Renovation of apartment blocks with BIPV: energy and economic evaluation in temperate climate

This paper investigates the energy and economic profitability of renovating residential buildings in temperate climatethrough the integration of PV panels on façades. The investigation regards a real multi-storey apartment block, representativeof a significant amount of edifices built in Italy in 1950–1990, which often need refurbishment because of obsolescence.This building type is generally well suited to receive a new double-skin façade, supporting both PV and othercommon cladding materials, while also representing a good compromise in terms of aesthetic quality, cost, weight, durabilityand ease of maintenance.In order to make general conclusions, a parametric analysis is performed, by virtually changing the orientation, thenumber of floors and the climatic conditions, and by considering different PV technologies. The results show that for an8-storey building with the main axis along E-W, the initial investment can be repaid within around nine years, if consideringthe current fiscal incentives and a 50% self-consumption rate for the electricity produced by the PV modules. Thepresence of fiscal incentives is essential to make the investment attractive.Better PV efficiencies, lower prices and higher self-consumption rates can enhance the economic profitability, whichmay generate a significant impact on the retrofit of European multi-storey residential stock. These results can be effectivelyextended to the PV integration on the façades of new apartment blocks too.