Optimal study of a hybrid solar-biomass heating system for rural household in cold regions of China

Background: Currently, the heating measures for rural households face significant disadvantages such as reliance on fossil fuels, poor thermal comfort, and high carbon emissions. Objectives: This study designed a solar-coupled domestic biomass boiler parallel heating system (SBPHS) with collaborative optimization. Methods: The SBPHS was developed based on a typical rural residence in cold regions. Subsequently, a parametric analysis was performed on both component configuration and operating parameters. Furthermore, we determined optimal configurations of the SBPHS using the life cycle cost (LCC) as the optimization objective. Solar fraction, total power consumption, effective heat collection and boiler runtime were used as performance indicators to evaluate the system. Results: Simulation results were in good agreement with measured data. Parametric analyses indicated that component design should consider energy performance and economics, especially in rural areas. As a start/stop signal for the collector system, the collector-tank temperature difference significantly affected effective heat collection and system energy consumption. Further, flow rates had significant impacts on all performance indicators, especially collector flow rate. Considering the optimum operating conditions throughout the system's life cycle, Hooke-Jeeves algorithm was adopted to optimize component configurations and operating parameters simultaneously. Post-optimization, LCC of the SBPHS was reduced by 12.3 %. The optimized system could achieve a solar energy share of up to 62.7 %, total energy consumption reduction of 13.6 %, and biomass fuel consumption reduction of 26.3 %, indicating significant energy savings. Conclusion: These findings enhance the feasibility of implementing the SBPHS in rural residences in cold areas and provide theoretical foundation for the design and operation of system.