1. MAGNETIC REFRIGERATION

2. OBJECTIVE
To develop more efficient and cost-effective small-scale H2 liquefiers as an alternative to vapour-compression cycles using magnetic refrigeration (adiabatic magnetization).

3. 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

4. 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.

5. 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.

6. 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.

7. COMPONENTS Magnets. Hot heat exchanger. Cold heat exchanger. Drive.
Magneto caloric
wheel.

8. Thermodynamic cycle Steps of thermodynamic cycle -
Adiabatic magnetization.
Isomagnetic enthalpic
transfer.
Adiabatic demagnetization.
Isomagnetic entropic

9. WORKING PRINCIPLE

10. BENEFITS TECHNICAL High efficiency. Reduced cost. Compactness.
Reliability
SOCIO-ECONOMIC
Competition in global market.
Low capital cost.
Key factor to new technologies.

11. MAGNETIC MATERIALS
Gd alloys: Gd5(Si2Ge2); Gd5(Si0.33Ge3.67); Gd0.54Er0.46)NiAl

12. REGENERATORS
Tubes.
Perforated plates.
Wire screens.
Particle beds.

13. SUPER CONDUCTING MAGNETS

14. 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.

15. COMPARISON

16. 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.

17. ACTIVITIES ( PRESENT & FUTURE )
Development of optimized magnetic refrigerants.
( large magneto caloric effect )
Performance simulations of magnetic refrigerants.
Design of a magnetic liquefier.

18. CONCLUSION
Magnetic refrigeration technology could provide a ‘green’ alternative to traditional energy-guzzling gas-compression 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.

19. Promoting energy efficiency
THANK YOU…