The method relies on solid magnetic substances called magnetocaloric materials to act as the refrigerant in miniaturized magnetic refrigerators.
As the team describes in the journal Applied Physics Letters, these materials are the key to the development of a green cooling technology whose efficiency is able to scale directly with the generated magnetocaloric effect.
The magnetocaloric effect is the thermal response of a magnetic material to the change of an external magnetic field, which manifests as a change in its temperature, according to Mohamed Balli, a researcher in the physics department at the Université de Sherbrooke in Quebec, Canada.
Ferromagnetic materials, for example, are known to heat up when magnetized and to cool down when the magnetic field is removed.
The presence of a magnetic field makes ferromagnetic materials become more ordered. This is accompanied by “disorder within the atomic lattice,” which causes an increase in the material’s temperatur. Inversely, the absence of a magnetic field means that the atomic lattice is more ordered and results in a temperature decrease. Magnetic refrigeration essentially works by recapturing produced cooling energy via a heat transfer fluid, such as water, according to Balli.
Researchers expect the discovery to lead to efficient, green cooling systems for both domestic and industrial applications.
In 2013, outdoor retailer REI retrofitted its Seattle data center, resulting in a 93 percent reduction in the cooling energy used to operate the facility. The retrofit uses “free cooling” via a rooftop evaporative cooling tower to keep servers at optimal temperatures.
The system reduces the need for mechanical cooling nearly year-round, or about 8,672 hours annually.