Evaluation of the energy flexibility potential associated with reversible heat pumps in Italian residential building archetypes

This study investigates the thermal flexibility potential of residential buildings in the Italian context, focusing on two archetypal typologies: single-family houses (SFH) and apartment blocks (AB). Simulations were performed using detailed building energy models under two seasonal control strategies: one based on solar irradiance (as a proxy for photovoltaic generation on an aggregate of various buildings, as e.g. an energy community) and one based on the Italian day-ahead electricity market price. Three energy efficiency levels (existing, renovated/NZEB and new/Passive) and three climatic zones (Milan, Rome, Palermo) were considered. Flexibility performance was assessed using the Flexibility Index (FI) and the Peak Load Reduction Factor (PLRF), evaluated separately for the heating and cooling seasons. Results show that solar-based control enables higher flexibility than price-based control, particularly during the heating season and in retrofitted buildings. While Passive buildings offer limited active flexibility due to their very low energy needs for heating and cooling , they lower baseline consumption and indirectly enable greater system-level flexibility. The analysis highlights the importance of building characteristics, control signal selection, and technical building systems design in maximizing residential demand-side flexibility.