Sunday, October 31, 2021

Densified Liquid Hydrogen and No-Loss (Zero Boil-off) Systems

Conference: Center for Hydrogen Safety (CHS) Asia-Pacific Conference, Nov 30 - Dec 2, 2021 AEST (Nov 29 - Dec 1 PST)

Abstract: Liquid hydrogen (LH2) can be thermodynamically conditioned to increase storage density compared to normal boiling point conditions in a process known as densification. A variety of methods to produce densified hydrogen have been successfully demonstrated using vacuum pumping or cryo-refrigeration. Additional system advantages beyond increased storage capacity include: increased cooling capacity for longer storage times or heat sink functions; greater vehicle payloads and/or range; higher mass flow rates; smaller hydrogen delivery components; and the potential for more efficient oxidizer-fuel ratios for some applications. No-loss LH2 systems have been demonstrated using cryo-refrigeration which enables zero boil-off storage and transfer operations. Gaseous hydrogen can also be liquified or re-liquefied in either continuous or batch processes. Additionally, high pressure and temperature LH2 can be thermodynamically conditioned to colder and lower pressure conditions without venting using cryo-refrigeration. The resulting system can operate for years without any boil-off losses. In the case of all these densified and zero boil-off LH2 systems, a key safety risk is the potential for subatmospheric conditions within the storage vessel and other fluid system components. The associated potential for air in-leakage and structural buckling failures can result in a catastrophic event. Proven mitigation methods are presented to manage this risk.


Matt Moran is the Managing Member at Moran Innovation LLC, and previous Managing Partner at Isotherm Energy. He's been developing power and propulsion systems for more than 40 years; and first-of-a-kind liquid, slush and gaseous hydrogen systems since the mid-1980s. Matt was also the Sector Manager for Energy & Materials in his last position at NASA where he worked for 31 years. He's been a cofounder in seven technology based start-ups; and provided R&D and engineering support to many industrial, government and research organizations. Matt has three patents and more than 50 publications including the Cryogenic Fluid Management report series. More about him can be found here.