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 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.

In various aspects, methods of making perovskite manganese oxide particles are provided as well as perovskite manganese oxide particles made therefrom. The perovskite manganese oxide particles exhibit a strong magnetocaloric effect, making them well suited for applications in power generation and magnetic refrigeration, especially at or near room temperature. The methods can include forming an aqueous mixture of (i) a low-molecular-weight polymeric polyalcohol gel precursor, (ii) a stoichiometric amount of metal salts or hydrates thereof, wherein the metal salts or hydrates thereof comprise at least a Manganese (Mn), and (iii) a polybasic carboxylic acid; polymerizing the aqueous mixture to form a gel containing perovskite manganese oxide nanoparticles entrapped therein; and calcining the gel to remove at least a portion of organic material in the gel and form the perovskite manganese oxide particles. Method and systems are also provided for power generation and magnetic refrigeration using the perovskite manganese oxide particles.

An article for magnetic heat exchange comprising a magnetocalorically active phase with a NaZn.sub.13-type crystal structure is provided by hydrogenating a bulk precursor article. The bulk precursor article is heated from a temperature of less than 50° C. to at least 300° C. in an inert atmosphere and hydrogen gas only introduced when a temperature of at least 300° C. is reached. The bulk precursor article is maintained in a hydrogen containing atmosphere at a temperature in the range 300° C. to 700° C. for a selected duration of time, and then cooled to a temperature of less than 50° C.

This invention provides a regenerator material having a high specific heat, particularly in the temperature range of 10 to 25K, and a regenerator and a refrigerator comprising the regenerator material. The present invention specifically provides an HoCu-based regenerator material represented by general formula (1): HoCu.sub.2-xM.sub.x (1), wherein x is 0<x≤1, and M is at least one member selected from the group consisting of Al and transition metal elements (excluding Cu), as well as a regenerator and a refrigerator comprising the regenerator material.

The invention provides an alloy comprising e.g. manganese, iron, vanadium, phosphor and silicon. The invention also provides an apparatus comprising a magnetic field generator, a heat sink, the thermo element, a heat source, and a control system, wherein in a controlling mode the control system is configured to select between (i) a first configuration wherein the magnetic field generator generates a magnetic field, the thermo element is exposed to the magnetic field, and heat from the thermo element is transferred to the heat sink, and (ii) a second configuration, wherein the thermo element is not exposed to the magnetic field, and heat from a heat source is transferred to the thermo element.

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 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.

Described are magnetocaloric materials comprising manganese, iron, phosphorus, silicon, carbon and optionally one or both of nitrogen and boron, and processes for producing said magnetocaloric materials.

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.