A novel energy flow-based approach for long-term performance evaluation of solar photothermal and photovoltaic systems

Existing solar thermal photovoltaic system evaluation methods face two key challenges: the "pre-evaluation" approach based on simulation shows significant deviations from actual results, while the "post-evaluation" method relying on physical testing requires prolonged assessment periods. Therefore, this paper analyzes the system's annual average performance under typical conditions based on its energy flow, proposing a correction method for operational performance under varying meteorological conditions. To align with China's zero-carbon building development goals, this study adopts a system-wide lifecycle carbon reduction effect as the core evaluation dimension. It selects carbon retention rate as the key assessment indicator to construct an evaluation framework (including average annual carbon reduction, carbon loss rate, and carbon retention rate). Validation involves comparing full-life-cycle indicators (photovoltaic array's annual carbon reduction, heat collection array's heating-period average carbon reduction rate, heat storage tank's annual carbon retention rate) with corrected random node data. Results show corrected carbon reduction deviations of 1%–7% and carbon retention rate deviations of 6%–13%. This study provides a simplified approach for rapid evaluation of PV/T systems' actual full-life-cycle performance.