Thermal performance simulation and numerical analysis of a fuel cell waste heat utilization system for automotive application

To recover the waste heat generated by proton exchange membrane fuel cells, an onboard fuel cell waste heat utilization system used for cockpit heating was constructed in this study. The heat transfer numerical model of the system was established, and experimental data validated the feasibility of the model. Additionally, the thermal performance of the onboard fuel cell waste heat utilization system was analyzed under various operational conditions. The results indicate that the air temperature and heat transfer coefficient of the heat exchanger are positively correlated with the thermal performance of the cockpit heating, while the radiator inlet air velocity and pump speed show a negative correlation with the system's performance. Under other steady conditions, the stabilized temperature of the cockpit is increased by 150 % when the air temperature increases from 0 degrees C to 40 degrees C, and the cockpit temperature is reduced by 20 % when the water pump speed accelerates from 100 to 300 r/min. Furthermore, under 20 degrees C ambient temperatures and with an inlet air velocity of 3 m/s, water pump speed of 500 r/min, and a heat exchange coefficient of 5,000 W & sdot;m- 2 & sdot;K- 1 , the fuel cell waste heat utilization system achieves an optimal waste heat utilization efficiency of 50.8 % underrated working conditions. In summary, this study offers theoretical guidance for designing and numerically evaluating a vehicular waste heat utilization system using fuel cells.