Hydrogen has several remarkable properties. It stores enormous amounts of energy, has a boiling point as low as -253 °C, and differs significantly from most other fuels and energy carriers in terms of energy density. Liquid hydrogen (LH2) has about 1.7 times higher volumetric energy density than compressed hydrogen at 700 bar. However, one of its main drawbacks is the large amount of energy that is needed during liquefaction -about 1/3 of the total energy content of the hydrogen molecule. LH2 at an industrial scale is produced with a gas compression-expansion cycle and consumes about 10-12 kWh/kg. In the HYLICAL project coordinated by institutt for energiteknikk (IFE), we plan to develop competence on an alternative and more energy-efficient method to liquefy and cool hydrogen: magnetic cooling employing the so-called magnetocaloric effect. How does it work? When you place certain materials into a magnetic field they will heat up. Similarly, when you remove them from the field region, they cool down. Couple this to heat exchange steps and run the process in a cyclic fashion and you can cool. Overall, it is like how your refrigerator functions at home but with two main differences: 1.) the working material is a solid instead of a gas, which means much better heat transfer, and 2.) we employ a magnetic field instead of inefficient gas compressors. With magnetic cooling it will be possible to decrease the energy consumption down to about 6 kWh/kg. However, the materials that show a large cooling capacity are all based on heavy rare-earth elements. The focus in HYLICAL is therefore the search for new materials that are made from non-critical and abundant elements. Another research aspect is the design of an efficient magnetic field source based on superconducting tapes and the optimization of the heat transfer processes. All these activities may ultimately lead to a more energy-efficient and cost-effective liquefaction process.
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.