Energy retrofit towards net ZEB. Application of BIPV on an apartment block in southern Italy

The energy retrofit of residential buildings towards net-ZEB standard represents today the best practice to reduce significantlyenergy demand and dependence on fossil fuels. In order to get the net-ZEB standard in retrofitting actions, this paper proposes a flexibletechnical solution for improving the energy performance of the Italianresidential real estate built in 1950-1990, i.e. before the enforcementof specific regulations about the reduction of energy consumption. Tothis aim, a typical apartment block located in Catania (Sicily) has beenconsidered as a case study. For this building, a new modular façadesystem has been designed, hosting ceramic and photovoltaic panels.These panels represent a good compromise in terms of aesthetic qualityand efficiency, and are supposed to be combined in order to maximizethe solar energy collection and to enhance the architectural image.The proposed system will be installed through a steel frame, which allowseasy application and effective rear panel ventilation, while an insulationlayer is provided to improve the thermal transmittance of thebuilding envelope. The improvement of the envelope insulation and ofthe energy systems, as well as the on-site energy production, allowreaching the net-ZEB standard, with an investment payback time of 7-11 years.