Multi-objective optimization analysis of on-demand design in multi-source heating system for low carbon development

A multi-energy complementary heating system (MEHS) is essential for the development of low-carbon building heating. However, limited research has been conducted on the optimal heat load allocation. In light of heat balancing, heat source operation, and energy resource limits, this study proposes a MEHS model based on life cycle assessment, with costs, CO₂ emissions, and energy efficiency serving as the objective functions. By optimizing, the Pareto frontier solution is obtained, and the relationships between the objective and the heat load allocation ratios of heating subsystems are analyzed. Finally, the impact of the power industry's low-carbon transition and increasing carbon trading prices on the MEHS is investigated. The results show that the optimal heat load allocation ratios for the air source heat pump, natural gas-fired, biomass-fired, coal-fired, thermal storage electric boiler, and ground source heat pump heating subsystems are 44.42 %, 13.41 %, 0.71 %, 32.18 %, 0.56 %, and 8.72 %, respectively. Costs and CO₂ emissions during operation account for more than 80 % of the total life cycle impact. CO₂ emissions can be reduced by 16 % when the power grid CO₂ emission factor is reduced to 0.2530 kg CO₂/kWh, and by 4.5 % when the carbon price increases to 200 CNY/t.