39454157-magnetic-refrigration-my-presentation.pptx

SEMINAR ON

MAGNETIC REFRIGRATION ATTRACTIVE ALTERNATIVE COOLING TECHNOLOGY

BY : RAMAKANTH P JOSHI 1JS06ME034

OUTLINE

Magnetocaloric effect Principle

Prototype : Ames lab & astronaut corp America Advantages of magnetic refrigeration Technology comparison Future scope

MAGNETS Ferromagnetic materials – alloy of Al, Ni,Fe,Co Paramagnetic materials – Cr,Mn, Pt, Pd, K, Cu. Diamagnetic materials – Zn, Bismuth, antimony.

WAYS TO COOL 

Expansion and compression of gas <30%

Fridge, Bicycle pump



Evaporation of liquids

very robust

plants, animals, weather



Peltier effects

not very efficient Radiators



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)

DEMONSTRATION OF MCE 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

GRAPHICAL REPRESENTATION

REGENERATORS (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

DESIRED PROPERTIES OF WORKING MATERIALS

Large magneto calorific effect  Significant MCE at reasonable fields  Curie temperature  Environment friendly materials  Affordable, abundant and easily synthesizable materials 

WORKING MATERIALS

COMPARISON Analogy between magnetic refrigeration and vapor cycle refrigeration

TECHNOLOGY COMPARISON

Environmental impact Cooling efficiency durability

COMPRESSION

MAGNETIC

Liquid based (CFC) <40%

Environmentally safe ≥60%

~20 years

~50 years

ADVANTAGES OF MAGNETIC REFRIGERATION

Green technology  Noise-less technology  Very high thermodynamic efficiency  Low energy consumption  Simple design and building  Long life  Low pressure 

IDEAL APPLICATIONS 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. 2. 3. 4.

most efficient very compact eco friendly 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 www.wikipedia.com www.freepatentsonline.com www.globlespec.com Research paper: magnetic refrigeration by JEFF JOHNSON