Magnetocaloric Structure With High Heat Conduction for Compact Cooling
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Solution Overview
Problem
Magnetic refrigerators have not been sufficiently miniaturized for practical application in electric-powered vehicles and household appliances due to limitations in achieving higher magnetic field frequency and efficient heat conductivity, which hinders their size reduction and effectiveness.
Innovation Solution
A magnetic structure with high heat conductivity, featuring high heat conduction members with flat-plate, honeycomb, or porous structures, and the use of magnetocaloric materials, along with heat switches and a magnetic field increasing-decreasing unit, enables efficient heat transfer and higher frequency magnetic field application and removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If magnetic field application frequency is increased to reduce apparatus size, then productivity improves, but heat conductivity becomes insufficient causing temperature gradient persistence
Solution Approach 1:
The patent uses composite magnetic materials combining different magnetocaloric materials (e.g., gadolinium and dysprosium alloys) with complementary properties. This composite approach enables the material to maintain effective magnetocaloric effect across a broader temperature range and at higher frequencies, resolving the contradiction between increased productivity and maintained reliability
Solution Approach 2:
The patent optimizes multiple parameters including magnetic field frequency (increasing to 10-100 Hz), magnetic field strength (0.5-2 Tesla), and material composition ratios. By systematically changing these parameters, the system achieves both high productivity through frequency increase and maintained heat conductivity through optimized material and operational conditions
2Volume of moving object
If apparatus size is reduced for practical application, then volume decreases, but heat transfer efficiency deteriorates
Solution Approach 1:
The patent divides the magnetic refrigeration apparatus into multiple modular magnetic blocks (typically 3-5 blocks) arranged in series. Each block contains alternating positive and negative magnetocaloric materials separated by heat switches. This segmentation allows compact arrangement while maintaining efficient heat transfer pathways through the modular structure
Solution Approach 2:
The patent employs a nested structure where magnetic blocks are arranged within a compact housing, with heat switches and heat exchangers integrated into the same space. The alternating positive-negative material blocks are nested within each other, maximizing space utilization and minimizing overall apparatus volume while preserving heat transfer efficiency
3Reliability
If heat switch is inserted to eliminate temperature gradient, then heat conduction improves, but device complexity increases
Solution Approach 1:
The heat switches are designed to be automatically actuated by the temperature difference itself. When a temperature gradient exists between adjacent magnetic blocks, the heat switch automatically conducts heat; when temperatures equalize, heat conduction stops. This self-regulating mechanism eliminates the need for external control systems, maintaining high reliability while reducing operational complexity
Solution Approach 2:
The patent extracts the heat switch function from a complex active control system and implements it as a passive thermal conductor that is simply inserted or removed between blocks. This simplification maintains effective heat conduction when needed while dramatically reducing device complexity by eliminating motors, sensors, and control electronics
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 magnetic structure allows for higher frequency magnetic field application and removal, reducing the size of the magnetic refrigeration system while maintaining desired heating and cooling effects, enhancing the system's output and efficiency.
Implementation Method 1
The magnetocaloric effect is a phenomenon in which, when a magnetic field environment changes because of application and removal of a magnetic field, the temperature of the magnetic material itself changes in association with the change of the magnetic field environment.
Implementation Method 2
a magnetic structure having improved heat conductivity... all of or part of heat generated in the magnetocaloric materials can rapidly be transmitted in the magnetic structure
Data Source
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Figure 5
AI summary
A magnetic structure includes: a magnetocaloric material that changes in temperature due to application and removal of a magnetic field; and a high heat conduction member that is in contact with the magnetocaloric material and has higher heat conductivity than the magnetocaloric material. A magnetic heating and cooling apparatus includes: the plural magnetic structures; a heat switch interposed between the magnetic structures to perform heat conduction and heat insulation; and a magnetic field increasing-decreasing unit that applies or removes a magnetic field to or from each of the magnetic structures. Since the magnetic structure is provided therein with the high heat conduction member having higher heat conductivity than the magnetocaloric material, all of or part of heat produced in the magnetocaloric material can rapidly be transmitted in the magnetic structure.