Life-cycle performance analysis of a building integrated energy system considering equipment performance degradation

This study develops a life-cycle analysis framework for building-integrated energy systems that accounts for equipment degradation and dynamic energy demand growth over time. A community-scale integrated energy system in Beijing is modeled, consisting of photovoltaic panels, electric, thermal and hydrogen storage systems, as well as multi-energy conversion devices. Component degradation is represented using a coupled calendar-cycling aging model for storage systems and a piecewise degradation model for energy converters. The rain-flow counting method quantifies cycling-induced degradation, enabling realistic performance simulation over a 20-year horizon. Results indicate that photovoltaic generation meets demand for the first 15 years, but after year 15, degradation coupled with load growth causes supply–demand mismatches. Over 20 years, storage capacities decline by approximately 30 %, total system cost increases by 18.02 %, carbon emissions rise by 24.3 %, and independent operation time decreases by 15.9 %. Sensitivity analyses show PV degradation has a significant impact on economic and environmental performance, while population growth notably affects carbon emissions. The combined effects of equipment performance degradation and load growth substantially affect IES sustainability and economic viability. These insights provide valuable guidance for long-term system planning and optimization.