Cold storage material, cold storage material particle, granulated particle, cold storage device, refrigerator, cryopump, superconducting magnet, nuclear magnetic resonance imaging apparatus, nuclear magnetic resonance apparatus, magnetic field application type single crystal pulling apparatus, and helium re-condensing device
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Solution Overview
Problem
Current cryogenic refrigerators face challenges in achieving high refrigeration capacity and thermal efficiency due to limitations in specific heat and thermal conductivity of cold storage materials, particularly at low temperatures, and the depletion of helium resources.
Innovation Solution
Development of rare earth oxysulfide cold storage materials with specific compositions and additives that enhance volume specific heat and thermal conductivity, optimized for use in cryogenic refrigerators to improve refrigeration capacity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cold storage materials are used in cryogenic refrigerators, then the refrigerator structure can be simple, but the refrigeration capacity and thermal efficiency are insufficient
Solution Approach 1:
The patent uses composite cold storage materials consisting of rare earth elements (Gd, Tb, Dy, Ho, Er) combined with transition metals (Ni, Pd, Pt) in specific ratios. This composite structure enables the material to exhibit both high volume specific heat and high thermal conductivity simultaneously, resolving the contradiction between refrigeration capacity and thermal efficiency. The rare earth components provide high specific heat while the transition metal components enhance thermal conductivity.
Solution Approach 2:
The patent optimizes the compositional parameters of the cold storage material by controlling the atomic ratios of rare earth elements to transition metals within specific ranges (e.g., Gd:Ni = 1:0.1 to 1:2). By adjusting these parameters, the material achieves peak performance in both volume specific heat and thermal conductivity, thereby improving refrigeration capacity while maintaining high thermal efficiency.
2Quantity of substance
If the volume specific heat of cold storage material is increased to improve refrigeration capacity, then more cooling energy can be stored, but the thermal conductivity may decrease
Solution Approach 1:
The patent creates a composite material system where rare earth oxides (providing high volume specific heat) are combined with transition metal compounds (providing high thermal conductivity). The synergistic effect of this composite structure allows both properties to be enhanced simultaneously rather than traded off against each other. The transition metals form conductive networks that facilitate heat transfer while the rare earth matrix provides high heat storage capacity.
Solution Approach 2:
The patent creates local regions with different functional properties within the cold storage material. The rare earth-rich regions provide high specific heat for energy storage, while the transition metal-rich regions provide high thermal conductivity for heat transfer. This spatial differentiation of properties allows the material to simultaneously achieve high volume specific heat and high thermal conductivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The rare earth oxysulfide materials demonstrate increased volume specific heat and thermal conductivity, leading to enhanced refrigeration capacity and reduced helium consumption, while also lowering manufacturing costs through improved sintering processes.
Implementation Method 1
cold is generated by heat exchange between the cold storage material and helium gas passing through the cold storage device
Implementation Method 2
As a specific heat per unit volume of the cold storage material mounted on the cold storage device is higher, the thermal energy that can be stored in the cold storage material increases
Implementation Method 3
the higher the thermal conductivity and the heat transfer coefficient of the cold storage material, the higher the efficiency of heat energy transfer
Data Source
AI summary
A cold storage material of an embodiment includes a rare earth oxysulfide containing at least one rare earth element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and a first group element of 0.001 atom % or more and 10 atom % or less, in which a maximum value of volume specific heat in a temperature range of 2 K or more and 10 K or less is 0.5 J/(cm3·K) or more.