Liquid hydrogen storage system for heavy duty trucks: Capacity, dormancy, refueling, and discharge

Abstract

Continuing the previous work on configuration, performance, cost, and safety of liquid hydrogen (LH2) storage for Class 8 heavy-duty trucks, we examine and demonstrate the feasibility of meeting the targets of 750 mile (1200 km) driving range, 65 kg H2 storage capacity, 8–10 kg/min refueling rate, 4.6 g H2/s peak discharge rate, 1–3 day dormancy, 5000 refueling cycles, 15% gravimetric capacity, 35 g/L volumetric capacity, and $8/kWh total system cost. A thermodynamic model is developed to determine the useable H2 density considering ullage and LH2 heel subject to heat transfer through the multilayer vacuum insulation and dormancy in the limits of “full” and “empty” fuel tanks. Dynamic simulations are conducted to determine the fraction of gaseous H2 returned to the station Dewar during refueling and heat input by H2 recirculation through an in-tank heat exchanger during discharge. The system gravimetric and volumetric capacities are affected by availability of on-board LH2 pump, discharge pressure, and dormancy. Compared to compressed H2 at 350 and 700 bar in carbon fiber wound Type 4 tanks, LH2 storage in double walled, vacuum insulated, low-pressure Type 1 tanks for heavy duty trucks shows advantages of 34–54% higher useable H2 storage density, 59–68% higher gravimetric capacity, 25–48% higher volumetric capacity, and 36–41% lower cost.