The use of photovoltaic (PV) energy in combination with heat pump systems for heating and cooling of residential buildings can lead to renewable energy self-consumption, reducing the energy required from the grid and the carbon footprint of the building uses. However, energy storage technologies and control strategies are essential to enhance the self-consumption level. This paper proposes and analyzes a new control strategy for the operation of a modulating air-source heat pump, based on the actual PV availability. The solar energy surplus is stored as thermal energy by the use of water tanks and the activation of the thermal capacitance of the building. The efficacy of the control strategy is evaluated considering different rule-based strategies, and different boundary conditions. The effect of climate data, building insulation level and thermal inertia are investigated and compared. The results show the efficacy of the proposed strategy to decrease up to 17% the amount of electricity purchased from the grid and to increase the self-consumption by 22%, considering a high-insulated building in Bolzano, Northern Italy. The thermal mass activation is found effective to increase the self-consumption of the system. Nonetheless, the achievable energy reduction depends largely on the building characteristics and the boundary conditions.

The main part of Italian building stock was built before the energy and seismic regulations, so most of buildings need comprehensive refurbishment to achieve the performance required by laws that are in force. This paper presents an experimental study for an energy and structural upgrade methodology, applied to an existing school building in the north-east of Italy. The methodology is based on the International Energy Agency–Energy in Buildings and Communities Programme (IEA–EBC) Annex 56 project guidelines. For the energy retrofit, a set of interventions is defined concerning the building envelope and systems. Among these interventions, the optimal cost is identified: this minimizes the energy demand and the CO₂ emissions, and reduces the financial commitment. The analysis of the seismic retrofit is developed using innovative techniques of intervention and high-performance materials. The proposed interventions are evaluated in terms of efficacy and cost. The results show that it is possible to identify a comprehensive energy retrofit at optimal cost, thanks to high energy saving and subsidies. For the seismic retrofit, the intervention with the higher cost-effectiveness ratio is determined, but the related investment does not have a payback time. The union of the two retrofits permits the combination of benefits and has a payback time for both the interventions. It is possible to state that the cost of a combined intervention is lower than the costs of two different interventions; therefore, when a single retrofit is needed, the possibility of a combined intervention should be evaluated.