Voltage-Controlled Magnetocaloric Refrigeration Without Magnetic Fields
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Solution Overview
Problem
Current refrigeration technologies rely heavily on magnetic fields, which are inefficient, noisy, and prone to mechanical issues, limiting the effectiveness of magnetocaloric refrigeration systems.
Innovation Solution
A method and apparatus utilizing voltage-controlled entropy change in piezoelectric and magnetic materials, such as La-Sr-Mn-O compounds, to induce strain and alter temperature without the need for external magnetic fields, enabling efficient and compact refrigeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If magnetic field-based magnetocaloric refrigeration is used, then refrigeration function is achieved, but mechanical vibrations and noise occur
Solution Approach 1:
The patent replaces the traditional magnetic field-based magnetocaloric effect with an electric field-based electrocaloric effect. By applying voltage to electrocaloric materials (such as PbZr1-xTixO3 or Pb(Mg3Nb2/3)O3-PbTiO3), the system induces polarization changes that directly alter material temperature without requiring mechanical movement or generating vibrations, thus eliminating noise while maintaining refrigeration functionality
Solution Approach 2:
The patent changes the fundamental control parameter from magnetic field strength to electric field voltage. By controlling the voltage applied to electrocaloric materials, the system achieves temperature changes through electrocaloric effect, where electric field-induced polarization changes cause entropy and temperature variations in the material, providing a vibration-free refrigeration mechanism
2Volume of moving object
If traditional vapor-compression refrigeration is used, then refrigeration is achieved, but the system is large and not suitable for portable devices
Solution Approach 1:
The patent extracts and eliminates the complex mechanical components of traditional vapor-compression systems (compressors, condensers, expansion valves, refrigerant lines) by adopting solid-state electrocaloric materials. The refrigeration function is achieved purely through voltage-controlled temperature changes in the electrocaloric material, dramatically reducing system volume while maintaining effectiveness
Solution Approach 2:
The patent utilizes the electrocaloric phase transition phenomenon where electrocaloric materials undergo polarization phase changes when exposed to electric fields. This phase transition causes reversible temperature changes in the material, enabling compact solid-state refrigeration without mechanical moving parts or large system components
3Use of energy by moving object
If magnetic field-based refrigeration is used, then cooling is achieved, but energy efficiency is reduced
Solution Approach 1:
The patent replaces energy-intensive magnetic field generation and mechanical compression with low-power electric field application. The electrocaloric effect requires only voltage application to induce temperature changes, eliminating the high energy consumption associated with magnetic field coils and mechanical compressors, thereby significantly improving overall energy efficiency
Solution Approach 2:
The patent employs periodic voltage application to electrocaloric materials to achieve continuous refrigeration. By cyclically applying and removing voltage, the material undergoes reversible temperature changes (cooling during voltage application, heating during voltage removal), enabling efficient heat pumping with minimal energy input compared to continuous magnetic field or mechanical compression systems
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 achieves significant temperature changes and refrigerant capacity without mechanical vibrations, offering a more efficient and compact refrigeration solution suitable for portable devices and room-temperature applications.
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.