BY : RAMAKANTH P JOSHI 1JS06ME034
Magnetocaloric effect Principle Prototype : Ames lab & astronaut corp America Advantages of magnetic refrigeration Technology comparison Future scope
Ferromagnetic materials – alloy of Al, Ni,Fe,Co Paramagnetic materials – Cr,Mn, Pt, Pd, K, Cu. Diamagnetic materials – Zn, Bismuth, antimony.
Expansion and compression of gas <30%Fridge, Bicycle pump Evaporation of liquids very robustplants, animals, weather Peltier effects not very efficientRadiators Magnetic refrigeration ~60%Proof of principle apparatus ( Cooling with the help of external magnetic field)
Introduction PRINCIPLE : Magnetocaloric effect due to variable field Currie temperature (768°C for Fe)
In a small physics experiment the magneto calorific effect in a gadolinium sample is demonstrated. Magnetization heats the sample up and demagnetization cools it down B
THERMO DYNAMIC CYCLE Steps of thermodynamic cycle Adiabatic magnetization Isomagnetic enthalpic transfer Adiabatic demagnetization Isomagnetic entropic transfer
(a) Tubes – Cu or Ag (b) Perforated plates – stainless steel (c) Wire screens - Cu (d) Particle beds – ceramic or metal sphere AIM : To achieve good thermal conductivity
Large magneto calorific effect Significant MCE at reasonable fields Curie temperature Environment friendly materials Affordable, abundant and easily synthesizable materials
COMPARISON Analogy between magnetic refrigeration and vapor cycle refrigeration
COMPRESSIONMAGNETIC Environmental impact Liquid based (CFC) Environmentally safe Cooling efficiency <40%≥60% durability~20 years~50 years
Green technology Noise-less technology Very high thermodynamic efficiency Low energy consumption Simple design and building Long life Low pressure
1)House hold refrigerators appliances 2)Central cooling systems 3)Room air conditioners 4)Supermarket refrigeration ( display cabinets)
Future scope Less mass of magnet by 3-d field concentration Higher volume fractions of porous structures Higher frequencies of rotation Application of hybrid materials
CONCLUSION MCE : dH implies dS Magnetic refrigeration can be cycled Magnetic refrigeration demonstrated to be 1.most efficient 2.very compact 3.eco friendly 4.Trouble free Prominent MCE materials for room temperature : Rare earth metals.
BIBLIOGRAPHY BASIC AND APPLIED THERMODYNAMICS by Dr. P K Nag 2/e TMH publication Research paper: magnetic refrigeration by JEFF JOHNSON