Magnetic refrigeration technology could increase the efficiency of refrigerators and make them easier to recycle.
The refrigerator that emits that tireless hum in your kitchen is running on technology from almost 100 years ago. It uses vapour-compression refrigeration, which makes use of the interplay between high and low pressures, so that the heat in the refrigerator and freezer compartments is absorbed. It’s a system that has worked well for many years, but after a century, it’s time for a change. Researchers at General Electric (GE) have been working on it, and they recently demonstrated a prototype of a machine that uses magnetic refrigeration.
The research is still in the testing phase, and there is a long way to go before it can be implemented commercially. The scientists at General Electric calculate that within ten years, these new refrigerators could be available for sale. And although for the time being, they’re not much more than a combination of metal cylinders, tubes and wires, the company hopes that in the future, magnetic refrigeration for a refrigerator will be reduced to a single cylindrical motor that fits in your hand.
Magnetic cooling is based on the magnetocaloric effect, a property of some materials that allows their temperature to change if they are subjected to a magnetic field. So scientists create a magnetic field and expose a metal alloy to it. The alloy responds by heating up if the field is intensified, and cooling when it is reduced.
Once they can control the heating and cooling of the metal, all that’s left to do is to transmit the heat. To do this, they use a liquid inside a metal tube that is responsible for transporting the heat from one place to another. This is how they manage to reduce the temperature inside the refrigerator cabinet (which is thermally insulated from the exterior) and discharge the heat to the kitchen.
Researchers have managed to drop the temperature by 80 degrees, which is a milestone in the field of refrigeration. Refrigerators that run with this new system would be 20% to 30% more energy efficient and wouldn’t require chemical refrigerants, which is a plus when it comes time to recycle them. And another thing, it will get rid of the continuous electrical hum: magnetic refrigeration is silent.
And of course, this technology can be applied to more than just refrigerators. It can also be implemented at an industrial scale. In factories where advanced cooling processes are required, or, looking no further than data centres that expend a lot of energy on this task, General Electric’s development represents a more efficient option.
Image: Samuel van Dijk