Magnetic refrigeration (MR) at room temperature is an emerging technology and has shown real potential to enter conventional markets. This type of refrigeration is proven to be energy efficient and also environmentally friendly. Moreover, as no refrigerant gases are required, there is no concern about ozone depletion or greenhouse effect, which contributes further to environmental friendliness. MR is developed on the theory of magneto-caloric effect (MCE), which is caused by a magnetic field on the materials that bear the property of varying the magnetic entropy, as well as its temperature, when varying the magnetic field.
How it works?
Due to the presence of a magnetic field, ferromagnetic materials closely align to each other in motion which causes an increase in the material’s temperature. Now consider a reverse scenario, where the absence of a magnetic field would mean that the atoms are not closely aligned and consequently a decline in temperature. MR basically works by recapturing produced cooling energy through a heat transfer fluid, such as water. To create this magneto-caloric effect on a refrigerating system, a rotating crystal of Holmium Manganese Oxide is rotated within a constant magnetic field, without the need to move it in and out of the magnetic field zone.
Delays in implementation
The concept of magnetic refrigerators is not new, but to date, significant progress has been hampered by the need for extremely strong magnetic fields. The past few years have seen substantial improvements to the magneto-caloric materials being used and manufacturers look forward to incorporate them into working prototypes suitable for everyday use. These state-of-the-art cooling refrigerators will basically be using a newly developed material that changes temperature based on how strongly magnetized it becomes. Put the food close to the magnet (high magnetization) and it will become hotter. Move it away (demagnetization) and the food cools down.
Researchers predict these cooling refrigerators could reduce energy consumption by 20%, in addition to being a quieter and greener alternative for consumers. It is estimated that when magnetic refrigerators are fully developed, they could reduce energy usage by approximately $10 billion per year, along with significant reductions in carbon dioxide emissions. In addition, magnetic refrigeration doesn’t use ozone-depleting or global warming gases.
Researchers have recently concluded their work on developing the next generation of magneto-caloric materials and permanent magnets. Though still in the early stages, these new magnetic materials would further improve the competitiveness of magnetic refrigeration technology. So in the next five years, we could say that magnets wouldn’t be just decoration for our refrigerator doors but the next big thing on the inside of your fridge.