k10741 rupesh ppt on RAC

1. PRESENTATION ON BASIC THERMOELECTRIC
EFFECT ON MAGNETIC MANOSTRUCTURE
Name- Rupesh Kumar Das
UID- k10741
Course- B.Tech
Branch- Mechanical
Sem- 6th
Sub- Refrigeration and Air conditioning

2.  Thermoelectric effect on magnetic nanostructure gives rise to
magnetic refrigeration.
 It is based on magneto caloric effect.
 Effect is caused due to varying magnetic entropy of magnetic
materials.
 It can be easily used in place of VC cycle. It has lower cost
than VC cycle and consumes less electricity.

3.  It is a magneto thermodynamic phenomena.
 Defined as the heating and cooling of magnetoelectric
material when it is magnetised and demagnetised
respectively where pressure has no influence.
 Entropy- It is defined as degree of randomness of the system.

6.  Substance placed in insulated environment.
 Magnetic field and heat increases
 This causes magnetic dipoles of atoms to align.
 The net result is that the total entropy of the item is not
reduced and items heats up.
Adiabatic demagnetisation
Substance returns to another adiabatic state
Entropy remains constant
Magnetic field is decreased
Thermal energy causes magnetic moments to overcomes the
field and sample cools

10. No compressor
No refrigerant gas
Low pressure operation
Low running cost
Safety cooling and very less environment impact
Disadvantages
Initial investment is more as compared with conventional.
Magneto caloric material are rare earth material hence their
availability also adds up disadvantages .

11. Conclusion
 The conventional gas compression refrigerators have been
mainly used for refrigeration applications. Generally, such
refrigerators are not power-efficient. In addition, gases used
in these refrigerators causes harmful effects on the
environments. This has led to the development of magnetic
refrigeration technology. Over the last decade or so, magnetic
refrigeration at room temperature has become the subject of
considerable attention.
 This technology is based on the use of magnetocaloric effect:
that is the response of a solid to an applied magnetic field
which emerges as a change in its temperature. This
technology is ultimately aimed at developing a standard
refrigerator for home use.

12. References
Allab, F. (2008). Conception et réalisation d’un dispositif de
réfrigération magnétique base sur l’effet magnétocalorique et
dédié a la climatisation automobile, Thèse de doctorat,
Grenoble, Institut National Polytechnique de Grenoble.
Bianchi, A.M., Fautrelle, Y., Etay, J. (2004). Transferts
thermiques, première édition, Presses polytechnique et
universitaires romandes, ISBN 2-88074-496-2, Lausanne.
Bjork, R., Bahl, C.R.H., Smith, A., Pryds, N. (2010). Review and
comparison of magnet designs for magnetic refrigeration.
International. Journal of Refrigeration. 33, 437-448.