Edward Youn’s research while affiliated with Mountain View College and other places

We have demonstrated a hydrogen (H2) refueling solution capable of delivering precooled, compressed gaseous hydrogen for heavy duty vehicle (HDV) refueling applications by refueling transit buses over a three-month period under real-world conditions. The system uses a submerged pump to deliver pressurized liquid H2 from a cryogenic storage tank to a dispensing control loop that vaporizes the liquid and adjusts the pressure and temperature of the resulting gas to enable refueling at 35 MPa and temperatures as low as −40 °C, consistent with the SAE J2601 standard. Using our full-scale mobile refueler, we completed 118 individual bus filling events using 13 different vehicles, involving a total of 3,700 kg of H2 dispensed. We report filling statistics from the entire campaign, details on individual fills (including fill times, final state of charge, benefits of pre-cooled fills, and back-to-back filling capabilities), and discuss transit agency feedback on technology performance. In our final test, the system successfully completed an endurance test using a single dispenser involving 52 consecutive individual fills over an 11.5-h period, dispensing 1,322 kg of H2 with an average fill rate of 3.4 kg/min and peak rate of 7.1 kg/min, and reaching an average SOC of 97.6% across all fills.

We have developed a hydrogen (H2) refueling solution capable of delivering precooled, compressed gaseous hydrogen for heavy duty vehicle (HDV) refueling applications. The system uses a submerged pump to deliver pressurized liquid H2 from a cryogenic storage tank to a dispensing control loop that vaporizes the liquid and adjusts the pressure and temperature of the resulting gas to enable refueling at 35 MPa and temperatures as low as −40 °C. A full-scale mobile refueler was fabricated and tested over a 6-month campaign to validate its performance. We report results from tests involving a total of 9000 kg of liquid H2 pumped and 1350 filling cycles over a range of conditions. Notably, the system was able to repeatably complete multiple, back-to-back 30 kg filling cycles in under 6 min each, in full compliance with the SAE J2601-2 standard, demonstrating its potential for rapid-throughput HDV refueling applications.