Integrated design and thermodynamic analysis of a Multi-Energy coupling system for heavy oil thermal recovery

A multi-energy coupled integrated system for steam-assisted gravity drainage (SAGD) is developed to reduce fossil fuel consumption and enhance renewable energy utilization in heavy oil thermal recovery. The proposed system integrates a central receiver solar tower, an iron-nickel mixed oxygen carrier chemical looping cycle, power generation units, and cascaded waste heat recovery, enabling the upgrading of solar energy from low-grade thermal energy to higher-grade chemical energy. While satisfying the thermal demand for steam injection, the system simultaneously produces steam, electricity, and hydrogen, along with inherent CO₂ capture. Based on the principles of energy and exergy conservation, detailed thermodynamic models are developed for the key subsystems, and the overall system performance is quantitatively evaluated. Under the design operating conditions, the overall energy utilization efficiency reaches 72.41%, the system exergy efficiency is 29.26%, and the CO₂ capture rate is 96.50%. In addition, renewable energy accounts for 51.60% of the total energy input, and the overall energy ratio is 0.42. The results indicate that the proposed multi-energy coupled system significantly reduces irreversible losses compared with conventional steam generation for heavy oil recovery, while enhancing renewable energy utilization and carbon mitigation potential. A thermodynamically consistent framework for system integration can effectively improve the efficiency and sustainability of heavy oil thermal recovery processes.