This document discusses magnetic refrigeration, which uses the magnetocaloric effect to provide cooling. It works by applying and removing a magnetic field from magnetocaloric materials, causing their temperature to change. The document outlines the components, thermodynamic cycle steps, requirements, examples of prototypes, advantages like efficiency and sustainability, and challenges like initial costs. It also covers potential applications like household refrigeration and compares magnetic refrigeration to current technologies under development.

2.  Introduction
 Objective
 Magneto Calorific effect
 Components
 Thermodynamic Cycle
 Steps of Thermodynamic cycle
 Requirements for practical application
 Example of a prototype Rotary AMRR
 Advantages
 Disadvantages
 Future Applications
 Comparison
 Magnetic refrigeration under development
 Conclusion
CONTENTs

3.  Refrigeration is a process in which work is done to move heat from one
location to another.
 Magnetic refrigeration is a cooling technology based on the magneto
caloric effect.
 Magneto caloric effect Invented by Emil Warburg in 1880.

4.  To understand the Principle and mechanism
for generating cooling effect using the
magnet
 To solve the problem of hydrogen
storage

5.  A reversible change in temperature of
a
suitable material
 Variation of internal energy of the
material when applied magnetic field
changes
 Intensive property and Extensive
property

6. Magnets
Hot Heat exchanger
Cold Heat Exchanger
Drive
Magneto caloric wheel

8. Adiabatic magnetization.
Isomagnetic enthalpic
transfer.
Adiabatic demagnetization.
Isomagnetic entropic
transfer

9.  The substance is placed in an insulated environment.
 External magnetic field (+H) increased.
 Magnetic dipoles of atoms to align, thereby magnetic
entropy and heat capacity decreases.
 Total Entropy of the item is not reduced, and item
heats up.
Adiabatic Magnetization

10.  This added heat can then be removed by a fluid like water or
helium (-Q).
 The magnetic field is held constant to prevent the dipoles from
reabsorbing the heat
 After sufficient cooling, the magneto caloric material and
the coolant are separated (H=0).

11.  Substance returned to another adiabatic ( insulated ) condition
 Total Entropy remains constant
 Magnetic field is decreased,
 Thermal energy causes the magnetic moments to overcome the field and
sample cools ( adiabatic temperature change )
 Energy transfers from thermal entropy to magnetic entropy ( disorder of
the magnetic dipoles )

12.  Material is placed in thermal contact with the environment being
refrigerated.
 Magnetic field held constant to prevent from heating back up
 Because the working material is cooler than the refrigerated
environment, heat energy migrates into the working material ( +Q )

13.  Magnetic Materials
 Regenerators
 Super Conducting Magnets
 Active Magnetic Regenerators(AMR’s)

14. Gd alloys: Gd5(Si2Ge2); Gd5(Si0.33Ge3.67); Gd0.54Er0.46)NiAl
Gd5(SixGe1 − x)4, La(FexSi1 − x)13Hx and MnFeP1 − xAsx alloys are
some of the most promising substitutes for Gadolinium and its alloys

16. a) Tubes.
b) Perforated
plates.
c) Wire screens.
d) Particle beds.

18.  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.

20. Example of a Prototype Rotary
AMRR
Fluid pump
Drive motor
Magneto
caloric wheel
Cold HX
Permanent
magnet

21.  Noise-less technology
 Very high thermodynamic efficiency
 Lower energy consumption
 Simple design and building
 Low maintenance costs
 Long life
 Low pressure
 Green technology (no use of conventional refrigerants)
 High performance

22.  Initial cost
 Magneto caloric material are rare earth metals
 Temperature span.
 Protection of electronic components from magnetic fields.
 Curie temperature of the magneto caloric material
 Moving machines need high precision

23.  Magnetic household refrigeration
 Central cooling system
 Magnetic cooling and air conditioning in buildings and houses
 Refrigeration in medicine
 Cooling in food industry and storage
 Laptop
 Vehicle air conditioning
 Storage of Hydrogen

25. A rotating magnetic refrigerator developing by
Astronautics Corporation of America Ltd. In
collaboration with the Ames Laboratory.

26.  No hazardous chemicals used [Environment friendly]
 Improved efficiency about 25% increase
 Larger temperature span
 Permanent magnet need to produce strong magnetic
field over 10tesla
 Some thermal and hysteresis problem

27.  Experiments done on Ames Laboratory
 Magnetic Refrigeration, ASHRAE Journal (2007), by John Dieckmann, Kurt Roth and James
Brodrick
 Lounasmaa, experimental principles and methods, academic press
 www.google.com
 http://www.sciencedirect.com/science/article/pii/S014070071200117X
 http://www.ameslab.gov/files/MagFridge_Foundation.pdf