Magnetic Refrigration My Presentationx - 123SeminarsOnly

measlyincompetentUrban and Civil

Nov 29, 2013 (3 years and 11 months ago)

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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
s
phere

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

COMPRESSION

MAGNETIC

Environmental
impact

Liquid

based

(CFC)

Environmentally

safe

Cooling

efficiency

<40%

≥60%

dura扩bity

縲~

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.
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



www.wikipedia.com



www.freepatentsonline.com



www.globlespec.com



Research paper: magnetic refrigeration by JEFF JOHNSON