Optimization on volume ratio of three-stage cascade storage system in hydrogen refueling stations

Three-stage cascade storage systems are widely adopted in hydrogen refueling stations. Their volume ratio has a remarkable impact on the performance of refueling systems. In this study, a thermodynamic model that considers the complete refueling–recovery process is developed. The effects of volume ratio on the utilization ratio and the specific energy consumption of the model is investigated, and the optimization of the volume ratio is explored and discussed. The utilization ratio decreases with the increase in the proportion of low-pressure stage volume (pLP), and a proper volume of medium-pressure stage improves the utilization ratio. The specific energy consumption decreases as pLP increases when the stationary storage capacity is relatively small. However, when the stationary storage capacity is relatively large, the specific energy consumption does not decrease monotonically, and a low specific energy consumption and a high utilization ratio can be simultaneously obtained at low pLP.