采用可逆质子交换膜燃料电池/膨胀机的综合能源系统性能研究

To improve the utilization of renewable energy in combined cooling, heating and power system (CCHP), a new scheme of CCHP based on a hybrid of reversible proton exchange membrane fuel cell (RPEMFC) and expander is proposed, where the pressure energy of electrolyzed oxygen is recovered by ejector and expander. The exhaust heat and cool air of RPEMFC and expander are used to improve the system efficiency. A thermodynamic model is developed to conduct the sensitivity analysis of energy efficiency, exergy efficiency, energy consumption of compressor, energy recovery of expander, heat and cool air supply. The results show that the 50 kW RPEMFC based CCHP system can obtain electrical efficiency 56.2%, thermal efficiency 35.2%, overall efficiency 91.4%, and exergy efficiency 54%. The energy efficiency of the system exceeds 89% within the range of power generation from 15 kW to 85 kW. The exergy efficiency and energy efficiency of the system are sensitive to the changes of ejector flow ratio and the pressure of ejector driving flow. The change of compressor outlet pressure has little influence on the energy efficiency of the system, but its increase is beneficial to the cool air supply of the system.