ABSTRACT — One of the major global challenges we are embracing is supply of sustainable, economical, and environmentally friendly fuels for transportation uses. Several unique properties of hydrogen make it an attractive candidate, especially given importance of reducing impact of high-carbon fuels on climate change. Although hydrogen has very high gravimetric energy density, it has very low volumetric energy density. For cost-effective storage, transport, distribution and use on-board heavy-duty fuel-cell electric vehicles, marine vessels, railway engines, and avionic applications, liquid hydrogen (LH₂) is required. Efficient, distributed scale magnetocaloric liquefiers are under development to fill a need for safe, reliable, economic, and expanding LH₂ refueling infrastructure. Cost-effective active magnetic regenerative liquefiers (AMRLs) require optimal integration of about eight subsystems into modular units to achieve high thermodynamic efficiency at 1-10 metric tons/day capacity. Most of the development have focused on three critical subsystems; magnetic refrigerants in magnetic regenerator(s), liquid, and gas heat transfer fluid flow(s); and superconducting magnets with regions of constant magnetic flux densities of 6-7 tesla. This talk will describe some recent advances in AMRLs for LH₂ with emphasis on the superconducting magnet subsystem. Trade-offs between use of Nb₃Sn at 4 K vs. ReBCO at 20 K will be briefly discussed.

Keywords: Magnetic, Refrigeration, Liquefaction, LH2