Magnetic cooling, or refrigeration, is a cooling technology based on the magnetocaloric effect, a technique which can be used to attain extremely low temperatures including the ranges used in domestic refrigerators.
The principle advantages of magnetic cooling are:
How is a magnetic field used for cooling?
Magnetic cooling technology exploits the fact that when a magnetic material, in this case the element gadolinium, is magnetised, heat is produced as a by-product of entropy.
The principle of entropy is that there will always be a constant amount of order/disorder in a substance. When the magnet puts the substance in “order”, it has to get rid of the excess disorder – and this becomes heat. Conversely, when the magnetic field is again removed, the substance becomes cold.
The heat is transferred to a fluid that is pumped back and forth past the substance inside a cylinder. The end that becomes cold will be located inside the refrigerator and the warm end will be outside.