Coupled Thermodynamic Analysis of Hydrogen Refueling Station StorageSystems: Adiabatic Blowdown Dynamics and Compressor ChargingPerformance for H35 and H70 Infrastructure

Abstract

Hydrogen refueling stations (HRS) require rigorous thermodynamic control during high-pressure dispensing (blowdown) and buffer storage replenishment (charging). This study presents complementary 0-D lumped-parameter models: an ideal-gas discharge model and a real-gas charging model using CoolProp for hydrogen behavior up to 100 MPa. Blowdown is analyzed for Type II (200 bar, 3.0 m3) and Type III (500 bar, 3.0 m3) vessels across three outflow profiles, while charging is evaluated for a 1.0 m3 buffer tank across H35 and H70 tiers at compressor flow rates of 0.005 and 0.01 kg/s. Results show that constant-rate discharge cools 200 bar tanks by 25–30 K over 300 s, compared to only 10–12 K for 500 bar tanks. Charging terminal states are flow-rate independent—doubling the flow rate halves duration without altering final conditions—while increasing initial mass inventory provides a pronounced thermal-buffering effect (e.g., raising m0 from 40 to 45 kg in the H70 tier lowers peak temperature by 20 K, from 324.4 to 305.1 K). All scenarios comply with the 358.15 K (85◦C) structural safety limit, maintaining a margin of at least 33.7 K. Overall, buffer tanks undergo severe cooling during discharge and moderate heating during charging, demonstrating that robust HRS control must jointly manage mass-based replenishment targets with explicit pressure ceilings.