2OBJECTIVETo develop more efficient and cost-effective small-scale H2 liquefiers as an alternative to vapour-compression cycles using magnetic refrigeration (adiabatic magnetization).
3CONTENTS Introduction History Basic principle of Magnetic RefrigerationComponentsThermodynamic cycleWorkingBenefitsMagnetic materialsRegenerators & Superconducting MagnetsActive magnetic regenerators (AMR’s)ComparisonActivities
4INTRODUCTIONMagnetic 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.
5HISTORY 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.
6Magneto 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.
14AMR’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 offluid flow.Low porosity.Affordable materials.Ease of manufacture.
16CONTD…… 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.
17ACTIVITIES ( PRESENT & FUTURE ) Development of optimized magnetic refrigerants.( large magneto caloric effect )Performance simulations of magnetic refrigerants.Design of a magnetic liquefier.
18CONCLUSIONMagnetic 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.