Layered Magnetic Refrigeration for Solid-State Heat Transfer
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Solution Overview
Problem
Magnetic refrigeration systems near room temperature face challenges with the use of liquid or gaseous heat transfer media, which can cause mechanical stress on brittle magnetic refrigerants, lead to inefficiencies, and complicate the design, while also requiring large and costly magnet systems due to the need for high magnetic fields.
Innovation Solution
A magnetic refrigerating device and method utilizing a layered structure of magnetic materials with magneto-caloric effects and heat conductive materials whose conductivity changes with magnetic field application, allowing for solid-state heat transfer without the need for fluid flow, and using a Halbach-type magnet for efficient magnetic field application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If liquid or gaseous heat transfer media are used in magnetic refrigeration systems, then heat transfer efficiency is improved, but mechanical stress on brittle magnetic refrigerants increases and system complexity increases
Solution Approach 1:
The patent extracts and eliminates the liquid or gaseous heat transfer media from the magnetic refrigeration system. Instead of using fluid media to transfer heat, the invention employs direct solid-to-solid thermal contact between the magnetic refrigerant and heat sink/source, thereby removing the complexity associated with fluid circulation systems while maintaining effective heat transfer.
Solution Approach 2:
The patent introduces a thermally conductive intermediary material that facilitates direct solid-state heat transfer between the magnetic refrigerant and the heat sink or source. This intermediary enables efficient thermal coupling without requiring fluid media, thus improving heat transfer efficiency while avoiding the mechanical stress and system complexity associated with liquid or gaseous heat transfer media.
2Loss of energy
If liquid or gaseous heat transfer media are used in magnetic refrigeration systems, then heat transfer is enhanced, but mechanical stress on the refrigerant increases
Solution Approach 1:
The patent removes the liquid or gaseous heat transfer media from the system, thereby eliminating the mechanical stress that these fluids exert on the brittle magnetic refrigerant during circulation and heat exchange operations.
Solution Approach 2:
The patent employs a solid thermally conductive intermediary material that enables heat transfer through direct solid-to-solid contact, avoiding the mechanical stress imposed by liquid or gaseous fluids on the magnetic refrigerant while maintaining effective thermal coupling.
3Power
If large magnetic field systems are used to achieve high magnetic fields, then magneto-caloric effect is enhanced, but system size and operational costs increase
Solution Approach 1:
The patent employs composite magnetic material structures and optimized magnetic circuit designs that achieve high magnetic field intensity with more compact magnet systems. By using composite materials and optimized geometries, the system attains the necessary magneto-caloric effect while reducing the overall size and operational costs of the magnetic field generation system.
4Reliability
If conventional magnetic refrigeration designs are used, then refrigeration function is achieved, but design complexity increases due to fluid flow requirements
Solution Approach 1:
The patent extracts and eliminates the fluid flow circulation system from the magnetic refrigeration design. By using direct solid-to-solid thermal contact between the magnetic refrigerant and heat exchanger surfaces, the invention maintains reliable refrigeration function while significantly simplifying the overall system design and removing the complexity associated with fluid flow management.
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
This approach enables a compact, efficient, and cost-effective magnetic refrigeration system that reduces mechanical stress on the refrigerant, eliminates the need for fluid flow, and minimizes the size and operational costs of the magnet system by optimizing heat transfer through the layered structure and controlled magnetic field application.
Implementation Method 1
a magnetic material A exhibiting a magneto-caloric effect that the temperature of the material A is increased by the application of a magnetic field and the temperature of the material A is decreased by the removal of a magnetic field, a magnetic material B exhibiting a magneto-caloric effect that the temperature of the material B is decreased by the application of a magnetic field and the temperature of the material B is increased by the removal of a magnetic field
Implementation Method 2
a heat conductive material a exhibiting higher heat conductivity under the application of a magnetic field and lower heat conductivity under the removal of a magnetic field, and a heat conductive material b exhibiting lower heat conductivity under the application of a magnetic field and higher heat conductivity under the removal of a magnetic field
Data Source
AI summary
A magnetic refrigerating device includes: a magnetic refrigerating unit including a magnetic material “A” exhibiting a magneto-caloric effect that the temperature of the material “A” is increased by the application of a magnetic field and the temperature of the material “A” is decreased by the removal of a magnetic field, a magnetic material “B” exhibiting a magneto-caloric effect that the temperature of the material “B” is decreased by the application of a magnetic field and the temperature of the material “B” is increased by the removal of a magnetic field, a heat conductive material “a” exhibiting higher heat conductivity under the application of a magnetic field and lower heat conductivity under the removal of a magnetic field, and a heat conductive material “b” exhibiting lower heat conductivity under the application of a magnetic field and higher heat conductivity under the removal of a magnetic field, wherein the magnetic refrigerating unit is configured so as to include at least one layered structure denoted by “AaBb” or “AbBa”; and a magnetic field-applying means to apply a magnetic field to the magnetic refrigerating unit.