Voltage-Controlled Magnetocaloric Cooling Without External Fields
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Solution Overview
Problem
Current refrigeration technologies, particularly those relying on magnetic field-induced entropy changes, face limitations such as high energy consumption, mechanical noise, and wear due to moving parts, and are inefficient in achieving significant temperature changes without external magnetic fields.
Innovation Solution
A method and apparatus utilizing voltage-controlled entropy change by applying voltage signals to piezoelectric materials to induce strain in magnetocaloric materials, allowing for temperature modulation without the need for external magnetic fields, using a combination of piezoelectric and magnetic thin films in a layered structure to achieve efficient cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If magnetic field-induced entropy change is used for refrigeration, then temperature change can be achieved, but energy consumption increases and mechanical noise is generated
Solution Approach 1:
The patent replaces the magnetic field-induced magnetocaloric effect with a voltage-induced strain-controlled elastocaloric effect. This substitution eliminates the need for complex magnetic field generation systems and moving parts, thereby reducing energy consumption and mechanical noise while achieving temperature change through pure voltage control of piezoelectric materials.
Solution Approach 2:
The patent changes the control parameter from magnetic field strength to voltage/strain. By applying voltage to piezoelectric materials, strain is induced which directly controls the entropy change in elastocaloric materials, achieving temperature modulation without the energy-intensive magnetic field generation process.
2Temperature
If magnetic field-induced entropy change is used for refrigeration, then temperature change can be achieved, but mechanical noise and wear occur due to moving parts
Solution Approach 1:
The patent replaces mechanical moving parts with a voltage-controlled piezoelectric system. The piezoelectric material generates strain directly in response to voltage, eliminating motors, pistons, and other mechanical components that produce noise and wear, thereby significantly improving reliability.
Solution Approach 2:
The piezoelectric material serves multiple functions: it acts as both the actuator that generates strain and the control element that responds to voltage signals. This self-service capability eliminates the need for separate mechanical actuators and control systems, reducing moving parts and improving reliability.
3Temperature
If external magnetic fields are used for refrigeration, then entropy change can be induced, but device complexity and size increase
Solution Approach 1:
The patent substitutes complex magnetic field generation equipment with simple voltage signal generators and piezoelectric materials. This replacement dramatically simplifies device architecture, reducing both complexity and size while maintaining the ability to induce entropy change for refrigeration.
Solution Approach 2:
The patent employs thin film structures for both piezoelectric and elastocaloric materials, enabling compact integration and reducing overall device size. The thin film configuration allows for flexible design and miniaturization, contrasting with the bulky magnetic field generation equipment required by conventional approaches.
4Temperature
If voltage-controlled strain is applied to magnetic materials, then temperature change can be achieved, but material compatibility and integration difficulty increase
Solution Approach 1:
The patent creates a composite structure where piezoelectric material and elastocaloric material are integrated in direct contact. This composite approach allows the piezoelectric strain to be directly transferred to the elastocaloric material, enabling effective coupling while managing material compatibility through careful selection and interface design.
Solution Approach 2:
The patent selects materials with matched physical and chemical properties to ensure compatibility. By carefully choosing piezoelectric and elastocaloric materials with compatible thermal, mechanical, and dimensional properties, the integration challenges are reduced while maintaining effective strain transfer for temperature control.
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 compact, efficient, and portable cooling solutions with significant temperature changes, reducing energy consumption and mechanical noise, and broadening the range of applications by leveraging the magnetocaloric effect through pure voltage control.
Implementation Method 1
applying a voltage signal to a piezoelectric material to generate strain in the piezoelectric material
Implementation Method 2
generating a change in a temperature of the magnetic material in response to the strain in the magnetic material
Data Source
AI summary
A method for refrigeration through voltage-controlled entropy change includes applying a voltage signal to a piezoelectric material to generate strain in the piezoelectric material, generating strain in a magnetic material attached to the piezoelectric material, and generating a change in a temperature of the magnetic material in response to the strain in the magnetic material.