Performance analysis of integrating solar energy with low-grade waste heat recovery for decarbonising industrial heating

Industrial waste heat recovery is essential for decarbonizing manufacturing sectors. To address the high energy consumption and carbon emissions associated with long term fossil fuel based industrial heating, this study proposes and evaluates a low-carbon industrial heating system (LCIHS) based on a retrofit and demonstration project at a manufacturing facility. A transient numerical model is developed and validated against measured operating data to quantify the system energy use, carbon emissions, and economic performance under representative seasonal boundary conditions. Compared with the conventional steam heating system, the LCIHS achieves total energy savings of 78.3% and 67.1% in a representative nonheating month and a representative heating month, respectively, with corresponding carbon emission reductions of 73.2% and 56.7%. By annual aggregation of the transient simulations, the carbon reduction reaches approximately 56.2%. Economic analysis indicates a dynamic payback period of 7.2 years under the local tariff conditions. These results demonstrate the energy saving potential and economic feasibility of coupling solar energy with low-grade waste heat recovery for industrial heating applications.