Macro-scale renovation strategies to incorporate hybrid Photovoltaic–Heat Pump systems in public residential buildings using multi-objective optimization

The residential sector is facing a global energy transition, making energy renovation measures in building energy systems a matter of urgency. This work develops a flexible and systematic methodology to integrate photovoltaic (PV) renewable technology with heat-pump (HP) in existing installations, including electrical storage systems (EES) and thermal storage (TES), focused on 128 public rental buildings in the Basque Autonomous Community. The optimized design of these systems minimizes CO2 emissions and energy consumption from grid and maximizes PV self-consumption. In the multi-objective optimization, installation design variables are optimized, such as the volume of the heating TES tank (), and the temperature ranges in which the control intervenes. The work presents the rehabilitation strategies of six buildings covering heterogeneous types of buildings. The optimization results show values of between 6-9 m3 and DHW circuit controls conditioned by health regulations. The results highlight that the dominant variable is the photovoltaic surface area available per dwelling “”, rather than the building size or the dwelling number, serving as a normalization parameter. It is demonstrated that, on the one hand, for higher buildings, control is related to high-temperature thermal storage strategies and the use of PV surplus. On the other hand, low buildings are associated with efficient HP operation strategies and smaller thermal tanks. As a result, one of the main advantages of the methodology is its replicability on a macro scale, as the optimization process is automatically adapted to each building, allowing the integration of customized energy solutions for them.