A system including: an active magnetic regenerative refrigerator apparatus that includes a high magnetic field section in which a hydrogen heat transfer fluid can flow from a cold side to a hot side through at least one magnetized bed of at least one magnetic refrigerant, and a low magnetic field or demagnetized section in which the hydrogen heat transfer fluid can flow from a hot side to a cold side through the demagnetized bed; a first conduit fluidly coupled between the cold side of the low magnetic field or demagnetized section and the cold side of the high magnetic field section; and a second conduit fluid coupled to the first conduit, an expander and at least one liquefied hydrogen storage module.

A system including: an active magnetic regenerative refrigerator apparatus that includes a high magnetic field section in which a hydrogen heat transfer fluid can flow from a cold side to a hot side through at least one magnetized bed of at least one magnetic refrigerant, and a low magnetic field or demagnetized section in which the hydrogen heat transfer fluid can flow from a hot side to a cold side through the demagnetized bed; a first conduit fluidly coupled between the cold side of the low magnetic field or demagnetized section and the cold side of the high magnetic field section; and a second conduit fluid coupled to the first conduit, an expander and at least one liquefied hydrogen storage module.

Various implementations of the invention correspond to an improved vortex flux generator. In some implementations of the invention, the improved vortex flux generator includes a magnetic circuit configured to produce a magnetic field; a quench controller configured to provide a variable current; a vortex material configured to form and subsequently dissipate a vortex in response to the variable current, wherein upon formation of the vortex, a magnetic field density surrounding the vortex is urged to decrease, and wherein upon subsequent dissipation of the vortex, the urging to decrease ceases and the magnetic field density increases prior to a reformation of the vortex, and wherein the decrease of the magnetic field density and the increase of the magnetic field density correspond to a modulation of the magnetic field; an inductor disposed in a vicinity of the vortex such that the modulation of the magnetic field induces an electrical current in the inductor; and a dissipation superconductor electrically disposed in parallel with the vortex material and configured to carry, without quenching, an entirety of the variable current during dissipation of the vortex in the vortex material.

Various implementations of the invention correspond to an improved vortex flux generator. In some implementations of the invention, the improved vortex flux generator includes a magnetic circuit configured to produce a magnetic field; a quench controller configured to provide a variable current; a vortex material configured to form and subsequently dissipate a vortex in response to the variable current, wherein upon formation of the vortex, a magnetic field density surrounding the vortex is urged to decrease, and wherein upon subsequent dissipation of the vortex, the urging to decrease ceases and the magnetic field density increases prior to a reformation of the vortex, and wherein the decrease of the magnetic field density and the increase of the magnetic field density correspond to a modulation of the magnetic field; an inductor disposed in a vicinity of the vortex such that the modulation of the magnetic field induces an electrical current in the inductor; and a dissipation superconductor electrically disposed in parallel with the vortex material and configured to carry, without quenching, an entirety of the variable current during dissipation of the vortex in the vortex material.

A magnetocaloric cascade contains a sequence of magnetocaloric material layers having different Curie temperatures T.sub.C, wherein the magnetocaloric material layers include a cold-side outer layer, a hot-side outer layer and at least three inner layers between the cold-side outer layer and the hot-side outer layer, and each pair of next neighboring magnetocaloric layers of the magnetocaloric cascade has a respective Curie-temperature difference amount ΔT.sub.C between their respective Curie temperatures, wherein the hot-side outer layer or the cold-side outer layer or both the hot-side and cold-side outer layer exhibits a larger ratio mΔS.sub.max/ΔT.sub.C in comparison with any of the inner layers, m denoting the mass of the respective magnetocaloric material layer and ΔS.sub.max denoting a maximum amount of isothermal magnetic entropy change achievable in a magnetic phase transition of the respective magnetocaloric material layer.

A magnetocaloric cascade contains a sequence of magnetocaloric material layers having different Curie temperatures T.sub.C, wherein the magnetocaloric material layers include a cold-side outer layer, a hot-side outer layer and at least three inner layers between the cold-side outer layer and the hot-side outer layer, and each pair of next neighboring magnetocaloric layers of the magnetocaloric cascade has a respective Curie-temperature difference amount ΔT.sub.C between their respective Curie temperatures, wherein the hot-side outer layer or the cold-side outer layer or both the hot-side and cold-side outer layer exhibits a larger ratio mΔS.sub.max/ΔT.sub.C in comparison with any of the inner layers, m denoting the mass of the respective magnetocaloric material layer and ΔS.sub.max denoting a maximum amount of isothermal magnetic entropy change achievable in a magnetic phase transition of the respective magnetocaloric material layer.

A cooling system for electrical and optical devices includes an electrocaloric cooler (EEC). A fluid circuit is in thermal communication with the EEC to dump heat from a working fluid of the fluid circuit into the EEC. The system can include a second EEC, a second fluid circuit in thermal communication with the second EEC to dump heat from a working fluid of the second fluid circuit into the EEC, and a second heat sink in thermal communication with the second fluid circuit to dump heat into the working fluid of the second fluid circuit. The second EEC, second fluid circuit, and second heat sink can be cascaded with the first EEC, first heat sink, and first fluid circuit wherein the second heat sink is in thermal communication with the first EEC to accept heat therefrom.

A cooling system for electrical and optical devices includes an electrocaloric cooler (EEC). A fluid circuit is in thermal communication with the EEC to dump heat from a working fluid of the fluid circuit into the EEC. The system can include a second EEC, a second fluid circuit in thermal communication with the second EEC to dump heat from a working fluid of the second fluid circuit into the EEC, and a second heat sink in thermal communication with the second fluid circuit to dump heat into the working fluid of the second fluid circuit. The second EEC, second fluid circuit, and second heat sink can be cascaded with the first EEC, first heat sink, and first fluid circuit wherein the second heat sink is in thermal communication with the first EEC to accept heat therefrom.

A cold storage material, which has a large specific heat and a small magnetization in an extremely low temperature region and has satisfactory manufacturability, is provided, and a method for manufacturing the same is provided. Further, a refrigerator having high efficiency and excellent cooling performance is provided by filling this refrigerator with the above-described cold storage material. Moreover, a device incorporating a superconducting coil capable of reducing influence of magnetic noise derived from a cold storage material is provided. The cold storage material of embodiments is a granular body composed of an intermetallic compound in which the ThCr.sub.2Si.sub.2-type structure 11 occupies 80% by volume or more, and has a crystallite size of 70 nm or less.

A cold storage material, which has a large specific heat and a small magnetization in an extremely low temperature region and has satisfactory manufacturability, is provided, and a method for manufacturing the same is provided. Further, a refrigerator having high efficiency and excellent cooling performance is provided by filling this refrigerator with the above-described cold storage material. Moreover, a device incorporating a superconducting coil capable of reducing influence of magnetic noise derived from a cold storage material is provided. The cold storage material of embodiments is a granular body composed of an intermetallic compound in which the ThCr.sub.2Si.sub.2-type structure 11 occupies 80% by volume or more, and has a crystallite size of 70 nm or less.