MAGNETIC REFRIGERATION
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Transcript MAGNETIC REFRIGERATION
MAGNETIC REFRIGERATION
OBJECTIVE
To develop more efficient and costeffective small-scale H2 liquefiers as an
alternative to vapour-compression cycles
using
magnetic
refrigeration
(adiabatic magnetization).
CONTENTS
Introduction
History
Basic principle of Magnetic Refrigeration
Components
Thermodynamic cycle
Working
Benefits
Magnetic materials
Regenerators & Superconducting Magnets
Active magnetic regenerators (AMR’s)
Comparison
Activities
INTRODUCTION
Magnetic refrigeration is a physical process that
exploits the magnetic properties of certain solid
materials to produce refrigeration.
Magnetic refrigeration is a cooling technology
based on the magneto caloric effect. This
technique can be used to attain extremely low
temperatures (well below 1 Kelvin), as well as the
ranges used in common refrigerators, depending
on the design of the system.
HISTORY
Magneto caloric effect was discovered in pure iron in 1881 by
E. Warburg.
Debye (1926) & Giauque (1927) proposed a improved
technique of cooling via adiabatic demagnetization
independently.
The cooling technology was first demonstrated
experimentally in 1933 by chemist Nobel Laureate William
F. Giauque & his colleague Dr. D. P. MacDougall for
cryogenic purposes.
In 1997, Prof. Karl A. Gschneidner, Jr. by the Iowa State
University at Ames Laboratory, demonstrated the first near
room temperature proof of concept magnetic refrigerator.
Magneto Caloric Effect
MCE
is
a
magneto-thermodynamic
phenomenon in which a reversible change in
temperature of a suitable material is caused by
exposing the material to changing magnetic
field.
COMPONENTS
Magnets.
Hot heat exchanger.
Cold heat
exchanger.
Drive.
Magneto caloric
wheel.
Thermodynamic cycle
Steps of thermodynamic
cycle Adiabatic magnetization.
Isomagnetic enthalpic
transfer.
Adiabatic demagnetization.
Isomagnetic entropic
transfer.
WORKING PRINCIPLE
BENEFITS
TECHNICAL
SOCIO-ECONOMIC
High efficiency.
Reduced cost.
Compactness.
Reliability
Competition in global
market.
Low capital cost.
Key factor to new
technologies.
MAGNETIC MATERIALS
Gd alloys: Gd5(Si2Ge2); Gd5(Si0.33Ge3.67); Gd0.54Er0.46)NiAl
REGENERATORS
a) Tubes.
b) Perforated
plates.
c) Wire screens.
d) Particle beds.
SUPER CONDUCTING MAGNETS
AMR’s
High heat transfer rate.
Low pressure drop of the heat transfer fluid.
High magneto caloric effect.
Sufficient structural integrity.
Low thermal conduction in the direction of
fluid flow.
Low porosity.
Affordable materials.
Ease of manufacture.
COMPARISON
CONTD……
Do the same job, but with metallic
compounds, not gases.
Environmentally friendly alternative to
conventional vapor-cycle refrigeration.
It eliminates the need of the compressor.
Save costs.
ACTIVITIES ( PRESENT & FUTURE )
Development of optimized magnetic refrigerants.
( large magneto caloric effect )
Performance simulations of magnetic refrigerants.
Design of a magnetic liquefier.
CONCLUSION
Magnetic refrigeration technology could provide a
‘green’ alternative to traditional energy-guzzling gascompression fridges and air conditioners.
Computer models have shown 25% efficiency
improvement over vapor compression systems.
Two advantages to using Magnetic Refrigeration over
vapor compressed systems are no hazardous
chemicals used and they can be up to 60% efficient.
THANK YOU…