Magnetic Refrigration - My Presentation
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8/8/2019 Magnetic Refrigration - My Presentation
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SEMINAR ON
MAGNETIC REFRIGRATIONATTRACTIVE ALTERNATIVE COOLING TECHNOLOGY
BY :
RAMAKANTH P JOSHI
1JS06ME034
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OUTLINE
Magnetocaloric effect
Principle
Prototype : Ames lab & astronaut corp
America
Advantages of magnetic refrigeration
Technology comparison
Future scope
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MAGNETS
Ferromagnetic materials ² alloy of Al, Ni,Fe,Co
Paramagnetic materials ² Cr,Mn, Pt, Pd, K, Cu.
Diamagnetic materials ² Zn, Bismuth, antimony.
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W AYS TO COOL
Expansion and compression of gas <30% Fridge, Bicycle pump
Evaporation of liquids very robust plants, animals, weather
Peltier effects not very efficient Radiators
Magnetic refrigeration ~60% Proof of principle apparatus ( Cooling with the help of external magnetic field)
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INTRODUCTION
PRINCIPLE : Magnetocaloric effect due
to variable field
Currie temperature
(768°C for Fe)
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DEMONSTRATION OF MCE
In a small physics experiment the magneto calorific effect in a gadolinium
sample is demonstrated. Magnetization heats the sample up and
demagnetization cools it down
B
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THERMO DYNAMIC CYCLE THERMO DYNAMIC CYCLE
Steps of thermodynamic cycle
Adiabatic magnetization
Isomagnetic enthalpic transfer
Adiabatic demagnetization
Isomagnetic entropic transfer
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GRAPHICAL REPRESENTATION
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REGENERATORS
(a) Tubes ± Cu or Ag
( b) Perforated plates ± stainless steel
(c) Wire screens - Cu
(d) Particle beds ± ceramic or metal sphere
AIM : To achieve good thermal conductivity
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DESIRED PROPERTIES OF WORKING
MATERIALS
Large magneto calorific effect
Significant MCE at reasonable fields Curie temperature
Environment friendly materials
Affordable, abundant and easily synthesizable materials
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WORKING MATERIALS
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COMPARISONCOMPARISON
Analogy between magnetic refrigeration and vapor cycle refrigeration
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TECHNOLOGY COMPARISON
COMPRESSION MAGNETIC
Environmental
impact
Liquid based
(CFC)
Environmentally
safe
Cooling
efficiency
<40% 60%
durability ~20 years ~50 years
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ADV ANTAGES OF MAGNETIC
REFRIGERATION
Green technology
Noise-less technology
Very high thermodynamic efficiency Low energy consumption
Simple design and building
Long life Low pressure
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IDEAL APPLICATIONS
1) House hold refrigerators appliances
2) Central cooling systems
3) Room air conditioners
4) Supermarket refrigeration ( display cabinets)
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FUTURE SCOPE
Less mass of magnet by 3-d field concentration
Higher volume fractions of porous structures
Higher frequencies of rotation
Application of hybrid materials
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CONCLUSION
MCE : dH implies dS
Magnetic refrigeration can be cycled
Magnetic refrigeration demonstrated to be
1. most efficient
2. very compact
3. eco friendly
4. Trouble free
Prominent MCE materials for room temperature : Rare earth metals.
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BIBLIOGRAPHY
BASIC AND APPLIED THERMOD YNAMICS by Dr. P K Nag 2/e TMH publication
www.wikipedia.com
www.freepatentsonline.com
www.globlespec.com
Research paper: magnetic refrigeration by JEFF JOHNSON
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