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…