Magnetic heating and cooling device
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Solution Overview
Problem
Conventional magnetic refrigerators have limitations in heat exchange efficiency between magnetic bodies and liquid refrigerants, which can be improved by optimizing the reciprocating movement of the liquid refrigerant, but further enhancements are needed beyond frequency optimization.
Innovation Solution
The magnetic heating and cooling device employs a heat exchanger with flat plate magnetic bodies having passages with sharp corners, utilizing the leading edge effect to enhance heat transfer efficiency by actively manipulating the magnetic field and liquid refrigerant movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reciprocating movement of liquid refrigerant is optimized for high frequency, then heat exchange efficiency is improved, but there is a limit to further enhancement
Solution Approach 1:
The patent applies local quality by creating sharp corners at specific locations (open ends of passages) within the magnetic body rather than changing the entire structure. This localized geometric feature generates leading edge effects precisely where the liquid refrigerant enters the passages, enhancing heat transfer coefficients at critical heat exchange interfaces without requiring system-wide modifications.
Solution Approach 2:
The patent utilizes the leading edge effect created by sharp corners, which is a geometric principle similar to how aerodynamic shapes utilize curvature. The sharp corners act as leading edges that thin the thermal boundary layer, and this geometric feature is strategically positioned at passage openings to maximize its effect on heat transfer.
2Area of stationary object
If multiple flat plate magnetic bodies are laminated with gaps, then heat exchange surface area is increased, but device size and weight increase
Solution Approach 1:
The patent changes the geometric parameters of the passages within the magnetic bodies, specifically creating sharp corners at passage openings. This parameter change leads to leading edge effects that significantly enhance the heat transfer coefficient, allowing the system to achieve higher heat exchange efficiency with fewer or smaller magnetic bodies, thereby reducing device weight.
3Power
If passages with sharp corners are introduced in magnetic bodies, then heat transfer coefficient is enhanced through leading edge effect, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating sharp corners at specific locations (open ends of passages) within the magnetic body rather than changing the entire structure. This localized geometric feature generates leading edge effects precisely where the liquid refrigerant enters the passages, enhancing heat transfer coefficients at critical heat exchange interfaces without requiring system-wide modifications.
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 achieves higher heat exchange efficiency, allowing for downsizing and weight reduction of the magnetic air-conditioning device while maintaining or improving heat transfer capacity.
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 magneto-caloric effect.
Implementation Method 2
By actively taking advantage of the leading edge effect, it is possible to proceed with the higher frequency to thereby obtain higher heat exchange efficiency along with the higher frequencies.
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
[Problem] To increase heat transport efficiency between a magnetic body and a liquid refrigerant. [Solution] A magnetic heating and cooling device comprises: a heat exchanger (10) that includes a magnetic body (50) having a magnetocaloric effect; a magnetic field applying and removing unit (20) that selectively applies to or removes from the magnetic body (50) a magnetic field; and a liquid refrigerant moving unit (30) that reciprocates a liquid refrigerant (60) from one end to the other end, or from the other end to the one end, of the heat exchanger (10) to exchange heat with the magnetic body (50) inside the heat exchanger (10). The magnetic body (50) is constituted by a plurality of flat magnetic members (50A to 50H). At least one flat magnetic member (50A) has at least one slit that opens in the direction perpendicular to the movement direction of the liquid refrigerant (60), and the open end of each slit forms a corner to increase heat exchange efficiency.