What is it?
Hydrogen is cooled to cryogenic temperatures and compressed to pressures approaching 300 bar into a supercritical fluid. The cryo-compressed hydrogen can be further compressed to pressures up to 700 bar.
Why is it important?
More financially viable where high density hydrogen storage is required under limited space, or where a larger roundtrip distance is involved.
- Volumetric hydrogen density: 49.6 g/L at 700 bar, 50.9 g/L at 350 bar
- Gravimetric hydrogen density: 7.0% at 700 bar, 10.0% at 350 bar
- Storage conditions: Commonly 250 to 350 bar, 23 to 35K. 78K at 700 bar, 66K at 350 bar also recorded
- Well-to-tank efficiency efficiency range is 40-45%. The energy required to liquify the hydrogen is 6- 8 kW/kg H2. Well-to-tank efficiency includes from the feedstock natural gas consumed to the low heating value of H2 delivered to tank.
- Higher volumetric storage capacity than compressed gas
- Fewer evaporation losses (boil off losses) than in typical compression mechanisms or liquid hydrogen
- Cryo-compressed can be denser than liquid hydrogen – cryo-compressed hydrogen can be in liquid or gaseous state.
- The dormancy is greatly extended as the allowable pressure inside the vessel increases
- Requires advanced and more expensive storage material
- Reduce boil-off (i.e. vaporisation) rates
- Improve engineering, insulation, heat exchangers and coolants
- Create larger and better insulated storage tanks
- Increase loss-free dormancy time (time before hydrogen will need to be vented from the tank)
- Reduce material costs and improve durability for increased lifetime
Known active organisations
- The University of Western Australia