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MAGNETIC REFRIGERATION. O BJECTIVE To develop more efficient and cost-effective small-scale H 2 liquefiers as an alternative to vapour-compression cycles using magnetic refrigeration (adiabatic magnetization). CONTENTS Introduction History
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OBJECTIVE To develop more efficient and cost-effective small-scale H2 liquefiers as an alternative to vapour-compression cycles using magneticrefrigeration (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.
BENEFITS TECHNICAL • High efficiency. • Reduced cost. • Compactness. • Reliability SOCIO-ECONOMIC • 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 Tubes. Perforated plates. Wire screens. Particle beds.
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.
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 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.
THANK YOU… Promoting energy efficiency