GEECO Developing Higher Efficiency H2 Liquefaction

15 June 2008

Gas Equipment Engineering Corporation (GEECO), in partnership with MIT, Avalence LLC and R&D Dynamic, is developing a new hydrogen liquefaction cycle that promises an increase in efficiency from the current 30%-35% of Carnot in state-of-the-art systems to 44% resulting in a decrease in power use from 9.7 kWh/kg to 7.4 kWh/kg.

Final design of the single-pass, high-pressure H2 liquefaction system. Click to enlarge.

The main features of the approach in the DOE-funded project include:

• Once-through H₂ liquefaction with 100% yield;

• A Collins-style cycle with He as the refrigeration loop working fluid;

• Constant, supercritical pressure in H₂;

• Components use established technology and facilitate scalability; and

• Efficiency through effective staging of expanders.

The development of catalytic heat exchangers would further increase efficiency and lower cost.

While storing hydrogen in a liquid state offers greater energy density than compressed storage schemes, the energy requirement for hydrogen liquefaction is high; currently, typically 30% of the heating value of hydrogen is required for liquefaction.