Design and performance evaluation of a building-integrated multi-component energy system with PV/T and thermal storage for electricity and heat supply

Facing global energy shortages and environmental pollution, photovoltaic-thermal (PV/T) systems demonstrate significant potential in building energy supply. However, standalone PV/T systems still face significant challenges in practical building applications: energy supply instability constrained by meteorological conditions, and temporal mismatch between energy production and end-use demand. To address these issues, this study proposes a multi-component integrated energy system combining photovoltaic-thermal collectors, water-source heat pumps, and underground thermal storage tanks, achieving combined electricity and heat supply in a 36-square-meter laboratory. Four operational strategies were designed, with system performance analyzed via TRNSYS numerical modeling and validated through field experiments. Based on actual building loads and local meteorological data, a year-round comparative analysis of operational strategies demonstrated the energy-saving advantages of direct solar fresh air preheating over the conventional “collection-storage-supply” pathway. Results indicate stable system operation, maintaining indoor temperatures within the 19-21 °C range. The optimal strategy (daytime solar tile preheating of fresh air) achieved a system coefficient of performance (COP) of 3.10 with only 6.46% municipal electricity supplementation, significantly reducing building energy consumption. Through energy level matching (direct solar utilization for low-grade fresh air heating) and cross-seasonal thermal storage (achieved via underground tanks), the underground tank stores surplus solar energy during non-heating seasons for stable supply. Direct fresh air preheating avoids multi-stage energy losses, significantly enhancing energy utilization efficiency. This study provides a feasible low-carbon energy solution for buildings in cold regions, demonstrating promising engineering application prospects for reducing reliance on traditional energy sources for building heating.