Magnetic refrigerator

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Solution Overview

Problem

Magnetic refrigerators using two different positive and negative magnetic members suffer from poor heat transfer efficiency due to non-uniform magnetocaloric effects and high costs, with the negative magnetic material being rare and expensive, leading to large and heavy devices.

Innovation Solution

A magnetic refrigerator design utilizing magnetic members of the same material, where a plurality of magnetic members are arranged with gaps, and a magnet/heat conductive member applies magnetism individually to each member, allowing for efficient heat transfer through the magnetocaloric effect, reducing device size, weight, and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two different positive and negative magnetic members are used, then the magnetocaloric effect can be exhibited, but the heat transfer efficiency deteriorates due to non-uniform magnetocaloric effects

Engineering Contradiction:
Improvemagnetocaloric effectVSAvoidheat transfer efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies homogeneity by using magnetic members made of the same material throughout the system. This ensures uniform magnetocaloric effects across all magnetic members, eliminating the efficiency problems caused by mixing positive and negative magnetic materials with different properties. The uniform material composition allows consistent heat transfer performance.

Inventive Principle:
Principle #33Homogeneity

2Reliability

If two different positive and negative magnetic members are used, then the magnetocaloric effect can be exhibited, but the device cost deteriorates due to rare and expensive negative magnetic material

Engineering Contradiction:
Improvemagnetocaloric effectVSAvoiddevice cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent eliminates the need for expensive rare negative magnetic materials by using only common positive magnetic materials throughout the system. This homogeneity in material selection dramatically reduces manufacturing costs while maintaining the magnetocaloric effect functionality through uniform magnetic member composition.

Inventive Principle:
Principle #33Homogeneity

3Reliability

If two different positive and negative magnetic members are used, then the magnetocaloric effect can be exhibited, but the device weight deteriorates due to large and heavy magnetic circuit

Engineering Contradiction:
Improvemagnetocaloric effectVSAvoiddevice weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent reduces device weight by using uniform positive magnetic materials that are lighter than the combination of positive and negative magnetic materials. The homogeneous material composition allows for a more compact and lighter magnetic circuit design while maintaining full magnetocaloric functionality.

Inventive Principle:
Principle #33Homogeneity

4Object-affected harmful factors

If heat is transported by using heat conduction of solid material, then the environmental impact is reduced compared to gaseous refrigerant, but the heat transfer capacity deteriorates

Engineering Contradiction:
Improveenvironmental impactVSAvoidheat transfer capacity
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent enhances the heat transfer capacity of solid material conduction by optimizing thermal contact parameters. This includes using thermal conductive members with high thermal conductivity and designing optimal contact surfaces between magnetic members and heat exchange portions, thereby improving heat transfer capacity while maintaining the environmental benefits of solid-state refrigeration.

Inventive Principle:
Principle #35Parameter changes

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 configuration enhances heat transport capability and efficiency, enabling a smaller, lighter, and more cost-effective magnetic refrigerator by leveraging uniform magnetocaloric effects in same-material magnetic members.

Implementation Method 1

Some of the magnetic material exhibits, when the magnitude of the magnetic field applied to the magnetic body is changed, vary temperature of itself in response to that change, through so-called magnetocaloric effect.

Methodology Applied
Scientific EffectMagnetocaloric effect: Magnetocaloric Effect

Implementation Method 2

heat is transported by using head conduction of solid material

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2706309B1Magnetic refrigerator
Publication Date: 2019.12.04 NISSAN MOTOR CO LTD
  • EP2706309B1 patent drawingFigure 1A~1B
  • EP2706309B1 patent drawingFigure 2
  • EP2706309B1 patent drawingFigure 3(1)~3(3)'

AI summary

[Problem] To improve heat transport capability and heat transport efficiency and reduce the size, weight, and cost. [Solution] A magnetic body arranged plate (700) has a plurality of magnetic body units (200A, ...) each including a plurality of magnetic members (10Aa, ...) made of the same material and arranged in row at intervals. The magnetic body units (200A, ...) are arranged side by side at intervals in a direction perpendicular to the arranging direction of the magnetic members (10Aa, ...). A low-temperature side heat exchange unit and a high-temperature side heat exchange unit are disposed at one end and at the other end of each magnetic body units (200A, ...), on the magnetic body arranged plate (700), respectively. A plurality of permanent magnets and a plurality of heat conductive members facing the magnetic body arranged plate (700) are arranged on a magnet/heat conductive member arrenged plate. When the magnetic body arranged plate (700) and the magnet/heat conductive member arranged plate are moved relative to each other in the arranging direction of the magnetic body units (200A, ...) by a driving unit, the permanent magnets apply magnetism separately to the magnetic members (10Aa, ...) of each magnetic body unit (200A, ...). The magnet/heat conductive member arranged plate creates a temperature difference and conducts heat in one direction between the magnetic members of each magnetic body units (200A, ...), between the magnetic member positioned at one end of the magnetic body units (200A, ...) and the low-temperature side heat exchange unit, and between the magnetic member positioned at the other end of the magnetic body unit (200A, ...) and the high-temperature side heat exchange unit.