ACTIVE INTERFACES. Holistic design strategies for renovation projects with buildingintegrated photovoltaics (BIPV): case study from the 1900s in Neuchâtel (Switzerland).

As the majority of buildings that will exist in 2050 are already built, with many of them having a low level of energy performance, urban renewal processes play an essential role towards the sustainable development of cities. In this context, BIPV systems can potentially provide a crucial response to the energy turnaround targets. Functioning both as envelope material and electricity generator, they can simultaneously reduce the use of fossil fuels and GHG emissions while providing savings in materials and electricity costs. Focusing on the architectural design, this paper presents the results of a multi-criteria evaluation in terms of Life-Cycle Assessment and Cost of different renovation scenarios, integrating into the design process: (1) Passive strategies, to improve the envelope through low-embodied energy materials and construction systems; (2) BIPV strategies, using innovative photovoltaic products as a new construction material for façades and roofs; (3) Active strategies, adapting HVAC systems to improve their efficiency by maximizing the consumption of the energy produced on-site. The research methodology presented in this paper, through a representative case study of an archetypal building from the 1900s in Neuchâtel (Switzerland), proposes a new way to address rehabilitation projects of existing buildings in urban environments. The main outcome provides - to architects and engineers - advanced BIPV renovation strategies depending on the building typology, the architectural design goals, and the level of intervention (conservation, renovation or transformation).