Fe-Rh Magnetocaloric Ribbons for Low-Field Room-Temperature Cooling
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Solution Overview
Problem
Existing magnetocaloric materials do not efficiently exhibit a giant magnetocaloric effect at low magnetic field changes, which is necessary for advanced cooling and heating applications.
Innovation Solution
The development of polycrystalline Fe100-xRhx magnetocaloric materials with a chemically ordered bcc CsCl-type crystalline structure, produced through rapid solidification using the melt spinning technique, which enhances the magnetocaloric properties at low magnetic field changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional magnetocaloric materials are used, then they can exhibit magnetocaloric effect, but they do not efficiently exhibit giant magnetocaloric effect at low magnetic field changes
Solution Approach 1:
The patent changes the chemical composition parameters by precisely controlling Rh content in the range of 48-52 at.% and Fe content of 97-100 at.%, which optimizes the magnetocaloric effect at low magnetic fields while maintaining performance consistency through the specific compositional range
Solution Approach 2:
The patent creates a composite material system combining Fe and Rh in specific proportions to achieve enhanced magnetocaloric properties at low magnetic field changes, utilizing the synergistic effects of the two elements in the defined composition ranges
2Temperature
If magnetocaloric materials are used for cooling applications, then cooling effect is achieved, but energy efficiency compared to conventional refrigeration is reduced
Solution Approach 1:
The patent utilizes first-order magneto-structural phase transitions in the Fe-Rh alloy system to achieve large adiabatic temperature changes and magnetic entropy changes, which enhance the cooling effect while improving energy efficiency through the inherent thermodynamic properties of the phase transition
Solution Approach 2:
The patent optimizes the magnetic field change parameter to operate in the low magnetic field range where the material exhibits maximum magnetocaloric effect, thereby improving energy efficiency while maintaining effective cooling performance
3Temperature
If magnetocaloric materials are used for heating applications, then heating effect is achieved, but control precision of temperature release is reduced
Solution Approach 1:
The patent controls the magnetic field change parameter to precisely regulate the temperature release characteristics of the material, enabling accurate control of heating effects while maintaining the desired heating performance through optimized magnetic field application
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
These materials demonstrate improved magnetocaloric properties, including a giant low magnetic field-induced maximum magnetic entropy change and enhanced refrigerant capacity, making them suitable for efficient cooling and heating applications.
Implementation Method 1
Magnetic materials that undergo a significant increase, or decrease, in temperature upon the application or removal of an external magnetic field in the temperature region in which a first- or second-order phase transition has been experienced, referred as magnetocaloric materials
Implementation Method 2
the first-order magneto-structural phase transition that the chemically-ordered CsCl-type crystal structure undergoes
Implementation Method 3
A magnetocaloric material with a giant magneto-caloric effect associated to a magneto-elastic transition that can be also used in a mechanocaloric heater or refrigerator system
Implementation Method 4
rapid solidification into ribbons with an average thickness varying between 10 and 50 μm
Implementation Method 5
has a chemically ordered bcc CsCl-type crystalline structure
Implementation Method 6
adiabatic temperature ΔTadmax changes, together with the refrigerant capacity RC
Implementation Method 7
ΔTad characterizes the driving force for heat transfer between the cold and hot sinks
Data Source
AI summary
A polycrystalline magnetocaloric material based on thermally annealed Fe100-xRhx melt-spun ribbons with chemical composition x in the interval 48≤x≤52 at. % and the bcc CsCl-type crystal structure and method for manufacturing the same. The material has improved magnetocaloric properties associated to first-order magneto-elastic phase transition compared to bulk alloys of similar chemical composition manufactured by conventional melting techniques; exhibiting low-magnetic field induced giant magnetocaloric effects and enhanced refrigeration capacity close to the room temperature range, due to the fast increase of a magnetic entropy change at low fields followed by a broad table-like magnetic entropy change as function in the temperature curve. The material is useful as a working substance for the applications involving heating or cooling upon removal or application of an external magnetic field, including magnetocaloric refrigeration, heat exchangers, controllable delivery and release of bioactive substances imbedded in a thermo-sensitive polymer.