Speakers: Prof. Yasuyuki Shirai
Abstract
It is considered appropriate to operate high-temperature superconducting wires at temperatures between 15 and 40 K from the viewpoints of current-magnetic field characteristics and stability. Liquid hydrogen can be used as a so-called refrigerant in this temperature range. Especially for large magnets and special magnets that are not suitable for refrigerator cooling, liquid hydrogen has significant characteristics such as a large latent heat and a small viscosity coefficient. However, because of its wide explosion range and low ignition energy, there has been little research on liquid hydrogen as a refrigerant for superconducting magnets.
On the other hand, research and development toward carbon-free energy infrastructure is progressing, and liquid hydrogen is one of the most important energy carriers. We propose the effective use of the cryogenic heat of liquid hydrogen to create an energy infrastructure that coordinates electricity and hydrogen, with liquid hydrogen-cooled superconducting power equipment as a key component.
To this end, 1) to systematically understand the heat transfer characteristics of liquid hydrogen as a refrigerant for superconducting equipment (immersion cooling and forced convection cooling) and to develop a database for design and fabrication, 2) to measure the electromagnetic characteristics of superconducting wires or magnets cooled by liquid hydrogen, 3) to design and fabricate experimental facilities to enable these measurements, and 4) to provide guidelines for the safety design of liquid hydrogen cooling equipment. The research project has been carried out for 14 years since 2008.
Here, we introduce the outline of the test facility, the measurement results of the heat transfer characteristics of liquid hydrogen, and the measurement results of the electrical and magnetic properties of superconducting materials under liquid hydrogen cooling.
Connection: https://lbnl.zoom.us/j/94399311647
Xiaorong Wang