Traditional air conditioners use a lot of energy; according to the U.S. Department of Energy, residential air conditioning accounts for a whopping 16% of all household electricity use in America.
There is, however, an alternative air conditioning method right on the horizon: devices that use magnets to cool the air.
Traditional air conditioners use a liquid refrigerant to cool the air. The refrigerant is undergoes a chemical process that absorbs heat from the outside air and turns the refrigerant into gas. The gas is then compressed and cooled, converting it back into a liquid. Both processes need electrical energy to be performed.
Magnetic air conditioners revolutionize this air-cooling process, opting to use magnetic forces instead of gas and refrigerant. They are engineered to take advantage of the magnetocaloric effect. According to the finders of this effect, magnetic materials heat up when they are exposed to a magnetic field, then cool down when the field is removed. The magnetocaloric effect’s discovery dates back to 1881, when German physicist Emil Warburg discovered a slight change in temperature among his iron samples. The effect was largely useless, however, until it became possible for scientists to create magnetic alloys that could create larger effects in temperature.
Nowadays, it’s possible to cool the air by repeatedly exposing a magnetocaloric material to a magnetic field in rapid succession. The following is a summation of the way this process is used to create a cooling effect:
“In one prototype designed by Astronautics Corporation of America in conjunction with the U.S. DOE’s Ames Laboratory, a wheel containing the rare-Earth element gadolinium spins through the field of a stationary magnet. As the disk spins, the gadolinium alloy heats up, then cools as it passed through a gap in the field, cooling the water that surrounds it as it makes its trip.”
That may be some difficult information to swallow, but basically all you need to know is that the temperature of an object can now be manipulated using magnetic fields. The alloy replaces the refrigerant of more traditional air conditioning designs, and water replaces the hydrochlorofluorocarbons. These HCFC’s are environmentally harmful to create and use, so making them unnecessary is another plus. It’s also worth mentioning that some the original examples of magnetocaloric materials were extremely expensive and environmentally toxic to make; they’ve since been revised to be cheaper and more environmentally safe.
Magnetic air conditioners would also be powered by electricity, but they are expected to be much more efficient. Their disk-spinning motor should necessitate much less energy to create the same cooling effect than a traditional air conditioner would.
The technology is picking up speed as more and more people realize that magnetic air cooling is the way of the future. The National Laboratory for Sustainable Energy at the Technical University of Denmark runs its own “MagCool” curriculum, while researchers at Penn State in the United States have worked hard to advance the understanding of magnetocaloric principles. Magnetic refrigeration is another example of a use of this technology that still needs some time to become prevalent and affordable, but with the help of our world’s best scientists, we’re likely to see that dream become a reality.