Performance Evaluation of the Hybrid Heat Pump to Decarbonize the Buildings Sector: Energetic, Environmental and Economic Characterization

Decarbonising the building sector, particularly residential heating, represents a critical challenge for achieving carbon-neutral energy systems. Efficient solutions must integrate both technological performance and renewable energy sources while considering operational constraints of existing systems. This study investigates a hybrid heating system combining a natural gas boiler (NGB) with an air-to-water heat pump (AWHP), evaluated through a combination of laboratory experiments and dynamic modelling. A prototype developed in the Electrical and Energy Engineering Laboratory enabled the characterization of both heat generators, the collection of experimental data, and the calibration of a MATLAB/Simulink model, including emissions and exhaust analyses. Sensitivity analyses were performed to identify optimal configurations for energy efficiency and system control, accounting for interactions between subsystems. Results highlight that hybridisation significantly improves primary energy efficiency and reduces fuel consumption compared to conventional NGB-only systems. Environmental performance, assessed through CO2 and NOx emissions and renewable energy integration, demonstrates the benefits of partial electrification in the residential sector. Economic assessment further quantifies decarbonization costs and fuel savings, illustrating trade-offs between low-capital, moderate-performance systems and high-efficiency, high-renewable solutions requiring larger investments. The analysis shows that strategic decisions for residential decarbonisation cannot be separated from system-wide considerations, including control strategies, component integration, and economic feasibility. The study underlines the importance of hybrid and renewable-based solutions as pivotal pathways for energy transition in the residential building sector.