. Buildings located in sites with higher global horizontal irradiation (GHI) tend to have lower PV area ratios.