Magnetic refrigerator for hydrogen liquefaction

Abstract

Magnetic refrigeration which is based on the magnetocaloric effect of solids has the potential to achieve high thermal efficiency for hydrogen liquefaction. We have been developing a magnetic refrigerator for hydrogen liquefaction which cools down hydrogen gas from liquid natural gas temperature and liquefies at 20 K. The magnetic liquefaction system consists of two magnetic refrigerators: Carnot magnetic refrigerator (CMR) and active magnetic regenerator (AMR) device. CMR with Carnot cycle succeeded in liquefying hydrogen at 20K. Above liquefaction temperature, a regenerative refrigeration cycle should be necessary to precool hydrogen gas, because adiabatic temperature change of magnetic material is reduced due to a large lattice specific heat of magnetic materials. We have tested an AMR device as the precooling stage. It was confirmed for the first time that AMR cycle worked around 20 K.

Analysis of the Anisotropic Magnetocaloric Effect in RMn2O5 Single Crystals

“…However, the search for materials with excellent magnetocaloric properties in the temperature range from about 2 to 30 K is of great interest from fundamental, practical, and economical points of view, due to their potential use as refrigerants in several low temperature applications such as the space industry, scientific instruments, and gas liquefaction [14][15][16][17][18][19][20][21][22][23][24][25]. On the other hand, the development of new designs that can render magnetic cooling more competitive is also a key parameter for the commercialization of this emergent technology.…”

Effect of Gd polarization on the large magnetocaloric effect ofGdCrO4in a broad temperature range

“…It reduces expenses and improves profitability for liquefying fuel gases before transportation. Matsumoto et al described a hydrogen liquefier based on the Dy 3 (Ga,Al) 5 O 12 garnet [11,12]. Therefore, magnetocaloric materials can be used as efficient refrigerants in the lowtemperature range with the aim of producing the liquefaction of He, H 2 , or natural gas [13].…”

Giant magnetocaloric effect in magnetoelectric Eu1-xBaxTiO3

“…Despite the current race for near room-temperature refrigeration, there has been a need to find new and efficient magnetic refrigerants suitable for cryogenic magnetic cooling applications (e.g. liquefaction of hydrogen, infrared bolometer) in the temperature range of 1 -20 K. 7 Superparamagnetic molecular magnetic clusters and gadolinium garnet (Gd 3 Ga 5 O 12 ) are considered as potential magnetic refrigerants in this temperature range. 8 In this work, we report the occurrence of a giant magnetocaloric effect at cryogenic temperatures (T < 30 K) in a novel class of magnetoelectric materials, Eu 1-x Ba x TiO 3, whose end members have distinct ferroic orders.…”