Performance analysis of PV-BESS-ASHP-LTRTs system based on experimental study in a cold-climate residential building

Traditional solar thermal systems with water as the working fluid are prone to both freezing and overheating, which impose operational challenges in cold regions. A solar-assisted heat pump integrating battery storage and radiant terminal energy system is proposed to meet the demands in well-insulated residential buildings. The heat pump converts the power generated by photovoltaic arrays into heat and further store in batteries and the building envelope. A test-bed in Shaanxi, China is employed to conduct full-time, 12-h, solar-based, and shutdown experiments, enabling a performance analysis of the operational characteristics and the building's thermal response. This study also develops a theoretical model for the proposed system and validates it using the measured data. Field experimental results show that the proposed system operates stably under cold-climate conditions. PV generation reaches 18.10 kWh/day and the high solar contribution is up to 83.0%. The system maintains indoor air temperature of seven rooms within 16.1-26.4 °C, even with 60 h of downtime, while the PMV values mostly fall within the Class I and Class II thermal comfort zones. Furthermore, the proposed system achieves the lowest carbon emissions among the compared energy systems. This verifies that the proposed system has significant research and application potential.