液体水素冷却超電導応用エネルギー機器の開発

抄録

A hydrogen based energy infrastructure, where liquid hydrogen (LH₂) is one of the important energy carriers, has recently been being developed in support of a future carbon-free society. Effective utilization of LH₂ cold energy is one of the key issues. We have been developing a hydrogen-cooled energy apparatus under a grant from the Japan Science and Technology Agency (JST). LH₂ has good physical properties for cooling, including a low boiling point, a high latent heat, a high specific heat and low viscosity properties. Moreover, its low boiling point (20.3 K) is advantageous in view of the excellent electromagnetic properties of high-critical-temperature superconductors, such as YBCO, BSCCO and MgB₂, which have been under development for many years. It is important to understand the heat transfer characteristics of LH₂ in order to design LH₂ cooled superconducting devices. For this purpose, we have designed and constructed basic experimental facilities, such as a thermal-hydraulics experimental system for LH₂, in order to carry out systematic investigation of the forced-flow heat transfer, set up experiments for investigating the electro-magnetic properties of superconductors or superconducting magnets, and introduced an LH₂ supply and exhaust test system for superconducting rotating machines. Using these facilities, we have conducted systematic experiments relevant to LH₂ cooling properties, and LH₂-cooled superconductor and superconducting magnet properties, and hence, have accumulated operational experience for handling LH₂ safely throughout over 25 test events.