Development of efficient hydrogen refueling station by process optimization and control

Abstract

Development of efficient hydrogen refueling station (HRS) is highly desirable to reduce the hydrogen cost and hence the life cycle expense of fuel cell vehicles (FCVs), which is hindering the large scale application of hydrogen mobility. In this work, we demonstrate the optimization of gaseous HRS process and control method to perform fast and efficient refueling, with reduced energy consumption and increased daily fueling capacity. The HRS was modeled with thermodynamics using a numerical integration method and the accuracy for hydrogen refueling simulation was confirmed by experimental data, showing only 2 °C of temperature rise deviation. The refueling protocols for heavy duty FCVs were first optimized, demonstrating an average fueling rate of 2 kg/min and pre-cooling demand of less than 7 kW for 35 MPa type III tanks. Fast refueling of type IV tanks results in more significant temperature rise, and the required pre-cooling temperature is lowered by 20 K to achieve comparable fueling rate. The station process was also optimized to improve the daily fueling capacity. It is revealed that the hydrogen storage amount is cost-effective to be 25–30% that of the nominal daily refueling capacity, to enhance the refueling performance at peak time and minimize the start and stop cycles of compressor. A novel control method for cascade replenishment was developed by switching among the three banks in the order of decreased pressure, and results show that the daily refueling capacity of HRS is increased by 5%. Therefore, the refueling and station process optimization is effective to promote the efficiency of gaseous HRS.