Cryogenic Hydrogen Thermal Design Options

A key storage consideration for liquid hydrogen is the vaporization rate caused by environmental heat loads, often referred to as boil-off. The above graphic shows some of the established methods for mitigating or eliminating boil-off categorized by the input power required [1].

Passive techniques require no input power and include design and material selection for insulation, structural supports, piping, and other tank interfaces that minimize heat transfer to the inner tank wall. Hybrid methods require some input power for valve actuation, mixers, pumps, or other components to reduce the boil-off rate. 

Finally, active techniques require power input for cryo-refrigeration or densification processes. Depending on the concept of operation for the system, application of the appropriate combination of these methods can minimize or eliminate boil-off losses [2].

[1] Image source: Liquid Hydrogen Systems Course, 2025.
[2] Text source: Decarbonizing Mobility with Liquid Hydrogen, SAE Research Report EPR2024015, 2024.

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 break-through 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 co-founder in seven technology startups; and provided R&D and engineering support to many organizations. Matt has three patents and more than 50 publications including the Cryogenic Fluid Management series. He also teaches courses, workshops, and webinars on liquid hydrogen systems.