Refrigeration as well as air conditioning operates on the principle of the compression and expansion of refrigerants. When compressed, the refrigerant changes into a liquid state. When it expands, it evaporates again. To evaporate it needs heat which is taken from whatever it touches and cools it down.

But now, research being done at the University of Cambridge in England is focusing on what is called “magnetic cooling,” based on the straining of materials. The results have been published in the journal Nature Materials and quoted at the website.

Researchers with the Spanish scientific group CIC nanoGUNE worked with researchers from the University of Cambridge among others, to develop the new technology. The idea is to reduce a refrigerant’s impact on the environment and possible inefficiencies due to wear in traditional refrigeration systems.

The Challenge

Magnetic cooling, according to the research, consists of using a magnetic material instead of a refrigerant, and magnetizing and demagnetizing cycles instead of compression-expansion cycles.

The approach is based on what was described as “the magnetocaloric effect.” As defined by the researchers, it is “ based on the properties displayed by certain materials to modify their temperature when a magnetic field is applied to them.”

One of the problems the researchers had to deal with relates to the magnetic fields and miniaturized technological devices such as electronic chips and computer memories. “The magnetic field can interact negatively owing to its effect on nearby units,” it was reported. “In this respect, the quest for new ways of controlling the magnetization is crucial.”

The Approach

The researchers said they have discovered that by using the straining of materials, they can get around the problems of applying a magnetic field. “By straining the material and then relaxing it, an effect similar to that of a magnetic field is created, thus inducing the magnetocaloric effect responsible for cooling,” explained Luis Hueso, leader nanoGUNE research team.

“This new technology enables us to have a more local and more controlled cooling method, without interfering with the other units in the device, and in line with the trend in the miniaturization of technological devices,” he said.

Films (20 nanometers) consisting of lanthanum, calcium, manganese and oxygen have been developed. According to Hueso, “The aim of this field of research is to find materials that are efficient, economical, and environmentally friendly.”

Although the method is currently being geared for microelectronics, the researchers said the same technology can be used in such refrigeration equipment as refrigerators and freezers, athough they did say the economics currently would not be the same for such large equipment as with microelectronics.

But the current research has applications for larger air conditioning as related to computer rooms. “Today, most of the money spent on the huge dataservers goes on cooling. That is why this new technology could be effective in applications of this kind,” it was reported. “Likewise, one of the great limitations that computer processors have today is that they cannot operate as fast as one would like because they can easily overheat. If we could cool them down properly, they would be more effective and could work faster,” said Hueso.

Publication date: 7/15/2013