Comprehensive performance analysis and optimization for PEMFC-heat pump combined system considering dual heat source

Traditional proton exchange membrane fuel cell (PEMFC) systems face the challenges of strong thermal–electrical coupling and insufficient heating capacity. This study proposes a PEMFC–heat pump combined system considering dual heat source, which effectively utilizes fuel cell waste heat and environmental heat to achieve significant improvements in thermal–electrical decoupling and heating capacity. Energy, economic, and environmental analysis models were established, and the effects of key parameters on the combined system were systematically analyzed, followed by multi-objective optimization. Results show that the PEMFC current density has the largest effect on the heating capacity, while the heat flow ratio exerts the strongest influence on economic performance. The minimum pollutant emissions are achieved when wind power is adopted for hydrogen production. Under an ambient temperature of 248.15 K, the combined system increases the heating capacity by 12.8 % and reduces the levelized cost of energy and greenhouse gas emissions by 7.85 % and 15.9 %, respectively. The optimal solution presents a strong nonlinear relationship with the PEMFC current density and condenser undercooling, the heat flow ratio is close to the upper limit (0.99), and the operating temperature is close to the lower limit (333.4 K). These findings provide innovative thermoelectric decoupling and efficient energy supply solutions for PEMFC systems and have important implications for accelerating the low-carbon transition of regional energy systems.