Hydrogen Liquefaction With Caloric Materials

The main focus of the LIQUID-H project has been to search for novel materials that are less critical, more abundant and cost-effective alternatives to the ones currently employed for magnetocaloric hydrogen liquefaction. The project has been running for more than 2 years now and is progressing according to schedule. We have predicted the Curie temperatures of more than 200 new compounds and compositions by different machine learning algorithms such as Random Forest Regressors, Gradient Boosted Regressors and Neural networks. Several of the predicted materials were then successfully synthesized in the laboratory and their structural and thermo-magnetic properties were characterized by X-ray and neutron diffraction, scanning electron microscopy and temperature- and field-dependent measurements of their magnetization. The latter was then used to quantify the magnetic entropy and adiabatic temperature change across a wide temperature range. We were able to discover several new compounds containing less critical elements such as Neodymium and Praseodymium that had an isothermal entropy change exceeding 10 J/kg*K and adiabatic temperature changes in the range of 2-3 K in external fields of 5 Tesla, making them suitable for magnetocaloric hydrogen liquefaction.

HYLICAL will develop novel compounds with less than 50 % content of critical raw materials (rare-earth) for the cryogenic region (20-100 K) of a magnetocaloric hydrogen liquefaction (MCHL) process. We will provide design concepts for the active magnetic regenerator (AMR) and superconducting magnet subsystem. The project addresses several important scientific challenges: (i) High content of CRM in the materials (mostly binary compounds) employed today. This will be tackled by exploring the vast phase-space of multicomponent alloys with drastically reduced CRM content, and improved mechanical/chemical stability. (ii) Inefficient heat exchange between magnetocaloric materials and heat-transfer medium (HTM). This will be addressed by numerical simulations that search for new geometries with improved contact between the magnetocaloric material and the HTM. (iii) Superconducting field source must be developed. This will be dealt with by developing the concept for an innovative AMR-magnet subsystem based on superconducting tapes. This competence-building project will be an important first step towards establishing MCHL as an energy-efficient technology (target: 6-7 kWh/kgH2) for hydrogen liquefaction and for enabling zero boil-off during transport and storage. The project is led by Institute for Energy Technology, in collaboration with international partners from the Technical University of Denmark and Universidad de Sevilla (Spain). The project is financially supported in part by A/S Norske Shell, Greenstat ASA, IC Technology AS, Teco 2030 ASA, and NEL ASA as industry partners.