magnetic refrigeration

  ABSTRACT

                                     In this paper a new type of refrigeration technology, Magnetic Refrigeration has been discussed. The objective of this paper is to explain the principle, construction, working and the operating cycles of Magnetic Refrigerator. The development of this system leads to improve the COP and to reduce Ozone layer Depletion and Global Warming.

                                    The main principle behind this refrigeration system is Magneto Caloric Effect (MCE). According to this effect whenever some magnetic materials like Gadolinium are subjected to a magnetic field the temperature of that material increases. Whenever the magnetic field is removed the temperature of that material diminishes down again. This is because of the randomization and alignment of atoms in the magnetic material.

                                 The magnetic refrigerator uses the above effect in the following way. Gadolinium is arranged to pass through a magnetic field. As it passes through the field, the gadolinium heats up as it exhibits magneto caloric effect. If it is taken out of the field then it comes down to original temperature. But we will circulate the water to draw the heat out of the metal when it is in the magnetic field. As the material leaves the magnetic field, the material cools to a temperature much below the original temperature as a result of the magneto caloric effect. Then this cold Gadolinium is used to remove the heat from the refrigerator’s coils.

                                  The permanent magnets and the gadolinium don’t require any energy inputs to make them work, so the only energy it takes is the electricity for the motors to spin the wheel and drive the water pumps. Hence the power required to operate this refrigerator is also very less. Magnetic refrigerators have two main advantages over today's commercial devices: they do not use hazardous or environmentally damaging chemicals, such as chlorofluorocarbons, and they are up to 60% efficient. In contrast, the best gas-compression refrigerators achieve a maximum efficiency of about 40%.