System Design and Economic Evaluation of a Liquid Hydrogen Superstation

Abstract

Liquid hydrogen (LH₂)-based hydrogen refueling stations (HRSs) are promising for high-capacity refueling, given the high density of LH₂, which facilitates large-scale transportation and storage. However, in LH₂ HRSs, the cryogenic cold energy of LH₂ is wasted during the vaporization process required to refuel hydrogen for fuel cell vehicles. To overcome this issue, this study proposes a novel LH₂-based hydrogen superstation (HSS) that recovers the otherwise wasted cold energy to generate electricity for the station, with any excess electricity used to charge electric vehicles. To explore the most cost-effective configuration for cold energy recovery in the HSS, two power generation cycles were designed: one incorporating a Brayton cycle followed by a Rankine cycle (BC-RC), and another using two Rankine cycles in series (RC-RC). Combining the BC-RC and RC-RC configurations, this two-stage design is adopted to efficiently recover cold energy across a broad temperature range during the vaporization process. The HSS using the BC-RC configuration achieves 53% more cold energy recovery, generates 19% more power, and experiences 8% less exergy waste compared to the HSS with the RC-RC setup. However, in smaller-scale cold energy recovery systems applied to HSS, the cost savings from using pumps instead of compressors outweigh the additional power generation benefits of the Brayton cycle. Consequently, the HSS with the RC-RC configuration demonstrates the highest economic feasibility, with a 2% higher net present value.